Welding Quality and Inspection

8/10/2019 Welding Quality and Inspection

1/16

By Duane K. Miller, Sc.D., P.E.

The James F. Lincoln Arc Welding Foundation


2/16

The serviceability of a product or structure utilizing the type of information presentedherein is, and must be, the sole responsibility of the builder/user. Many variables

beyond the control of The James F. Lincoln Arc Welding Foundation or The Lincoln

Electric Company affect the results obtained in applying this type of information.These variables include, but are not limited to, welding procedure, plate chemistry

and temperature, weldment design, fabrication methods, and service requirements.

This guide makes extensive reference to the AWS D1.1 Structural Welding Code-Steel,

but it is not intended to be a comprehensive review of all code requirements, nor is itintended to be a substitution for the D1.1 code. Users of this guide are encouraged to

obtain a copy of the latest edition of the D1.1 code from the American Welding Society,550 N.W. LeJeune Road, Miami, Florida 33126. (800) 443-9353.

This information has been provided by

The James F. Lincoln Arc Welding Foundationto assist the general welding industry.


3/16

By Duane K. Miller, Sc.D., P.E.Manager, Engineering ServicesThe Lincoln Electric Company

Cleveland, Ohio

In a mature industry such as weldedsteel construction, it is reasonable to

believe that the role of the various indi-viduals involved with a given project

will be well understood and welldefined. Unfortunately, experienceindicates that there is a great deal of

confusion in this area. Perhaps this isa reflection of misperceptions about

the technology itself. Too many other-wise knowledgeable people still regard

welding as a black art, rather than ascience that can be understood andcontrolled. The level of understanding

among many Engineers regarding thisimportant construction process is limit-

ed. Regardless of the reason,Engineers frequently do not perform

their professional responsibilities asthey relate to welding. Too often, they

delegate this authority to Inspectors.

Over-zealous Inspectors frequentlyoverstep their role, making judgment

calls that should be the purview of theEngineer. Furthermore, Fabricators do

not always take full advantage ofcode-provided latitude for the resolu-tion of many problems. In the end,

Owners often pay too much for struc-tures that have been plagued by

delays, unnecessary repairs, andextraneous activities that add little or

no value to the project.

Many problems result when the proper

roles of the various individuals on theproject are not understood. The most

serious infractions occur when peopleaccept responsibility for areas in which

they have no authority or qualifica-tions. This can result in disaster, but

fortunately such cases are rare. M

frequently, key individuals fail to caout all of their appropriate respons

ties, causing costly delays.

With the design-build approach commonly used in Europe, communica

is enhanced because one organizahas financial responsibility for theentire project. In the U.S.A., howev

the common practice that separatethe design phase from the construc

tion phase requires a clear under-standing of the responsibilities of th

various parties. The roles are definin codes, specifications, and contradocuments. The AWS D1.1-98

Structural Welding Code - Steel,defines such roles as they relate towelded construction. In addition to

restating sections of the code itselfthis paper will outline a philosophy

is conducive to increased cooperatand communication, and will foster

creation of higher quality productswhile minimizing fabrication costs.

This three-part series on ensuring weld quality in structural applicationscovers the following:

Part I reexamines the roles of the Engineer, the Fabricator, and the

Inspector, as they relate to welded construction. The proper roles aredefined, and misunderstandings corrected. First published in

Welding Innovation, Vol. XIII, #2, 1996.

Part II emphasizes the importance of effective visual inspection and itsvital role in achieving weld quality. First published in Welding Innovation,

Vol. XIII, #3, 1996.

Part III discusses alternate acceptance criteria and explains the Engineersresponsibility for invoking such criteria. First published in Welding

Innovation, Vol. XIV, #1, 1997.

Throughout the series, references have been updated to cite specificsections of the AWS D1.1-98 Structural Welding Code - Steel.


4/16

At the heart of the issue is the proper

definition of the roles and the responsi-bilities of various individuals involved in

welded fabrication. The following areaken from the AISC Code of StandardPractice and/or the AWS D1. 1-98

Structural Welding Code - Steel:

Owner:The owner of the proposed structure

OR that individuals designated repre-sentatives, who may be the Architect,Engineer, General Contractor, Public

Authority, or others.

Architect/Engineer:The Owners designated representa-

ive with the full responsibility for thedesign and integrity of the structure.

General Contractor:The Owners designated representa-

ive with the full responsibility for theconstruction of the structure.

Fabricator:The party responsible for furnishing

abricated structural steel.

Erector:The party responsible for the erection

of the structural steel.

Verification Inspector:

The duly designated person who actsfor, and on behalf of, the Owner or the

Engineer in all inspection and qualitymatters within the scope of the con-

tract documents. (In some codes, suchas AASHTO/AWS D1.5-96 BridgeWelding Code, this Inspector is known

as the Q.A. Inspector, that is, theQuality Assurance Inspector.)

Fabrication/Erection Inspector:

The duly designated person who actsfor, and on behalf of, the Contractor inall inspection and quality matters with-

in the scope of the contract docu-ments. (In D1.5, this Inspector is

known as the Q.C. Inspector, that is,the Quality Control Inspector.)

Inspector:When the term Inspector is used with-

out further qualification, it appliesequally to both the Verification and

Fabrication/Erection Inspector.

For the purposes of this paper, com-ments directed toward the Fabricatorapply equally to the Erector. Since

most or all of the welding will be per-formed by either the Fabricator or

Erector, the General Contractor willnot be considered in this discussion.

The term Engineer will be used in lieuof Architect/Engineer.

The Engineer has the ultimate and fullresponsibility for the integrity of the

structure. It is the Engineer who mustestablish the required quality level forall welded fabrications. This may be

done by invoking a standard such as

the D1.1 Code. It is imperative thatthe Engineer understand the require-ments, restrictions, and implications of

the full code. The Engineer is respon-sible to ensure that the code provi-

sions are adequate for the structure.Additional provisions may be requiredfor unique structures, and these

requirements must be invoked incontract documents. The Engineer is

responsible for determining and speci-fying the level of quality required. The

Engineer is also responsible to ensure

that the specified level of quality isdelivered by the Fabricator. The

Engineer has a professional responsi-bility to the Owner to deliver the

project in a timely fashion, and atan appropriate cost.

To assist in the quality issues, theEngineer may employ the services of

a Verification Inspector. Under D1.1,this is left up to the Engineers discre-

tion. A Verification Inspector may beengaged either to duplicate the ser-

vices of the Fabrication Inspector, orto supply spot checks. However, theEngineer may choose to rely solely

upon the Fabrication Inspector toensure the necessary quality is

achieved. Many factors enter into thisdecision, including:

the complexity of the structure; the degree of redundancy involved;

and

the relative level of confidence theEngineer has in the Fabricator.

The Fabricator is responsible for deliv-

ering a quality product to the Engineer.While the Engineer must be responsi-ble to ensure the level of quality is

achieved, it is ultimately theFabricators responsibility to produce a

quality product. To this end, theFabricator will employ Fabrication

Inspectors (Q.C. Inspectors) to monitorthe welding operations and inspect the

Effective visual inspection requires that the Inspector be present when welding

s being performed.


5/16

final product. Under a shop qualifica-tion program, it is required that the

inspection functions be kept organiza-tionally separate from the manufactur-

ing operations, in order to give theQ.C. Inspectors the necessary authori-ty to carry out their responsibilities.

It is important to understand that sincethe Fabricator does all the welding,only the Fabricator can produce quali-

ty welds. Inspectors cannot improvethe quality of the product that has

been produced. The Inspector simplymeasures the level of quality achieved,and accepts those products that are

within conformance.

Inspectors are responsible to ascertainthat all fabrication and erection by

welding is performed in accordance

with the requirements of the contractdocuments. When contract docu-

ments invoke certain specifications orcodes, the Inspector must ensure that

all such requirements are met. It is

important to note that the emphasis is

placed on acceptance and compli-ance to the specification. A prevail-ingbut mistakenimpression of

Inspectors is that their primary respon-sibility is to reject out-of-compliance

work. This is more than an issue ofsemantics. The ability to reject a par-

ticular weldment is ultimately theEngineers responsibility. TheInspectors responsibility is to accept

materials that are in compliance.

While this approach may seem new orrevolutionary to some people, the

author believes that it is the primaryphilosophy presented in codes. And,to eliminate any dispute or potential

misrepresentation of code intentions, itis the authors opinion that this should

be the philosophy of the code evenwhen it is not, because it will result in

optimum value to the Owner.

The belief that the primary function of

Inspectors is acceptance of productsthat are within established criteria isgenerally supported by the D1.1 Code,

although deviation from this general

philosophy is sometimes expressed inthe code. In the authors opinion, thisis more a reflection of poor wording on

the part of the code writers than a rep-resentation of overall philosophy. The

examples that conflict with the generaltrend will be cited, and proposedrefinements presented.

The following references with appropri-

ately highlighted portions support thecontention presented above:

Fabrication/erection ... inspection

and tests shall be performed ... toensure that materials and workman-

ship meet the requirements of thecontract documents (6.1.2.1).

The Inspector shall ascertain thatall fabrication and erection by weld-

ing is performed in accordance withthe requirements of the contractdocuments (6.1.5).

The Inspector shall make certainthat only materials conforming to

the requirements of the code areused (6.2).

The Inspector shall verify that allWPSs have been approved by theEngineer in conformance with 4.1.1

(6.3.1). The Inspector shall inspect the weld-

ing equipment to be used for thework to make certain that it con-

forms to the requirements of 5.11(6.3.2).

The Inspector shall permit welding

to be performed only by welders ...who are qualified ... or shall make

certain that each welder ... has pre-viously demonstrated such qualifica-

tion under other acceptablesupervision and approved by theEngineer (6.4.1).

The Inspector shall make certainthat the sizes, length, and location of

welds conform to the requirementsof this code... (6.5.1).

The Inspector shall examine thework to make certain that it meets

the requirements of this code.

Other acceptance criteria, differefrom those thus provided in the

code, may be used when approby the Engineer [Note: the

Engineer has the authority to utilalternate acceptance criteria](6.5.5).

Table 6.1 lists Visual Inspection

Acceptance Criteria.

The foregoing passages make it cl

that the emphasis is on acceptingproducts within compliance, and m

ing certain that proper proceduresare followed. It can be argued thatwhen the Inspector refuses to acce

a part, it is equivalent to rejecting tpart. The code writers, however, h

not chosen to use this language.Ultimately, all projects must be acc

ed. This is the role of the Inspecto

In two notable examples, the D1.1-

Code deviates from this general prple. The provisions of Section 6.1.

state that, Inspectors responsible facceptance or rejection of material

and workmanship shall be qualifiedThis paragraph fits under the headInspector Qualification Requireme

Clearly, the emphasis is not on thefunction of the Inspector, but rather

the lnspectors qualification. Had tcode writers deleted the words or

rejection, the provision would havebeen consistent with the rest of thecode. In the authors opinion, this

wording is unfortunate, since it is nin the same spirit as the rest of the

code. The second deviation from toverall philosophy of acceptance

occurs in Section 6.6 Obligations othe Contractor. The provisions of 6require that The contractor shall c

ply with all requests of the Inspectoto correct deficiencies in materials

workmanship as provided in the cotract documents. Notice, however,

this provision is under the heading the Obligations of the Contractor.

Even though these two referencesdeviate slightly from the general

concept of acceptance, they do nocontradict the overall philosophy.

Moreover, because of their locationthey do not present a strong case fan alternate approach.


6/16

A modification to these provisions of6.1.4.1 that would delete the words or

ejection would clarify the situation.Also, in Section 6.6.2, the following

phrase would be a proposed improve-ment: The Contractor shall complywith all requests of the Engineer to

correct deficiencies in materials and

workmanship as provided in the con-ract documents. This language wouldeaffirm the proper role of the

Engineer. However, it is obvious thator minor nonconformances, the

Engineer should not be consulted on aoutine basis. Once again, this falls

within the discretion of the Contractor.

f the Inspector was being granted theull authority to direct all the activities

of the Contractor, this would certainlyhave been included under a different

heading.

t is interesting to note that the equiva-

ent provision in the D1.5-96 BridgeWelding Codechanges the word from

he all-inclusive Inspectors used inD1.1 to QA Inspectors. While the

D1.1 provisions apply equally to bothabrication and verification inspection,he D1.5 words are exclusively applied

o QA (verification) inspection. Thiswording is probably more correct, but

since verification inspection is optionalunder D1.1, alternate words were

selected.

Abuses of, and deviations from, the

philosophy outlined here are wide-spread. They can be perpetrated by

Engineers, Inspectors or Fabricators.For instance, the Engineer may dele-gate engineering authority to the

nspector. The rationale for this typeof decision appears to be fairly

straightforward: the Engineer may notbe familiar with the intricacies of the

code and/or fabrication process, andherefore may empower the Inspectoro make decisions on his/her behalf.

On the surface, this appears to be avery logical approach, particularly

when the Inspector is highly qualified,perhaps an Engineer by training. On

he other hand, another Inspector maynot have the background necessary to

make these types of decisions.Moreover, rarely will the Inspector

have the benefit of understanding theoverall structural implications of vari-

ous decisions. For example, a filletweld has been sized based upon theminimum prequalified fillet weld sizes.

This fact obviously should enter into

the considerations regarding theacceptability of a slightly undersizedfillet weld. In the absence of this

design data, the Inspector does nothave the necessary information to

make the most responsible decision.

The descriptions assigned to various

Inspectors by Fabricators generally fitinto one of two categories: First, there

are the Inspectors who are reason-able, practical, someone we can

work with, etc. The second category

would cover those who are a realstickler for details, see everything as

black or white, or cut us no slack, etc.

The implication is that the first groupof Inspectors utilize some judgment

call when making their decision. Theycan negotiate, bargain, and give trade-offs. These are hardly the terms asso-

ciated with the engineering profession.Fabricators may love this type of

Inspector, but are the Engineers oblig-ations to the Owner fulfilled if such an

Inspector compromises quality in acritical area?

The second type of Inspector seeseverything as falling into one of two

categories: acceptable or unaccept-able. This individual knows every code

provision and requires strict adher-ence to these requirements. On thesurface, this may seem to be the opti-

mum type of Inspector, from theOwners point of view. However, two

things must be considered: First, anEngineers full dependence on this

type of Inspector eliminates theEngineers opportunities to utilizecode-permitted engineering evalua-

tions of situations that deviate from thecode requirements. Secondly, this

approach may unnecessarily increasecosts, cause delays, and necessitate

weld repairs that can actually impairthe quality of the overall project.

These implications will be developedand discussed in detail in Part III of

this series, Alternate AcceptanceCriteria.

Inspectors are not immune from errorseither. Some are all too eager to

assume responsibility and authority

beyond their role qualifications. SomeInspectors are fond of pointing outtheir interpretation of code provi-

sions. Codes are meant to be fol-lowed, not interpreted. The term

interpretation has a very specificmeaning when applied to codes. Aninterpretation, or more properly, an

official interpretation, is the decisionrendered by the code-writing body that

may, in the extreme, constitute a newcode requirement. Only the code-writ-

ing body has the authority to issue an

interpretation.

Inspectors should see that the code isfollowed, and report nonconformance

to the Engineer. When the coderequires that the Engineer be notified

prior to some action, it is not theInspector who should be notified.Inspectors are not in the business of

deciding new acceptance criteria.That is the Engineers responsibility.

Inspectors should not be determiningwhether code provisions are adequate

or overly restrictive. They are chargedwith following the established codeprovisions.

Many Inspectors feel they are the

ultimate authority on the project. It isimportant to note that the Engineer

has the authority to review theInspectors credentials. Although theFabrication Inspector is paid by the

Fabricator, that lnspectors credentialsand capabilities are subject to

approval by the Engineer. TheEngineer directly employs the

Verification Inspector, who obviouslyis responsible to the Engineer.

Fabricators also make errors. Somecompanies will attempt to hide prob-

lems from the Inspector. More blatantabuses include offering bribes to

Inspectors. Such activities are illegal,immoral, and unprofessional. The


7/16

entire industry is hurt when a smallminority thus abuses its responsibility.

The Fabricator may also err by failingto utilize provisions within the code

which permit deviation from standardacceptance criteria. Fabricators mustknow the entire code and understand

what is mandatory, what is permitted,

and what can be changed. Withoutreading the complete code,Fabricators will frequently apply one

set of provisions in a universal fashion,believing it to be all-encompassing.

Unnecessary increases in fabricationcosts usually result. It is imperativethat the whole code be understood in

its entirety in order to meet the qualityrequirements at a reasonable cost.

Engineers are responsible for thor-

oughly understanding the code, the

fabrication processes, and the properroles of the Inspector and the

Fabricator. If the Engineer of Recordis not familiar with the intricacies of the

welding processes or those of weldingcodes, it is imperative to consult a

Welding Engineer, another profession-al, separate and distinct from the

Inspector. The Inspector must under-stand how to enforce the application of

the code, accept work that conformsto code requirements, and report tothe Fabricator deviations from these

requirements. The Inspector mustknow the whole code, and apply it to

the situation, not interpret it.

The Fabricator must know the entirecode, accept the lnspectors report ofdeficient work, and either repair defi-

ciencies or propose an alternative tothe Engineer. With the report of non-

conformance, the Engineer can applyengineering judgment to resolve the

problem. This approach leaves theultimate responsibility for the project

with the Engineer of Record, where itmust remain. The Inspector has not

exercised engineering judgment, theFabricator has gained all the latitude

necessary, and ultimately, the result isa project of the required quality at areasonable cost.

To illustrate the ideal application,

consider the following situation which(unfortunately) is true. Details have

been changed slightly to protect boththe innocent and the guilty!

Field erection of a steel frame buildinghad progressed several stories when

the Inspector reported to the Engineerthat no preheat was being employed

for the welding procedures. The

Fabricator claimed he did not knowpreheat was required. The Inspector

then announced that the buildingwould have to be systematically disas-

sembled and re-erected. TheEngineer did not know what to think

but was wise enough to consult aWelding Engineer for advice. TheEngineer was obviously concerned

about the integrity of the structure, butwas also worried about the significant

delays that would be incurred if thestructure was disassembled. The

tremendous cost could have resultedin bankruptcy of the Fabricator/Erector. On every front, the project

was a mess.

Before a resolution of this project ispresented, a review of the mistakes

made is appropriate. The Fabricator/Erector had selected to use weldingprocedures (or more correctly welding

procedure specifications, usuallyabbreviated WPSs) that could be pre-

qualified under the provisions of D1.1.These WPSs are exempt from the

mechanical testing requirements thatapply to WPSs that are qualified bytest. Prequalification of WPSs, howev-

er, does not eliminate the need for awritten WPS. During the creation of

the WPS, the Fabricator would havebeen forced to evaluate the require-

ments for preheat. However, the firsterror was that written WPSs were notemployed (3.6).

The Inspector is responsible for thereview of all WPSs. An important

of the Inspector is to make sure theWPSs are complete and followed.

the WPS was never written, it obvioly could not have been approved.Therefore, erection welding should

never have begun (6.3.1).

Furthermore, the Engineer has theresponsibility to judge the suitability

the prequalified joints to the application. The specific joint detail is defi

in the WPS, but, once again, in theabsence of a written welding procedure, this obviously was not done (

The structure certainly should not

have progressed to the height of seeral stories before the discovery of

oversight. The Inspector is respon

ble to ensure proper procedures arutilized (6.5).

While everyone bears some of the

fault here, the Engineer did executhis responsibilities appropriately w

the available alternatives were invegated. By consulting an expert in tfield, he was able to obtain a profe

sional, unbiased opinion regarding implications and possible corrective

actions. In this particular situation,minimum prequalified preheat leve

would have been 150 degrees F.Construction had taken place durinthe summer when the ambient tem

ature was typically 70 degrees F.

Without question, the deviation in pheat requirements prohibited the

Inspector from being able to accepthese welds, regardless of the finaquality. The Engineer did have the

tude, however, to employ alternateacceptance criteria. The consultan

pointed out that the preheat levelswere minimum requirements for pre

qualified procedures. The code itsindicates that under some conditioof restraint, base metal compositio

and levels of weld metal hydrogencontent, higher preheat levels wou

be required. Moreover, the codeadmits that in some situations, low

levels of preheat could be employe(3.5). WPSs that are qualified by te


8/16

under the provisions of Section 4 ofhe code do not mandate the prequali-

ied minimum preheat temperatures.Rather, an alternate preheat level

could be selected if the procedureswere qualified by test. Therefore, if aprocedure qualification test duplicating

he conditions actually used were

employed, and if the mechanicallyested specimens exhibited the ductili-y, strength, and soundness required

by the code, a WPS could be qualifiedby a test that utilized a 70 degree F

or ambient) preheat level. This wouldbe in complete compliance with thecode, except that normally, the proce-

dure would have been qualified beforeabrication began.

n addition to requiring a procedure

qualification test, the Engineer was

advised to employ extra measures ofnondestructive testing. The disconti-

nuity of greatest concern is a weld

crack. When adequate preheat levelsare not maintained, cracking is the

most obvious expected discontinuity.Therefore, the nondestructive testing

method with the greatest ability todetect cracks was employed, that is,ultrasonic inspection, which also lends

itself well to field inspection. Spot

inspections were recommended.Locations were selected based uponwork records reflecting which joints

were likely to be welded on the coldestdays and times during the project.

The welding procedure qualificationtest was successful. Ultrasonic

inspection revealed no cracks on thejoints examined, which constituted

approximately 25% of the total. Theproject was able to proceed, although

preheat was mandated for subsequent

fabrication. In spite of the problems,the situation was resolved with a mini-

mum amount of cost and delay

because in this case, the Engineerexercised his responsibilities.

In many situations involving welding,Engineers simply do not have the

background or experience necessary

to perform all of the engineeringresponsibilities essential to the suc-cess of a given project. Therefore, it is

incumbent upon the professionalEngineer to admit the limits of his or

her knowledge and consult an expertin the field. While both Inspectors andFabricators have essential roles to

play, the Engineer is responsible forthe structural integrity of the project.

Therefore, the Engineer must see to itthat all other essential individuals fulfill

their functions toward that end, no less

and no more.

Visual inspection is the most powerfulool that can be employed to ensureweld quality. The more technologically

sophisticated nondestructive process-es, such as ultrasonic or radiographic

nspection, can only verify that thedesired quality is present once welding

s complete. Effective visual inspectionexamines each step of the weldingprocess, well before the weld is com-

pleted. According to A. M. Gresnight ofDelft University, the Netherlands, Most

serious failures in performance are dueo gross error; e.g., wrong consum-

ables or omission of preheat, and notminor non-compliances.

Everyone involved in a welding projectcanand shouldparticipate in in-

process visual inspection, includingthe welders, Inspectors, foremen, etc.Minor discontinuities can be detected

and corrected during the fabricationprocess, precluding the need for more

expensive and complicated repair afterthe fabrication is complete. In order

to be effective, visual inspection musttake place prior to, during, and afterwelding. Obviously, visual inspection

requires good eyesight and good light-ing. Frequently, good lighting is scarce

in a fabrication shop or even in certainparts of a construction site, so a sim-

ple flashlight can be a valuable aid tovisual inspection.

To understand how visual inspectioncan be utilized to improve weld quality,

consider the approach used in therestaurant industry. A perfectly good

steak is delivered on a plate, accentedby appropriate side dishes and gar-

nish. The customer applies a visualinspection to satisfy his/her desire fora high-quality meal. Dirty dishes,

burned edges on the meat, and inap-propriate sizing of portions would

detract from an image of quality. It isalso important to note that the steak is

complete; that is, a test portion of thesteak has not been removed for exam-


9/16

ination in the kitchen. It is strange toeven consider the notion that a wedge

of meat might be removed for inspec-tion or testing. The steak has not

received either nondestructive ordestructive testing. Rather, theprocess of creating the dinner has

been carefully controlled by regular

visual inspections at each step in thepreparation.

Examining the process in total, thedinner starts with meat that has been

graded by a suitable governmentagency. The kitchen facility has beenapproved by the Board of Health. The

chef has appropriate training and cre-dentials. The recipe has been taste-

tested and time-proven. All theingredients involved with the meal are

suitably controlled, with the proper

amount of each added at the proper

time. The temperature of the broiler,and the amount of time the beef will

be cooked, are both carefully con-trolled and regularly verified. The fin-

ished product is visually inspected bythe chef, the waiter, and finally by theconsumer. Without visual inspection,

most people would be unable to detecta poorly prepared piece of meat

before it is consumed. However, bythe application of visual inspection

throughout the process, the desiredresults are achieved.

The same approach can be used in

welding because, like cooking, weldingis a process.The fabrication shop isroutinely inspected and approved by

some outside agency such as theAISC Shop Certification Program.

The steels employed are governedby agencies such as ASTM, and the

Certificates of Conformance ensure

product integrity. Welders are requiredto pass operator qualification tests to

verify their ability. Like the chef, theyare trained to carry out specific opera-

tions. In the welding industry, thewelding procedure specification (WPS)is like a recipe. In the WPS, specific

welding parameters are set forth,

including preheat and interpass tem-peratures, wire feed speeds, voltageused, travel speeds, etc. Finally, the

completed welds are required to bevisually inspected. With the major

exception of gas metal arc/short arctransfer, visually acceptable weldsroutinely exhibit the required quality

for their application.

Over the years, welding has beendescribed as both an art and a sci-

ence. While it is both, there has been

a disproportionate emphasis on the artof welding. Welding is a complex sci-

ence involving the interaction of manydisciplines. Nevertheless, the welding

process is subject to certain physicaland chemical laws that allow it to be

controlled and the results predicted.

The quality of a completed weld is pre-

dictable, providing the input variablesare known. Unfortunately, input vari-

ables (even critical input variables) areoften misunderstood, ignored, or

uncontrolled, resulting in welds ofunpredictable quality. Variables maybe overlooked for several reasons.

During procedure qualification testing,for example, it is essential that critical

welding parameters be evaluated andidentified. During the qualification and

testing of welders, the unique require-ments of the specific application mustbe communicated to them. When all

input variables are properly identifiedand controlled, welds of the required

quality will be consistently achieved.Effective visual inspection can ensure

that significant variables are con-trolled, resulting in welds of therequired quality.

Discontinuities in welds do not occur

by mere chance. They are the result offailing to identify and control for one or

more critical variables. (Authors note:

In our formal training, many of ushave been taught the scientific

method, a system by which onevariable is examined at a time.

Experience demonstrates that vari-ables rarely exist in isolation. First,most applications, problems will be

attributed to more than one variable

Secondly, the interaction of multiplevariables is often overlooked. Themore complex, but much more accu

rate methods associated with thedesign of experiments address the

situations.) Even when critical variables are identified, they are frequeignored or not properly communica

to the individuals involved.

While visual inspection is a powerftool, its potency may be questioned

because of past experience. For

example, if a visual inspection is sopowerful, why are weld discontinuit

and defects routinely found by nonstructive testing methods?

One plausible explanation is that v

al inspection is rarely properly per-formed. Welding is a process, and process must be observed through

its application. If an Inspector arrivon the job site after the welds are

complete, it is impossible to properapply visual inspection. Because t

nondestructive testing methods evaate completed welds, Inspectors artrained to focus on finished produc

Attention must be refocused on visly inspecting the process, not mere

the finished result.

Fillet weld sizes can be measured w

gages. (Photo courtesy of G.A.L. Ga


10/16

To provide practical information abouthe requirements for conducting visualnspections, the American Welding

Society has published a concise, 28-

page document, AWS B1.11, entitledGuide for Visual Inspection of Welds.

Consistent with the philosophy already

presented in this series of articles,AWS B1.11 emphasizes the impor-

ance of inspection prior to welding,during welding, and after welding.Practical suggestions, presented in a

checklist format, are offered for eachphase.

n Section 3.2 of B1.11, the following

tems are highlighted as part of

nspection prior to welding:. Review drawings and specifications.

2. Check qualifications or proceduresand personnel to be utilized.

3. Establish checkpoints.4. Set up a plan for recording results.

5. Review materials to be utilized.6. Check for base metal

discontinuities.

7. Check fitup and alignmentof welded joints.

8. Check preheat, if required.

When appropriate attention is paid tohese issues, the quality of the yet-to-

be-made weld can be expected to

mprove as a result of the pre-weldingnspection. For example, when fitup

and alignment of the joint are carefullynspected, consistent uniform fusion to

he root of the weld and avoidance ofexcessive distortion and/or residualstresses can be achieved.

tem No.3 discusses checkpoints. This

s particularly critical on large weld-ments or complex projects when sub-

sequent fabrication activities maypreclude further inspection of the fabri-cation process. Concurrent with this

dea is the establishment of holdpoints where approval is required

before further fabrication can be con-

tinued. This must be coordinated withthe various contractors involved so

that the overall project can proceed asexpected. Establishment of hold

points, and communication with allparties involved, are critical to main-taining both quality and the job sched-

ule.

In Section 3.3 of B1.11, items thatshould be inspected during welding

are outlined. These include:1. Quality of weld root bead.

2. Joint root preparation prior to weldingthe second side.

3. Preheat and interpass temperatures.

4. Sequence of welding passes.5. Subsequent layer for apparent

weld quality.6. Cleaning between passes.

7. Conformance with the applicable

procedure.

The root pass, often the most criticalpart of the weld, is often made under

the most difficult conditions.Maintenance of the proper preheat

and interpass temperatures is criticalfor the metallurgical integrity of boththe weld metal and the heat affected

zone. Inspection of intermediate weld

layers, including removal of slag

between layers, is absolutely essentialfor applications where only visual

inspection will be applied.Conformance with the maximum layerthicknesses and bead widths as gov-

erned by the applicable welding codeor WPS requirements can be visually

verified at this point.

The requirements for post-weldinspection are covered in Section 3.4of B1.11. Before the checklist is pro-

vided, the following statement is made:Many people feel that visual inspec-

tion commences once the welding hasbeen completed. However, if all of the

previously discussed steps have beentaken before and during welding, this

final phase of visual inspection will beaccomplished easily. It will simply pro-

vide a check to be sure that the stepstaken have resulted in a satisfactoryweld. This statement endorses the

power of an effective visual inspection.

The checklist of items to inspect afterwelding includes the following:1. Final weld appearance.

2. Final weld size.3. Weld length.

4. Dimensional accuracy.5. Amount of distortion.6. Post-weld heat treatment.

The importance of these issues is self-

evident. The appearance of the weldis a strong indicator of the suitability of

the actual welding procedure used,

and the ability of the individual welder.More than merely a cosmetic issue,

weld appearance provides someinsight into how the weld was made.

Inspecting the work in process is not a

new concept, but rather is part of thestandard codes already. Take, for

example, the D1.1-98 StructuralWelding Code - Steel. In that code,

visual inspection is mandated by 6.9,which states: All welds shall be visu-ally inspected.... In the chapter on

Inspection, the following directions aregiven to the Inspector:

The Inspector shall make certain

that only materials conforming to therequirements of this code are used(6.2).

The Inspector shall verify that all

WPSs have been approved by theEngineer in conformance with 4.1.1

(6.3.1).

The Inspector shall inspect all weld-

ing equipment to be used in the workto make certain that it conforms to

the requirements of 5.11 (6.3.2).


11/16

Discontinuity Category and Inspection Criteria

(1) Crack Prohibition

The weld shall have no cracks.

(2) Weld/Base-Metal Fusion

Thorough fusion shall exist between adjacent layers of weld metal and between weld

metal and base metal.

(3) Crater Cross Section

All craters shall be filled to the full cross section of the weld, except for the ends of

intermittent fillet welds outside of their effective length.

(4) Weld Profiles

Weld profiles shall be in conformance with 5.24.

(5) Time of Inspection

Visual inspection of welds in all steels may begin immediately after the completedwelds have cooled to ambient temperature. Acceptance criteria for ASTM A514 and

A517 steels shall be based on visual inspection performed not less than 48 hours

after completion of the weld.

(6) Underrun

A fillet weld in any single continuous weld shall be permitted to underrun the

nominal fillet size specified by 1/16 in. (1.6 mm) without correction, provided that

the undersize portion of the weld does not exceed 10% of the length of the weld.

On web-to-flange welds on girders, no underrun is permitted at the ends for a length

equal to twice the width of the flange.

(7) Undercut

(A) For material less than 1 in. (25.4 mm) thick, undercut shall not exceed 1/32 in.

(1 mm), except that a maximum 1/16 in. (1.6 mm) is permitted for an accumulated

length of 2 in. (50 mm) in any 12 in. (305 mm). For material equal to or greater than

1 in. thick, undercut shall not exceed 1/16 in. for any length of weld.

(B) In primary members, undercut shall be no more than 0.01 in. (0.25 mm) deep

when the weld is transverse to tensile stress under any design loading condition.

Undercut shall be no more than 1/32 in. (1 mm) deep for all other cases.

(8) Porosity

(A) Complete joint penetration groove welds in butt joints transverse to the direction

of computed tensile stress shall have no visible piping porosity. For all other groove

welds and for fillet welds, the sum of the visible piping porosity 1/32 in. (1 mm) or

greater in diameter shall not exceed 3/8 in. (10 mm) in any linear inch of weld and

shall not exceed 3/4 in. (19 mm) in any 12 in. (305 mm) length of weld.

(B) The frequency of piping porosity in fillet welds shall not exceed one in each 4 in.

(100 mm) of weld length and the maximum diameter shall not exceed 3/32 in.(2 mm). Exception: for fillet welds connecting stiffeners to web, the sum of the

diameters of piping porosity shall not exceed 3/8 in. (10 mm) in any linear inch of

weld and shall not exceed 3/4 in. (19 mm) in any 12 in. (305 mm) length of weld.

(C) Complete joint penetration groove welds in butt joints transverse to the direction

of computed tensile stress shall have no piping porosity. For all other groove welds,

the frequency of piping porosity shall not exceed one in 4 in. (100 mm) of length and

the maximum diameter shall not exceed 3/32 in. (2 mm).

1. An X indicates applicability for the connection type; a shaded area indicates non-applicability.

Reprinted, with permission, from ANSI/AWS D1.1-98, Structural Welding Code, Steel.

Statistically

Loaded

Nontubular

Connections

X X X

X X X

X X X

X X X

X X X

X X X

X

X X

X

X X

X X

Cyclically

Loaded

Nontubular

Connections

Tubular

Connections

(All Loads)

Table 6.1Visual Inspection Acceptance Criteria1 (see 6.9)


12/16

The Inspector shall permit welding tobe performed only by welders, weld-

ing operators, and tack welders whoare qualified in accordance with the

requirements of Section 4 (6.4.1).

The Inspector shall make certain

that only welding procedures are

employed which meet the provisionsof Section 3 or Section 4 (6.5.2).

The Inspector shall make certainthat electrodes are used only in the

positions and with the type of weld-ing current polarity for which theyare classified (6.5.3).

The Inspector shall, at suitable inter-

vals, observe joint preparation,assembly practice, the welding

techniques, and performance of

each welder, welding operator, andtack welder to make certain the

applicable requirements of this codeare met (6.5.4).

These code requirements make it

obvious that visual inspection mustake place well before the work is

completed. This may deviate from the

approach used by many Inspectors,but it is the only approach that can

actually prevent the formation of weld-ng defects. For example, when the

base materials being used are exam-ned, the Inspector can prevent theuse of the wrong type of material in a

specific application. Careful examina-ion of welding procedures will reveal

he suitability of a specific procedureor a particular application. The

welders credentials will help deter-mine the suitability of that individual forhe specific application.

Most of the emphasis to this point has

been upon process inspection. Thequality of a completed weld can alsobe visually determined in many situa-

tions. The single exception to this, as

previously noted, is gas metal arc/short arc transfer. With this process, aweld may have an excellent appear-

ance and lack the essential fusionnecessary for all forms of welding. In

this case, extra emphasis on processinspection and nondestructive testingwill be warranted. A good-looking

weld is generally a good weld. A poor-

appearing weld may or may not be apoor weld. However, the presence ofvisually discernible criteria that deviate

from good appearance is generally anindication that one or more variables

are not being properly addressed. Forexample, excessive spatter may not

detract from the quality of the weld.However, it is a sign that the processis not being controlled sufficiently.

In a meeting several years ago, a

series of fatigue and brittle fracturesthat occurred on highway bridges was

being examined. The organizer of themeeting was attempting to establishthe need for more rigorous welded

fabrication requirements. Hydrogencracking, brittle fracture, fracture

mechanics, and fatigue details were alldiscussed. Most revealing in the

meeting, however, was a commentmade by a very skilled technician, a

welder, who had no formal engineeringtraining. His comment was as follows:

I dont understand fracture mechan-ics, fatigue, or hydrogen embrittlement.

However, from what I see in thesephotographs, none of these welds thatfailed would have met the visual

acceptance criteria of the code. The

silence in the room was deafening.The welder was correct. All of thetechnical issues that were being dis-

cussed had entered into these failures,but none of the welds should have

ever been accepted based on simplevisual inspection criteria.

The traditionally understood inspectionresponsibilities are summarized con-

cisely in Table 6.1 of the D1.1-98code, reproduced on the previous

page.

Welding is a process. Only by properly

controlling every element of the processcan product quality be controlled. It is

essential, however, that all the inputvariables be properly identified and con-trolled. During procedure qualification

testing, critical variables can be identi-fied. During welder qualification and

training, important parameters must beappropriately stressed. Effective visual

inspection can ensure that the variablesare properly controlled and identified.

There are applications where additionalnondestructive testing methods should

be specified. However, in all situations,effective visual inspection must be

employed to ensure weld quality. It isincumbent upon Engineers to properlydirect Inspectors attention to those

issues that will contribute to higherquality products. When this is done,

the quality of welding will improve, thecost will be reduced, and the Owners

best interests will be served.


13/16

Quality is tied to a given specification.The specification must be suitable to

meet the needs of the ultimate Owner.For most welded construction, the

AWS D1.1-98 Structural Welding Code

- Steelprovides adequate acceptancecriteria for welded construction.

Unusual structures, however, maydemand additional requirements. D1.1

criteria may be overly restrictive forsome lesser structures. For noncon-

formances to a standard specification,alternate acceptance criteria may beutilized in order to avoid unnecessary

weld repairs. It is the Engineersresponsibility to evaluate the appropri-

ateness of an alternate acceptancecriterion before invoking it for a

specific project.

One of the currently popular definitions

of a quality product is as follows: Aquality product is one that meets spec-

ification requirements. By this defini-tion, quality is integrally linked to theapplicable specification. As long as

the product meets those requirements,it is deemed quality. Unfortunately, if

the specification is incorrect or inap-propriate, conformance to those

requirements may satisfy this definitionbut would not satisfy the wants anddesires of the ultimate customer. Only

when a proper specification is utilized,and when the product integrity meets

or exceeds those specification require-ments, will a true quality product have

been produced that meets customerrequirements. Therefore, a moreappropriate definition of quality would

include the concept of meeting cus-tomer expectations in addition to the

standard specification requirements.This philosophy is summarized by

A.M. Gresnight of Delft University, theNetherlands, as follows:

A good weld is any weld which

does the job it is intended for dur-ing the service life of the structure.

In the structural field, the customer

(Owner) has a representative (theEngineer) who develops the necessaryspecifications (contract documents

and cited codes and standards) thatenable the manufacturer (Fabricator)

to deliver a quality product. In the caseof fabricated steel, the commonly cited

standard for quality is the AWS D196 Structural Welding Code - Stee

An understanding of the philosophybehind the D1.1 Code will help the

Engineer to determine whether it wadequately address the needs of thOwner. Section 6.8, Engineers

Approval for Alternate AcceptanceCriteria, states: The fundamental

premise of the code is to provide geral stipulations applicable to most

uations. The emphasis is significaIt is important to consider the scopthe D1.1 Code, which covers struc

tures that are static and dynamic: oand off-shore applications that utiliz

plate, rolled shapes, and tubular mbers. The products covered range f

Heavy sections may require especially rigorous alternate acceptance criteria


14/16

simple single story metal-framed build-ngs to 100-story-plus skyscrapers and

offshore drilling platforms. In somecircumstances, these general stipula-

ions may be overly restrictive, and inother situations, they may not ade-quately address the demands of the

structure. Evaluating the suitability of

he specification for the application iscertainly the responsibility of theEngineer.

n the commentary to Section 6.8 of

he code, the following can be found:The criteria provided in section 5,

Fabrication, are based upon knowl-

edgeable judgment of what is achiev-able by a qualified welder. The criteria

n Section 5 should not be considered

as a boundary of suitability for service.Suitability for service analysis would

ead to widely varying workmanshipcriteria unsuitable for a standard code.

Furthermore, in some cases, the crite-ia would be more liberal than what is

desirable and producible by a qualified

welder. In general, the appropriatequality acceptance criteria and whether

a deviation produces a harmful productshould be the Engineers decision.

When modifications are approved,evaluation of suitability for serviceusing modern fracture mechanics tech-

niques, a history of satisfactory servicen similar structures, or experimental

evidence is recognized as a suitablebasis for alternate acceptance criteria

or welds. This commentary makes itclear that the code has utilized what isachievable as the acceptance criterion,

not what is necessary for the particularapplication. This is a reasonable

approach for a standard specification,and as is indicated in the commentary,

precludes the need for widely varying

fabrication standards which would bedifficult to monitor in a typical fabrica-

tion facility. When the weld qualitydoes not meet these standards, how-

ever, it is inappropriate to automaticallyassume that the weld will be unaccept-able for service. This should, however,

drive the Engineer to look to fitness-

for-service type criteria for furtherevaluation.

Few Engineers recognize that theD1.1 code permits the use of alternate

acceptance criteria for welds.According to Section 6.8: Acceptancecriteria for production welds different

from those specified in the code maybe used for a particular application,

provided they are suitably documentedby the proposer and approved by the

Engineer. These alternate acceptance

criteria can be based upon evaluationof suitability for service using past

experience, experimental evidence, orengineering analysis concerning mate-

rial type, service load effects, andenvironmental factors.

These provisions permit the Engineerto utilize alternate acceptance criteria.

Since quality is integrally linked to theapplicable specification, the accep-

tance criteria will have a major impacton the final product. The Engineers

responsibility is to assess the suitabili-ty of a standard specification to a par-ticular project, as well as to approve

an alternate should the need arise.

There are three areas in which alter-nate acceptance criteria should be

considered: First, there are situationswhere standard acceptance criteria

are inadequate to the demands of thestructure. Secondly, standard accep-

tance criteria may be overly restrictivefor a particular application. Finally,there are cases in which fabrication is

routinely performed to a standardspecification, with minor noncompli-

ances that can be accepted throughthe use of an alternate acceptance cri-

terion. All three are significant issuesand will be addressed here.

Certain structures make unusualdemands upon welds and weld quality.

When new materials are employed,significant deviations from standard

material thicknesses are utilized, newwelding processes are employed,and/or when the design of the struc-

ture involves a significant departure

from established practices, it is pru-dent for the Engineer to critically eval-uate the suitability of standard

specifications.

For example, the steel fabricationindustry learned many lessons whenjumbo sections were initially applied

to tension applications in trusses.Standard materials (hot rolled, carbon

and/or low alloy steel shapes) inunusual thicknesses (flanges exceed-

ing 5 in thickness) were being used in

new applications (direct tension con-nections). The common workmanship

criteria set forth in the various codesand specifications, as well as normally

acceptable workmanship criteria,proved to be inadequate in a number

of structures. In hindsight, it wouldhave been prudent to employ morerigorous alternate acceptance criteria

for these types of structures. Sincethat time, provisions have been written

to address these situations and havebeen presented in a variety of techni-

cal journals. Indeed, the standardspecifications now include more rigor-ous requirements.

The second situation occurs when the

standard acceptance criteria are moredemanding than is justified for the par-

ticular application. An example in thestructural field would be in the fabrica-tion of steel joists. These components

in steel buildings are usually coveredby another specification that is more

applicable to the particular productinvolved. Application of the same

acceptance criteria as are applied toother fabricated steel structures andmandated by D1.1 would be overly

restrictive, justifying alternate accep-tance criteria. The Engineer should be

careful when routinely suggesting thatalternate acceptance criteria be

employed which deviate from, or are


15/16

less rigorous than, a national consen-sus standard such as D1.1. This prac-

tice would be recommended only forspecific applications for components

where well established, time-provenpractices that have a history of ade-quacy have been used, and where

deviation from these practices would

constitute a major hardship. The D1.1code, however, clearly gives theEngineer the authority to accept an

alternate standard in these situations.

The most important use of alternateacceptance criteria, however, appliesto the third situation, where standard

acceptance criteria have been utilizedfor the fabrication practice and minor

nonconformances have been uncov-ered. Alternate acceptance criteria

can be utilized to accept these non-

conformances and eliminate the needfor unnecessary repairs. Obviously,

the alternate acceptance criteria cho-sen must, as is true in the case of all

engineering decisions, be applicableand appropriate for the application.

Neither poor workmanship nor poorquality can be accepted. However,when the weld that does not conform

to the standard specification is suitablefor the specific situation, alternate

acceptance criteria may be employedto eliminate the need for a repair.

There are many reasons why this maybe desirable for all (that is, the Owner,the Engineer, and the Fabricator).

Unnecessary delays may be avoided.Costly repairs are avoided. Finally,

and perhaps most importantly, anacceptable repaired weld may actual-

ly be inferior to the weld initially reject-ed as unacceptable. Again,according to A.M. Gresnight:

Standards for weld discontinuities

traditionally are based on goodworkmanship criteria. By extending

the traditional standards with thesecond quality level, based on fit-ness for purpose, unnecessary and

potentially harmful repairs can beavoided.

Weld discontinuities fit into two broadcategories: planar and volumetric.

Planar discontinuities include cracksand lack of fusion. These are serious

discontinuities that are unacceptable,and particularly critical in structuressubject to fatigue. Volumetric disconti-

nuities include items such as porosity,slag inclusion, and undercut. These

are less significant, and when heldwithin certain limits, are acceptable by

most codes even under dynamic load-ing situations.

Volumetric discontinuities are readilydiscernible by nondestructive testing

methods and, in many cases, by visualinspection. Planar discontinuities are

harder to detect, and may even beoverlooked by radiographic nonde-structive testing. It has been shown

that, during initial fabrication, most dis-continuities are volumetric in nature.

Under repair welding conditions, whichare more demanding than original fab-

rication circumstances, planar disconti-nuities are more likely to develop.Notice the progression: readily

detectable, less significant volumetricdiscontinuities observed in the original

fabrication may be removed andreplaced with welds that contain less

detectable, but more significant, planar

discontinuities. This is not to say o

imply that welds cannot be effectivrepaired. It does mean, however, t

haphazard demands for weld repaimay actually result in a product of

decreased value to the Owner. Itshould also be noted that the depotion of additional weld metal is like

increase distortion and residual stres in the structure. When the nonc

forming weld is adequate for theparticular application, the responsi

approach is to utilize an alternateacceptance criterion to eliminate thunnecessary repair.

Most Engineers are unsure of the s

ability of alternate acceptance criteThe search for appropriate docume

that employ the fitness for purposeapproach is generally a frustratingexperience. Apart from finding info

mation regarding the methods thatmay be employed for analysis, prac

cal ideas as they relate to welds arall too scarce. Mr. Robert E. Shaw,

P.E., of Steel Structures TechnologCenter, Inc., (40612 Village OaksDrive, Novi, Michigan 48375-4462)

has provided Engineers with a usesource of information regarding alte

nate acceptance criteria. Shaw hasystematically evaluated specific d

continuities, the D1.1 Code require

The 7 in (180 mm) flanges of these transfer girders require careful consideraof the NDT acceptance criteria.


16/16

ments, and other standards that couldbe used as alternates. His summary

s excellent and provides practicaloptions to Engineers.

Undersized welds are a common prob-em. The situation is simple: the

drawings call for a 5/16 in (8 mm) fillet

weld and the welder deposits a 1/4 in6 mm) fillet. At least two options are

available: first, additional weld metal

can be deposited over the surface to

build it up to the required size; second-

y, an alternate acceptance criterioncould be employed that would allow

hese welds to be acceptable asdeposited. It should be noted that theD1.1 Code would allow the welds to

underrun the nominal fillet weld sizeby 1/16 in (1.6 mm) without correction

provided that the undersized portion ofhe weld does not exceed 10% of the

weld length (D1.1-98, Table 6.1, see

Part II of this series). If the entireweld, however, is undersized, this pro-

vision would not be applicable. Inmany cases, the deposition of addi-

tional weld metal would be routine andwould not constitute a major problem.However, the initial weld may have

been produced with an automatic,

submerged arc welding machine whenthe travel speed happened to beslightly too high, resulting in a slightly

undersized weld. The weld may bebeautiful and meet all criteria except

for the size. To make the weld repair, agang of manual or semiautomaticwelders may be assigned to deposit

the additional weld metal. The fin-ished product may be visually inferior,

and subject to all of the potential dis-continuities of the starts and stops

associated with manual and semiauto-

matic welding.

Has the product quality beenenhanced by the repair? First, it must

be determined if the undersized weldwould have been acceptable. As is

the case in many situations involvingfabricated plate girders, the weld sizemay have been based upon the mini-

mum prequalified fillet weld size pre-scribed in the D1.1 Code. The design

basis was not strength, but this mini-mum size. A quality, 1/4 in (6 mm)

fillet weld would have provided all thenecessary strength in this particularsituation. The reasoning behind the

minimum fillet weld size in the code isbased upon good workmanship prac-

tices and controlling the heat input topreclude weld cracking. However, in

this example, it has been assumed

that the initial weld is a quality weld,free of cracks, with acceptable weld

contours, etc. If this is the situation,leaving the undersized weld in place,

unrepaired, is a more responsibleapproach than demanding the weld

repair. The initial weld is probably ofhigher quality than the repaired weld

would be, will have less distortion, isless costly, and will eliminate unneces-

sary delays.

The decision to invoke alternateacceptance criteria must be made bythe Engineer. In a separate article in

this series, the roles of the Engineer,the Inspector, and the Fabricator are

defined. The Inspector cannot makethis decision and neither can the

Fabricator. Only the Engineer with anunderstanding of the loading, design

assumptions, and overall structuralsignificance can make these types ofdecisions.

For most applications, the AWS D1.1-98 Structural Welding Code - Steelprovides adequate acceptance criteria

for welded construction. For weldsthat deviate from standard acceptance

criteria, engineering judgment shouldbe applied before repairs are mandat-

ed. If the weld will meet the structuralrequirements for the project withoutmodification, the responsible approach

of the Engineer is to utilize alternateacceptance criteria and accept these

welds. Ultimately, a product ofimproved quality at reasonable cost

will be the result of this approach.

Welding Quality and Inspection

Documents

Transcript of Welding Quality and Inspection