研究了淬火冷却工艺对含0.2%体积分数、0.2~1.2mm粒径ZrC的20Mn2钢在大形变量轧制后的组织与力学性能的影响。性能测试结果表明，在水淬状态下，20Mn2的σb=1854Mpa、σ0.2=1722Mpa、δ5=12.6%，经200℃×200min低温回火的σb=1685Mpa、σ0.2=1582Mpa、δ5=14.1%，；在油淬状态下，20Mn2的σb=1073Mpa、σ0.2=839Mpa、δ5=19%,经200℃×200min低温回火的σb=1039Mpa、σ0.2=810Mpa、δ5=21.1%。研究表明，ZrC粒子作为大形变量热轧变形中的奥氏体形变核心及再结晶核心，对奥氏体晶粒的超细化起到了显著作用，而显著细化的晶粒提高了完全获得马氏体组织的临界冷却速度，使水冷淬火态的马氏体数量、长度和宽度减小，使油淬态珠光体数量减少、渗碳体片变短变薄。同时在冷却过程中，细小的奥氏体晶粒转变为更为细小（1～2mm）的铁素体晶粒，并保留了热轧变形时的形变位错组织，这些组织使20Mn2钢水淬态在保持延伸率不下降的同时强度成倍提高，使油淬态在强度大幅度提高的同时延伸率成倍提高。
Effect of quenching process on the microstructure and mechanical property of 20Mn2 steel containing ZrC of 0.2% in volume fraction and 0.2~1.2μm in diameter after rolling with large total reduction has been investigated.Experimental results show that at state qenched in water, the mechanical property of 20Mn2 reaches σb=1854Mpa、σ0.2=1722Mpa、δ5=12.6%，after tempered at 200℃ for 200min，that of 20Mn2 reachesσb=1685Mpa、σ0.2=1582Mpa、δ5=14.1%；in the state quenched in oil，that of 20Mn2 reaches σb=1073Mpa、σ0.2=839Mpa、δ5=19%，after tempered at 200℃ for 200min，that of 20Mn2 reachesσb=1039Mpa、σ0.2=810Mpa、δ5=21.1%．It is indicated that ZrC partical plays an obvious active role in grain super-refining of austenite by acting as a deformation nucleus and recrystallization nucleus,and obvious refined grain increases critical cooling rate for obtaining matensite that decreases the number、length and width of matensite in water-quenching state，and the number of pearlite in oil-quenching state while ferric carbide becomes shorter and thinner．Meanwhile，in subsequent cooling refined austenite grain transforms to a finer ferrite grain（1~2 um），and keeps in deformed microstructrue in hot rolling，which leads to a double increase in the strength of 20Mn2 in water-quenching state without decrease in enlogation，and a double increase in enlogation of oil-quenching state with a concurrent great increase in the strength．
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