终轧温度对Si-Mn系热轧双相钢组织和性能的影响

文章研究了在采用低温区大变形和轧后连续冷却工艺时,终轧温度对传统Si-Mn系热轧双相钢组织和性能的影响。结果表明,在试验工艺条件下,试验钢的最终组织均为铁素体+马氏体的双相组织。随着终轧温度(770℃~850℃)的升高,试验钢的屈服强度由415MPa急剧降低到335MPa,而抗拉强度变化不大,约为690MPa;随着终轧温度的升高,铁素体晶粒尺寸逐渐均匀,平均晶粒尺寸先增大,后减小,铁素体含量约为88%;试验钢的n值和延伸率,则随着终轧温度的升高而升高,在温度850℃时,n值达到0.23,延伸率达到28.7%。

Effect of finishing rolling temperature on the microstructure and mechanical properties of Si-Mn hot-rolled dual-phase steel

The effect of finishing rolling temperature on microstructure and mechanical properties of Si-Mn hot-rolled dual-phase steel had been studied when using large deformation in low temperature area and continuous cooling after rolling.The results reveal some facts as follows.Under the condition of the tested process,the final microstructure of the tested steel is composed with ferrite and martensite.With increase of finishing rolling temperature(770℃~850℃),the yield strength of tested steel rapidly decrease from 415MPa to 335MPa,but the tensile strength changes slightly,remaining around 690MPa;the dimension of ferrite grains become uniform,and the average size of ferrite grain increases first and then decreases,the percentage composition of ferrite is about 88%.The n-value and elongation increase with the increase of finishing rolling temperature.When the finishing rolling temperature is 850℃,the n-value is 0.23 and the elongation is 28.7%.