摘要
为了揭示极端高温暴晒服役条件和火灾服役条件下DP800钢的力学性能,采用“加热-保温-空冷”与“加热-保温-水冷”方法分别模拟两种高温服役条件,通过显微组织观测和静载拉伸试验研究高温服役后DP800钢的微观组织形貌特征和力学性能变化规律。结果表明:不同高温空冷条件下(室温~200℃),DP800钢的组织均为铁素体和分布在其晶界上的岛状马氏体,随着服役温度的升高和时间的增加,其力学性能得到明显改善;高温水冷对DP800钢的微观组织和力学性能影响显著,随着服役温度的不断升高,两种保温时间下DP800钢的微观组织均经历了“马氏体铁素体化(300~700℃)→铁素体+马氏体双相组织(700~900℃)”的变化规律,其抗拉强度和屈服强度均呈现出“不断下降(300~700℃)→持续增大(700~850℃)→再次下降(850~900℃)”的变化规律。采用非线性回归法,构建了服役时间不超过60 min时高温水冷条件下DP800钢的抗拉强度、屈服强度随服役温度变化的经验预测模型,最大预测误差仅为7.88%,该模型可为高温服役后DP800钢力学性能变化评价提供理论参考。
In order to reveal the mechanical properties of DP800 steel under extreme high temperature exposure and fire service conditions,the“heating-holding-air cooling”and“heating-holding-water cooling”methods were used to simulate two high temperature service conditions.The microstructure morphology characteristics and mechanical property changes of the DP800 steel after high temperature service were studied by microstructure observation and static load tensile test.The results show that under different high-temperature air cooling conditions(room temperature-200℃),the microstructure of the DP800 steel is ferrite and island-like martensite which is distributed at the ferrite grain boundaries.With the increase of service temperature and time,the mechanical properties of the DP800 steel are improved.High temperature water cooling has a significant impact on the microstructure and mechanical properties of the DP800 steel.With the continuous increase of service temperature,the microstructure of the DP800 steel undergoes a change law of“martensite ferritization(300-700℃)→ferrite+martensite dual phase structure(700-900℃)”under both holding time,and the tensile strength and yield strength show a change law of“continuous decrease(300-700℃)→continuous increase(700-850℃)→decrease again(850-900℃)”.Using nonlinear regression method,an empirical model for predicting the changes of the tensile strength and yield strength of the DP800 steel under high-temperature water cooling conditions with service time not exceeding 60 min with service temperature is constructed,and the maximum prediction error is only 7.88%,which can provide theoretical reference for the evaluation of the mechanical properties of the DP800 steel after high-temperature service.
作者
缑瑞宾
徐浩
于敏
师泽宇
石文可
GOU Rui-bin;XU Hao;YU Min;SHI Ze-yu;SHI Wen-ke(College of Mechanical Engineering,Anhui Science and Technology University,Fengyang 233100,China;Faculty of Materials and Manufacturing,Beijing University of Technology,Beijing 100124,China;College of Architecture,Anhui Science and Technology University,Bengbu 233000,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2024年第3期148-157,共10页
Transactions of Materials and Heat Treatment
基金
安徽省教育厅科学研究重点项目(2022AH051630,KJ2021A0862)。
关键词
双相高强钢
DP800
高温服役
力学性能
微观组织
dual phase steel
DP800
high temperature service
mechanical property
microstructure
