| 摘要 |
PURPOSE:To obtain an Ni-contg. Fe alloy which obviates the generation of surface flaws by spraying a Cr-contg. iron alloy over the entire surface of a casting ingot, etc. of the Ni-contg. Fe alloy to form the coating layer sprayed with the Cr-contg. Fe alloy having the specified difference in the coefft. of thermal expansion from the above-mentioned alloy and layer thickness then hot rolling such ingot. CONSTITUTION:A large-sized casting ingot, slab or billet consisting of an Fe-(20-82%)Ni alloy, Fe-<=7% Cr-(20-82%)Ni alloy or Fe-(12-20%) Co-(28-72%)Ni alloy is prepd. The Fe alloy contg. 8-20% Cr having the high effect of withstanding oxidation is sprayed over the entire surface of the large- sized casting ingot, etc. to form the thermally sprayed coating layer having <=15X10<-6>(cm/cm deg.C, RT-1,280 deg.C) difference in the coefft. of thermal expansion from the above-mentioned alloy and 0.2-2mm layer thickness. The Ni-contg. alloy formed with such sprayed coating layer is then heated to 1,000-1,280 deg.C and is subjected to hot rolling or blooming and hot rolling. The intended Ni- contg. Fe alloy which obviates the partial exfoliation of the coating layer and the generation of the surface flaws and can be rolled is thus obtd. |
