45钢亚温淬火组织及性能研究

45钢是我国目前用量较大的调质钢,通过研究45钢经调质和亚温淬火热处理后的硬度,冲击韧度和金相组织,来寻求合适的45钢热处理工艺.结果表明,45钢仅采用调质处理,不能满足高硬度高韧性的技术要求,采用亚温淬火热处理配合可解决上述问题,得到最优的综合力学性能,考虑经济性时可直接采用770℃淬火500℃回火的热处理工艺.在保证45钢强度和硬度的同时,要提高韧性的最理想的热处理工艺为840℃淬火550℃回火＋770℃淬火500℃回火.

Study of Microstructure and Properties Based on Sub-temperature Quenching Technique for 45 Steel

45 steel is used widely as a kind of quenched and tempered steel.The hardness,impact toughness and the microstructure of the 45 steel based on sub-temperature quenching technique and traditional heat treatment are studied to establish a prior heat treatment process.The results show that the high hardness and toughness can＇t come into being by the traditional heat treatment simultaneously;but the problem can be solved by the method of traditional heat treatment plus sub-temperature quenching.It is more economical that sub-temperature quenching is only used,such as quenching at 770℃ and tempering at 500℃.The best heat treatment process with quenching at 840℃ and tempering at 500℃ and sub-temperature quenching at 790℃and tempering at 500℃ is proposed,by which the excellent properties,especially the toughness can be obtained.