A casting process for automobile crankshaft

Abstract

The invention belongs to the technical field of mechanical casting casting, and particularly provides a casting process of an automobile crankshaft. A sand mold adopted for the casting process comprises a sand box. The sand box is composed of an upper box body and a lower box body. Molding sand is arranged in the sand box, and a cavity for casting the crankshaft is formed in the middle of the molding sand. The two ends of the cavity communicate with the top of the molding sand through casting holes. A heating hole is formed in the wall thickness mutation position of the cavity, and the heatinghole is used for preheating the molding sand. Flame preheating is carried out on the heating hole, so that the cooling speed of the wall thickness mutation position of the cavity is reduced. The heating hole is heated through a torch, the temperature of the position, corresponding to the heating hole, of the molding sand is increased, the temperature of the wall thickness mutation position of thecavity is increased, then the cooling speed of the position with the large thickness of a crankshaft blank and the cooling speed of the position with the small thickness are consistent, and internalshrinkage and generation of shrinkage cavities caused by different heat dissipation speeds of the thickness mutation position of the crankshaft blank are reduced.

Description

technical field [0001] The invention belongs to the technical field of casting of mechanical castings, in particular to a casting process of an automobile crankshaft. Background technique [0002] The crankshaft is the most important component in the engine. It bears the force transmitted by the connecting rod and converts it into torque through the crankshaft output and drives other accessories on the engine to work. The crankshaft is subjected to the joint action of the centrifugal force of the rotating mass, the periodically changing gas inertial force and the reciprocating inertial force, so that the crankshaft is subjected to the bending torsional load. Therefore, the crankshaft is required to have sufficient strength and rigidity, and the surface of the journal needs to be wear-resistant, work evenly, and have good balance. [0003] Spheroidal graphite cast iron is obtained through spheroidization and inoculation treatment, which effectively improves the mechanical p...

AI Technical Summary

Problems solved by technology

[0004] When the automobile crankshaft is cast with ductile iron, after the casting is completed, due to the different thickness of the parts of the crankshaft, the cooling speed of each part of the crankshaft is different, and it is easy to form shrinkage cavities and shrinkage porosity in the part where the thickness of the crankshaft changes suddenly, reducing the strength of the crankshaft and making it Stress concentration inside the crankshaft affects the service life of the crankshaft

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