X-Ray Residual Stress Measurement of Boronized Steels

Abstract

Boronizing is one of the chemical methods to achieve case hardening of steels. The boronized layer has above 1400 Vickers hardness and a high resistance especially against wear. In the present study, the X-ray method was successfully applied to measure the residual stress distribution in a boronized steel. The X-ray elastic constants were determined separately for FeB and Fe₂B phases of the boronized layer, and compared with the mechanically measured values. The results obtained are summarized as follows;
(1) The X-ray elastic constants determined were
S₁=9.10×10^-7(MPa^-1), S₂/2=2.93×10^-6(MPa^-1)
for FeB (212) phase, and
S₁=4.95×10^-7(MPa-1), S₂/2=2.13×10^-6(MPa^-1)
for Fe₂B (330) phase.
The Young's modulus of FeB and Fe₂B phases were 494(GPa) and 611(GPa) which were higher than the mechanically determined values of 370(GPa) and 260(GPa), respectively.
(2) The residual stress distribution determined by X-rays indicated high compressive stress above 2000(MPa) in the boronized layer. The effect of the boronizing process on the residual stress distribution was examined.