ASME B16.25-2012 pdf – Buttwelding Ends.
1.5 Referenced Standards
Standards and specifications adopted by reference in this Standard arc shown in Mandatory Appendix II. It is not considered practical to identity the specific edition ci each standard and specification in the individual references. instead, the specific edition reference is identified In Mandatory Appendix II. A product made in conformance with a prior edition of referenced standards will be considered to be in conformance, even though the edition reference may be changed in a subsequent revision of the standard.
L6 Quality Systems
Nonmandatory requirements relating to the manufacturer’s quality system program are described in Nonmandatory Appendix A.
1.7 Convention
For determining conformance with this Standard, the convention for fixing significant digits where limits (maximum and minimum values) an- specified shall be as defined in ASTM E29. This requires that an observed or calculated value be rounded oil to the nearest unit in the last right-hand digit used for expressing the limit. Decimal values and tolerances do not imply a particular method of measurement.
2 TRANSITiON CONTOURS
Figure 1 delineates the maximum envelope in which transitions from welding bevel to the outer surface of the component and from the root face to the inner surface of the component must lie. Except as specified in Note (5) to Fig. l,and as otherwise specified by the purchaser. the exact contour within this envelope is the manufacturer’s option, provided it maintains the specified minimum
3 WELDING BEVEL DESIGN
3.1 Bevels for Other Than GTAW Root Pass
(a) Components having nominal wall thicknesses of 3 mm (0.12 in.) and less shall have ends cut square or slightly chamfered.
(b) Components having nominal wall thicknesses over 3 mm (0.12 in.) to 22 mm (OHS in.) inclusive shall have single angle bevels as Illustrated in Fig. 2.
(c) Components having nominal wall thicknesses greater than 22 mm (0,88 in.) shall have compound angle bevels as illustrated in Fig. 3.
3.2 Bevels for G1AW Root Pass
(a) Components having nominal wall thicknesses of 3 mm (0.12 in.) and less shall have ends cut square or slightly chamfered.
(b) Components having nominal wall thicknesses over 3 mm (0.12 in.) to II) mm (0.38 in.) inclusive shall have 37-deg ± 2’.deg bevels or slightly concave bevels ( Fig. 4).
(c) Components having nominal wall thicknesses over 10 mm (0.38 in.) to 25 mm (1.0 in.) inclusive shall have bevels as shown in Fig. 5.
(d) Components having nominal wall thicknesses greater than 25 mm (1.0 in.) shall have bevels as shown in Fig. 6.
3.3 Outside Diameter it Welding Ends
Dimension A shall be either that specilied in the applicable component standard or that specified in the purchaser’s component specification. In the absence of a requirement for dimension A in a component standard or a purchaser’s specification, the values for dimen. sion A in Table I or Table I-I may be used.
4 PREPARATION OF INSIDE DIAMETER OF WELDING END
4.1 General
Pn.paration ot the inside diameter at tne end ol a component shall be in accordance with one of the Following. as specified by the purchaser
(a) Components to be welded without backing rings shall meet the requirements of the standard or specificat on for the component.
(b) Components to be welded using split or noncontinuous backing rings shall be contoured with a cylindrical surface at the end as shown in Fig. 2, illustration (b) and Fig. 3, illustration (b). If the backing ring contour is other than rectangular, details must be hirnished by the purchaser.