ZrC粒子对低碳钢晶粒细化及力学性能的影响

Effect of ZrC particle on grain refining and properties of low-carbon and low-alloy steel

在低碳低合金钢熔炼过程中加入平均粒径为 0 .5 μm ,体积分数为 0 .8%的ZrC粒子 ,研究了不同轧制变形量条件下的晶粒细化行为及力学性能 .轧制变形过程中在ZrC粒子周围形成高位错密度和高晶格畸变区 ,成为形变核心和再结晶核心 ,促进了高温奥氏体非自发再结晶细化奥氏体晶粒 ;由于奥氏体晶粒尺寸细化 ,奥氏体晶界面积增大 ,随后进行的铁素体相变的铁素体形核位置增多 ,从而大大细化了铁素体晶粒尺寸 ;轧制变形量与ZrC粒子体积分数存在一定的最佳配合才能对晶粒细化有作用 .本实验中轧制变形量为 62 % ,ZrC粒子体积分数 0 .8%以及轧后水冷条件下 ,铁素体晶粒尺寸细化到 9.8μm ,屈服强度和抗拉强度明显提高 ,分别达到 3 86.4MPa和 5 2 2 .1MPa ;同时冲击吸收功 (AKV=118.5J)不降低且延伸率 (δ5=3 4 .5 % )有所提高 。

By adding ZrC particles of average diameter 0.5 μm and volume fraction 0.8% into low carbon steel when melting, grain refining response and mechanical properties of the test steel were investigated. The region of high density of dislocation and distorted lattice can be produced around ZrC particles during hot rolling process, which, therefore, can promote recrystallization to refine austenite grain size and subsequent ferrite grain size at elevated temperature. The study indicated that in the condition of 62% rolling reduction and water quench after hot rolling, average ferrite grain size was refined to 9.8 μm and yield strength and ultimate tensile strength increased to 386.4 MPa and 522.1 MPa respectively, while toughness ( A KV =118.5 J) and ductility ( δ 5=34.5%) of the test steel did not decrease.