ASME B 31.1 Acceptance Criteria PDF [PDF]

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HI-TECH INSPECTION SERVICES LLC – OMAN P.O.Box 1809, Ruwi, P.C. : 112, Sultanate of Oman Tel.: +968 24501134/24501189/24591212 Fax: +968 24501132 Email : [email protected], Website : www.hitechoman.net



ACCEPTANCE CRITERIA AS PER ASME B 31.1



PREPARED BY



APPROVED BY



NAME



Mr. Vinayak R. Jadhav



Mr. Indrajit Gupta



DATE



01.08.2014



01.08.2014



SIGNATURE



SEAL



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ACCEPTANCE CRITERIA AS PER ASME B 31.1 Acceptance criteria B 31.1 (Edition 2012) Magnetic Particle Testing as per Para. 136.4.3 Evaluation of indications: 1. Mechanical discontinuities at the surface will be indicated by the retention of the examination medium. All indications are not necessarily defects; however, certain metallurgical discontinuities and magnetic permeability variations may produce similar indications which are not relevant to the detection of unacceptable discontinuities. 2. Any indication which is believed to be nonrelevant shall be reexamined to verify whether or not actual defects are present. Surface conditioning may precede the reexamination. Nonrelevant indications which would mask indications of defects are unacceptable. 3. Relevant indications are those which result from unacceptable mechanical discontinuities. Linear indications are those indications in which the length is more than three times the width. Rounded indications are indications which are circular or elliptical with the length less than three times the width. 4. An indication of a discontinuity may be larger than the discontinuity that causes it; however, the size of the indication and not the size of the discontinuity is the basis of acceptance or rejection. Acceptance standard: Indications whose major dimensions are greater than 1⁄16 in. (2.0 mm) shall be considered relevant. The following relevant indications are unacceptable:



1. Any cracks or linear indications 2. Rounded indications with dimensions greater than 3⁄16 in. (5.0 mm) 3. Four or more rounded indications in a line separated by 1⁄16 in. (2.0 mm) or less,



edge to edge 4. Ten or more rounded indications in any 6 in. square (3870 mm2) of surface with the major dimension of this area not to exceed 6 in. (150 mm) with the area taken in the most unfavorable location relative to the indications being evaluated



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ACCEPTANCE CRITERIA AS PER ASME B 31.1 Acceptance criteria B 31.1 (Edition 2012) Liquid Penetrant Testing as per Para. 136.4.4 Evaluation of indications:



1. Mechanical discontinuities at the surface will be indicated by bleeding out of the



penetrant; however, localized surface imperfections, such as may occur from machining marks or surface conditions, may produce similar indications which are nonrelevant to the detection of unacceptable discontinuities.



2. Any indication that is believed to be nonrelevant shall be regarded as a defect and shall be reexamined to verify whether or not actual defects are present. Surface conditioning may precede the reexamination. Nonrelevant indications and broad areas of pigmentation which would mask indications of defects are unacceptable.



3. Relevant indications are those which result from mechanical discontinuities. Linear indications are those indications in which the length is more than three times the width. Rounded indications are indications which are circular or elliptical with the length less than three times the width.



4. An indication of a discontinuity may be larger than the discontinuity that causes it;



however, the size of the indication and not the size of the discontinuity is the basis of acceptance or rejection.



Acceptance standard: Indications whose major dimensions are greater than 1⁄16 in. (2.0 mm) shall be considered relevant. The following relevant indications are unacceptable:



1. Any cracks or linear indications 2. Rounded indications with dimensions greater than 3⁄16 in. (5.0 mm) 3. Four or more rounded indications in a line separated by 1⁄16 in. (2.0 mm) or less, edge to edge



4. Ten or more rounded indications in any 6 in. square (3870 mm2) of surface with the



major dimension of this area not to exceed 6 in. (150 mm) with the area taken in the most unfavorable location relative to the indications being evaluated



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ACCEPTANCE CRITERIA AS PER ASME B 31.1 Acceptance criteria B 31.1 (Edition 2012) Radiographic Testing as per Para. 136.4.5 When required by this Chapter (see Table 136.4), radiographic examination shall be performed in accordance with Article 2 of Section V of the ASME Boiler and Pressure Vessel Code, except that the requirements of T-285 are to be used as a guide but not for the rejection of radiographs unless the geometrical unsharpness exceeds 0.07 in. (2.0 mm). Acceptance Standards: Welds that are shown by radiography to have any of the following types of discontinuities are unacceptable:



1. Any type of crack or zone of incomplete fusion or penetration 2. a. b. c.



any other elongated indication which has a length greater than 1⁄4 in. (6.0 mm) for t up to 3⁄4 in. (19.0 mm),inclusive 1⁄3t for t from 3⁄4 in. (19.0 mm) to 21⁄4 in. 3⁄4 in. (19.0 mm) for t over 21⁄4 in. (57.0 mm) Where t is the thickness of the thinner portion of the weld



NOTE:



t referred to in (A.2.1), (A.2.2), and (A.2.3) above pertains to the thickness of the weld being examined; if a weld joins two members having different thickness at the weld, t is the thinner of these two thickness.



3. Any group of indications in line that have an aggregate length greater than t in a length of 12t, except where the distance between the successive indications exceeds 6L where L is the longest indication in the group 4. Porosity in excess of that shown as acceptable in Appendix A-250 of Section I of the ASME Boiler and Pressure Vessel Code



5. Root concavity when there is an abrupt change in density, as indicated on the radiograph



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ACCEPTANCE CRITERIA AS PER ASME B 31.1 APPENDIX A-250 ASME SEC I ROUNDED INDICATION CHARTS A-250 ACCEPTANCE STANDARD FOR RADIOGRAPHICALLY DETERMINED ROUNDED INDICATIONS IN WELDS A-250.1 Applicability of These Standards. These standards are applicable to ferritic, austenitic, and nonferrous materials. A-250.2 Terminology A-250.2.1 Rounded Indications. Indications with a maximum length of three times the width or less on the radiograph are defined as rounded indications. These indications may be circular, elliptical, conical, or irregular in shape and may have tails. When evaluating the size of an indication, the tail shall be included. The indication may be from any imperfection in the weld, such as porosity, slag, or tungsten. A-250.2.2 Aligned Indications. A sequence of four or more rounded indications shall be considered to be aligned when they touch a line parallel to the length of the weld drawn through the center of the two outer rounded indications. A-250.2.3 Thickness t. t is the thickness of the weld, of the pressure–retaining material, or of the thinner of the sections being joined, whichever is least. If a full penetration weld includes a fillet weld, the thickness of the fillet weld throat shall be included in t. A-250.3 Acceptance Criteria A-250.3.1 Image Density. Density within the image of the indication may vary and is not a criterion for acceptance or rejection. A-250.3.2 Relevant Indications (See Table A-250.3.2 for Examples). Only those rounded indications which exceed the following dimensions shall be considered relevant: (a) 1⁄10 t for t less than 1⁄8 in. (3 mm) (b) 1⁄64 in. (0.4 mm) for t 1⁄8 in. to 1⁄4 in. (6 mm), inclusive (c) 1⁄32 in. (0.8 mm) for t 1⁄4 in. (6 mm) to 2 in. (50 mm),inclusive (d) 1⁄16 in. (1.6 mm) for t greater than 2 in. (50 mm)



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ACCEPTANCE CRITERIA AS PER ASME B 31.1 A-250.3.3 Maximum Size of Rounded Indication (See Table A-250.3.2 for Examples). The maximum permissible size of any indication shall be 1⁄4t, or 5⁄32 in. (4 mm), whichever is smaller; except that an isolated indication separated from an adjacent indication by 1 in. (25 mm) or more may be 1⁄3t, or 1⁄4 in. (6 mm), whichever is less. For t greater than 2 in. (50 mm) the maximum permissible size of an isolated indication shall beincreased to 3⁄8 in. (10 mm).



A-250.3.4 Aligned Rounded Indications. Aligned rounded indications are acceptable when the summation of the diameters of the indications is less than t in a length of 12t (see Fig. A-250.3.4-1). The length of groups of aligned rounded indications and the spacing between the groups shall meet the requirements of Fig. A-250-3.4-2. A-250.3.5 Spacing. The distance between adjacent rounded indications is not a factor in determining acceptance or rejection, except as required for isolated indications or groups of aligned indications.



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ACCEPTANCE CRITERIA AS PER ASME B 31.1 TABLE A-250.3.2 MAXIMUM PERMISSIBLE SIZE OFROUNDED INDICATION (Examples Only)



A-250.3.6 Rounded Indication Charts. The rounded indications characterized as imperfections shall not exceed that shown in the charts.The charts in Figs. A-250.3.6-1 through A-250.3.6-6 illustrate various types of assorted, randomly dispersed, and clustered rounded indications for different weld thicknesses greater than 1⁄8 in. (3 mm). These charts represent the maximum acceptable concentration limits for roundedindications. The chart for each thickness range represents full-scale 6 in. (150 mm) radiographs, and shall not be enlarged or reduced. The distributions shown are not necessarily thepatterns that may appear on the radiograph, but are typical of the concentration and size of indications permitted.



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ACCEPTANCE CRITERIA AS PER ASME B 31.1



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ACCEPTANCE CRITERIA AS PER ASME B 31.1 A-250.3.7 Weld Thickness t Less Than 1⁄8 in. (3 mm). For t less than 1⁄8 in. (3 mm), the maximum number of rounded indications shall not exceed 12 in a 6 in. (150 mm) length of weld. A proportionally fewernumber of indications shall be permitted in welds less than 6 in. (150 mm) in length. A-250.3.8 Clustered Indications. The illustrations for clustered indications show up to four times as many indications in a local area, as that shown in the illustrations for random indications. The length of an acceptable cluster shall not exceed the lesser of 1 in. (25 mm) or 2t. Where more than one cluster is present, the sum of the lengths of the clusters shall not exceed 1 in. (25 mm) in a 6 in. (150 mm) length of weld.



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ACCEPTANCE CRITERIA AS PER ASME B 31.1



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ACCEPTANCE CRITERIA AS PER ASME B 31.1



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ACCEPTANCE CRITERIA AS PER ASME B 31.1



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ACCEPTANCE CRITERIA AS PER ASME B 31.1 Acceptance criteria B 31.1 (Edition 2012) Ultrasonic Testing as per Para. 136.4.6 Acceptance Standards: Welds that are shown by ultrasonic examination to have discontinuities that produce an indication greater than 20% of the reference level shall be investigated to the extent that ultrasonic examination personnel can determine their shape, identity, and location so that they may evaluate each discontinuity for acceptance in accordance with (1) and (2) below.



1. Discontinuities evaluated as being cracks, lack of fusion, or incomplete penetration is unacceptable regardless of length.



2. Other discontinuities are unacceptable if the indication exceeds the reference level and their length exceeds the following:



a. 1⁄4 in. (6.0 mm) for t up to 3⁄4 in. (19.0 mm). b. 1⁄3t for t from 3⁄4 in. (19.0 mm) to 21⁄4 in. (57.0 mm). c. 3⁄4 in. (19.0 mm) for t over 21⁄4 in. (57.0 mm) Where t is the thickness of the weld being examined. If the weld joins two members having different thicknesses at the weld, t is the thinner of these two thicknesses.



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