HOOD AS-ENGINE 3967693 - Caterpillar

Figure 11 - Several electrode angles and weave patterns cam be used for flat welding.For horizontal fillet welds, the electrode should be held midway between the horizontal and vertical plates (45° work angle) on the first pass so an equal force from the arc is directed against each surface (Figure 12). The second pass should be deposited against the horizontal plate to form a flat ledge on which the third pass can be laid. The second pass and all subsequent passes that do not contact the vertical plate should be made with a 20° work angle (Figure 12). The third pass and all subsequent passes that do not contact the vertical plate should be made with a 60° work angle. On all passes the electrode should be tilted in the direction of travel (Figure 13) so it makes a 60° angle with the horizontal plate (30° lead angle).
Figure 12 - Different work angles are needed on various passes for horizontal fillet welds.The weave patterns for horizontal fillet welds utilize the force of the arc to wash molten metal up onto the vertical surface. This technique permits accurate forming of the weld deposit without undercutting (Figure 13).
Figure 13 - A 30° lead angle puts the electrode 60° from horizontalFor horizontal butt welds, the electrode holder should be held somewhat below the joint so the electrode is directed slightly upward. The electrode again should be tilted in the direction of travel so it has a lead angle of about 10°. The electrode is directed upward so the force of the arc will hold the puddle of weld metal in position until it freezes. The weave patterns recommended for horizontal fillet welds (Figure 13) should be used for horizontal butt welds, also. This is done so molten metal can be washed up onto the upper surface to prevent undercutting.Overhead and Vertical Welding
A weld joint is in the overhead position when the axis of the joint is within 10° of horizontal and the welding is performed on the lower side of the joint (Figure 14). If the axis of a joint is between 10° and 90° from horizontal, the joint is said to be in the vertical position (Figure 14). Even thorough a joint inclined at, for instance, 30°, is closer to the horizontal than vertical, it is classified as a vertical weld because the problems encountered are essentially the same as those of a joint that is completely upright.
Figure 14 - Vertical and overhead welding is called out-of-position welding.When working in the overhead and vertical positions, the welder must constantly take steps to counteract the effect of the force of gravity on the puddle of molten metal. The size of the puddle must be limited by reducing welding current, arc length and deposition rate. This keeps molten metal from dropping from the weld or running down over the work. The amount of slag shield must be reduced through proper electrode selection so the weld metal will freeze more quickly and in