Effect of Boron and Chromium on Hardenability in 0.33% C Cold Heading Steel

摘要

The effect of B and Cr on hardenability in 0.33% C cold heading steel was studied. The results show that the hardenability enhanced from adding 0.0020% B or 0.28% Cr. The length of high hardness stability region of the Jominy Curve obviously increased with adding B, and the hardness of low hardness stability region of the Jominy Curve increased significantly with adding Cr. The ideal critical diameter DI of the experimental steels was calculated, the DI is 20.0 mm of the base steel with 0.33% C and no other alloying element addition, but the DI becomes 29.5 mm with adding 0.28% Cr and 46.4mm with adding 0.0020% B. The hardenability of the test steels was calculated by the nonlinear equation and compared with the experimental results. The calculated Jominy curve did not reflect characteristics of 2# steel with B and needs to be further optimized.