PART QB BRAZING

ARTICLE XIBRAZING GENERAL REQUIREMENTS

QB-100 GENERAL

Section IX of the ASME Boiler and Pressure VesselCode relates to the qualification of welders, weldingoperators, brazers, and brazing operators, and the proce-dures that they employ in welding and brazing accordingto the ASME Boiler and Pressure Vessel Code andthe ASME B31 Code for Pressure Piping. It is dividedinto two parts: Part QW gives requirements for weldingand Part QB contains requirements for brazing.

QB-100.1 The purpose of the Brazing ProcedureSpecification (BPS) and Procedure Qualification Record(PQR) is to determine that the brazement proposedfor construction is capable of providing the requiredproperties for its intended application. It is presupposedthat the brazer or brazing operator performing thebrazing procedure qualification test is a skilled workman.That is, the brazing procedure qualification test estab-lishes the properties of the brazement, not the skill ofthe brazer or brazing operator. Briefly, a BPS liststhe variables, both essential and nonessential, and theacceptable ranges of these variables when using theBPS. The BPS is intended to provide direction for thebrazer or brazing operator. The PQR lists what wasused in qualifying the BPS and the test results.

QB-100.2 In performance qualification, the basiccriterion established for brazer qualification is to deter-mine the brazer’s ability to make a sound brazed joint.The purpose of the performance qualification test forthe brazing operator is to determine the operator’smechanical ability to operate the brazing equipment.

QB-100.3 Brazing Procedure Specifications (BPS)written and qualified in accordance with the rules ofthis Section, and brazers and operators of automaticand machine brazing equipment also qualified in accord-ance with these rules may be used in any constructionbuilt to the requirements of the ASME Boiler and

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Pressure Vessel Code or the ASME B31 Code forPressure Piping.

However, other Sections of the Code state the condi-tions under which Section IX requirements are manda-tory, in whole or in part, and give additional require-ments. The reader is advised to take these provisionsinto consideration when using this Section.

Brazing Procedure Specifications, Procedure Qualifi-cation Records, and Brazer or Brazing Operator Per-formance Qualifications made in accordance with therequirements of the 1962 Edition or any later Editionof Section IX may be used in any construction builtto the ASME Boiler and Pressure Vessel Code or theASME B31 Code for Pressure Piping.

Brazing Procedure Specifications, Procedure Qualifi-cation Records, and Brazer or Brazing Operator Per-formance Qualifications made in accordance with therequirements of the Editions of Section IX prior to1962, in which all of the requirements of the 1962Edition or later Editions are met, may also be used.

Brazing Procedure Specifications and Brazer /BrazingOperator Performance Qualification Records meetingthe above requirements do not need to be amended toinclude any variables required by later Editions andAddenda.

Qualification of new Brazing Procedure Specificationsor Brazers/Brazing Operators and requalification ofexisting Brazing Procedure Specifications orBrazers/Brazing Operators shall be in accordance withthe current Edition (see Foreword) and Addenda ofSection IX.

QB-101 Scope

The rules in this Section apply to the preparationof Brazing Procedure Specifications, and the qual-ification of brazing procedures, brazers, and brazingoperators for all types of manual and machine brazing

QB-101 2001 SECTION VI QB-141

processes permitted in this Section. These rules mayalso be applied, insofar as they are applicable, to othermanual or machine brazing processes, permitted inother Sections.

QB-102 Terms and Definitions

Some of the more common terms relating to brazingare defined in QW/QB-492. These are in substantialagreement with the definitions of the American WeldingSociety given in its document, A3.0-89, Standard Weld-ing Terms and Definitions.

Wherever the word pipe is designated, tubes shallalso be applicable.

QB-103 Responsibility

QB-103.1 Brazing.Each manufacturer1 or contractor1

is responsible for the brazing done by his organization,and shall conduct the tests required in this Section toqualify the brazing procedures he uses in the construc-tion of the brazed assemblies built under this Codeand the performance of brazers and brazing operatorswho apply these procedures.

QB-103.2 Records.Each manufacturer or contractorshall maintain a record of the results obtained in brazingprocedure and brazer or brazing operator performancequalifications. These records shall be certified by themanufacturer or contractor and shall be accessible tothe Authorized Inspector. Refer to recommended Formsin Nonmandatory Appendix B.

QB-110 BRAZE ORIENTATION

The orientations of brazes with respect to planes ofreference are classified in accordance with QB-461 intofour positions2 (A, B, C, and D in column 1), basedon the basic flow of brazing filler metal through joints.These positions are flat flow, vertical downflow, verticalupflow, and horizontal flow.

QB-120 TEST POSITIONS FOR LAP, BUTT,SCARF, OR RABBET JOINTS

Brazed joints may be made in test coupons orientedin any of the positions in QB-461 and as describedin the following paragraphs, except that angular devia-

1 Wherever these words are used in Section IX, they shall includeinstaller or assembler.2 In the following paragraphs the wordposition is synonymous withflow position.

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tion from the specified horizontal and vertical flowplanes in accordance with column 1 of QB-461 ispermitted during brazing.

QB-121 Flat-Flow Position

The joints in position suitable for applying brazingfiller metal in rod, strip, or other suitable form underthe flat-flow conditions are shown in sketches (1)through (5) of Line A in QB-461. The maximumpermitted angular deviation from the specified flowplane is ±15 deg.

QB-122 Vertical-Downflow Position

The joints in a position suitable for applying brazingfiller metal in rod, strip, or other suitable form underthe vertical-downflow conditions are shown in sketches(1) through (4) of Line B in QB-461. The brazingfiller metal flows by capillary action with the aid ofgravity downward into the joint. The maximum permit-ted angular deviation from the specified flow plane is±75 deg.

QB-123 Vertical-Upflow Position

The joints in position suitable for applying brazingfiller metal in rod, strip, or other suitable form underthe vertical-upflow conditions are shown in sketches(1) through (4) of Line C in QB-461. The brazingfiller metal flows by capillary action through the joint.The maximum permitted angular deviation from thespecified flow plane is ±75 deg.

QB-124 Horizontal-Flow Position

The joints in a position suitable for applying brazingfiller metal in rod, strip, or other suitable form underthe horizontal-flow conditions are shown in sketches(1) and (2) of Line D of QB-461. The brazing fillermetal flows horizontally by capillary action throughthe joint. The maximum permitted angular deviationfrom the specified flow plane is ±75 deg.

QB-140 TYPES AND PURPOSES OF TESTSAND EXAMINATIONS

QB-141 Tests

Tests used in brazing procedure and performancequalifications are as follows.

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QB-141.1 GENERAL REQUIREMENTS QB-152

QB-141.1 Tension Tests. Tension tests, as describedin QB-150, are used to determine the ultimate strengthof brazed butt, scarf, lap, and rabbet joints.

QB-141.2 Guided-Bend Tests. Guided-bend tests,as described in QB-160, are used to determine thedegree of soundness and ductility of butt and scarfjoints.

QB-141.3 Peel Tests. Peel tests, as described in QB-170, are used to determine the quality of the bond andthe amount of defects in lap joints.

QB-141.4 Sectioning Tests. Sectioning tests, i.e.,the sectioning of test coupons, as described in QB-180, are used to determine the soundness of workman-ship coupons or test specimens. Sectioning tests arealso a substitute for the peel test when the peel testis impractical to perform, e.g., when the strength ofbrazing filler material is equal to or greater than thestrength of the base metals.

QB-141.5 Workmanship Coupons. Workmanshipcoupons, as described in QB-182, are used to determinethe soundness of joints other than the standard butt,scarf, lap, and rabbet joints.

QB-141.6 Visual Examination. Visual examinationof brazed joints is used for estimating the soundnessby external appearance, such as continuity of the brazingfiller metal, size, contour, and wetting of fillet alongthe joint and, where appropriate, to determine if fillermetal flowed through the joint from the side of applica-tion to the opposite side.

QB-150 TENSION TESTS

QB-151 Specimens

Tension test specimens shall conform to one of thetypes illustrated in QB-462.1(a) through QB-462.1(f),and shall meet the requirements of QB-153.

QB-151.1 Reduced Section — Plate. Reduced-sec-tion specimens conforming to the requirements givenin QB-462.1(a) and QB-462.1(c) may be used fortension tests on all thicknesses of plate. The specimensmay be tested in a support fixture in substantial accord-ance with QB-462.1(f).

(a) For thicknesses up to and including 1 in. (25 mm),a full thickness specimen shall be used for each requiredtension test.

(b) For plate thicknesses greater than 1 in. (25 mm),full thickness specimens or multiple specimens may

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be used, provided QB-151.1(c) and QB-151.1(d) arecomplied with.

(c) When multiple specimens are used in lieu of fullthickness specimens, each set shall represent a singletension test of the full plate thickness. Collectively, allof the specimens required to represent the full thicknessof the brazed joint at one location shall comprise a set.

(d) When multiple specimens are necessary, the entirethickness shall be mechanically cut into a minimumnumber of approximately equal strips of a size thatcan be tested in the available equipment. Each specimenof the set shall be tested and meet the requirementsof QB-153.

QB-151.2 Reduced Section — Pipe. Reduced-sec-tion specimens conforming to the requirements givenin QB-462.1(b) may be used for tension tests on allthicknesses of pipe or tube having an outside diametergreater than 3 in. (76 mm). The specimens may betested in a support fixture in substantial accordancewith QB-462.1(f).

(a) For thicknesses up to and including 1 in. (25 mm),a full thickness specimen shall be used for each requiredtension test.

(b) For pipe thicknesses greater than 1 in. (25 mm),full thickness specimens or multiple specimens maybe used, provided QB-151.2(c) and QB-151.2(d) arecomplied with.

(c) When multiple specimens are used in lieu of fullthickness specimens, each set shall represent a singletension test of the full pipe thickness. Collectively, allof the specimens required to represent the full thicknessof the brazed joint at one location shall comprise a set.

(d) When multiple specimens are necessary, the entirethickness shall be mechanically cut into a minimumnumber of approximately equal strips of a size thatcan be tested in the available equipment. Each specimenof the set shall be tested and meet the requirementsof QB-153.

QB-151.3 Full-Section Specimens for Pipe. Tensionspecimens conforming to the dimensions given in QB-462.1(e) may be used for testing pipe with an outsidediameter of 3 in. (76 mm) or less.

QB-152 Tension Test Procedure

The tension test specimen shall be ruptured undertensile load. The tensile strength shall be computed bydividing the ultimate total load by the least cross-sectional area of the specimen as measured before theload is applied.

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QB-153 2001 SECTION IX QB-162.1

QB-153 Acceptance Criteria — Tension Tests

QB-153.1 Tensile Strength. Minimum values forprocedure qualification are provided under the columnheading “Minimum Specified Tensile, ksi” of QW/QB-422. In order to pass the tension test, the specimenshall have a tensile strength that is not less than:

(a) the specified minimum tensile strength of thebase metal in the annealed condition; or

(b) the specified minimum tensile strength of theweaker of the two in the annealed condition, if basemetals of different specified minimum tensile strengthsare used; or

(c) if the specimen breaks in the base metal outsideof the braze, the test shall be accepted as meeting therequirements, provided the strength is not more than5% below the minimum specified tensile strength ofthe base metal in the annealed condition.

(d) the specified minimum tensile strength is for fullthickness specimens including cladding for AluminumAlclad materials (P-No. 104 and P-No. 105) 0.499 in.(12.5 mm) and less. For Aluminum Alclad materials0.5 in. (13 mm) and greater, the specified minimumtensile strength is for both full thickness specimensthat include cladding and specimens taken from the core.

QB-160 GUIDED-BEND TESTS

QB-161 Specimens

Guided-bend test specimens shall be prepared bycutting the test plate or pipe to form specimens ofapproximately rectangular cross section. The cut sur-faces shall be designated the sides of the specimen.The other two surfaces shall be designated the firstand second surfaces. The specimen thickness and bendradius are shown in QB-466.1, QB-466.2, and QB-466.3.Guided-bend specimens are of five types, depending onwhether the axis of the joint is transverse or parallelto the longitudinal axis of the specimen, and whichsurface (first or second) is on the convex (outer) sideof the bent specimen. The five types are defined asfollows.

QB-161.1 Transverse First Surface Bend. The jointis transverse to the longitudinal axis of the specimen,which is bent so that the first surface becomes theconvex surface of the bent specimen. In general, thefirst surface is defined as that surface from which thebrazing filler metal is applied and is fed by capillaryattraction into the joint. Transverse first surface bendspecimens shall conform to the dimensions shown in

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QB-462.2(a). For subsize first surface bends, see QB-161.3.

QB-161.2 Transverse Second Surface Bend. Thejoint is transverse to the longitudinal axis of the speci-men, which is bent so that the second surface becomesthe convex surface of the bent specimen. In general,the second surface is defined as the surface oppositeto that from which the brazing filler metal is placedor fed, but definitely is the surface opposite to thatdesignated as the first surface, irrespective of how thebrazing filler metal is fed. Transverse second surfacebend specimens shall conform to the dimensions shownin QB-462.2(a). For subsize first surface bends, seeQB-161.3.

QB-161.3 Subsize Transverse Bend. In those caseswhere the wall thickness of the tube or pipe is lessthan 3⁄8 in. (10 mm) and the diameter-to-thickness ratiodoes not permit the preparation of full-size rectangularguided-bend specimens, the 11⁄2 in. (38 mm) widestandard guided-bend specimen shown in QB-462.2(a)may be replaced by three subsize specimens having awidth of 3⁄8 in. (10 mm) or 4t, whichever is less.

QB-161.4 Longitudinal-Bend Tests. Longitudinal-bend tests may be used in lieu of the transverse-bendtests for testing braze metal or base metal combinations,which differ markedly in bending properties between

(a) the two base metals; or(b) the braze metal and the base metal.

QB-161.5 Longitudinal First Surface Bend. Thejoint is parallel to the longitudinal axis of the specimen,which is bent so that the first surface becomes theconvex surface of the bent specimen. The definitionof first surface is as given in QB-161.1. Longitudinal firstsurface bend specimens shall conform to the dimensionsgiven in QB-462.2(b).

QB-161.6 Longitudinal Second Surface Bend. Thejoint is parallel to the longitudinal axis of the specimen,which is bent so that the second surface becomes theconvex surface of the specimen. The definition of thesecond surface is given in QB-161.2. Longitudinalsecond surface bend specimens shall conform to thedimensions given in QB-462.2(b).

QB-162 Guided-Bend Test Procedure

QB-162.1 Jigs. Guided-bend specimens shall be bentin test jigs that are in substantial accordance with QB-466. When using the jigs in accordance with QB-466.1or QB-466.2, the side of the specimen turned towardthe gap of the jig shall be the first surface for first

QB-162.1 GENERAL REQUIREMENTS QB-182

surface bend specimens (defined in QB-161.1), and thesecond surface for second surface bend specimens(defined in QB-161.2). The specimen shall be forcedinto the die by applying load on the plunger until thecurvature of the specimen is such that a1⁄8 in. (3.2 mm)diameter wire cannot be inserted between the specimenand the die of QB-466.1, or the specimen is bottomejected, if the roller type of jig (QB-466.2) is used.

When using the wrap around jig (QB-466.3) the sideof the specimen turned toward the roller shall be thefirst surface for first surface bend specimens, and thesecond surface for second surface bend specimens.

QB-163 Acceptance Criteria — Bend Tests

The joint of a transverse-bend specimen shall becompletely within the bent portion of the specimenafter testing.

The guided-bend specimens shall have no open dis-continuities exceeding1⁄8 in. (3.2 mm), measured inany direction on the convex surface of the specimenafter bending. Cracks occurring on the corners of thespecimen during testing shall not be considered, unlessthere is definite evidence that they result from fluxinclusions, voids, or other internal discontinuities.

QB-170 PEEL TESTS

QB-171 Specimens

The dimensions and preparation of the peel testspecimen shall conform to the requirements of QB-462.3.

QB-172 Acceptance Criteria — Peel Test

In order to pass the peel test, the specimens shallshow evidence of brazing filler metal along each edgeof the joint. Specimens shall be separated or peeled

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either by clamping Section A and striking Section Bwith a suitable tool such that the bending occurs atthe fulcrum point (see QB-462.3), or by clampingSection A and Section B in a machine suitable forseparating the sections under tension. The separatedfaying surfaces of joints shall meet the following criteria.

(a) The total area of discontinuities (unbrazed areas,flux inclusions, etc.) shall not exceed 25% of the totalarea of any individual faying surface.

(b) The sum of the lengths of the discontinuitiesmeasured on any one line in the direction of the lapshall not exceed 25% of the lap.

(c) No discontinuity shall extend continuously fromone edge of the joint to the other edge, irrespectiveof its direction.

QB-180 SECTIONING TESTS ANDWORKMANSHIP COUPONS

QB-181 Sectioning Test Specimens

The dimensions and configuration of the sectioningtest specimens shall conform to the requirements ofQB-462.4. Each side of the specimen shall be polishedand examined with at least a four-power magnifyingglass. The sum of the length of unbrazed areas oneither side, considered individually, shall not exceed20% of the length of the joint overlap.

QB-182 Workmanship Coupons

The dimensions and configuration of the workmanshipcoupon shall conform to the nearest approximationof the actual application. Some typical workmanshipcoupons are shown in QB-462.5. Each side of thespecimen shall be polished and examined with at leasta four-power magnifying glass. The sum of the lengthof unbrazed areas on either side, considered individually,shall not exceed 20% of the length of the joint overlap.