经深冷处理的4Cr5MoSiV1钢的回火组织和力学性能

Microstructure and Mechanical Properties of Tempered Deep Cryogenic Treated 4Cr5MoSiVl Steel

研究了4Cr5MoSiV1钢经淬火+深冷处理+回火后的组织和力学性能。结果表明,试验钢在470℃左右回火时硬度达到峰值,二次硬化峰较普通处理的4Cr5MoSiV1钢有所左移。400-470℃回火后试验钢的抗拉强度为2 000-2 100 MPa,冲击功约为35-20 J,回火温度高于560℃时,强度与硬度均有所下降,冲击功增加。 M2C、MC型碳化物的弥散析出可能是引起上述组织与力学性能变化的重要原因。

The microstructure and mechanical properties of 4Cr5MoSiV1 steel in quenched, deep cryogenic treated and tempered condition were investigated. It was found that the hardness of sample arrived a peak when tempered at 470 ℃. The peak secondary hardening intensity of the sample appeared earlier than that treated ordinarily. When tempered at 400-470 ℃, the ssmple had high tensile strength of 2 000-2 100 MPa, and impact energy of 35-20 J. Decline in hardness and strength as well as an increase in impact energy were observed when tempering temperature was increased to above 560 ℃. The precipitation of M2C and MC carbides is the possible important reason for change of microstructure and mechanical properties.