不锈钢管表面多孔层真空制备工艺试验研究

Experimental Study on Vacuum Manufacture of Porous Layer on Stainless Steel Tube Surface

为确定不锈钢表面多孔层的烧结工艺参数,通过改变粉末类型、粒径以及烧结气氛等因素,在不同烧结温度下进行了烧结试验,最终确定了合适的工艺。结果表明:烧结气氛是决定烧结结构以及母材性能的关键因素,真空烧结可保证烧结过程的顺利进行;随着烧结温度的升高,烧结时间的延长,烧结结构的结合强度升高,而孔隙率则呈急剧下降的趋势;粉末粒径不是影响孔隙率的主要因素,但是孔隙的当量直径随粒径的增大有变大的趋势,而混合粒径的粉末得到的烧结结构能得到孔隙当量直径分布较宽的烧结结构。另外,烧结管可有效提高沸腾传热系数,降低沸腾温差。

In order to determine the sintering process parameters of porous layer on the surface of stainless steel,sintering experiments were carried out at different sintering temperatures by changing powder type,particle size and sintering atmosphere.The proper sintering process was finally determined.The results show that the sintering atmosphere is the key factor to the sintering structure and properties of base metal.Vacuum sintering can ensure the sintering process going smoothly.With the increase of sintering temperature and holding time,the bonding strength of the sintered structure increases, but the porosity shows a sharp decline.The particle size is not the main factor affecting the porosity,however,with the increase of particle size,the equivalent diameter of the pore increases,while the sintered structure obtained from powder with mixing particle size is able to get the sintered structure with wide distribution of pore equivalent diameter.The sintered porous tube can effectively improve the boiling heat transfer coefficient and reduce the boiling temperature difference.