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本文报道了45、40Cr钢在高温形变调质处理时,奥氏体状态对过冷奥氏体等温分解及形变调质处理后机械性能的影响。研究结果表明:提高形变前奥氏体化温度,可推迟形变后过冷奥氏体在珠光体转变区的等温分解,而奥氏体状态下塑性变形的作用则相反,但前者起主导作用,因而其综合效果是提高钢的淬透性;形变—调质处理后的综合机械性能较普通调质处理的高;形变前的奥氏体化温度,以及大于15%的形变量,对高温形变调质处理后的机械性能影响不大。许多研究工作表明,高温形变热处理不仅可以提高钢材强度,保持良好的塑性及韧性,而且可以降低回火脆性的敏感性。采用较高的形变温度,形变淬火强化效果也可保持至较高的回火温度。据此,对普通调质处理状态使用的钢制零件,有可能把高温塑性变形成型工序与调质处理工序结合起来,构成所谓锻热淬火或形变—调质处理。本文研究了45及40Cr钢形变—调质处理时,形变前的奥氏体化温度及形变量对过冷奥氏体的稳定性及形变—调质处理后强化效果的影响。
This paper reports the effect of austenite on the mechanical properties of sub-cooled austenite during deformation and tempering of 45 and 40Cr steels at high temperature. The results show that increasing the pre-deformation austenitization temperature can delay the isothermal decomposition of the supercooled austenite in the pearlite transformation zone, whereas the plastic deformation in the austenite state has the opposite effect, but the former plays a leading role. Therefore, its comprehensive effect is to improve the hardenability of steel. The mechanical properties after deformation-quenching are higher than those of ordinary quenching and tempering treatment. The pre-deformation austenitizing temperature and the deformation of more than 15% Variable quenching after the mechanical properties of little effect. Many research work shows that high temperature deformation heat treatment can not only improve the strength of steel, maintain good ductility and toughness, but also reduce the sensitivity of temper brittleness. With a higher deformation temperature, deformation quench hardening can also be maintained to a higher tempering temperature. Accordingly, it is possible to combine the high-temperature plastic deformation forming process and the tempering process with the steel parts used in the ordinary tempering process to form a so-called forging quenching or deformation-quenching process. In this paper, 45 and 40Cr steel deformation - quenching process, before the deformation of the austenitizing temperature and deformation of the supercooled austenite stability and deformation - hardening after quenching effect.