摘要
研究了在不同双相处理工艺条件下加Nb(0.033%)和加Cr(0.44%)两种低碳低硅冷轧双相钢的组织演变规律和性能特点。分析了合金元素Cr和Nb对双相组织中马氏体体积分数、马氏体形态和铁素体晶粒尺寸的影响。结果表明,Nb的作用主要是通过NbC粒子的析出阻碍再结晶晶粒的长大,从而在同样较低温度热处理工艺条件下,加Nb双相钢中的铁素体晶粒较细。随着处理温度的升高,当相变先于再结晶发生时,NbC对细化晶粒的作用不明显,因而加Nb和加Cr钢具有相近的铁素体晶粒尺寸。Cr提高奥氏体形成温度,导致双相处理时奥氏体的体积分数以及淬火后马氏体的体积分数的减少。力学性能分析表明,在同样的双相处理条件下,加Nb钢具有较高的强度和较低的屈强比;而加Cr钢则表现出较好的塑性。
Microstructure evolution and mechanical properties of two cold rolled low carbon and low silicon dual-phase steels with Nb alloying （0.033 % ） or Cr alloying （0.44 % ） respectively were investigated under different intereritieal annealing processes. Effect of alloying elements Cr and Nb on volume fraction of martensite, mierostructural morphology and ferrite grain size were analyzed. Experimental results indicate that Nb could suppress the growth of recrystallization grains by means of precipitation of NbC particles. Therefore, finer ferrite grain size was observed in Nb alloyed samples heated at lower temperature. However, similar ferrite grain size were obtained both in Nb alloyed and Cr alloyed steels as the heating temperature increased, while the phase transformation was prior to recrystallization and the effect of NbC on grain size became neglectable. The volume fraction of martensite in Cr alloyed steel was lower after quenching than that in Nb alloyed steel because lower volume fraction of austenite at the heating temperature since Cr increased the austenitizing temperature. Higher strength and lower ratio of yield strength to tensile strength were obtained in Nb alloyed steel, but better plasticity was obtained in Cr alloyed steel under the same thermal processing.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2009年第1期96-99,103,共5页
Transactions of Materials and Heat Treatment
关键词
高强度双相钢
合金元素
晶粒细化
组织性能
high slrength dual phase steel
alloying elements
refinement of grain size
microstructure and properties
