等温淬火对球墨可锻铸铁力学性能的影响  

Effects of Austempering Temperature and Time on Mechanical Properties of Spheroidal Graphite Malleable Cast Iron

作　　者：刘生发[1] 艾小玲[2] 

机构地区：[1]武汉理工大学材料科学与工程学院,湖北武汉430070 [2]武汉职业技术学院机械工程系,湖北武汉430074

出　　处：《现代铸铁》2005年第1期7-11,共5页Modern Cast Iron

摘　　要：研究了等温淬火温度与时间对球墨可锻铸铁组织和性能的影响。试样成分(wB/%)为:3.0C,1.8Si,0.4Mn,0.1P,0.1S。采用中频炉熔炼,用稀土镁球化剂进行球化处理,孕育剂为Bi+FeSi。热处理工艺为:加热至920℃,保温120min,然后分别在370℃、325℃、280℃和235℃等温淬火60min,以研究等淬温度对性能和组织的影响;为研究等温时间的影响,分别在370℃等温15min、30min、60min和120min;在325℃等淬30min、60min和120min。结果表明,在370℃等淬60min所得到的奥贝球墨可锻铸铁具有最佳的综合力学性能(σb≥950MPa,δ>5%,αk>50J/cm2)。而且,等淬温度在325～370℃之间波动,等淬时间在60～120min之间变化,力学性能仍能维持在较高的水平。The influences of austempering temperature and duration on structures and mechanical properties of S. G. malleable iron were investigated. The composition of the test block was (w B / %):3.0 C, 1.8 Si, 0.4 Mn, 0.1 P, 0.1 S. An Induction furnace was used to melt the iron, RE-Mg-Si-Fe alloy and Bi+FeSi was used as nodularizing agent and inoculant respectively. The heat treatment process was: heating to 920 ℃ and holding for 120 min, austempering at 370 ℃,325 ℃,280 ℃ and 235 ℃ of 60 min to investigate the influence of austempering temperature on structure and properties. To investigate the influence of austempering duration on structure and properties, the samples was austempered at 370 ℃ for 15 min, 30 min, 60 min and 120 min;as well as tempered at 325 ℃ for 30 min,60 min and 120 min. The results showed that the austenite-bainite S. G. malleable iron austempered at 370 ℃ for 60 min has best comprehensive properties: σb≥950 MPa,δ>5%,αk>50 J / cm2. Moreover, the properties of austenite-bainitie S. G. malleable iron could be kept still at quite high level when the austempering temperature was fluctuating between 325～370 ℃,and austempering duration was changed between 60～120 min.

关 键 词：球墨可锻铸铁 等温淬火 力学性能 

分 类 号：TG156.31[金属学及工艺—热处理]