Effect of casting and mould parameters on surface decarburisation in lost wax casting of DIN CK 45 steel

摘要

The effect of mould preheating temperature, casting modulus and graphite addition method on surface decarburisation during lost wax casting of CK 45 steel has been investigated. For this purpose, a novel image analysis program was developed to determine the carbon concentration profile. It was observed that on increasing the preheating temperature and casting modulus, the depth of decarburisation increases significantly. This behaviour was related to the decreased cooling rate of the samples which enhances the loss of carbon by reaction with the surrounding atmosphere. It was also found that the distribution of graphite in different layers of the mould and the distance of these layers from the mould inner surface affect the surface decarburisation of the samples. Therefore, choice of the most appropriate method of graphite addition can greatly increase the effectiveness of measures to decrease surface decarburisation.