1) Weld tendency of large deformation and crack formation. Coefficient of linear expansion and shrinkage of a crystalline aluminum than steel is about twice as large, easy to produce high welding stress deformation of the rigid structure will cause heat cracks. Thermal conductivity 2) large aluminum (aluminum 0.538 card /Cm.s.℃). About four times that of steel, the engine recovered, therefore, when welding aluminum and aluminum alloys, car engine recovery than welding steel to consume more calories. 3) evaporation of the burning of alloying elements. Aluminum containing low boiling point elements (such as magnesium, zinc, manganese, etc.), at a high temperature arcing, burning easily evaporate, thereby changing the chemical composition of the weld metal, weld performance. 4) low temperature strength and ductility. High temperature strength and ductility of aluminum is very low, undermining the weld metal forming, sometimes also likely to cause collapse of the weld metal and weld wear phenomenon. 5) no color change. Aluminum and aluminum alloy from the solid state into liquid, no color change, the engine recovered, so that the operator is difficult to grasp the heating temperature. Molten oxide particles formed craters and pores become nuclear goods. In the absence of oxide impurities, pores and micro pores grind it basically disappeared. For the production of cast aluminum, to reduce the cyanide particularly important impurity foot condition. Because they are typically liquid line and ask solidus of a very large amplitude poor, and in a state of porous condensate, it is difficult to provide a supply void. Oxide film casting failure is the formation of highly fragile surface, cast aluminum mechanical properties of unevenness is precisely due to the presence of these oxide films caused, waste engine recovery, if none of these oxide films. Inhomogeneity will be reduced, the casting will be better than the performance of repetitive forgings, with X-ray examination, these oxide films are usually not visible, but it must be done to prevention rather than repair isochronous later found again. Recycling car engine | Engine Recycling | Sun Shine recycling scrap metal recycling scrap metal from the Linyi City Shengxin Limited. Linyi City Shengxin scrap metal recycling Ltd. (shengxin.tz1288.com) strong, credible, in Linyi, Shandong scrap metal industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead Shengxin scrap metal recycling into the brilliant and you work for a better future!