摘要
采用Gleeble-3500热模拟试验机对不同均热温度和过时效温度下的C-Si-Mn-Al系DH780双相钢进行了工艺模拟,并对不同工艺下的显微组织和力学性能进行了对比分析。结果表明:均热温度为750℃时,最终冷却后生成的马氏体占比约32%,组织中仍可见明显的带状组织。随着均热温度的升高,两相区奥氏体中的含碳量逐渐降低,冷却后生成的铁素体和马氏体等组织的形态和比例也发生变化,均热温度为820℃时,最终冷却后生成的马氏体占比约40%,同时含有少量的残留奥氏体和贝氏体,最终使得材料的抗拉强度呈下降趋势,屈服强度出现升高趋势;随着过时效温度的升高,马氏体中的碳原子向晶界扩散,过饱和度降低,高密度位错减少,残留奥氏体及部分马氏体发生分解,当过时效温度高于310℃时,最终的抗拉强度呈下降趋势,屈服强度则变化不大。当均热温度为800℃、过时效温度为320℃时,抗拉强度达到847 MPa,屈服强度为328 MPa,可以获得弥散分布的马氏体,带状组织基本消除,C-Si-Mn-Al系DH780钢的综合性能较为良好。
Effects of the soaking temperature and over-aging temperature during continuous annealing on microstructure and mechanical properties of C-Si-Mn-Al steel DH780 were investigated by using the Gleeble-3500 thermal simulator,and the microstructure and mechanical properties under different processes were compared and analyzed.The results show that when the soaking temperature is 750℃,the martensite content in the microstructure after cooling is about 32%,and there is still obvious banded structure.As the soaking temperature increases,the carbon content of austenite in the two-phase region gradually decreases,and the morphology and proportion of the ferrite and martensite formed by cooling also change.When the soaking temperature is 820℃,the microstructure after cooling is composed of about 40%martensite and a small amount of retained austenite and bainite,and ultimately,the tensile strength shows a downward trend,while the yield strength shows an upward trend.As the over-aging temperature increases,the carbon atoms in the martensite diffuse to the grain boundaries,the degree of over-saturation decreases,the high-density dislocations decrease,the retained austenite and part of the martensite decompose,and when the over-aging temperature is higher than 310℃,it leads to a downward trend in the final tensile strength and the change of the yield strength is not significant.When the soaking temperature is 800℃and the over-aging temperature is 320℃,the tensile strength is 847 MPa and the yield strength is 328 MPa,which can obtain dispersed martensite and basically eliminate the banded structure.The C-Si-Mn-Al steel DH780 can obtain relatively good comprehensive properties.
作者
王淑华
王朝
杨峰
逯志强
冯硕
刘爱平
Wang Shuhua;Wang Zhao;Yang Feng;Lu Zhiqiang;Feng Shuo;Liu Aiping(Technology Center,Tangshan Iron and Steel Group Co.,Ltd.,Tangshan Hebei 063016,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2024年第12期52-56,共5页
Heat Treatment of Metals
关键词
DH780钢
均热温度
过时效温度
力学性能
DH780 steel
soaking temperature
over-aging temperature
mechanical properties
