大截面高强度中锰锻钢淬透性研究

摘要：通过末端淬火试验和非线性方程计算模拟方法，研究了2种大截面高强度中锰锻钢的淬透性及Mn元素的作用。结果表明，在距淬火端距离为50mm时，2种试验钢的硬度分别是48HRC和50HRC，且未呈现下降趋势；根据非线性方程计算模型得出，2种试验钢的半马距分别大于1000和3000mm。Mn元素的添加显著地提高了2种试验钢的淬透性，且满足大截面构件用钢对高淬透性的要求。利用室温单轴拉伸试验研究不同退火处理对2种试验钢拉伸性能的影响。结果表明，2种试验钢在600℃×4h退火处理后均获得优异的强塑性匹配，这是因为在此退火工艺下发生了奥氏体逆转变，导致奥氏体稳定性降低，使其在拉伸变形过程中充分发生TRIP效应。

Study on hardenability of large cross-sectional high strength medium-Mn forged steels

Abstract： The hardenability of two large cross sectional high strength medium Mn forged steels were investigated using Jominy tests and nonlinear equation calculation model, and the effect of Mn element was discussed. The results show that the hardness of the steels is not less than 48HRC and 50HRC at a distance of 50mm from the quenching end, respectively, and keeps no decreasing trend. Moreover, the distance holding martensitic volume fraction of 50% in the steels is more than 1000mm and 3000mm based on the nonlinear equation calculation model, respectively. The addition of Mn improves the hardenability which meets the requirements for high hardenability of large cross-sectional components. In addition, the effects of annealing treatments on the tensile properties of the steels were investigated using uniaxial tensile tests at room temperature. Excellent combinations of tensile strength and total elongation are obtained through the annealing treatment at 600℃×4h, which is due to the occurrence of austenite reverse transformation, lowering the stability of austenite, thus, resulting in TRIP effect during the tensile deformation.