Improve The Negative Pressure Pattern Casting Low-cr White Cast Iron Performance

In this paper, the reason why low-chromium white cast iron produced in EPC process shows bad synthetic property is profoundly analyzed. Then, based on the profound analysis of the technical connotation of EPC which is called as the casting technology of 21st century, we proposed a scientific measure to improve the synthetic property of low-chromium white cast iron produced in EPC process according to the theory of metal solidification and forming. Moreover, a study was given on the effect on the structure and property of cast iron which is caused by adopting special sands and introducing mini internal chiller. This study provides a theory basis for the generalization of EPC in the field of production of mini-ball with excellent property. With the silica sand being replaced by some special one, the solidification property of castings can be greatly improved, structure further refined and the morphology of carbide contained in low-chromium white cast iron greatly improved. Compared with the low-chromium white cast iron produced by routine EPC processes, the mechanical properties and wear-resistance have been greatly improved, impact toughness improved by 17.8%, degree of hardness strengthened by HRC2~?3, wear resistance raised by 31 %. Uniformly distributed in the mold, mini internal chiller iron which can change the solidification property of metal liquid, refinery the structure and cause type change of carbide within some micro-part during the process of mold filling by filling it in EPS in advance, results in a significant increase of synthetic property of low- chromium white cast iron produced by EPC process. Compared with that produced by routine EPC process, the mechanical properties and wear resistance have been greatly improved, impact toughness improved by 45%, degree of hardness strengthened by HRC4---4.5, wear-resisting raised by 35 %.