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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。
The microstructures and mechanical properties of V-Ti and Nb-V-Ti micro-alloyed non-quenched and tempered steels were investigated by metallography, scanning and transmission electron microscopy. The results show that adding Nb can significantly increase the austenite coarsening temperature of non-quenched and tempered steel, prevent the rapid growth of austenite grains, refine the non-quenched and tempered steel grains, reduce the pearlite layer spacing, In addition, the addition of Nb promotes the dispersion and precipitation of fine niobium-containing carbides in the V-Ti non-quenched and tempered steel, refining the matrix structure and improving the strength of the non-quenched and tempered steel. Therefore, Nb-V-Ti composite microalloying non-quenched and tempered steel can be obtained after the deformation of the non-recrystallization region uniform fine ferrite - pearlite dual phase structure, and at relatively low temperatures for deformation can be effectively improved Strength and Toughness of Nb-V-Ti Microalloy Non-quenched and Tempered Steel.