终锻温度对Nb-V-Ti复合非调质钢组织及性能的影响

通过金相、扫描、透射电镜研究不同锻造工艺下V-Ti、Nb-V-Ti两种微合金化非调质钢的微观组织结构及力学性能。结果显示:添加Nb能够显著提高非调质钢的奥氏体粗化温度,有效阻止奥氏体晶粒的快速长大,细化非调质钢晶粒,降低珠光体层片间距,使渗碳体呈粒状或球状分布;另外,添加的Nb促进V-Ti非调质钢中细小含铌碳化物的弥散析出,细化基体组织,同时提高非调质钢的强度。因此,Nb-V-Ti复合微合金化非调质钢经过未再结晶区变形后可获得均匀细小的铁素体-珠光体双相组织,且在相对较低的温度进行形变处理能够有效改善Nb-V-Ti微合金非调质钢的强韧性。

Effect of forging process on microstructure and property of Nb-V-Ti microalloyed non-quenched and tempered steel

The microstructure and mechanical properties of V-Ti,Nb-V-Ti microalloyed non-quenched and tem-pered steel were investigated by optical microscopy,scanning electron microscopy,transmission electron microsco-py.The results show that niobium addition could raise the coarsening temperature of austenite,effectively inhibit quick growth of austenite,and reduce the grain size and space of pearlite lamellar.The rod cemenite gradually transformed into granular or spherical cemenite.Additionally,Nb could promote the precipitation of fine-dispersed carbides in V-Ti alloyed non-quenched and tempered steel.Therefore,after non-recrystallization region deforma-tion,the Nb-V-Ti alloyed steel could obtain the fine dual phase structure with ferrite and pearlite.and the relative-ly low temperature deformation could further improve the strength and toughness of Nb-V-Ti non-quenched and tempered steel.