Welding Terminologies

actual throat - The shortest distance between the weld root and the face of the fillet weld.

back weld - A weld made at the back of a single groove welded joint after the completion of the groove weld.

backing - A material or deviced placed against the back side of the joint, or at both side of the weld in electroslag and electrogas welding, to support and retain molten weld metal. the material maybe partially fused or remain unfused during welding and maybe either metal or nonmetal.

backing weld - Backing in the form of a weld made from primary weld.

bevel - An angular edge shape.

complete joint penetration - A joint root condition in a groove weld in which weld metal extends completely trhough the joint thickness.

corner joint - A joint betwen two members located approximately at right angles to each other in the form of an L.

depth of bevel - The perpendicular distance from the base metal surface to the root edge or the begining of th root face.

depth of fusion - The distance that fusion extends into the base metal or previous bead from the surface melted during welding.

edge joint - A joint betwen the edges of two or more parallel or nearly parallel members.

edge preparation - The preparation of the the edges of the joint members, cutting, cleaning, plating, or other means.

edge weld - A weld in an edge joint, a flange butt joint or a flange corner joint in which the full thickness of the members are fused.

effective throat - The minimum distance minus any convexity, betwen the weld root and the face of a fillet weld.

face reinforcement - Weld reinforcement on the side of the joint from which welding was done.

fillet weld - A weld of approximately traingular cross section joining two surfaces approximately at right angles to each other in a lap-, T-, or corner joint.

fillet weld leg - The distance from the joint root to the toe of the fillet weld.

fusion - The melting together of filler metal and base metal, or base metal only, to produce a weld.

fusion face - A surface of th base metal that will be melted during welding or the area of base metal melted as determined on the cross section of the weld.

groove angle - The total included angle of the groove between workpieces. In joints where both edges of the workpieces are prepared at an angle this dimension is the total of both.

groove weld - A weld in a groove between workpieces.

joint - The junction of members or the edges of members that are to be joined or had been joined.

joint design - The shape, dimensions and configuration of the joint.

joint filler - A metal plate inserted between a splice member and a thinner joint member to accommodate joint members of dissimilar thickness in a spliced butt joint.

joint geometry - The shape and dimensions of a joint in cross section prior to welding.

joint type - A weld joint classification base on five basic joint configurations such as butt joint, corner joint, edge joint, lap joint and T-joint.

Electrical Characteristics

To supply the electrical energy necessary for arc welding processes, a number of different power supplies can be used. The most common classification is constant current power supplies and constant voltage power supplies. In arc welding, the voltage is directly related to the length of the arc, and the current is related to the amount of heat input.

Constant current power supplies are most often used for manual welding processes such as gas tungsten arc welding and shielded metal arc welding, because they maintain a relatively constant current even as the voltage varies. This is important because in manual welding, it can be difficult to hold the electrode perfectly steady, and as a result, the arc length and thus voltage tend to fluctuate.

Constant voltage power supplies hold the voltage constant and vary the current, and as a result, are most often used for automated welding processes such as gas metal arc welding, flux cored arc welding, and submerged arc welding. In these processes, arc length is kept constant, since any fluctuation in the distance between the wire and the base material is quickly rectified by a large change in current.

For example, if the wire and the base material get too close, the current will rapidly increase, which in turn causes the heat to increase and the tip of the wire to melt, returning it to its original separation distance.

The direction of current used in arc welding also plays an important role in welding. Consumable electrode processes such as shielded metal arc welding and gas metal arc welding generally use direct current, but the electrode can be charged either positively or negatively.

In welding, the positively charged anode will have a greater heat concentration and, as a result, changing the polarity of the electrode has an impact on weld properties. If the electrode is positively charged, it will melt more quickly, increasing weld penetration and welding speed. Alternatively, a negatively charged electrode results in more shallow welds.

Non-consumable electrode processes, such as gas tungsten arc welding, can use either type of direct current, as well as alternating current. With direct current however, because the electrode only creates the arc and does not provide filler material, a positively charged electrode causes shallow welds, while a negatively charged electrode makes deeper welds.

Alternating current (AC) rapidly moves between these two, resulting in medium-penetration welds. One disadvantage of AC, the fact that the arc must be re-ignited after every zero crossing, has been addressed with the invention of special power units that produce a square wave pattern instead of the normal sine wave, eliminating low-voltage time after the zero crossings and minimizing the effects of the problem.

POLARITY

SMAW GTAW GMAW FCAW SAW

DCEP DCEN DCEP DCEP DCEP

DCEP - Direct Current Electrode Positive or Reverse Polarity DCEN - Direct Current Electrode Negative or Straight Polarity

Postweld Heat Treatment

Temperature Range

Base Metal P-No. and Group Metal Temperature Range (°C)

P-No. Base Metal Group ASME B31.3 Table 331.1.1

ASME B31.1 Table 132

ASME VIII Table UCS-56

1 Carbon steel 593-649 600-650 650 min.

3 Alloy steels, Cr ≤ ½%

593-718 600-650 595 min.

4 Alloy steels, ½% < Cr ≤ 2%

704-746 700-750 650 min.

5A,5B,5C Alloy steels (2¼% ≤ Cr ≤ 10%)

704-760 700-760

675 min. for 5A,5B,5C Gr 1,

705 min. for 5B Gr 2

6High alloy steel martensiticA240 Gr 429

732-788621-663

760-800Not mentioned Not mentioned

7 High alloy steel ferritic

None 730-775 Not mentioned

8 High alloy steel austenitic

None None Not mentioned

9A,9B Nickel alloy steels 593-635 600-650 for 9A600-630 for 9B

595 min.

10(A/B/C/K/J) Cr-Cu steels 760-816 Not mentioned

595 min for 10A650 min. for 10B540 min. for 10C540 min. for 10H

10H Duplex stainless See Table See Table 132 Not mentioned

steels 331.1.1Note (7)

General Note (I)

10I 27Cr steels 663-704 730-815 Not mentioned

11A SG1 8Ni, 9Ni steels 552-585 Not mentioned Not mentioned

11B SG2 5Ni steel 552-585 Not mentioned Not mentioned

62 Zr R60705 538-593 Not mentioned Not mentioned

Time Range

Gas

The properties of gases affect the performance of all welding processes. The ionization potential of the shielding gas influences the ease of arc initiation and stability. Thermal conductivity of a gas determines the voltage and energy constant of the arc. Gases such as carbon dioxide can have higher heat conductivity than helium at arc temperatures because of the effect of disassociation and recombination.

Reactive and oxidizing gases such as carbon dioxide (CO2) and oxygen (O2) can have detrimental effects on base metals such as aluminum, nickel, titanium, zirconium, and tungsten. For this reason, carbon dioxide or oxygen cannot be used as the shielding gas for gas tungsten arc welding.

Proper gas selection is crucial to efficient welding in the most cost-effective manner. Many factors must be considered. These are not limited to the following:

a. Type and thickness of base metal being welded b. Arc characteristics c. Metal transfer d. Travel speed e. Depth and width of fusion f. Cost of welding g. Mechanical properties h. Cleanliness of the basemetal i. Spatter j. Arc cleaning action k. Gas purity l. Joint configuration m. Welding position n. Fume generation

Gas

Mixture

Flow Rate

Backing Gas

Shielding Gas

Trailing Gas

Preheat

Preheat Temp. Min - Minimun preheat temperature as required per base metal thickness and/or basemetal P-No. prehet requirement.

Interpass Temp. Max - Maximum interpass temperature.

Preheat Maintenance - As required, preheat temperature must be maintained and preheat maintenance method shall be specified in the WPS.

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Filler Metals

Spec.No.(SFA) - It's the ASME designated Specification.

List of ASME Designated Filler Metal SpecificationSFA-5.1 Carbon Steel Electrodes for Shielded Metal Arc WeldingSFA-5.2 Carbon and Low Alloy Steel Rods for Oxyfuel Gas WeldingSFA-5.3 Aluminum and Aluminum-Alloy Electrodes for Shielded Metal Arc WeldingSFA-5.4 Stainless Steel Electrodes for Shielded Metal Arc WeldingSFA-5.5 Low-Alloy steel Electrodes for Shielded Metal Arc WeldingSFA-5.6 Covered Copper and Copper Alloy Arc Welding ElectrodesSFA-5.7 Copper and Copper Alloy Bare Welding Rods and ElectrodesSFA-5.8 Filler Metal for Brazing and Braze WeldingSFA-5.9 Bare Stainless Steel Welding Electrodes and RodsSFA-5.10 Bare Aluminum and Aluminum-Alloy Welding Electrodes and RodsSFA-5.11 Nickel and Nickle-Alloy Welding Electrodes for Shielded Metal Arc WeldingSFA-5.12 Tungsten and Tungsten-Alloy Electrodes for Arc Welding and CuttingSFA-5.13 Surfacing Electrodes for Shielded Metal Arc WeldingSFA-5.14 Nickle and Nickle-Alloy Bare Welding Electrodes and RodsSFA-5.15 Welding Electrodes and Rods for Cast IronSFA-5.16 Titanium and Titanium-Alloy for Welding Electrodes and RodsSFA-5.17 Carbon Steel Electrodes and Fluxes for Submerged Arc WeldingSFA-5.18 Carbon Steel Electrodes and Rods for Gas Shielded Arc WeldingSFA-5.20 Carbon Steel Electrodes for Flux cored Arc WeldingSFA-5.21 Bare Electrode and Rods for Surfacing

SFA-5.22 Stainless Steel Electrodes for Flux Cored Arc Welding and Stainless Steel Flux Cored Rods for Gas Tungsten Arc Welding

SFA-5.23 Low-Alloy Steel Electrodes and Fluxes for Submerged Arc Welding

SFA-5.24 Zirconium and Zirconium-Alloy Welding Electrodes and RodsSFA-5.25 Carbon and Low-Alloy Steel Electrodes and Fluxes for Electroslag WeldingSFA-5.26 Carbon and Low-alloy Steel Electrodes for Electrogas WeldingSFA-5.28 Low-Alloy Steel Electrodes and Rods for Gas Shielded Arc WeldingSFA-5.29 Low-Alloy Steel Electrodes for Flux Cored Arc weldingSFA-5.30 Consumables InsertsSFA-5.31 Fluxes for Brazing and Braze WeldingSFA-5.32 Welding Shielding Gases

AWS No.(Class) - AWS designated filler metal classification

F-No. - Grouping of electrodes and welding rods for qualification.

A-No. - Classification of ferrous weld metals analysis for procedure qualification.

Size of Filler metals(Ø) - Size of electrode(s) to be used is in diameter. One or more applicable eletrode sizes can be specified in the WPS

Electrode-Flux (Class) - Applicable for Submerged Arc Welding (SAW) process

Flux Trade Name - Applicable for Submerged Arc Welding (SAW) process

Consumable Insert - Refer to SFA-5.30 of ASME II Part C for consumable insert specification

Other - Weld metal thickness may be specified here or maximum allowable weld deposit per pass.

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Base Metals

P-No. and Group No. - Refer to the table for material groupings in ASME IX QW-422 Grouping

of Base Metal for Qualification pages 69-130.

Base Metal P-No. and Groupings

P-No. Base Metal Group

1 Carbon steel

3 Alloy steels, Cr ≤ ½%

4 Alloy steels, ½% < Cr ≤ 2%

5A,5B,5C Alloy steels (2¼% ≤ Cr ≤ 10%)

6 High alloy steel martensitic

7 High alloy steel ferritic

8 High alloy steel austenitic

9A,9B Nickel alloy steels

10(A/B/C/K/J) Cr-Cu steels

10H Duplex stainless steels

10I 27Cr steels

11A SG1 8Ni, 9Ni steels

11B SG2 5Ni steel

62 Zr R60705

Specification Type or Grade - base on the design or fabrication reference drawings write the base metal's Material Specification to be welded together and its Type or Grade that will be covered by the WPS.

There are also steel material specifications that don't specify any type or grade like, SA-36 plate and shapes materials, SA-105 flanges & fittings materials and others.

Chem. Analysis and Mech. Prop.(Optional) - chemical analysis and mechanical properties of the base metals to be welded.

Thickness Range: GROOVE - The maximum base metal or weld metal thickness that can be welded and deposited respectively should depend on the base metal thickness(T) of the Procedure Qualification Test (PQR) test piece, plate or pipe; or deposited weld metal thickness(t) in the PQR test piece. Example, If test piece thickness(T) is 12 mm, the maximum thicknes(T) limit should be 24 mm.

For the minimum thickness limit, refer to QW-451.1 of ASME IX - Procedure Qualification Thickness Limits and Test Specimen

FILLET - Once the PQR was done in groove weld unlimited thickness is qualified for fillet weld.

Joints

Joint Design - write what is the type of the joint that will be prepared in production welding. Is it groove/butt joint or fillet joint? Your reference for appropriate joint design should be the applicable fabrication detailed drawings. It is not necessary to write a very specific joint design on this space, such as "Vee groove", "single bevel", "Tee joint", etc. Either groove or fillet or groove and fillet would be understandable. You may just draw a detailed illustrations of the specific or typical joint designs in the WPS and follow the note on the sample below.

Backing - Mark the "(Yes)" space with "X" if there is a backing material to be provided prior to welding the initial pass or root pass. Mark the "(No)" space if there's none.

For the joint with combination of weld processes - the initial weld process can be consider as the backing of second welding process to be initiated. For example, in combined GTAW + SMAW processes the GTAW process is a backing of the SMAW process.

Backing Material(Type) - Refer to both backing and retainers.

Welding Processes

The AWS definition for a welding process is "a materials joining process which produces coalescence of materials by heating them to suitable temperatures with or without the application of pressure or by the application of pressure alone and with or without the use of filler material". AWS has grouped the processes together according to the "mode of energy transfer" as the primary consideration. A secondary factor is the "influence of capillary attraction in effecting distribution of filler metal" in the joint. Capillary attraction distinguishes the welding processes grouped under "Brazing" and "Soldering" from "Arc Welding", "Gas Welding", "Resistance Welding", "Solid State Welding", and "Other Processes."

Shielded Metal Arc Welding (SMAW) - also known as manual metal arc (MMA) welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode coated in flux to lay the weld. An electric current, in the form of either alternating current or direct current from a welding power supply, is used to form an electric arc between the electrode and the metals to be joined. As the weld is laid, the flux coating of the electrode disintegrates, giving off vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination.Gas Tungsten Arc Welding (GTAW) - also known as tungsten inert gas (TIG) welding] and was defined as "an arc welding process which produces coalescence of metals by heating them with an arc between a tungsten (non-consumable) electrode and the work piece. Shielding is obtained from a gas or gas mixture." It is an arc welding process that uses a nonconsumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by a shielding gas (usually an inert gas such as argon), and a filler metal is normally used, though some welds, known as autogenous welds, do not require it. A constant-current welding power supply produces energy which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma.Gas Metal Arc Welding (GMAW) - It was developed in the late 1940s for welding aluminum and has become extremely popular. It is defined as "an arc welding process which produces coalescence of metals by heating them with an arc between a continuous filler metal (consumable) electrode and the work piece. Shielding is obtained entirely from an externally supplied gas or gas mixture." The electrode wire for GMAW is continuously fed into the arc and deposited as weld metal. This

process has many variations depending on the type of shielding gas, the type of metal transfer, and the type of metal welded. Flux Cored Arc Welding (FCAW) - It is defined as "an arc welding process which produces coalescence of metals by heating them with an arc between a continuous filler metal (consumable) electrode and the work piece. Shielding is provided by a flux contained within the tubular electrode." Additional shielding may or may not be obtained from an externally supplied gas or gas mixture. Submerged Arc Welding (SAW) - process that made automatic welding popular. Submerged arc welding is defined as "an arc welding process which produces coalescence of metals by heating them with an arc or arcs between a bare metal electrode or electrodes and the work piece. Pressure is not used and filler metal is obtained from the electrode and sometimes from a supplementary welding rod." It is normally limited to the flat or horizontal position.