欧标低合金结构钢粗晶热影响区组织和韧性的热模拟研究  

Thermal Simulation of Microstructure and Toughness of Coarse-grained HAZ of European Standard Low Alloy Structural Steel

作　　者：杜士青[1] 洪永昌[1] 孙希庆[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》2010年第2期35-41,共7页Heat Treatment

摘　　要：利用Gleeble-3500热模拟试验机模拟粗晶热影响区的焊接热循环,研究了热输入对欧标低合金结构钢粗晶热影响区晶粒长大、硬度及韧性和组织的影响。结果表明,随着峰值加热温度的提高和高温停留时间的延长,奥氏体晶粒将发生不同程度的长大,粗晶热影响区的最高硬度也逐渐提高;同时随着t_(8/5)的延长,粗晶热影响区的组织将由少量低碳马氏体、针状铁素体以及粒状贝氏体和大量块状铁素体组织,逐渐转化为大量侧板条贝氏体、粒状贝氏体以及粗大长条状M-A组元,甚至出现一定数量的上贝氏体,使得粗晶热影响区的低温冲击韧度急剧下降,由低温韧性断裂转化为低温脆性断裂。The effect of heat input on grain growth, hardness, toughness and microstructure of coarse-grained heat affected zone （HAZ） of European standard low alloy structural steel was investigated through simulating weld thermal cycle of the coarse-grained HAZ by means of Gleeble-3500 machine. The results show that with the increase of peak temperature and the prolongation of duration at the temperature the austenite grains of the steel will grow to different derees, and the maximum hardness of coarse-grained zone will gradully increase as well. Meanwhile, with the prolongation of ts/5 a small amount of low carbon marensite, acicular ferrite and granular bainite and a great deal of blocky ferrite will be changed to a large amount of strip bainite, granular bainite and coarse strip M-A component in the coarse-grained HAZ, resulting in sudden drop of the low temperature impact toughness and conversion of the low temperature ductile fracture to the low temperature brittle fracture so for as the coarse-grained HAZ.

关 键 词：结构钢 热影响区 热模拟 组织 韧性 

分 类 号：TG142.41[一般工业技术—材料科学与工程]