Chapter 3 Welding Joints, Positions, and Symbols 67 Projection welding is another process used to produce spot welds. To indicate which piece has the projections on it, the circle is placed above or below the reference line. The following information is given for a spot weld: size, strength, spacing, and the number of spot welds. The weld size is given to the left of the spot weld symbol. If the weld strength is specifi ed in the welding symbol, it is also shown to the left of the spot weld symbol and given in pounds or newtons per spot. The weld spacing is found to the right of the spot weld symbol. The number of welds desired is shown in parentheses, centered above or below the spot weld symbol, Figure 3-41. The welding process to be used is shown in the tail of the welding symbol. See Figure 3-41 for examples of the welding symbols used for spot welding. The welding symbol may be placed in any view of a drawing. 3.5.13 Seam Welds A seam weld is another method of joining two or more pieces together. Parts are assembled in either a lap joint or a butt joint. No hole or slot is cut into any of the parts. The weld can be made by resistance seam welding. The weld can also be made from one side by melting through the fi rst piece and melting into the second piece. The weld symbol may straddle the reference line if the joint is welded from both sides, as in resistance seam welding. For other processes used for seam welding, the symbol can be placed above or below the reference line. This indicates from which side of the part the weld is to be made. See Figure 3-42. The process to be used is shown in the tail. The size (width) of the weld and strength of the weld are shown to the left of the weld symbol. The strength is given in pounds per linear inch or in newtons per millimeter. The length of the seam may be shown to the right of the weld symbol. 3.6 Review of Welding Symbols Figure 3-43 shows examples of various welds and positions of welding. The ability to visualize the resulting weldment after reading the welding symbol is a very important skill for the welder to master. If you are not sure of the information given on the welding symbol or the location of needed information on the symbol, go back over this chapter. Reviewing this chapter periodically as you move through the material covered in this book will help build your print-reading confi dence. You may also wish to refer to ANSI/AWS A2.4, Standard Symbols for Welding, Brazing, and Nondestructive Examination. Figure 3-41. Welding symbols for multiple spot welds. A—The desired spacing of a series of electron beam spot welds is shown. B—The working drawing and welding symbol for the electron beam spot welds. C—Appearance of fi nished welds. D—Three .25″ diameter resistance spot welds at 1″ spacing are shown on the welding symbol on the working drawing. .25″ .62″ .62″ .62″ .62″ .1″ .25″ EWB .62 (5) .1 .5″ RSW .25 (3) 1 A C B D .5″ .5″ 1.0″ 1.0″ .25″