Machinery's Handbook, 31st Edition
Welding Symbols 1619 Basic Weld Symbols: These designate the type of welding to be performed. The basic symbols which are shown in the table Basic Weld Symbols are placed approximately in the center of the reference line, either above or below it or on both sides of it as shown in Fig. 1. Welds on the arrow side of the joint are shown by placing the weld symbols on the side of the reference line towards the reader (lower side). Welds on the other side of the joint are shown by placing the weld symbols on the side of the reference line away from the reader (upper side). Supplementary Symbols: These convey additional information relative to the extent of the welding, where the welding is to be performed, and the contour of the weld bead. The “weld-all-around” and “field” symbols are placed at the end of the reference line at the base of the arrow as shown in Fig. 1 and the table Supplementary Weld Symbols . Dimensions: These include the size, length, spacing, etc., of the weld or welds. The size of the weld is given to the left of the basic weld symbol and the length to the right. If the length is followed by a dash and another number, this number indicates the center-to- center spacing of intermittent welds. Other pertinent information such as groove angles, included angle of countersink for plug welds and the designation of the number of spot or projection welds are also located above or below the weld symbol. The number designat ing the number of spot or projection welds is always enclosed in parentheses. Contour and Finish Symbols: The contour symbol is placed above or below the weld symbol. The finish symbol always appears above or below the contour symbol (see Fig. 1). The following finish symbols indicate the method, not the degrees of finish: C— chipping; G—grinding; M—machining; R—rolling; and H—hammering. For indication of surface finish refer to the section SURFACE TEXTURE starting on page 808. Tail: The tail which appears on the end of the reference line opposite to the arrow end is used when a specification, process, or other reference is made in the welding symbol. When no specification, process, or other reference is used with a welding symbol, the tail may be omitted. Melt-Thru Symbol: The melt-thru symbol is used only where 100 percent joint or mem ber penetration plus reinforcement are required. Table 1. Basic Weld Symbols Groove Symbols
V Bevel
U
J
Flare-V Flare-bevel
Square
Scarf
Other Weld Symbols
Spot or projection
Back or backing
a
Surfacing
Edge
Fillet
Plug
Slot
Stud
Seam
Ø
Ø
Ø designates a round hole for a plug. For examples of basic weld symbol applications, see Application of American National Standard Welding Symbols starting on page 1543. a a Ø designates a round hole for a plug. For examples of basic weld symbol applications see Application of American National Standard Welding Symbols starting on page 1622.
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