*
(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). Page 26 of 29 Chptr 3 Print Reading
and Welding Symbols
(3) Embossment on the other side member of a joint for projection
welding
shall be indicated by placing the symbol on the -side of the reference
line away from the reader (fig. 3-73).
(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).
(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).
c. Spacing of Projection Welds. The pitch of projection welds shall be
shown to the right of the weld symbol (fig. 3- 76).
Page 27 of 29 Chptr 3 Print Reading and Welding Symbols
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).
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).
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).
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).
CHAPTER 4
JOINT DESIGN AND PREPARATION OF METALS
4-1. JOINT TYPES
Welds are made at the junction of the various pieces that make up the
weldment. The junctions of parts, or joints, are
defined as the location where two or more members are to be joined.
Parts being joined to produce the weldment may
be in the form of rolled plate, sheet, shapes, pipes, castings,
forgings,
or
billets. The five basic types of welding joints
are listed below.
a. B, Butt Joint. A joint between two members lying approximately in the
same plane.
b. C, Corner Joint. A joint between two members located approximately at
right angles to each other in the form of an angle.
c. E, Edge Joint. A joint between the edges of two or more parallel or
mainly parallel members.
d. L, Lap Joint. A joint between two overlapping members.
e. T, Tee Joint. A joint between two members located approximately at
right angles to each other in the form of a T.
4-2. WELD JOINTS
In order to produce weldments , it is necessary to combine the joint
types with weld types to produce weld joints for
joining the separate members. Each weld type cannot always be combined
with each joint type to make a weld joint.
Table 4-1 shows the welds applicable to the basic joints.
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Warmly,
Pat Mitchell
http://www.weldingsecrets.net/main.html
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