SDP2新型贝氏体塑料模具钢连续冷却相变与力学性能研究

Study on Continuous Cooling Transformation and Mechanical Properties of SDP2 New Bainite Plastic Die Steel

为满足大截面塑料模具钢需求,通过计算机模拟得到SDP2钢大模块锻后风冷条件下的冷速区间,以此为依据采用相变仪进行连续冷却试验,研究了冷速低至0.01℃/s时新型贝氏体塑料模具钢SDP2的相变特性与力学性能。结果显示,SDP2新型贝氏体钢的临界冷速为0.015℃/s。当冷速低于0.02℃/s、贝氏体开始转变温度升高至400℃左右,中温区相变产物以下贝氏体为主;560℃回火,SDP2钢硬度为31~34 HRC,抗拉强度为1081 MPa,冲击功达到33 J。因此,SDP2钢的力学性能满足大模块生产要求。

In order to meet the requirement of large section plastic die steel,the cooling rate range of SDP2 steel large module during air cooling after forging is obtained by computer simulation.On the basis of this,the continuous cooling test was carried out with a phase changer.The phase-change characteristics and mechanical properties of a new type of bainite plastic die steel SDP2 with cooling rate as low as 0.01℃/s were studied.The results show that,the critical cooling rate of SDP2 new bainitic steel is 0.015℃/s.When the cooling rate is lower than 0.02℃/s,the transformation temperature of bainite rises to about 400℃,and the trans formation product during the intermediate temperature region is mainly lower bainite.When tempering at 560℃,the hardness of SDP2 steel is 31-34 HRC,the tensile strength is 1081 MPa,and the impact work is33 J.Therefore,the mechanical properties of SDP2 steel meet the requirements of large module production.