摘要
通过调控等温温度,将同一成分的低碳Si-Mn-Cr试验钢在不同的热处理工艺下实现了590、780和980 MPa 3个强度级别双相钢的制备。结果表明,随着等温温度的提高,最终室温组织中的马氏体含量增加,试验钢的抗拉强度和屈服强度随之提高,总延伸率下降。与临界等温工艺相比,加入过时效步骤后,达到相同强度时,所需要的等温温度更高,组织中的马氏体分数更高。且随着过时效温度的升高,达到相同强度级别时所需的等温温度进一步提高,马氏体分数进一步增加。利用同一合金成分,采用两种热处理工艺,都可制备590、780和980 MPa 3种不同强度级别的双相钢。但当前试验钢的合金成分采用临界等温-过时效热处理工艺时,在高强度规格(980 MPa)下其组织接近全马氏体,不符合实际双相钢的组织特性。
Dual phase steels with three strength levels of 590,780 and 980 MPa were achieved simultaneously by regulating the isothermal temperature of a low-carbon Si-Mn-Cr steel under different heat treatment processes.The results show that the martensite content in the final microstructure is increased with the increase of isothermal temperature,and with a consequent increase in the tensile and yield strengths and a decrease in the total elongation of the tested steel.Compared with the intercritical isothermal process,the inclusion of the overaging step requires a higher isothermal temperature and a higher fraction of martensite in the microstructure to achieve the same strength.As the overaging temperature increases,the isothermal temperature required to reach the same strength level further increases and the martensite fraction further increases.Dual phase steels with three different strength levels of 590,780 and 980 MPa are prepared,respectively,by using the identical composition with both heat treatment processes.However,the 980 MPa steel after the intercritical isothermal-overaging process has nearly full martensite microstructure,which does not meet the microstructure characteristics of the actual dual phase steel.
作者
张钰
王灵禺
杨凯
卢琦
徐伟
Zhang Yu;Wang Lingyu;Yang Kai;Lu Qi;Xu Wei(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang Liaoning 110819,China;Shanghai Li Auto Technology Co.,Ltd.,Shanghai 201805,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2023年第10期59-65,共7页
Heat Treatment of Metals
基金
国家自然科学基金联合基金(U22A20106)。
关键词
双相钢
显微组织
力学性能
过时效
等温温度
dual phase steel
microstructure
mechanical properties
overaging
isothermal temperature
