ARTICLE KF-3FABRICATION REQUIREMENTS FOR MATERIALS

WITH PROTECTIVE LININGS

KF-300 SCOPE

This Article applies to materials with protectivelinings that are applied by integral cladding or weldoverlaying. Prestressed liners which are considered partof the shell for strength purposes are not covered bythis Article (see Article KF-8).

KF-301 Types of Joints Permitted

The types of joints and welding procedures usedshall be such as to minimize the formation of brittleweld composition by the mixture of metals of corrosion-resistant alloy and base material.1

KF-302 Weld Metal Composition

Welds that are exposed to the corrosive action ofthe contents of the vessel should have resistance tocorrosion that is not substantially less than that ofthe corrosion-resistant integral or weld metal overlaycladding or lining. The use of filler metal that willdeposit weld metal with practically the same composi-tion as the material joined is recommended. Weld metalof different composition may be used provided it hasbetter mechanical properties in the opinion of theManufacturer, and the User is satisfied that its resistanceto corrosion is satisfactory for the intended service. Thecolumbium content of columbium-stabilized austeniticstainless steel weld metal shall not exceed 1.00% exceptwhen a higher content is permitted in the materialbeing welded.

1 Because of the different coefficients of thermal expansion of dissimi-lar metals, caution should be exercised in design and constructionunder provisions of these paragraphs in order to avoid difficultiesin service under extreme temperature conditions or with unusualrestraint of parts such as may occur at points of stress concentration.

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KF-303 400 Series Alloy Filler Metals

400 Series alloy filler metals are not permitted whenthe filler metal is welded to the base metal.

KF-310 QUALIFICATION OF WELDINGPROCEDURES

The specification of the welding procedure that isproposed to be followed in clad, weld overlaid or linedconstruction shall be recorded in detail.

KF-311 Procedure to Be Qualified Per SectionIX

All weld procedures associated with protective linersshall be qualified in accordance with the provisions ofSection IX, QW-217.

KF-312 Qualification of Procedure forAttaching Linings

(a) Each welding procedure to be used for attachinglining material to the base material shall be qualifiedon lining attachment welds made in the form andarrangement to be used in construction and with materi-als that are within the ranges of chemical compositionof the materials to be used, respectively, for the basematerial, the linings, and the weld metal.

(b) Welds shall be made in each of the positionsdefined in Section IX, QW-120 that are to be used inconstruction. One specimen from each position to bequalified shall be sectioned, polished, and etched toshow clearly the demarcation between the fusion zoneand the base metal.

(c) For the procedure to qualify, the specimen shallshow, under visual examination without magnification,complete fusion and complete freedom from cracks inthe fusion zone and in the heat-affected metal.

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KF-313 PART KF — FABRICATION REQUIREMENTS KF-341

KF-313 Requirements for Composite Welds

KF-313.1 Procedure Qualification for GrooveWelds in Base Material With Corrosion-ResistantIntegral Cladding or Weld Metal Overlay. The re-quirements in Section IX, QW-217 for procedure quali-fication shall be followed. The procedure for groovewelds may be qualified as in KF-311, or the weld inthe base joint or cladding joint may be qualified individ-ually in accordance with the rules in Section IX.

KF-313.2 Performance Qualification for Compos-ite Welds.The requirements in Section IX, QW-310 andKF-313.1 or KF-313.3 shall be followed for performancequalification.

KF-313.3 Test Plates for Composite Welds.Perform-ance qualification tests shall be made in accordance withSection IX by preparing test material from integral clad orweld overlay material having the same P-Numbers in QW/QB-422 as that of the base material. Integral or weld metaloverlay cladding materials to be used in the test shall havethe same F-Number in QW-432 as the filler metal that willbe used in construction. When the integral clad or weldmetal overlay material is not listed in QW/QB-422, quali-fication shall be made on the same grade as used in thevessel. Heat treatment is not required but is permitted ifthe welder’s work on construction is to be heat treated. Thefollowing conditions shall also be met. A section cut fromthe test material perpendicular to the welding direction andproperly prepared and etched shall show no lack of fusionlonger than1⁄8 in. (3.2 mm). The total length of unfusedcladding shall not exceed 10% of the length of the test ma-terial perpendicular to the direction of welding.

KF-320 INTEGRALLY CLAD MATERIALS

A shear test shall demonstrate a minimum shearstrength of 20,000 psi (138 MPa) for integral cladmaterials.

KF-330 POSTWELD HEAT TREATMENTOF LININGS

KF-331 When Base Metal Must Be PostweldHeat Treated2

Vessels or parts of vessels constructed of an integrallyclad material or weld metal overlay shall be postweld

2 Postweld heat treatment temperatures may be in the carbide precipita-tion range for unstabilized austenitic chromium–nickel steel, as wellas within the range where a sigma phase may form. Impropertreatment could result in material of inferior physical properties andinferior corrosion resistance and could result in the ultimate failureof the vessel.

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heat treated when the base material is required to bepostweld heat treated. In applying these rules, thedetermining thickness shall be the total thickness ofbase material. When the thickness of the base materialrequires postweld heat treatment, it shall be performedafter the application of weld metal overlay or cladrestoration.

KF-332 Requirements When Base Metal orLining Is Chromium-Alloy Steel

Vessels or parts of vessels constructed of chromium-alloy stainless steel cladded base material and thoselined with chromium-alloy stainless steel applied liningsshall be postweld heat treated in all thicknesses, exceptthat vessels clad or lined with Type 405 or Type 410Sand welded with an austenitic electrode or non-air-hardening nickel–chromium–iron electrode need not bepostweld heat treated unless required by KF-331.

KF-333 Heat Treatment That May AffectVessel Stress Redistribution

The Manufacturer shall ensure and document, inaccordance with KG-323(d), that any heat treatmentgiven to a vessel or vessel part does not adverselyaffect the stress distribution required by Articles KD-5, 8, 9, and 10. In addition, for layered or autofrettagedvessels, the Manufacturer shall meet the requirementsfor heat treatment given in KF-830 or KF-540(b), asapplicable.

KF-340 EXAMINATION REQUIREMENTS

KF-341 Examination of Base MaterialsProtected by Welded Overlay

The examination required by the rules in ArticleKE-3 shall be made after the joint, including thecorrosion-resistant layer, is complete. The examinationmay be made on the weld in the base material beforethe alloy cover weld is deposited, provided the followingrequirements are met:

(a) the thickness of the base material at the weldedjoint is not less than that required by the designcalculation;

(b) the corrosion-resistant alloy weld deposit is non-air-hardening;

(c) the completed alloy weld deposit is examinedby any method that will detect cracks in accordancewith KE-233.

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KF-342 2001 SECTION VIII — DIVISION 3 KF-360

KF-342 Examination of Chromium-AlloyCladding Overlay

The joints between chromium-alloy cladding overlayor loose liner sheets shall be examined for cracks asfollows.

KF-342.1 Straight Chromium-Alloy Filler Metal(a) Joints welded with straight chromium-alloy filler

metal shall be examined throughout their full length.Chromium-alloy welds in continuous contact with thewelds in the base metal shall be examined in accordancewith Article KE-3.

(b) Liner welds that are attached to the base metal,but merely cross the seams in the base metal, shall beexamined in accordance with KE-334.

KF-342.2 Austenitic Chromium–Nickel Steel FillerMetal. Joints welded with austenitic chromium–nickelsteel filler metal or non-air-hardening nickel–chro-mium–iron filler metal shall be dye penetrant examinedover their entire length per KE-334 and spot UTexamined over 10% of their length in accordance withArticle KE-3.

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KF-350 INSPECTION AND TESTS

KF-351 General Requirements

The rules in the following paragraphs shall be usedin conjunction with the general requirements for inspec-tion in Part KE, and for testing in Part KE that pertainto the method of fabrication used.

KF-352 Leak Test of Protective Lining

A test for pressure tightness of the protective liningthat will be appropriate for the intended service isrecommended, but the details of the test shall bea matter for agreement between the User and theManufacturer. The test should not damage the load-carrying baseplate. When rapid corrosion of the basematerial is to be expected from contact with the contentsof the vessel, particular care should be taken in devisingand executing the leak test.

KF-360 STAMPING AND REPORTS

The provisions for stamping and reports in Part KSshall apply to vessels that are constructed of integralclad, weld metal overlay, or protective liners and shallinclude the specification and type of lining material.This information shall be included in the Manufacturer’sData Reports.

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