The Research On Homogeneous Cast Iron Electrode In The Casting Repair Welding Technology

Cast iron is one of the most widely used industrial alloy materials. The alloy is of excellent seismic performance, wear resistance and low cost. However, the whole casting process involves many operation steps, meanwhile, the current widespread use of sand mold casting and casting process, casting sand, slag, and size problems. If these defects can’t be effectively repaired, which would lead to scrap, and directly lead to increasing the casting costs. So these casting defect repair are very important.This paper deals with cast iron alloy rods and wire micro welding process, which respectively in the gray iron and ductile iron two materials test blocks, using different welding processes in the experiment(arc cold-welding, the thermoelectric arc welding and oxyacetylene welding). Through continuous adjusting the welding parameters(welding current, welding preheat temperature and preheat temperature). And ultimately determine the optimal welding parameters and process. And be used on a large ship and gas turbines castings.In arc welding, it was tested current of 160 A, 180 A, 200 A at 220 A, and the impact on the current tendency white and welding defects in the weld heat affected zone. Have the ideal welding current 180 A, it’s good to avoid welding defects, and also can minimize the tendency of white weld region.Heating arc welding were selected different current(160A, 180 A, 200 A and 220A) and different welding preheat temperature(300 ℃, 400 ℃, 500 ℃ and 600 ℃) were tested.Eventually arrive at a more suitable preheat temperature of 500 ℃, the welding current is180 A. In this case, the problem white weld region can be avoided, and also can make the color closer to the base metal after welding.In Oxyacetylene welding, the test different incubation temperatures(160A, 180 A, 200 A and 220A) and different incubation time(300 ℃, 400 ℃, 500 ℃ and 600 ℃) on the welding process area morphology, microstructure and properties of, immediately after welding the weld area is heated, and finally come to an ideal gray iron is preferable that a heating temperature of 500 ℃, baking duration 15 min. Ductile iron ideal heating temperature of 600 ℃, baking duration 15 min. In this case it could get a good weld quality.