15CrMoR钢的显微组织与时效冲击性能  

Microstuctures and aging impact properties of 15CrMoR steel

作　　者：陈广兴 许晓嫦[1] CHEN Guang-xing;XU Xiao-chang(School of Materials Science and Engineering,Central South University,Changsha 410083.Hunan,China;Technology Center,Baosteel Zhanjiang Iron and Steel Co.,Ltd.,Zhanjiang 524072,Guangdong,China)

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083 [2]宝钢湛江钢铁有限公司技术中心,广东湛江524072

出　　处：《钢铁》2022年第7期146-153,共8页Iron and Steel

摘　　要：为探索原始组织形态对15CrMoR钢时效过程低温冲击性能的影响,明确15CrMoR钢具有高时效冲击性能稳定性的原始组织形态,通过控制奥氏体化后的冷却方式获得了15CrMoR钢的3种原始组织,使用OM、SEM、EPMA和EBSD等材料结构表征方法和低温冲击测试研究了15CrMoR钢的显微组织和时效态低温冲击性能。结果表明,15CrMoR钢奥氏体化后分别以炉冷、空冷和风冷的方式冷却至室温,分别获得了粗大铁素体+片状珠光体组织、铁素体+退化珠光体组织和粒状贝氏体组织。片状珠光体组织中碳化物主要呈层片状,退化珠光体中的碳化物主要呈断续短杆状和颗粒状,粒状贝氏体中的富碳M-A岛主要沿晶界分布。3种原始组织形态的15CrMoR钢在循环时效过程中均发生了晶界碳化物析出和长大,导致低温冲击性能不断恶化。当晶界碳化物呈链状分布时,15CrMoR钢的低温冲击性能较差。粗大的铁素体+片状珠光体组织晶界面积较少,导致晶界碳化物容易呈链状分布;粒状贝氏体中主要沿晶界分布的富碳M-A岛也容易导致晶界碳化物呈链状分布。因此,原始组织为铁素体+退化珠光体的15CrMoR钢在循环时效过程中具有较好的冲击性能稳定性,经历6次循环时效后,-10℃平均冲击吸收功仍高达196 J;而原始组织为铁素体+片状珠光体和原始组织为粒状珠光体的15CrMoR钢,经历4次循环时效后,晶界处已形成呈链状分布的碳化物,-10℃平均冲击吸收功均仅为18 J。In order to explore the influence of primitive microstuctures on the low-temperature impact performance of 15 CrMoR steel during aging process and to clear the primitive microstuctures of 15 CrMoR steel with high aging impact performance stability,three primitive microstructures of 15 CrMoR steel were obtained by controlling the cooling method after austenitization.The microstructure and aging impact properties at low temperature of 15 CrMoR steel were investigated by means of OM,SEM,EPMA,EBSD and low temperature impact test.The results show that cooled to room temperature by furnace cooling,air cooling and wind cooling after austenitizing respectively,the microstructures of 15 CrMoR steel are coarse ferrite+lamellar pearlite,ferrite+degraded pearlite,and granular bainite.The carbides in the lamellar pearlite microstuctures are mainly lamellar,while mainly intermittent short rod and granular like in the lamellar pearlite microstuctures.And the carbon-rich M-A islands in granular bainite microstuctures are mainly distributed along the grain boundary.The precipitation and growth of carbides at grain boundary occurred during the cyclic aging process of the three kinds of 15 CrMoR steel with different primitive microstructures,which led to the continuous deterioration of low-temperature impact performance.When the grain boundary carbides are distributed in chains,the low-temperature impact performance of 15 CrMoR steel is poor.The coarse ferrite+lamellar pearlite microstructure has a small grain boundary area,which leads to a chain-like distribution of grain boundary carbides.And the carbon-rich M-A islands mainly distributed along the grain boundary in granular bainite can also lead to the chain-like distribution of grain boundary carbides easily.Therefor,15 CrMoR steel with the ferrite+degraded pearlite primitive microstructures has good impact performance stability during the cyclic aging process,which average impact absorption energy at-10℃is still as high as 196 J after 6 cycles of aging.However,the average im

关 键 词：15CRMOR钢 原始组织形态 碳化物 时效 冲击性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]