TC 9-237 – Chapter 3 – Section II – part 4

3-29. RESISTANCE SPOT WELDS

a. General. Resistance spot weld symbols (fig. 3-3) have no arrow or other side significance in themselves, although supplementary symbols used in con-junction with them may have such significance. Resistance spot weld symbols shall be centered on the reference line. Dimensions may be shown on either side of the reference line.

b. Size of Resistance Spot Welds. Resistance spot welds are dimensioned by either size or strength as follows:

(1) The size of resistance spot welds is designated as the diameter of the weld expressed in fractions or in decimals in hundredths of an inch and must be shown, with or without inch marks, to the left of the weld symbol (fig. 3-60).

size of resistance spot welds

(2) The strength of resistance spot welds is designated as the minimum acceptable shear strength in pounds per spot and must be shown to the left of the weld symbol (fig. 3-61).

strength of resistance spot welds

c. Spacing of Resistance Spot Welds.

(1) The pitch of resistance spot welds shall be shown to the right of the weld symbol (fig. 3-62).

spacing of resistance spot welds

(2) When the symbols are shown directly on the drawing, the spacing is shown by using dimension lines.

(3) When resistance spot welding extends less than the distance between abrupt changes in the direction of the welding or less than the full length of the joint, the extent must be dimensioned (fig. 3-63).

extent of resistance spot welds

d. Number of Resistance Spot Welds. When a definite number of welds is desired in a certain joint, the number must be shown in parentheses either above or below the weld symbol (fig. 3-64).

number of resistance spot welds

e. Flush Resistance Spot Welding Joints. When the exposed surface of one member of a resistance spot welded joint is to be flush, that surface shall be indicated by adding the flush contour symbol (fig. 3-3) to the weld symbol, (fig. 3-65) in accordance with location specifications given in paragraph 3-7.

contour of resistance spot welds

3-30. RESISTANCE SEAM WELDS

a. General.

(1) Resistance seam weld symbols have no arrow or other side significance in themselves, although supplementary symbols used in injunction with them may have such significance. Resistance seam weld symbols must be centered on the reference line.

(2) Dimensions of resistance seam welds may be shown on either side of the reference line.

b. Size of Resistance Seam Welds. Resistance seam welds must be dimensioned by either size or strength as follows:

(1) The size of resistance seam welds must be designated as the width of the weld 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 (fig. 3-66).

size of resistance seam welds

(2) The strength of resistance seam welds must be designated as the minimum acceptable shear strength in pounds per linear inch and must be shown to the left of the weld symbol (fig. 3-67).

strength of resistance seam welds

c. Length of Resistance Seam Welds.

(1) The length of a resistance seam weld, when indicated on the welding symbol, must be shown to the right of the welding symbol (fig. 3-68).

length of resistance seam welds

(2) When resistance seam welding extends for the full distance between abrupt changes in the direction of the welding, no length dimension need be shown on the welding symbol.

(3) When resistance seam welding extends less than the distance between abrupt changes in the direction of the welding or less than the full length of the joint, the extent must be dimensioned (fig. 3-69).

extent of resistance seam welds

d. Pitch of Resistance Seam Welds. The pitch of intermittent resistance seam welding shall be designated as the distance between centers of the weld increments and must be shown to the right of the length dimension (fig. 3-70).

dimensioning of intermittent resistance seam welds

e. Termination of Intermittent Resistance Seam Welding. When intermittent resistance seam welding is used by itself, the symbol indicates that increments are located at the ends of the dimensioned length. When used between continuous resistance seam welding, the symbol indicates that spaces equal to the pitch minus the length of one increment are left at the ends of the dimensional length. Separate symbols must be used for intermittent and continuous resistance seam welding when the two are combined.

f. Flush Projection Welded Joints. When the exposed surface of one member of a projection welded joint is to be made flush, that surface shall be indicated by adding the flush contour symbol (fig. 3-3) to the weld symbol, observing the usual location significance (fig. 3-79).

contour of projection welds

3-31. PROJECTION WELDS

a. General.

(1) When using projection welding, the spot weld symbol must be used with the projection welding process reference in the tail of the welding symbol. The spot weld symbol must be centered on the reference line.

(2) Embossments on the arrow side member of a joint for projection welding shall be indicated by placing the weld symbol on the side of the reference line toward the reader (fig. 3-72).

embossment on arrow side member of joint for projection welding

(3) Embossment on the other side member of a joint for projection welding shall be indicated by placing the weld symbol on the -side of the reference line away from the reader (fig. 3-73).

embossment on other side member of joint for projection welding

(4) Proportions of projections must be shown by a detail or other suitable means.

(5) Dimensions of projection welds must be shown on the same side of the reference line as the weld symbol.

b. Size of Projection Welds.

(1) Projection welds must be dimensioned by strength. Circular projection welds may be dimensioned by size.

(2) The size of circular projection welds shall be designated as the diameter of the weld 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 (fig. 3-74).

diameter of projection welds

(3) The strength of projection welds shall be designated as the minimum acceptable shear strength in pounds per weld and shall be shown to the left of the weld symbol (fig. 3-75).

strength of projection welds

c. Spacing of Projection Welds. The pitch of projection welds shall be shown to the right of the weld symbol (fig. 3-76).

spacing of projection welds

d. Number of Projection Welds. When a definite number of projection welds is desired in a certain joint, the number shall be shown in parentheses (F, fig. 3-77).

number of projection welds

e. Extent of Projection Welding. When the projection welding extends less than the distance between abrupt changes in the direction of the welding or less than the full length of the joint, the extent shall be dimensioned (fig. 3-78).

extent of projection welds

f. Flush Resistance Seam Welded Joints. When the exposed surface of one member of a resistance seam welded joint is to be flush, that surface shall be indicated by adding the flush contour symbol (fig. 3-3) to the weld symbol, observing the usual location significance (fig. 3-71).

contour of resistance seam welds

3-32. FLASH OR UPSET WELDS

a. General. Flash or upset weld symbols have no arrow side or other side significance in themselves, although supplementary symbols used in conjunction with then may have such significance. The weld symbols for flash or upset welding must be centered on the reference line. Dimensions need not be shown on the welding symbol.

b. Surface Contour of Flash or Upset Welds. The contour symbols (fig. 3-3) for flash or upset welds (fig. 3-80) are indicated in the same manner as that for fillet welds (paragraph 3-21).

surface contour of flash or upset welds
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