不同Al含量17-7PH钢热轧加工后的组织和性能

Effect of aluminum content on microstructure and properties of 17-7PH steels after hot-rolling

通过压力机和热轧机对WS-4非自耗真空电弧炉熔炼制备的Al质量分数为1%、1.5%、2%、2.5%、3%、3.5%的17-7PH钢进行开坯轧制,利用X射线衍射仪、光学显微镜、带能谱仪的场发射扫描电镜、拉伸试验和腐蚀试验,研究了不同Al含量17-7PH钢热轧加工后的组织和性能。结果表明,热轧后Al元素大部分以置换固溶体的形式存在;随着Al含量的增加,基体组织由M+F+残留A转变为F+A,合金的的断裂机理由韧窝加解理变为解理,均匀腐蚀速率先减小后增大,转变点均为2.5%;合金的抗拉强度随Al含量增加先提高后降低,而屈服强度和伸长率均先降低后升高再降低;Al含量为2%的合金综合性能较好。

17-7PH steels with 1%,1.5%,2%,2.5%,3%,3.5% aluminium content were prepared in WS-4 non-consumption of vacuum arc furnace and then cogged and rolled on press and hot-roller.Effect of aluminum content on microstructure and properties of 17-7PH steels after hot-rolling was investigated by means of X-ray diffraction analyzer( XRD),optical microscopy( OM),scan electron microscopy( SEM) equipped with an energy dispersive spectroscopy( EDS),tensile tests and corrosion tests.The results show that most of the aluminum is in the form of substitution solid solution after hot-rolling.With the increasing Al content,the matrix structure transforms from martensite + ferrite + retained austenite to ferrite + austenite,the fracture mechanism of the alloys changes from dimple and cleavage to cleavage,uniform corrosion rate decreases first and then increases,all of the transformation points are 2.5%.The tensile strength of the alloys firstly increases then decreases,while the yield strength and elongation decrease first then increase and decrease again with the increasing content of Al.The alloy containing 2% Al has better comprehensive performance.