Spot Seam and Arc Weld Symbols
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.
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 need 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.
For Additional Reading on Arc Weld Symbols
Page Author: Jeff Grill