回火工艺对针状铁素体钢组织和性能的影响  

Effect of Temper on Microstructure and Mechanical Properties of Acicular Ferrite Steel

作　　者：康军艳[1] 余伟[1] 陈银莉[1] 

机构地区：[1]北京科技大学高效轧制国家工程研究中心,北京100083

出　　处：《钢铁》2006年第9期65-69,共5页Iron and Steel

摘　　要：对针状铁素体钢进行540～630℃回火后的组织、性能进行了研究。与轧态相比，630℃回火后钢的屈服强度提高75MPa，伸长率的平均值降低1．9％，冲击功的平均值提高1．75J。对回火前、后钢板的组织和析出物进行了对比分析，结果表明：回火后晶粒内部的位错密度减小，亚晶板条部分消失；回火后析出物粒子的平均尺寸减小；回火温度越高，析出物粒子的平均尺寸越大。630℃回火以后，在1～10nm尺度范围内的粒子分布频度增加2～3倍，铌的析出量增加了166．9％，钒的析出量增加了584．6％。细小析出物的增加和亚晶板条的部分消失是强度提高、塑性改善的主要原因。The microstructure and properties of acicular ferrite steel tempered from 540 ℃ to 630 ℃ were studied. Compared with the steel as rolled, the yield strength of steel tempered at 630 ℃ was increased by 75 MPa, the mean elongation was decreased by 1.9 % and the mean impact toughness was almost unchanged. By comparison of the microstructure and precipitates before and after tempering, it can be concluded that in tempered steel the intragranular dislocation density is lower and part of plate-like subgrains is disappeared, but the mean size of precipitates is smaller. The mean size of precipitates becomes bigger with the raise of tempering temperature. After tempering at 630 ℃, the distribution frequency （f（D）） of precipitates in the range of 1 - 10 nm is increased by two to three times, the amount of precipitated niobium and vanadium was increased by 166, 9% and 584.6% respectively. It is considered that the enhancement of strength is mainly due to the increase in number of small precipitates and disappearance of part of plate-like subgrains.

关 键 词：针状铁素体 回火 显微组织 力学性能 析出 

分 类 号：TG113[金属学及工艺—物理冶金]