V-N微合金钢在线快速感应回火工艺中V(C,N)析出强化机制  

Effects of On-Line Rapid Induction Tempering on Pricipitation Strengthening Mechanism of V(C, N) in V-N Microalloyed Steel

作　　者：李晓林 崔阳 肖宝亮 张大伟 金钊[2] 程政[2] Xiaolin LI;Yang CUI;Baoliang XIAO;Dawei ZHANG;Zhao JIN;Zheng CHENG(Beijing Key Laboratory of Green Recyclable Process for Iron ＆ steel Production Technology,Research Institute of Technology,Shougang Group Co.Ltd.,Beijing 100043,China;Shougang Jingtang Steel Company,Tangshan 063200,China)

机构地区：[1]首钢集团有限公司技术研究院绿色可循环钢铁流程北京市重点实验室,北京100043 [2]首钢京唐钢铁联合有限责任公司,唐山063200

出　　处：《金属学报》2018年第10期1368-1376,共9页Acta Metallurgica Sinica

摘　　要：利用SEM、TEM以及三维原子探针(3DAP)等分析方法,研究了V-N微合金钢在线快速感应回火过程中,不同保温时间对力学性能以及析出强化机理的影响。结果表明,未经回火组织为粒状贝氏体;经过600℃回火后,组织为粒状贝氏体+铁素体。试样在600℃回火,保温300 s,硬度和屈服强度出现峰值,分别为330.45 HV和815 MPa,与未回火试样相比,屈服强度增加了173 MPa。屈服强度的增加主要依靠V或者VN原子团簇,团簇中V、N原子的分布近似单原子层,类似析出相的GP区,其内部总的原子数量在20～100个之间,这些细小的纳米团簇与位错有较强的相互作用,与V(C, N)析出相相比,V或VN团簇具有更佳的强化效果。The low carbon bainite steel with high strength, excellent toughness and plasticity was widely used for pipeline, engineering machinery, ocean station vessel and other fields. The light weight of structure of construction machines puts forward higher requirements for performance of steel, which promotes the development and application of low carbon microalloyed steel. A low carbon bainite steel combined with V-N microalloyed was designed for engineering machinery, to upgrade performance by microstructure control and the refinement and dispersion control of precipitates. This steel was tempered on-line with rapid heating rate after controlled rolling and accelerated cooling process. Effects of different holding time under rapid induction tempering on precipitation strengthening mechanism and mechanical property of V-N microalloyed steel were investigated by using three dimensional atom probe （3DAP）, SEM and TEM. The results showed that the main microstructures of tested steel are granular bainite before tempering, and granular bainite and ferrite appears after tempering at 600 ℃. The hardness and yield strength values reached its peak at 600 ℃ tempered for 300 s, which were 330.45 HV and 815 MPa, respectively. Compared with untempered sample, the measured strengthening increment in yield strength was 173 MPa which was due to the V-rich or VN-rich clusters with 20-100 atoms distributing similar to monoatomic layer and resembled the GP zones. These small nanoclusters have strong interaction with dislocation, and compared with V（C, N） particles, V or VN clusters have better strengthening effect.

关 键 词：三维原子探针(3DAP) 在线快速感应回火 V-N微合金钢 团簇强化 

分 类 号：TG142.1[一般工业技术—材料科学与工程]