20CrMo钢不同速率分段加热奥氏体化  

Austenitizing of 20CrMo Steel by Stepped Heating at Different Rates

作　　者：王志明 韩维雪 江雁 杨凯 代孟强 黄贞益[2] WANG Zhiming;HAN Weixue;JIANG Yan;YANG Kai;DAI Mengqiang;HUANG Zhenyi(Nanjing Iron and Steel Co.,Ltd.,Nanjing Jiangsu 211500,China;Institute of Metallurgy,Anhui University of Technology,Maanshan Anhui 243000,China)

机构地区：[1]南京钢铁股份有限公司,江苏南京211500 [2]安徽工业大学冶金学院,安徽马鞍山243000

出　　处：《上海金属》2022年第3期35-43,共9页Shanghai Metals

摘　　要：采用DIL805A热膨胀仪,测定了20CrMo钢以3~180℃/min的速率加热奥氏体化过程中的膨胀量。根据杠杆原理计算了钢的奥氏体形成量。采用J-M-A方程进行了线性回归分析,以获得钢的等温奥氏体化动力学曲线。采用高温金相显微镜检测了以不同速率加热的20CrMo钢的奥氏体形成规律。结果表明:20CrMo钢的珠光体约在730~770℃开始转变为奥氏体,珠光体和铁素体约在860~890℃完全转变为奥氏体,奥氏体约在890℃以上温度达到成分均匀化。根据J-M-A方程计算的模型参数为:激活能Q约为6.014×10^(5) J/mol,n为0.607477,ln k0为62.44215;在1133 K以上温度钢中铁素体和珠光体转变为奥氏体的速率较快,转变时间在100 s以内;低于1093 K时,铁素体和珠光体转变为奥氏体的时间显著延长。Expansion amounts of 20CrMo steel during heating at rates of 3 to 180℃/min for austenizing were measured by DIL805A thermal dilatometer.The amount of austenite formation in the steel was calculated according to a lever principle.A linear regression analysis was carried out by J-M-A equation to obtain isothermal austenitizing kinetic curves of the steel.The formation law of austenite in the 20CrMo steel heated at different rates was detected by means of a high-temperature metallographic microscope.The results showed that for the 20CrMo steel,pearlite began to transform into austenite at about 730 to 770℃,both pearlite and ferrite transformed completely into austenite at about 860 to 890℃,and austenite composition homogenized at temperature above about 890℃.The model parameters calculated according to the J-M-A equation were as follows:activation energy Q value of about 6.014×10^(5) J/mol,n value of 0.607477,and ln k0 value of 62.44215.The ferrite and pearlite transformed faster into austenite at temperature above 1133 K,and the transformation time was within 100 s.The time required for both ferrite and pearlite to transform into austenite was significantly prolonged at temperature below 1093 K.

关 键 词：20CRMO钢 热膨胀 奥氏体化 J-M-A方程 

分 类 号：TG142[一般工业技术—材料科学与工程]