Abstract
Abstract
To meet the requirement of the mould industry, the new mould steels are sprung out to improve its properties such as toughness, corrosion resistance etc. However, there are some defections on the finish surface such as cracks, pores etc. In the paper, the two mould steels are chosen to study, one of which has nitrogen element while the other doesn’t have. The relationship between current, pulse on duration and EDM characteristic for two material are studied, and the influence of nitrogen on the cracks and pores are analysed as well. The results show that larger peak current will cause rough surface and little crack in the surface, while the high pulse on duration will increase the surface roughness and crack density. The existed of nitrogen achieves more pores on the surface, and the quantity of pores increases when lengthens the pulse on duration and weaken the peak current.