Spot Seam and Arc Weld Symbols

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Overview

The spot weld symbol, in accordance with its location in relation to the reference line, may or may not have arrow side or other side significance. Dimensions must be shown on the same side of the reference line as the symbol or on either side when the symbol is located astride the reference line and has no arrow side or other side significance. The process reference is indicated in the tail of the welding symbol. Then projection welding is to be used, the spot weld symbol shall be used with the projection welding process reference in the tail of the welding symbol. The spot weld symbol must be centered above or below the reference line.

Spot Weld Symbol

Seam Welding Symbol

Size of Arc Seam and Spot Welds

These welds may be dimensioned by either size or strength.

The size of arc spot welds must be designated as the diameter of the weld. Arc seam weld size shall be designated as the width of the weld.

Dimensions will be expressed in fractions or in decimals in hundredths of an inch and shall be shown, with or without inch marks, to the left of the weld symbol (A, fig. 3-38).

The strength of arc spot welds must be designated as the minimum accept-able shear strength in pounds or newtons per spot. In arc seam welds, strength is designated in pounds per linear inch. Strength is shown to the left of the weld symbol (B, fig. 3-38).

Arc Weld Symbols with Dimensions of Arc Spot and Arc Seam Welds

Spacing of Arc Spot and Arc Seam Welds

The pitch (center-to-center spacing) of arc spot welds and, when indicated, the length of arc seam welds, must be shown to the right of the weld symbol (C, fig. 3-38).

When spot welding or arc seam welding extends for the full distance between abrupt changes in the direction of welding, no length dimension needs to be shown on the welding symbol.

Extent and Number of Arc Spot Welds and Arc Seam Welds

When arc spot welding extends less than the distance between abrupt changes in the direction of welding or less than the full length of the joint, the extent must be dimensioned (fig. 3-39).

Symbol for Extent of Arc Spot Welding

When a definite number of arc spot welds is desired in a certain joint, the number must be shown in parentheses either above or below the related arc weld symbol (fig. 3-40).

Symbol for Number of Arc Spot Welds in a Joint

A group of spot welds may be located on a drawing by intersecting center lines. The arrows point to at least one of the center lines passing through each weld location.

Flush Arc Spot and Arc Seam Welded Joints

Flush Arc Spot and Arc Seam Welded Joints. When the exposed surface of one member of an arc spot or arc seam welded joint is to be flush, that surface must be indicated by adding the flush contour symbol (fig. 3-41) in the same manner as that for fillet welds.

Symbol for Surface Contour of Arc Spot and Arc Seam Welds

Details of Arc Seam Welds

Spacing, extent, orientation, and location of arc seam welds cannot be shown on the welding symbols. This data must be shown on the drawing.

About Jeff Grill

Jeff Grill hails from Long Island, a 118 mile stretch of land that starts just off the coast of Manhattan and stretches deep into the Atlantic ocean. He has always been interested in welding from an early age and has the cuts and bruises to prove it as he set out to work with a variety of metals.

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