Abstract: A heat-resisting steel suitable for use in valve parts of internal combustion engine is disclosed, which consists essentially by weight percentage of 0.3-0.5% of C, more than 1.0% to 2.5% of Si, 0.1-2.0% of Mn, 0.5-7.0% of Cr, 0.3-2.0% of Mo and 0.1-1.0% of V as basic ingredients, at least one of 0.3-2.0% of Cu and 0.001-0.05% of REM as sub-ingredients and if necessary, at least one of 0.1 to less than 2.0% of Ni, 0.1-1.5% of W and 0.03-1.0% of Nb+Ta, and the balance of Fe and inevitable impurities.

Abstract: A bolting bar material consists in weight ratio of 0.05.about.0.2% of C, 0.05.about.0.8% of Si, 0.8.about.2% of Mn, not more than 0.035% of P, not more than 0.030% of S, 0.005.about.0.05% of Nb, 0.01.about.0.05% of Al, 0.005.about.0.025% of N, 0.05.about.0.35% in total of at least one element selected from not more than 0.25% of V, not more than 0.25% of Ti and not more than 0.25% of Zr, and if necessary, 0.05.about.1.5% in total of at least one element selected from 0.05.about.0.5% of Ni, 0.05.about.0.5% of Cr and 0.05.about.0.5% of Mo, and the balance of Fe. In the production of the bolting bar material, the steel having the above composition is heated to 1000.degree..about.1100.degree. C., rolled at a finish rolling temperature of 750.degree..about.950.degree. C. and cooled at a rate of 5.degree..about.50.degree. C./sec on average.

Abstract: A process for removing an adhered substance from steel ingots, which comprises heating or cooling a steel ingot after the casting under such conditions that the heating or cooling rate at the surface layer portion of the steel ingot is not less than 2.degree. C./sec and the temperature difference between the starting and end points is not less than 300.degree. C.