轧制变形量对汽车用2205双相不锈钢组织和性能的影响

Effect of rolling deformation on microstructure and properties of 2205 dual phase steel for automotive application

对铝热法制备的铸态2205双相不锈钢进行了35%~75%变形量的轧制处理,采用X射线衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)和拉伸试验机等分析了2205不锈钢的物相组成、显微组织和力学性能等。结果表明,不同轧制变形量下2205不锈钢都由奥氏体和铁素体组成,随着轧制变形量的增加,2205不锈钢中铁素体含量逐渐增多;3种轧制变形量下2205不锈钢的组织中都可见微米晶晶粒、亚微米晶晶粒和纳米晶晶粒,且随着轧制变形量的增加,2205不锈钢中纳米晶平均尺寸增加而体积分数减少,亚微米晶平均尺寸和体积分数都逐渐增大。在轧制变形量为75%时,2205不锈钢的抗拉强度、屈服强度、伸长率和显微硬度相对普通2205不锈钢分别提高59%、73. 2%、118. 3%和24. 9%。

The as-cast 2205 duplex stainless steel prepared by thermite method was rolled with 35%-75%deformation rate.The phase composition,microstructure and mechanical properties of 2205 duplex stainless steel were analyzed by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM)and tensile testing machine.The results show that 2205 stainless steel is composed of austenite and ferrite under different rolling deformation.With the increase of rolling deformation,ferrite content in 2205 stainless steel increases gradually.Micron grain,submicron grain and nano-grain can be seen in the microstructure of 2205 stainless steel under three rolling deformation.With the increase of rolling deformation,the average size and volume fraction of nanocrystals in 2205 stainless steel increase while the volume fraction decreases,and the average size and volume fraction of submicron crystals increase gradually.When the rolling deformation is 75%,the tensile strength,yield strength,elongation and microhardness of 2205 stainless steel are59%,73.2%,118.3%and 24.9%,respectively,which are higher than those of ordinary 2205 stainless steel.