铸件厚度与热处理对RuT450蠕墨铸铁微观组织与力学性能的影响  

Effects of Casting Thickness and Heat Treatment on Microstructure and Mechanical Properties of RuT450 Compacted Graphite Iron

作　　者：孙志康 刘含莲[1,2] 郭毅 季良刚 苏瑞 牛佳慧 黄传真 SUN Zhikang;LIU Hanlian;GUO Yi;JI Lianggang;SU Rui;NIU Jiahui;HUANG Chuanzhen(Key Laboratory of High-efficiency and Clean Mechanical Manufacture(Shandong University),Ministry of Education,Jinan 250061,China;Centre for Advanced Jet Engineering Technologies,Shandong University,Jinan 250061,China;Jinan Power Co.,Ltd.,China National Heavy Duty Truck Group Co.,Ltd.,Jinan 250200,China;School of Construction Machinery,Shandong Jiaotong University,Jinan 250357,China;School of Mechanical Engineering,Yanshan University,Qinhuangdao 066000,China)

机构地区：[1]山东大学高效洁净机械制造教育部重点实验室,山东济南250061 [2]山东大学先进射流工程技术研究中心,山东济南250061 [3]中国重汽集团济南动力有限公司,山东济南250200 [4]山东交通学院工程机械学院,山东济南250357 [5]燕山大学机械工程学院,河北秦皇岛066000

出　　处：《热加工工艺》2024年第18期13-18,共6页Hot Working Technology

基　　金：国家自然科学基金项目(52075300);河北省全职引进国家高层次创新型人才科研项目(2021HBQZYCXY004)。

摘　　要：对重卡发动机的蠕墨铸铁缸体不同厚度部分进行取样,采用3D激光显微镜、扫描电子显微镜、电子万能材料试验机以及X射线应力分析仪等分析测试手段,研究了不同铸造厚度蠕墨铸铁RuT450的显微组织、蠕化率、表面残余应力、布氏硬度、拉伸强度等性能,还研究了去应力退火、不同时长的自然时效处理下蠕墨铸铁RuT450的组织变化和力学性能演变规律。结果表明:相对较厚的蠕墨铸铁铸件石墨蠕化率较高;蠕墨铸铁的铸态表层残余应力为压应力,且随试样厚度的增加而逐渐增大;在保证强度指标的前提下适度的退火处理比自然时效能更高效地释放表面残余应力;蠕墨铸铁表面硬度及强度随着试样厚度的增加而逐渐降低,退火处理可进一步降低表面硬度和强度。该研究结论对蠕墨铸铁切削性能评价及优选切削加工工艺提供了重要的理论依据。Different thickness parts of compacted graphite cast iron(CGI)cylinder blocks were sampled from heavy truck engines.The microstructure,vermicular rate,residual stress,hardness,and tensile strength of CGI RuT450 with different casting thickness were investigated by using 3D laser microscope,scanning electron microscope(SEM),electronic universal testing machine(UTM),and X-ray stress analyzer,as well as the microstructure changes and mechanical properties of CGI RuT450 after stress relief annealing and natural aging.The results show that the graphite vermicular rate of thicker CGI castings is higher,and the compressive stress that characterizes the as-cast surface residual stress of CGI increases progressively with the increase of the sample thickness.A mild annealing treatment can remove surface residual stress more effectively than natural time efficiency on the premise of ensuring strength index.With an increase in sample thickness,the surface hardness and strength steadily reduce,and annealing treatment can further weaken the surface performance.The research offers a crucial theoretical guidance for assessing cutting performance and optimizing the cutting process of CGI.

关 键 词：蠕墨铸铁 铸件厚度 退火 时效处理 蠕化率 微观组织 力学性能 

分 类 号：TG164[金属学及工艺—热处理]