Selection of cold rolled die steels by the roughness criterion of flat parts at CBN-grinding by normal porosity tools

Abstract

The purpose of the paper is to evaluate the machinability of die steels of five brands by the CBN grinding wheel CBN30 B107 100 0 VK27 of standard porosity by a minimum of altitude parameters , average pitch , maximum measured in the transverse direction (along the axis of the CBN-wheel), as well as by the lowest value of their scattering dispersions. Having observed the lack of dispersion homogeneity and distribution normality they are interpreted with the help of nonparametric statistics, the frequencies of which are medians and quartile latitudes. According to the location pitch roughness should be classified into three groups by the principle of their value increase: 1 - steels Cr12, Cr12Mo; 2 steel - C10A; 3 steels - Cr12V, CrWMn. Their growth is calculated within three categorical values. The process is characterized with highest stability when grinding die stamping parts made of steel Cr12Mo. Die steels should be selected with regard to their grindability and part purpose.