正火处理对破碎铁素体球墨铸铁组织和性能的影响  

Effect of Normalizing Treatment on Microstructure and Properties of Broken Ferrite Ductile Iron

作　　者：赖毅翔[1] 周秉文[1] 刘恒乐 王赛赛[1] 蔡勇 贾非[1] 张国辉 张兴国[1] 

机构地区：[1]大连理工大学材料科学与工程学院,辽宁大连116024 [2]辽宁北方曲轴有限公司,辽宁本溪117100

出　　处：《铸造》2013年第7期607-611,共5页Foundry

摘　　要：为了提高球墨铸铁曲轴的强度和韧性，对铸态球铁进行不完全奥氏体化正火处理，在球铁基体内获得了珠光体及分散状的破碎铁素体组织。分析正火保温温度及保温时间对球墨铸铁组织和性能的影响，发现在奥氏体、铁素体和石墨的三相共存区内，随着保温温度的升高、保温时间的延长，正火后球铁基体中珠光体含量增加、铁素体含量下降，试样的强度、硬度呈上升趋势，韧性塑性有一定的下降。在860～870℃下保温1．5h的曲轴，具有最佳的综合力学性能。Abstract： In order to improve the strength and toughness of the ductile iron crankshaft, an incomplete austenitizing normalizing treatment has been carried out on the as-cast ductile iron, and pearlite and dispersed broken ferrite appeared in the matrix of ductile iron. By analyzing the effect of temperature and holding time on the microstructure and mechanical properties of ductile iron, it is found that in the three-phase coexistence region ofaustenite, ferrite and graphite, with the increase of temperature and holding time, the content ofpearlite increases, while that of ferrite decreases after normalizing. At this moment, the strength and hardness of the sample rise and the toughness and plasticity decline to some extent. The crankshaft which was treated in 860-870 ℃ and held in this temperature for 1.5 h has the best comprehensive mechanical properties.

关 键 词：破碎铁素体球铁 正火 热处理 显微组织 力学性能 

分 类 号：TG156.4[金属学及工艺—热处理]