| 摘要 |
PURPOSE:To form a nitrided layer having high hardness and excellent wear resistance by subjecting the surface of a stainless steel to a wet blasting treatment and further to a pretreatment by an aq. soln. of water soluble halide followed by gas nitriding. CONSTITUTION:The surface of a stainless steel is subjected to a wet blasting treatment by a liquid contg. >=5% hard and pulverous powder of 280-350 mesh such as Al2O3, SiC, SiO2, Cr2O3 which do not absorb nitrogen by which the surface rust, passive film and work strain layer are removed and the homogeneously activated surface is formed. The activated surface enclosed with the hard and fine particles is not washed and contains >=5% said hard and fine particles and >=1% CaCl2 as halide. The steel is dipped in warm water and is dried after pulling up. Such steel is heated to 500-600 deg.C in an atmosphere of a gaseous mixture composed of gaseous NH3 and gaseous N2 to form the hard nitrided layer having uniform thickness on the surface of the stainless steel. The stainless steel having the surface of high hardness is thus produced. |
