高铝304奥氏体不锈钢温轧态的组织和性能研究

Microstructure and Properties Study of Warm-rolled 304 Austenite Stainless Steel with High Al Content

采用高铝304不锈钢为对象,对其进行温轧处理,研究铝含量和温轧变形量对微观组织和性能的影响规律,利用光学显微镜(0M)、电子探针(EPMA)和扫描电子显微镜(SEM)分析了合金的表面形貌和表面成分。结果表明:组织主要由灰色的奥氏体相和浅黑色的铁素体相组成,黑色析出物是由氮化铝和其他碳化物所组成的富集相,随铝含量增大,铁素体的含量增高。铝含量为1%的试样三种轧制变形量下的屈服强度分别是285,266,273 MPa,而含铝量为1.5%的试样屈服强度分别是350、365、322 MPa;合金的断口都是由大的等轴韧窝(5-30»m)和旁边排布的较小韧窝(W5»m)所构成,不同变形量下的断裂方式均是韧性断裂;含铝量为1%的试样具有较高的抗拉强度,而铝含量为1.5%的试样具有较高的屈服强度,高铝不锈钢各项性能指标有很大改善,对工业生产具有重要意义。

304 austenite stainless steels with high Al content were warm-rolled and subsequently solution-treated.The effects of Al content and deformation amount on microstructure and properties were investigated.The surface appearance and composition were analyzed by means of OM,EPMA and SEM.The results show that the alloys are composed of gray austenite phase and black ferrite phase.The precipitates consist of an enriched phase containing aluminum nitride and other carbides.With the increasing of Al content,the volume fraction of ferrite increases.The yield strengths of the alloys with 1% Al under different deformation amount are 285 MPa,266 MPa and 273 MPa,respectively.Nevertheless,the yield strengths of the alloys with 1.5% Al are 350 MPa,365 MPa and 322 MPa,respectively.The fracture surfaces of the alloys are composed of large isometric dimples(5~30 μm) and smaller dimples(≤5 μm) arranged next to each other.The fracture models belong to ductile fracture.The alloys with 1% Al have higher tensile strength,while the sample with 1.5% Al has higher yield strength.The performance indicators of the samples are improved greatly,which provides important guidance for industrial production.