Groove Welds Unit 16 - Goodheart-Willcox

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This sample chapter is for review purposes only. Copyright © The Goodheart-Willcox Co., Inc. All rights reserved. single-groove or a symmetrical double-groove weld. Figure 16-5 illustrates complete weld penetration for a double-groove joint. A dimension not in parentheses on the left of a bevel-, V-, J-, or U-groove weld symbol (in cases where the effective throat is not specified, or is specified elsewhere on the print) indicates the size of the weld preparation only, Figure 16-6. No such dimension is needed with a square-groove weld. Optional groove preparation with complete penetration is indicated when the letters CJP are shown in the tail of the reference line. No weld symbol is used, as in Figure 16-7. The weld size of a flare-groove weld is considered only to the tangent point (the point where the curved surfaces meet), Figure 16-8. 30° 7 7 8 8 30° Joint preparation Symbol Figure 16-6. Weld preparation only is indicated if no dimension is in parentheses to the left of the bevel-, V-, J-, or U-groove weld symbol. Desired weld Symbol CJP Figure 16-7. The letters CJP in the tail of the reference line indicate optional groove preparation with complete weld penetration. General Use of Groove Weld Symbol Different conventions are used for groove welding symbols depending on the dimensions that are specified and the information required. As previously discussed, dimensions for the preparation of groove welds are shown on the same side of the reference line as the weld symbol. See Figure 16-9. This example shows a J-groove weld. The information specified includes the depth of preparation, groove angle, and root opening. 0 3 4 30° Depth of preparation Unit 16 Groove Welds 199 Figure 16-8. Flare-groove weld size extends only to the tangent points of the joint members. Root opening 3 0 4 30° Desired preparation Symbol Groove angle 3 0 4 30° Figure 16-9. Specifications for the preparation of an arrow side J-groove weld. Double-groove welds are dimensioned on both sides of the reference line if no general note appears on the print, Figure 16-10. If the welds differ in size, they are dimensioned as in Figure 16-11. Groove welding symbols will not include dimensions when a general note determining groove weld size appears on 2 2 30° R R 30° 0 E R = User's standard Figure 16-10. Unless there is a general note on the print, double-groove welds are dimensioned on both sides of the reference line. S S(E) S = Depth extends from point of tangency to top of member E = Effective throat Desired weld Symbol 2 2 30° 0 0 30° Desired weld Symbol 200 Welding Print Reading the print, Figure 16-12. When a break in the arrow is used with bevel- and J-groove welds, the arrow points toward the member to be beveled, Figure 16-13. 60° 60° 3 4 7 8 Weld specified 3 1 90° 8( 2) 3 4( ) 60° 7 8 3 1 8 2 90° Desired weld Symbol Figure 16-11. Groove welds differing in size are dimensioned in the manner shown. NOTE- ALL V-GROOVE WELDS SHALL HAVE A 60° GROOVE ANGLE UNLESS OTHERWISE NOTED. Note and symbol Figure 16-12. If a general note indicating weld size is on the print, no groove weld dimensions are given with the welding symbol. Groove Dimensions Many companies have established their own standards for groove weld dimensions. These standards are observed unless otherwise noted on the print. When company standards for groove welds are not indicated, the following applies: ❍ The root opening is indicated inside the weld symbol, Figure 16-14. ❍ The groove angle or bevel angle is specified, Figure 16-15. ❍ The groove radii (used to form the shape of J- or U-groove welds) and root faces (the parts of the groove face within the joint root) are shown by cross section, detail, or other means with a reference on the welding symbol, Figure 16-16. Figure 16-13. A break in an arrow always points toward the member of the single-bevel-groove or J-groove joint to be beveled. 1 8 Figure 16-14. The root opening of a groove weld is specified inside the weld symbol when standards are not otherwise indicated. 1 8 Desired weld Symbol 15° 50° 60° 90° 45° 45° Other side bevel-groove weld symbol Desired weld Symbol Figure 16-15. Study how groove angles of groove welds are specified. 50° 15° Desired welds Symbols 45° 45° 90° 60°
This sample chapter is for review purposes only. Copyright © The Goodheart-Willcox Co., Inc. All rights reserved. 1 TO 3 16 16 ANGLE X 45° MIN 20° MIN 12° MIN X R 1 4 MIN 3 16 MAX. POSITION ALL F, V, O F DETAIL E (EXCEPT FROM DWG B2345, "GROOVE WELD STANDARDS") Figure 16-16. Groove radii and root faces of U- and J-groove welds are shown by cross section, detail, or other means with a welding symbol reference. Surface Finish and Contour of Groove Welds The buildup of the groove weld above the surface of the base material is called reinforcement. Sometimes the welding symbol specifies that the reinforcement be minimized or removed. Groove welds to be made approximately flush (but not generally finished flush mechanically) are specified by a flush contour symbol. This symbol is placed above the weld symbol, as in Figure 16-17. Groove welds to be Weld deposited flush with base metal SEE DWG B2345 DETAIL E Symbol Desired weld Symbol Figure 16-17. A flush contour symbol is placed above the weld symbol when the groove weld is to be made approximately flush and without the use of grinding, chipping, hammering, or machining. made flush by mechanical means are specified with a flush contour symbol and the method of making the weld flush, Figure 16-18. Groove welds to be finished mechanically with a convex contour are specified by a convex contour symbol. The method of finishing the weld to a convex contour is also given, Figure 16-19. Weld made flush with base metal by grinding Desired weld Symbol Figure 16-18. Groove welds to be made flush mechanically are specified by a flush contour symbol and by the method to use to make the weld flush. Finished to smooth convex contour by machining Unit 16 Groove Welds 201 Desired weld Symbol Figure 16-19. When groove welds are to be finished mechanically to a flush contour, they are specified by a convex contour symbol and the method of finishing. Melt-Through, Back, and Backing Welds The melt-through, back, and backing weld symbols show that a melt-through to the other side, bead-type back, or backing weld is needed with a single-groove weld. Points to remember include: ❍ A back weld is made after the groove weld. ❍ A backing weld is made before the groove weld. ❍ A melt-through is a visible reinforcement produced in a groove weld from one side. A note states whether a back or backing weld is to be made. This note is placed in the tail of the welding symbol, Figure 16-20. As shown, a back or backing weld symbol is located on the side of the reference line that is opposite the groove weld symbol. A flush contour symbol, added to the back or backing weld symbol, indicates the weld should be approximately flush with the base metal, Figure 16-21. If the back or backing weld is to be made flush by mechanical means, the method of making the weld flush is added to the flush contour symbol, Figure 16-22. When a back or backing weld is to be finished to a convex contour by mechanical means, a convex contour symbol and finish symbol are added to the weld symbol. G M M 202 Welding Print Reading NOTE- 1. GROOVE WELD MADE BEFORE WELDING OTHER SIDE. 2. (ABOVE FOUND ELSEWHERE ON PRINT) Back weld Desired welds Backing weld machined flush with base metal Weld deposited flush with base metal Symbol Desired welds Symbol Desired welds Symbol Figure 16-22. A symbol added above the flush contour symbol identifies the mechanical method used to finish the weld flush. With the exception of height, which is optional, no other back or backing weld dimensions are shown with the weld symbol, Figure 16-23. If other dimensions are required, they are shown on the drawing. A melt-through weld assures full joint penetration. The melt-through weld symbol is similar to the back or backing weld symbol with the bead filled in as shown in Figure 16-24. A dimension to the left of the symbol specifies the amount of melt-through. M NOTE 1 Figure 16-20. Specifications for a back weld. A note in the tail of the reference line indicates whether to make a back or backing weld. NOTE 1 Figure 16-21. A flush contour symbol indicates the weld is to be finished approximately flush with the base metal. NOTE 2 1 16 1 16 Desired weld Symbol Figure 16-23. Only the back or backing weld height dimension is shown on the welding symbol. If other dimensions are needed, they are given elsewhere on the print. 1 8 Desired weld Symbol Figure 16-24. The melt-through weld symbol resembles the back or backing weld symbol, but the bead is filled in. The height of root reinforcement may appear as a dimension specified to the left of the melt-through symbol. (American Welding Society) Backing, Joint Spacers, and Runoff Weld Tabs Backing is material placed against the back side of a joint to withstand molten weld metal, Figure 16-25. It is employed when full penetration groove welds are required and welding can only be done from one side. Backing is thoroughly penetrated by the weld and usually left in place. Backing Desired weld Symbol Figure 16-25. Backing used in a joint. A specification indicating its use is shown in the tail of the reference line. 1 8 B-3
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Groove Welds Unit 16 - Goodheart-Willcox

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