This document provides guidelines for welding bevel design on pipe components with different wall thicknesses. It discusses the appropriate bevel types and dimensions for various thickness ranges. Guidelines are provided for both gas tungsten arc welding (GTAW) and other welding processes. The document also addresses outside diameter and inside diameter preparation, including equations to determine the inside diameter dimension based on outside diameter, wall thickness, and tolerances. Tables with predetermined inside diameter dimensions are referenced for certain pipe size ranges.
This document provides guidelines for welding bevel design on pipe components with different wall thicknesses. It discusses the appropriate bevel types and dimensions for various thickness ranges. Guidelines are provided for both gas tungsten arc welding (GTAW) and other welding processes. The document also addresses outside diameter and inside diameter preparation, including equations to determine the inside diameter dimension based on outside diameter, wall thickness, and tolerances. Tables with predetermined inside diameter dimensions are referenced for certain pipe size ranges.
This document provides guidelines for welding bevel design on pipe components with different wall thicknesses. It discusses the appropriate bevel types and dimensions for various thickness ranges. Guidelines are provided for both gas tungsten arc welding (GTAW) and other welding processes. The document also addresses outside diameter and inside diameter preparation, including equations to determine the inside diameter dimension based on outside diameter, wall thickness, and tolerances. Tables with predetermined inside diameter dimensions are referenced for certain pipe size ranges.
This document provides guidelines for welding bevel design on pipe components with different wall thicknesses. It discusses the appropriate bevel types and dimensions for various thickness ranges. Guidelines are provided for both gas tungsten arc welding (GTAW) and other welding processes. The document also addresses outside diameter and inside diameter preparation, including equations to determine the inside diameter dimension based on outside diameter, wall thickness, and tolerances. Tables with predetermined inside diameter dimensions are referenced for certain pipe size ranges.
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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 (0.88 in.) inclusive shall have single angle bevels as illustrated in Figure 2. (c) Components having nominal wall thicknesses greater than 22 mm (0.88 in.) shall have compound angle bevels as illustrated in Figure 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∕2-deg ± 21∕2-deg bevels or slightly concave bevels (see Figure 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 Figure 5. (d) Components having nominal wall thicknesses greater than 25 mm (1.0 in.) shall have bevels as shown in Figure 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 1 or Table I-1 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 Figure 2, illustration (b) and Figure 3, illustration (b). If the backing ring contour is other than rectangular, details must be furnished by the purchaser. (c) Components to be welded using solid or continuous backing rings shall be contoured with a cylindrical or tapered surface at the end as specified by the purchaser. End preparation is illustrated in Figure 2, illustration (c) and Figure 3, illustration (c) for rectangular ends and in Figure 2, illustration (d) and Figure 3, illustration (d) for tapered ends. (d) Components to be welded using consumable insert rings or GTAW root pass shall be contoured with a cylindrical surface at the end as shown in Figures 4 through 6. 4.2 Dimension C ð17Þ Values for dimension C shown in Figure 2, illustrations (c) and (d); Figure 3, illustrations (c) and (d); and Figures 5 and 6 can be determined by the following equations: (SI Units) C = A O.D. tolerance 2 × tmin 0.25 (1) (U.S. Customary Units) C = A O.D. tolerance 2 × tmin 0.010 (2) where A = specified outside pipe diameter at welding end (see para. 3.3) O.D. tolerance = undertolerance on the pipe O.D. from the applicable piping specification tmin = t − manufacturing tolerance for pipe wall thickness per applicable pipe specification, mm (in.) t = nominal wall thickness of pipe, mm (in.) 0.25 (0.010) = plus machining tolerance on bore C, mm (in.) Based on tolerances specific to ASTM A106 [50 ≤ DN ≤ 1 200 (2 ≤ NPS ≤ 48)] and A335 [50 ≤ DN ≤ 300 (2 ≤ NPS ≤ 12)] pipe, including an undertolerance on wall thickness of 12.5%, eqs. (1) and (2) can be defined as follows: (SI Units) C = A 0.79 2 × 0.875t 0.25 (U.S. Customary Units) C = A 0.031 2 × 0.875t 0.010 Tables 1 and I-1 list the C values for pipe with an undertolerance on A of 0.79 mm (0.031 in.) and 12.5% on wall thickness for DN 50 to DN 1500 (NPS 2 to NPS 60) pipe. An undertolerance on A of 0.4 mm (0.015 in.) and wall thickness of 12.5% was used for DN 40 (NPS 11/2) and smaller pipe. For pipe with an A or pipe wall thickness undertolerance other than the above, do not use the C data from Tables 1 and I-1 [see para. 4.3(a)].