高温形变节能热处理技术

本文介绍了高温形变热处理的意义、分类、强韧化机理和应用实例。文中指出:40Cr钢经高温自由锻淬火并高温回火后,其屈服强度、夏氏冲击韧性、断裂韧性增高,脆性转折温度降低。其原因归结于钢的淬透性增加,高温回火后球形碳化物均匀分布于铁素体基体上,形成稳定的位错网络和晶界被净化。9CrSi钢经高温自由锻形变淬火和短时球化退火,可得到理想的球化组织和切削加工硬度。经最终热处理后强度提高382MPa,冲击韧性提高一倍。性能提高的原因归结为奥氏体晶粒、马氏体组织、末溶碳化物细化,位错密度增加,孪晶马氏体分布发生改变和胞状结构的遗传等。

Saving Energy Technigue of High-temperature Mechanical Heat Treament

In this paper, the significance, clarification, the mechanism of strenghening and toughening and application examples of hightemperature mechanical heat treatment (HTMT)have been introduced. By the process of HTMT followed by high temporature tempering, the yield strength, tensile strength, charpy impact toughness and fracture toughness of 40Cr steel are increased obviously and the transition temperature of brittleness is lowered. The contribution of HTMT to improved mechanical properties is attributed to hat the hardenability of 40Cr steel is increased, the tempered fine spheroidal carbide particles distribute uniformly in matrix of ferrite,stable regular dislocation networks were formed and austenite grain boundary are purified:After the 9CrSi steel treated by HTMT were with spheroidization short-time annealed,the saticfacterymicrostructure and hardness for machining may be aeguired. By final rehardening and low temperature tempering, the bending strength of 9CrSi steel increases by 382MPa and its impact tess is doubled. The contribution of HTMT to improve the properties of 9CrSi steel is attributed to the refinement of austenite grain size, martensite structure and undissolved carbides, increased dislocation density, the change of distribution of twinned martensite and the inheritance of cell structure etc.