预备热处理工艺对9Cr2Mo钢组织和硬度影响  

Effect of Preliminary Heat Treating Cycle on Microstucture and Hardness of 9Cr2Mo Steel

作　　者：单军战[1] 洪永昌[1] 

机构地区：[1]安徽工业大学材料科学与工程学院,安徽马鞍山243002

出　　处：《热处理》2013年第5期27-32,共6页Heat Treatment

摘　　要：利用金相显微镜、扫描电镜等试验手段,研究了经不同工艺预备热处理的9Cr2Mo钢的显微组织和碳化物形态、分布及大小,并测定了表面硬度。结果表明,9Cr2Mo钢淬火或正火态组织均为马氏体和下贝氏体,还有少量的未溶碳化物及残留奥氏体。钢的淬火组织中马氏体量要比正火组织中的多。经淬火+高温回火或正火+球化退火的9Cr2Mo钢,其组织均为铁素体基体和不同尺寸的碳化物颗粒,硬度基本能满足切削加工的要求。而经890℃×30 min油淬+690℃×10 h回火的钢,其组织中碳化物颗粒较均匀细小,是一种良好的预备热处理组织。Microstructure,morphology and distribution as well as size of carbides in 9Cr2Mo steel preliminary heat treated by different procedures were investigated by means of metallographic microscope and SEM , and its surface hardness was measured too .The results show that the microstructure of 9Cr2Mo steel after quenching or normalizing consists of martensite , lower bainite and small amount of undissolved carbide and retained austenite , and that amount of martensite in the as-quenched steel is more than that in the as-normalized steel .Furthermore , the microstructure of 9Cr2Mo steel hardened and high-temperature tempered or normalized and spheroidized is ferritic matrix with carbide particles different in size , and the resulting hardness is so low that the steel may be smoothly machined .After heating at 890 ℃for 30 min and oil quenching followed by tempering at 690 ℃for 10 h the steel offers fine and uniform carbides which is a proper microstructure developed by preliminary heat treating .

关 键 词：9CR2MO钢 预备热处理 组织 硬度 

分 类 号：TG115.21[金属学及工艺—物理冶金]