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

3-22. PLUG AND SLOT WELDING SYMBOLS

a. General. Neither the plug weld symbol nor the slot weld symbol may be used to designate fillet welds in holes.

b. Arrow Side and Other Side Indication of Plug and Slot Welds. Holes or slots in the arrow side member of a joint for plug or slot welding must be indicated by placing the weld symbol on the side of the reference line toward the reader (A, fig. 3-11). Holes or slots in the other side member of a joint shall be indicated by placing the weld symbol on the side of the reference line away from the reader (B, fig. 3-11).

c. Plug Weld Dimensions. Dimensions of plug welds must be shown on the same side of the reference line as the weld symbol. The size of a weld must be shown to the left of the weld symbol. Included angle of countersink of plug welds must be the user’s standard unless otherwise indicated. Included angle of countersink, when not the user’s standard, must be shown either above or below the weld symbol (A and C, fig. 3-34). The pitch (center-to-center spacing) of plug welds shall be shown to the right of the weld symbol.

plug and slot welding symbols indication location and dimensions of the weld

d. Depth of Filling of Plug and Slot Welds. Depth of filling of plug and slot welds shall be completed unless otherwise indicated. When the depth of filling is less than complete, the depth of filling shall be shown in inches inside the weld symbol (B, fig. 3-34).

e. Surface Contour of Plug Welds and Slot Welds. Plug welds that are to be welded approximately flush without recourse to any method of finishing must be shown by adding the finish contour symbol to the weld symbol (fig. 3-35). Plug welds that are to be welded flush by mechanical means must be shown by adding both the flush contour symbol and the user’s standard finish symbol to the weld symbol (fig. 3-36).

surface contour of slot welds and plug welds
surface contour of slot welds and plug welds with user's standard finish symbol

f. Slot Weld Dimensions. Dimensions of slot welds must be shown on the same side of the reference line as the weld symbol (fig. 3-37).

slot weld dimensions

g. Details of Slot Welds. Length, width, spacing, included angle of countersink, orientation, and location of slot welds cannot be shown on the welding symbols. This data must be shown on the drawing or by a detail with a reference to it on the welding symbol, in accordance with location specifications given in paragraph 3-7 (D, fig. 3-33).

3-23. ARC SPOT AND ARC SEAM WELDS

a. General. 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.

b. Size of Arc Spot and Arc Seam Welds.

(1) These welds may be dimensioned by either size or strength.

(2) 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).

dimensions of arc spot and arc seam welds

(3) 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).

c. Spacing of Arc Spot and Arc Seam Welds.

(1) 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).

(2) 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.

d. Extent and Number of Arc Spot Welds and Arc Seam Welds.

(1) 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).

extent of spot welding

(2) 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 weld symbol (fig. 3-40).

number of arc spot welds in a joint

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

e. 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 (para 3-21).

surface contour of arc spot and arc seam welds

f. 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.

3-24. GROOVE WELDS

a. General.

(1) Dimensions of groove welds must be shown on the same side of the reference line as the weld symbol (fig. 3-42).

groove weld dimensions

(2) When no general note governing the dimensions of double groove welds appears, dimensions shall be shown as follows:

(a) When both welds have the same dimensions, one or both may be dimensioned (fig. 3-43).

groove weld dimensions having no general note

(b) When the welds differ in dimensions, both shall be dimensioned (fig. 3-44).

groove welds with differing dimensions

(3) When a general note governing the dimensions of groove welds appears, the dimensions of double groove welds shall be indicated as follows:

(a) If the dimensions of both welds are as indicated in the note, neither symbol need be dimensioned.

(b) When the dimensions of one or both welds differ from the dimensions given in the general note, both welds shall be dimensioned (fig. 3-44).

b. Size of Groove Welds.

(1) The size of groove welds shall be shown to the left of the weld symbol (fig. 3-44).

(2) Specifications for groove welds with no specified root penetration are shown as follows:

(a) The size of single groove and symmetrical double groove welds which extend completely through the member or members being joined need not be shown on the welding symbol (A and B, fig. 3-45).

groove weld dimensions for welds extending through the members joined

(b) The size of groove welds which extend only partly through the member members being joined must be shown on the welding symbol (A and B, fig. 3-46).

groove weld dimensions for welds extending partly through the members joined

(3) The groove welds, size of groove welds with specified root penetration, except square must be indicated by showing the depth of chamfering and the root penetration separated by a plus mark and placed to the left of the weld symbol. The depth of chamfering and the root penetration must read in that order from left to right along the reference line (A and B, fig. 3-47). The size of square groove welds must be indicated by showing only the root penetration.

dimensions of groove welds with specified root penetrations

(4) The size of flare groove welds is considered to extend only to the tangent points as indicated by dimension lines (fig. 3-48).

flare groove welds

c. Groove Dimensions

(1) Root opening, groove angle, groove radii, and root faces of the U and J groove welds are the user’s standard unless otherwise indicated.

(2) When the user’s standard is not used, the weld symbols are as follows:

(a) Root opening is shown inside the weld symbol (fig. 3-49).

root opening

(b) Groove angle of groove welds is shown outside the weld symbol (fig. 3-42).

(c) Groove radii and root faces of U and J groove welds are shown by a cross section, detail, or other data, with a reference to it on the welding symbol, in accordance with location specifications given in paragraph 3-7 (fig. 3-22).

d. Back and Backing Welds. Bead-type back and backing welds of single-groove welds shall be shown by means of the back or backing weld symbol (fig. 3-50).

back or backing weld symbol

e. Surface Contour of Groove Welds. The contour symbols for groove welds (F, fig. 3-51) are indicated in the same manner as that for fillet welds (para 3-21).

surface contour of groove welds

(1) Groove welds that are to be welded approximately flush without recourse to any method of finishing shall be shown by adding the flush contour symbol to the weld symbol, in accordance with the location specifications given in paragraph 3-7 (fig. 3-52).

contours obtained by welding

(2) Groove welds that are to be made flush by mechanical means shall be shown by adding the flush contour symbol and the user’s standard finish symbol to the weld symbol, in accordance with the location specifications given in paragraph 3-7 (fig. 3-53).

flush contour by machining

(3) Groove welds that are to be mechanically finished to a convex contour shall be shown by adding both the convex contour symbol and the user’s standard finish symbol to the weld symbol, in accordance with the location specifications given in para 3-7 (fig. 3-54).

convex contour by machining

3-25. BACK OR BACKING WELDS

a. General.

(1) The back or backing weld symbol (fig. 3-50) must be used to indicate bead-type back or backing welds of single-groove welds.

(2) Back or backing welds of single-groove welds must be shown by placing a back or backing weld symbol on the side of the reference line opposite the groove weld symbol (fig. 3-50).

(3) Dimensions of back or backing welds should not be shown on the welding symbol. If it is desired to specify these dimensions, they must be shown on the drawing.

b. Surface Contour of Back or Backing Welds. The contour symbols (fig. 3-55) for back or backing welds are indicated in the same manner as that for fillet welds (para 3-21).

surface contour of back or backing welds

3-26. MELT-THRU WELDS

a. General.

(1) The melt-thru symbol shall be used where at least 100 percent joint penetration of the weld through the material is required in welds made from one side only (fig. 3-56).

melt-thru weld symbol

(2) Melt-thru welds shall be shown by placing the melt-thru weld symbol on the side of the reference line opposite the groove weld, flange, tee, or corner weld symbol (fig. 3-56).

(3) Dimensions of melt-thru welds should rot be shown on the welding symbol. If it is desired to specify these dimensions, they must be shown on the drawing.

b. Surface Contour of Melt-thru Welds. The contour symbols for melt-thru welds are indicated in the same manner as that for fillet welds (fig. 3-57).

surface contour of melt-thru welds

3-27. SURFACING WELDS

a. General.

(1) The surfacing weld symbol shall be used to indicate surfaces built up by welding (fig. 3-58), whether built up by single-or multiple-pass surfacing welds.

size of surfaces built up by welding

(2) The surfacing weld symbol does not indicate the welding of a joint and thus has no arrow or other side significance. This symbol shall be drawn on the side of the reference line toward the reader and the arrow shall point clearly to the surface on which the weld is to be deposited.

b. Size of Built-up Surfaces. The size (height) of a surface built up by welding shall be indicated by showing the minimum height of the weld deposit to the left of the weld symbol. The dimensions shall always be on the same side of the reference line as the weld symbol (fig. 3-58). When no specific height of weld deposit is desired, no size dimension need be shown on the welding symbol.

c. Extent, Location, and Orientation of Surfaces Built up by Welding. When the entire area of a plane or curved surface is to be built up by welding, no dimension, other than size, need be shown on the welding symbol. If only a portion of the area of a plane or curved surface is to be built up by welding, the extent, location, and orientation of the area to be built up shall be indicated on the drawing.

3-28. FLANGE WELDS

a. General.

(1) The following welding symbols are used for light gage metal joints involving the flaring or flanging of the edges to be joined (fig. 3-59). These symbols have no arrow or other side significance.

flange weld symbols

(2) Edge flange welds shall be shown by the edge flange weld symbol (A, fig. 3-59).

(3) Corner flange welds shall be shown by the corner flange weld symbol (B, fig. 3-59). In cases where the corner flange joint is not detailed, a break in the arrow is required to show which member is flanged (fig. 3-59).

b. Dimensions of Flange Welds.

(1) Dimensions of flange welds are shown on the same side of the reference line as the weld symbol.

(2) The radius and the height above the point of tangency must be indicated by showing the radius and height, separated by a plus mark, and placed to the left of the weld symbol. The radius and height must read in that order from left to right along the reference line (C, fig. 3-59).

(3) The size (thickness) of flange welds must be shown by a dimension placed outward of the flange dimensions (C, fig. 3-59).

(4) Root opening of flange welds are not shown on the welding symbol. If specification of this dimension is desired, it must be shown on the drawing.

c. Multiple-Joint Flange Welds. For flange welds in which one or more pieces are inserted between the two outer pieces, the same symbol shall be used as for the two outer pieces, regardless of the number of pieces inserted.

No tags for this post.