Microstructure and properties of low temperature composite chromized layer on H13 tool steel

作者：Wu CL^*; Luo CP; Zou GF

来源：Journal of Materials Science & Technology, 2005, 21(2): 251-255.

DOI：10.3321/j.issn:1005-0302.2005.02.024

• H13 tool steel
• low temperature composite chromizing
• nitride and carbide of chromium
• microhardness
• wear resistance

Low temperature composite chromizing is a process composed of a plain ion-carbonitriding or ion-nitriding at 550 similar to 580 degrees C, followed by a low-temperature chromizing in a salt-bath of 590 degrees C. The microstructure and, properties of the low temperature composite chromized layer on H13 tool steel were investigated using metallography, X-ray diffraction, microanalysis, hardness and wear tests. It was found that this low temperature process was thermodynamically and kinetically possible, and the composite chromized layer on H13 steel, with a thickness of 3 similar to 6 mu m, consisted of three sub-layers (bands), viz. the outer Cr-rich one, the intermediate (black) one, and the inner, original white layer. After chromizing, the former diffusion layer was thickened. The results of X-ray diffraction showed that the composite chromized layer contained such nitrides and carbides of chromium as CrN, Cr2N, (Cr, Fe)(23)C-6, and (Cr, Fe)(7)C-3, as well as plain alpha-(Fe, Cr). A high surface microhardness of 1450 similar to 1550 HV0.025, which is much higher than that obtained by the conventional ion carbonitriding and ion nitriding, was obtained. In addition, an excellent wear resistance was gained on the composite chromized layer.

• 出版日期2005-3
• 单位华南理工大学