高碳高硅纳米贝氏体钢回火后的组织与力学性能  

Microstructure and mechanical properties of tempered high-C-Si nano-bainite steel

作　　者：孙晓文 林诗慧 王天生[1,2] SUN Xiao-wen;LIN Shi-hui;WANG Tian-sheng(State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,China;National Engineering Research Center for Equipment and Technology of Cold Strip Rolling,Yanshan University,Qinhuangdao 066004,China)

机构地区：[1]燕山大学亚稳材料制备技术与科学国家重点实验室,河北秦皇岛066004 [2]燕山大学国家冷轧板带装备及工艺工程技术研究中心,河北秦皇岛066004

出　　处：《材料热处理学报》2021年第6期98-106,共9页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51471147)。

摘　　要：高碳高硅钢经300和340℃等温淬火后获得了纳米贝氏体组织,采用扫描电镜、透射电镜、显微硬度仪和拉伸及冲击试验等研究了其经200~600℃回火处理后的显微组织和力学性能。结果表明,在相同回火条件下,与340℃等温淬火试样相比,300℃等温淬火试样的强度、硬度和冲击韧性较高,塑性较低。纳米贝氏体组织在300℃以下具有良好的回火稳定性,450℃回火时薄膜状残留奥氏体开始分解,贝氏体铁素体板条开始合并粗化。低于450℃回火,试验钢的抗拉强度和屈服强度略有增高,伸长率和硬度变化不大。500℃回火,强度开始明显降低,塑性和冲击韧性最低,硬度升到最高而出现二次硬化。300℃回火后试验钢的冲击韧性最高,两种等温淬火试样均在300℃回火时得到最佳的综合力学性能。Nano-bainite structure of high-C-Si steel was obtained by austempering at 300℃and 340℃,and microstructure and mechanical properties of the steel after tempering at 200-600℃were investigated by means of scanning electron microscopy,transmission electron microscopy,microhardness tester and tensile and impact tests.The results show that under the same tempering temperature,compared with the steel austempered at 340℃,the strength,hardness and impact toughness of the steel austempered at 300℃are higher and the plasticity is lower.The nano-bainite microstructure has good tempering stability below 300℃and the thin film residual austenite begins to decompose during tempering at 450℃,and the bainite ferrite laths begin to merge and coarsen.When the tempering temperature is below 450℃,the tensile strength and yield strength of the steel increase slightly,and the elongation and hardness change little.After tempering at 500℃,the strength of the steel begins to decrease significantly,the plasticity and impact toughness are the lowest,and the hardness increases to the highest and secondary hardening occurs.The impact toughness of the steel after tempering at 300℃is the highest,and the comprehensive mechanical properties of the two kinds of austempered samples are the best after tempering at 300℃.

关 键 词：高碳高硅钢 等温淬火 纳米贝氏体 回火 组织 力学性能 

分 类 号：TG142.2[一般工业技术—材料科学与工程]