退火时间对超纯铁素体含铜不锈钢组织与性能的影响

Effects of annealing time on microstructure and properties of ultra purified ferritic stainless steel containing copper

为开发具有抗菌性能的超纯铁素体不锈钢,添加1.4%Cu于21%Cr铁素体不锈钢,研究了退火时间对试验钢组织、抗菌性能以及力学性能的影响。利用光学显微镜和透射电镜等微观分析方法对不同退火工艺试验钢进行了组织结构表征,利用电子背散射衍射测量了试验钢的微观织构,通过拉伸试验机测试了钢的拉伸性能。结果表明,退火时间1 h后,抗菌性能超过99%,屈服强度347 MPa,抗拉强度488 MPa,伸长率29.2%。随着退火时间的延长,析出相形貌由球状转变为杆状,尺寸增大,间距减小。试验钢的抗菌性能与铜的存在形式、析出量及形态有关,尺寸为500 nm左右的杆状铜析出相具有优良的抗菌效果。试验钢退火1 min时,析出相与基体呈半共格关系,强化作用最强。试验钢的第二相的临界转化尺寸为30 nm。

For developing the ultra purified ferritic anti-bacterial stainless steel,1. 4%Cu was added in 21%Cr ferritic stainless steel. Effects of annealing time on microstructure,mechanical properties and antibacterial property were analyzed. Microstructure of the steel after different annealing were investigated by means of optical microscope and transmission electron microscopy. Microtexture of the steel was measured by electron back scattering diffraction analysis and the mechanical properties were measured by tensile tester. The results show that the antibacterial rate of the steel annealed for 1 h is more than 99%,the yield strength is 347 MPa,tensile strength is 488 MPa,and the total elongation is 29. 2%. With the increase of annealing time,the morphology of the spherical precipitates change into rod,the size increases and spacing decreases. The antibacterial properties of the steel are related to the form,amount and morphology of the copper phaces. When the size of rod-shaped copper precipitates are about 500 nm,the antibacterial properties are excellent. When annealed for 1 min,the relationship between precipitation and matrix is semi-coherent,and the strengthening effect is the best. The critical size of the second phase of the steel is about 30 nm.