奥氏体化温度对改良型T23铁素体耐热钢微观组织与力学性能的影响  

Effect of Austenitization Temperature on the Microstructure and Mechanical Properties of Modified T23 Ferritic Heat-resistant Steel

作　　者：胡涛麟 刘静[1] 刘宏扬 范泽邦 葛锐 HU Taolin;LIU Jing;LIU Hongyang;FAN Zebang;GE Rui(The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430080,China)

机构地区：[1]武汉科技大学冶金与耐火材料国家重点实验室,武汉430080

出　　处：《安徽工业大学学报（自然科学版）》2024年第6期594-602,共9页Journal of Anhui University of Technology（Natural Science）

基　　金：湖北省JD攻关项目(2023BAA019);湖北省重点研发计划项目(2021BAA058)。

摘　　要：对改良型T23铁素体耐热钢试样进行不同奥氏体化温度的热处理试验,通过金相显微镜、扫描电镜、透射电镜对经不同奥氏体化温度处理试样的微观结构进行表征,且对其进行常温力学性能进行测试分析;结合采用Thermo–Calc热力学软件计算的T23铁素体耐热钢平衡相图,探讨C,N,V等元素在钢中基体和第二相间的分配关系,揭示奥氏体化温度对改良型T23铁素体耐热钢显微组织和力学性能的影响。结果表明:在1080~1140℃奥氏体化温度范围,随温度的升高,钢中的晶粒尺寸逐渐增大,贝氏体板条不断粗化,碳化物尺寸逐渐减小。当奥氏体化温度为1080℃时,细化的贝氏体板条可为碳化物聚集长大提供条件,钢中碳化物呈现团簇聚集倾向;当奥氏体化温度升至1120℃时,晶粒内部的贝氏体板条明显粗化,合金元素在基体中的固溶度提高,碳化物的形核位点减少且弥散化程度大大提升。同时,随奥氏体化温度的升高,改良型T23铁素体耐的屈服强度和抗拉强度呈现先降低后增加的趋势,延伸率呈现先增加后降低的趋势,这主要是由于晶粒尺寸、碳化物的尺寸与分布、合金的固溶强化随奥氏体化温度变化而产生的耦合作用所致。Heat treatment tests were conducted on the modified T23 ferritic heat-resistant steel samples at different austenitization temperatures.The microstructures of the samples treated at various austenitization temperatures were characterized by metallographic microscope,scanning electron microscope and transmission electron microscope.Additionally,room temperature mechanical property tests were performed and analyzed.Combining the equilibrium phase diagram of T23 ferritic heat-resistant steel calculated by Thermo–Calc thermodynamic software,the distribution relationship of elements such as C,N,and V between the matrix and secondary phases in the steel were explored,and the effect of austenitization temperature on the microstructure and mechanical properties of the modified T23 ferritic heat-resistant steel was revealed.The results show that in the austenitizing temperature range of 1080–1140℃,with the increase of temperature,the grain size in the steel gradually enlarges,the bainite laths continuously coarsen,and the carbide size gradually decreases.When the austenitization temperature is 1080℃,the refined bainite laths provide conditions for the aggregation and growth of carbides,leading to a tendency for carbides to cluster together.When the austenitization temperature rises to 1120℃,the bainite laths within the grain obviously coarsen,the solid solubility of alloy elements in the matrix increases,the nucleation sites of carbides decrease and the dispersion degree is greatly improves.At the same time,with the increase of austenitization temperature,the yield strength and tensile strength of the modified T23 ferritic heat-resistant steel first decrease and then increase,while the elongation first increases and then decreases.This is mainly due to the coupled effects of changes in grain size,carbide size and distribution,and solid solution strengthening of the alloy with the austenitizing temperature.

关 键 词：铁素体耐热钢 热处理 奥氏体化 析出相 力学性能 微观结构 平衡相图 

分 类 号：TG[金属学及工艺]