| In recent years, the auto industry of China is developing rapidly, especially the heavy truck market increases significantly, growing varieties, high-powered, low-emissions is the heavy truck development trends. Engine is the heart of the automobile, the crankshaft is one of important parts and the spinal in the engine used for supporting the impact load and driving force transmission. It affects not only the quality of engine, but also the reliability and life of the engine in large extent, so the crankshaft need a higher tensile strength, stiffness, fatigue, strength and wear resistance of the surface, while the heart ministry to have a certain toughness. The crankshaft performance is related except for the material, surface strengthening technology, machining accuracy and surface roughness.Hence this thesis analyzes the gas-soft-nitriding mechanism and surface heating induction quenching mechanism. From the beginning of analysis the crank shaft invalidation mode, investigating the mechanism of nitriding layer and the characteristic of induction calefaction, by adjusting the test parameters to strengthen the metal surface. This thesis introduces the crankshaft of Eurp III LANDKING, its material is 42CrMo, surface strengthening in two different technologies, demonstrating the fatigue intension results and making a conclusion which technology meet the product design requirement. Demonstrating the surface strengthening effects of the gas-soft-nitriding mechanism and surface heating induction quenching mechanism, then we advanced the crankshaft surface strengthening technology innovation.Compared the test results, the two technologies are able to meet the crank shaft requirement but in different degrees. The surface heating induction quenching mech- anism is better than gas-soft-nitriding mechanism. The technology of surface heating induction quenching mechanism is high reliability, and meets on the requirement of the LAND KING WP12 and be applied to actual production. |
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