不同碳含量粉末烧结钢冷压流变致密化行为研究  

Study on the flow and densification behaviors of powder sintered steel with different carbon contents during clod compression

作　　者：吴辉[1] 郭彪[1] 李强 王俊桃 敖进清[1,2] 宋欢 敖逸博[1] WU Hui;GUO Biao;LI Qiang;Wang Jun-tao;AO Jin-qing;SONG Huan;AO Yi-bo(School of Materials Science and Engineering,Xihua University,Chengdu 610039,China;Jiangsu Kailai Steel Pipe Co.,Ltd.,Huaian 223001,China)

机构地区：[1]西华大学材料科学与工程学院,成都610039 [2]江苏开来钢管有限公司,淮安223001

出　　处：《粉末冶金技术》2020年第5期323-331,共9页Powder Metallurgy Technology

基　　金：国家自然科学基金资助项目(51504197);教育部春晖计划资助项目(Z2015097);四川省粉末冶金工程技术研究中心开放基金资助项目(SC-FMYJ2018-04);西华大学“青年学者后备人才”支持计划项目;西华大学研究生创新基金资助项目(YCJJ2018072)。

摘　　要：在材料万能试验机上对碳含量(质量分数)为0%、0.3%、0.6%、0.9%、1.2%的粉末烧结钢进行冷压变形试验,利用Hollomon方程对粉末烧结钢流变应力数据进行非线性拟合,结合显微组织形貌分析烧结钢冷压流变致密化行为和孔隙、晶粒变形机制。结果表明:烧结钢冷压应变硬化行为符合Hollomon方程,随着碳含量的增加,极限断裂应变量逐渐减小;在相同应变下,随着碳含量的增加,烧结钢应变硬化率逐渐上升,致密化效果先增强后减弱,在碳质量分数为0.9%时最佳;随着应变增加,烧结钢孔隙闭合,晶粒由等轴状变为片状;烧结钢的流变致密化过程在低应变下以致密化和致密化硬化为主,在高应变下以变形和基体加工硬化为主。The cold compression tests of the powder sintered steels with the carbon mass fraction of 0%, 0.3%, 0.6%, 0.9%, and 1.2% were carried out on the universal material testing machine. The tested stress-strain data were nonlinearly fitted by the Hollomon equation. The behaviors of flow and densification and the deformation mechanisms of pore and grain were analyzed, combining with the microstructure analysis of the powder sintered steels. The results show that, the cold compression strain hardening behavior of the sintered steels conforms to the Hollomon equation, and the ultimate fracture strain decreases with the increase of the carbon content. In the same strain condition, the strain hardening rate of the sintered steels increases gradually with the increase of carbon content, and the densification effect first increases and then decreases, showing the best when the carbon content is 0.9%. With the increase of strain, the pores of the sintered steels are gradually closed, and the grains change from the equiaxed crystal into the flaky structure. During the flow and densification processes, the densification and densification hardening are dominant under the low strains, while the deformation and the matrix work-hardening are dominant under the high strains.

关 键 词：烧结钢 冷压 流变 致密化 

分 类 号：TF124.8[冶金工程—粉末冶金]