How many kinds of welding methods are there for cast iron?
Heating reduction zone method: the weld zone can expand freely and shrink cold.
Heat welding method |: welding the casting is preheated to 600 DEG -700 DEG, welding process, working temperature can be reduced to below 400 DEG C, which can reduce the temperature of the workpiece caused by the uneven distribution of welding stress. Immediately after welding, the temperature is heated to about 700 DEG C, and the stress and heat treatment is eliminated.
Using arc cold welding to prevent cracks, the concrete measures; (1) the weld become plastic metal well; (2) the small current intermittent welding, welding in narrow dispersion, the groove in the multi-layer welding methods to prevent welding heat input of the local area, in order to reduce the temperature difference between the whole and the and the resulting thermal stress; (3) by hammering the weld to eliminate stress, prevent crack; (4) the basic cold metal melting more, the fusion zone is white layer thickness, the weld is easy to peel. Therefore, the welding base is best to use fine diameter welding rod, small current welding. The above measures arc cold welding, welding in cast iron should be used at the same time, also sometimes welding thick wall deep groove can be used when welding plate, reduce stress and prevent peeling in rod joints.
