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SOLUTIONS: Cast Iron

beads of maximum length 20–30 mm (1") at a time. Weaving should be avoided or kept to the minimum required to "wash out" the deposit and to catch the sides of the groves. Do not wave in excess of one-half electrode diameter to each side of the direction of the weld. When each bead of 20–30 mm has been deposited, fill the crater and withdraw the electrode a little backward on the bead before breaking the arc. While the bead is still hot, peen it with a round-nosed peen hammer. Since the casting is quite rigid, the filler metal must be ductile. Peening the bead immediately after depositing will stretch it to accommodate some dimensional change in the weld area, and will provide some stress relief. Always peen from the crater back to the starting point. Use rapid moderate blows; just hard enough to leave a slight indent on the weld deposit is usually sufficient. Too heavy blows may cause cracks, while to light peening will have little or no effect in relieving stresses.

On thin dimensions the peening should not be vertical on the bead, as vibrations will reduce the effect:

Wrong

After the initial bead has been deposited and peened, the next bead should not be put down until the bare hand can be laid alongside the

R = 3 mm

Rounded edge

Recommended shape of head.

2.07

Weld contraction may cause cracks.

Peening offsets contraction forces.

Correct

first bead with comfort. If you burn yourself, it is too hot to go on with the welding. Take your time, do not spoil your work by trying to rush it. 91