Effect of aging treatment on microstructure and properties of high-speed linear guide made of 20Cr carburized steel

Abstract

In order to study the effects of microstructure and mechanical properties of 20Cr carburized steel high-speed linear guide under different aging treatment conditions, the microstructure, phase composition and residual stress of linear guide before and after aging treatment were analyzed by scanning electron microscopy (SEM), Х-ray diffractometer (XRD) and X-ray stress tester. The results show that after aging treatment, the martensite structure in the surface layer of 20Cr carburized steel is gradually refined, the fine carbides is precipitated and some residual austenite decompose, the surface hardness of the guide rail increases and the maximum hardness is 729.3HV1/5. Affected by the transformation of residual austenite structure and the change of ferrite content, the residual stress of the carburized layer of the guide rail is eliminated to varying degrees. After heated to 200 °C for 13 h, the residual stress relief effect on the surface of the guide rail is the most obvious, the residual stress value is reduced to -127.17 MPa and the elimination rate is as high as about 54.05%, and there is a polynomial function relationship between the residual stress and the depth of the carburized layer.

Keywords

• 20cr carburized steel
• high-speed linear guide
• aging treatment
• microstructure
• residual stress