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The rapid increase of vehicle over the past decade, not only brings convenience, but also a big problem of vehicle liquidation. Meanwhile, total amount of domestic engineering machinery becomes saturated, and engineering machinery has gradually entered the large-scale retirement stage at home. The treatment of engine is the core of the treatment of discarded cars and engineering machinery. The main treatment of discarded engine is to recycle raw materials before, the method for the scrap engine is negligible for the value of discarded engine, furthermore, it will cause the waste of energy, resources and environmental pollution. Currently, the treatment of discarded engine has gradually changed from the raw materials to remanufacturing to save resources, energy and protect the environment.Traditional remanufacturing repair methods consist of machining repair methods, hot weld methods, caking methods, etc. New remanufacturing repair technology consist of hot spraying technology, Thermal spray welding technology, plasma spraying technology, arc spraying technology, explosion spraying technology, cold welding technology, electrobruch plating repair technology, etc. At present, machining repair methods, electrobruch plating repair technology, cold welding technology is widely used in remanufacturing production. Cold welding technology is widely used in remanufacturing enterprises, the research of cold welding technology in remanufacturing engine block mainly focus on spark welding repair technology and Micro pulse resistance welding technology at home and abroad, imitation laser welding technology has not been carried out.The research of this paper couples with production practice, it intensivly study imitation laser welding technology widely used in remanufacturing enterprises. First, investigate the main failure mode of engine block and the cause. Next, design orthogonal tests (three factors and three level). Later on. evaluate the welding quality of imitation laser welding technology, include macroscopic weld defects, diffusion degree of weld area, color of weld area. Finally, research the impact of cold welding technological parameter on weld hardness, include changing regularity of hardness in weld area, average hardness of heat-affected zone, the width of heat-affected zone, average hardness of welding joint.
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