When fillet welds are not welded all around, or are not continuous, the extent of the welding can be shown by one of two methods. The first method shows the extent of welding graphically by the use of section lining, or some other similar definite indication, Figure 12.10. Extension lines are used as terminal points for the section lining; dimension lines with dimensions are included.
A second method makes use of multiple arrows to point out the sections to be welded. An arrow for each section is applied, Figure 12.11. In this case, dimensions are not used. It is assumed that each section is welded to the extent that it touches the other member of the joint. This method is used principally when it is awkward to dimension the drawing.
FIGURE 12.10 ■ Section lining denoting the extent of the welds.
FIGURE 12.11 ■ Using multiple arrows to indicate the
extent of welds.
PITCH AND INTERMITTENT WELDING
12.12 ■ Length and pitch of increments of intermittent welding.
Intermittent welding consists of a series of short welds. Each short weld is called an increment (represents length of weld). The center-to-center distance, in inches or millimeters of each increment, is the pitch. The pitch is shown on the welding symbol to the immediate right of the length of increment dimension, Figure 12.12. Note that if additional welds are required at the ends of the joint, they are specified by separate symbols and dimensions. Otherwise, the unwelded length should not exceed that length specified by the symbol.
Chain intermittent welding means that the welds appear directly opposite each other on the two sides of the joint, Figure 12.13. Staggered intermittent welds are those that are not directly opposite one another, Figure 12.14.
12.13 ■ Chain intermittent welding.
Notice that when the welds are staggered, the welding symbols above and below the reference line are not aligned with each other.
Continuous and chain or staggered intermittent welding are often used together in a weld - ment, Figure 12.15
When making such a combination, weld space should be left between the end of the continuous weld and the beginning of the first intermittent weld. This space is equal to the pitch minus the length of one increment.
Therefore, in Figure 12.15, the space equals 5" minus 2" — 3".
The length of the increment is extended to terminate the weld at the end of the joint when the length of the joint extends beyond the specified length of the increment. The same applies to staggered intermittent welds.
Note the 4" dimension between the continuous weld and the center of the first intermittent weld. This dimension minus half of the
length of the first 2" increment (or 1") gives FIGURE 12.14 ■ Staggered intermittent welding
the 3" space previously determined. symmetrically spaced (unless
FIGURE 12.15 ■ Combined chain intermittent and continuous welding.
FIGURE 12.16 ■ Use of extension and
dimension lines to locate and specify length of welds.
Extension and dimension lines are occasionally used with the welding symbol to locate the desired welds, Figure 12.16. Note that the arrows of the welding symbols point to the dimension lines rather than to surfaces.
CONTOUR AND FINISHING
Finish and contour indications are added to the weld symbols as required, Figure 12.17.
(a) FLAT CONTOUR
(b) CONVEX CONTOUR BY GRINDING.3 MACHINING V, CHIPPING £ ,
. v EST—
(сI FLAT CONTOUR BY GRINDING, MACHINING, CHIPP3NG, ROLLING, AND PLANISHING NOTE THAT THE LETTER "u." WHJCH SfGNfFIES "UNSPECIFIED," MAY ALSO BE APPLIED TO THE CONTOUR SYMBOLS, THUS PERMITTING
FIGURE 12.17 ■ Finish and contour specifications on filletweld symbol.