摘要
研究了含碳量为0.1%～0.4%的冷轧态中锰钢经650℃退火后微观组织和单轴拉伸性能的变化规律。利用SEM进行了组织形貌表征,采用XRD法测量了残余奥氏体量,通过拉伸试验机测试了钢的单轴拉伸性能。结果表明,冷轧态实验钢在退火过程中都发生奥氏体逆相变,获得具有一定量亚稳奥氏体的超细晶组织;随实验钢碳含量从0.1%增加到0.2%时,钢的抗拉强度(Rm)变化不大(约1000 MPa),而断后伸长率(A)从27%升高到43%时,强塑积(Rm×A)从28 GPa%提高到45 GPa%,而碳含量为0.4%时,钢的强度明显提高(约1200 MPa),但塑性却下降。分析认为,冷轧中锰钢中的碳有利于逆转变奥氏体的形成及稳定,但碳含量过高会形成大量碳锰化合物,不利于奥氏体的形成,从而降低塑性。亚稳奥氏体相的TRIP效应以及超细的晶粒尺寸是获得超高强度、高塑性及高强塑积的主要原因。
The effects of carbon content of 0.1%～0.4% on the microstructure and mechanical properties of cold-rolled medium manganese steel after annealing at 650 ℃ were investigated.The microstructure evolution during annealing process was characterized by scanning electron microscopy,the residual austenite content in the steel was determined by X-ray diffraction analysis,the mechanical properties of the annealed steel were measured by tensile tests.The results show that the austenite reverted transformation takes place,which results in a certain amount of austenite phase in the ultrafine grained annealed matrix.When carbon content increases from 0.1% to 0.2%,the tensile strength（Rm） changes little（about 1000 MPa）,the failure elongation（A） and the product of tensile strength and failure elongation（Rm × A） increases from 27% to 43% and from 28 GPa% to 45 GPa%,respectively.The carbon content of 0.4% significantly improves the strength of the steel（about 1200 MPa）,but the plasticity decreases.Analysis thinks that the carbon of cold-rolled medium manganese steel is conducive to the formation of reverted austenite and its stability.However,high carbon content can help form a large number of carbides,which is not conducive to the formation of austenite,reducing the plasticity.The Rm,A and Rm × A are attributed to the enhanced TRIP effects of the large fractioned metastable austenite and the superfine grain size.
出处
《热加工工艺》
CSCD
北大核心
2012年第2期5-8,27,共5页
Hot Working Technology
基金
国家"863"项目(2009AA033401
2009AA03Z519)
国家"973"项目(2010CB630803)
关键词
碳含量
冷轧中锰钢
双相区退火
亚稳奥氏体
TRIP效应
carbon content
cold-rolled medium Mn steel
intercritical annealing
metastable austenite
TRIP effects
