ASME B16.25 pdf free download

ASME B16.25-2012 pdf free download.Buttwelding Ends.
1.5 Referenced Standards
Standards and specifications adopted by reference in this Standard are shown in Mandatory Appendix II. It is not considered practical to identify the specific edition of 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.
1.6 Quality Systems
Nonmandatory requirements relating to the manufacturer ‘s quality system program are described in Nonmandatorv Appendix A.
1.7 Convention
For determining conformance with this Standard, the convention for fixing significant digits where limits (maximum and minimum values) are specified shall be as defined in ASTM E29. This requires that an observed or calculated value be rounded off 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. 1. and as otherwise specified by the purchaser. the exact contour within this envelope is the manufacturer’s option, provided it maintains the specified minimum wall thickness, has no slopes steeper than those indicated for the respective regions, and includes the proper surface for backing rings if specified.
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.
(I’) Components having nominal wall thicknesses over 3 mm (0.12 in.) to 22 mm (0.88 in.) inclusive shall have single angle bevels as illustrated in Fig. 2.
(d Components having nominal wall thicknesses greater than 22mm (0.88 in.) shall have compound angle bevels as illustrated in Fig. 3.
3.2 Bevels for 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 10 mm (0.38 in.) inclusive shall have 371’z-deg ± 2’4deg bevels or slightly concave bevels (see 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 at Welding Ends
Dimension A shall be either that specified 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 dimension A in Table I or Table 1-I may be used.
4 PREPARATION OF INSIDE DIAMETER OF WELDING END
4.1 General
Preparation of the inside diameter at the end of 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 specification 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 furnished by the purchaser.ASME B16.25 pdf download.