6) The bonding strength of the sprayed layer and the substrate: The tensile strength of the conventional flame sprayed coating is generally 20-30N / mm2. The ZK8032 powder multifunctional high speed flame spraying gun newly developed and manufactured by Shaanxi Zhongke Surface Engineering Co., The cast iron is sprayed on the sandblasting surface and sprayed on the aluminum clad nickel composite coating, the shear bond strength of the coating can reach 63.7N / mm2. Although the sprayed coating is not as strong as the bonding strength of the sprayed coating, After the failure of parts is sufficient to meet the needs.After calculation of scientific research units, in the liberation of CA141 car full load operation, the shear stress on the crankshaft seven main journals focus on a main journal only 15N / mm2; Dongfanghong 75 tractors Only 5.5N / mm2, these data is far below the shear strength of the spray coating.