| 摘要 |
PURPOSE:To obtain the title steel material having less gaseous adsorption on the surface by incorporating specific wt.% of Cr, Ni, B and N and specific % of one or two kinds of Ca and Mg with Fe and depositing boron nitride on the surface layer. CONSTITUTION:By weight, 15 to 25% Cr, 6 to 30% Ni, 0.005 to 0.03% B and 0.08 to 0.30% N and total 0.001 to 0.01% of one or two kinds of Ca and Mg are incorporated with Fe. Boron nitride is then deposited on the surface layer. Mo and W may be incorporated into the above compsn. The steel material contg. the above components is heated at 650 to 850 deg.C in vacuum of <=10<-5>Torr to deposit boron nitride. By this method, the steel material for high vacuum apparatus having less gaseous adsorption on the surface can be obtd. |
