热处理工艺对T8钢显微组织及硬度的影响  

Influences of heat treatment process on microstructure and hardness of T8 steel

作　　者：李晓理[1] 张文凤[2] 沈明钢[1] 

机构地区：[1]辽宁科技大学材料与冶金学院,辽宁鞍山114051 [2]中国科学院金属研究所,辽宁沈阳110016

出　　处：《辽宁科技大学学报》2014年第2期138-143,共6页Journal of University of Science and Technology Liaoning

摘　　要：T8钢由于含碳量高,过剩碳化物极多,塑性和韧性差,若热处理工艺不合适,使材料在服役早期出现开裂和破碎的现象。通过SEM,OPM及XRD等试验方法,研究了T8钢组织和性能随球化退火时间、淬火温度及回火温度的变化。结果表明：T8钢在600℃球化退火2 h后,原始组织中的碳化物即可获得充分球化,以粒状形式细小均匀地分布在基体中,延长退火时间不显著改变碳化物的球化效果;试样经（770±10）℃保温,6 min油淬后,获得的隐晶马氏体组织硬度最高;试样经180~210℃回火1 h空冷后,消除了淬火过程中产生的残余应力,最终获得有球状碳化物均匀分布的隐晶马氏体组织,回火试样硬度较淬火态略有下降。Because of high carbon content,surplus carbide,poor plasticity and toughness of T8 steel,the material will crack and crush in the early service if the heat treatment process is inappropriate. The effects of spheroidizing annealing time,quenching temperature and tempering temperature on microstructure and hardness of T8 steel are studied by methods of SEM,OPM and XRD.The results show that the carbide of original microstructure is grown in spheroid and dispersed in the matrix uniformly after spheroidizing annealing at600 ℃ for 2h.Prolonging annealing time will not significantly change the effect of spheroidizing. The organization turned into cryptocrystalline martensite has the highest hardness after oil quenching at（770±10）℃ for6 min.The quenched residual stress is fully released and finally cryptocrystalline martensite with much spherical carbides is obtained after tempering at 180~210 ℃ for 1h.The tempering hardness is decreased a little by comparing with quenching.

关 键 词：T8钢 热处理 显微组织 硬度 

分 类 号：TG156.3[金属学及工艺—热处理]