Abstract: A process of pickling surfaces of a steel-based metallic material containing iron, carbon and chromium at a high speed wherein the surfaces of the metallic material are pickled at a high speed by dipping and then pickling the surfaces of the metallic material in an aqueous solution of hydrochloric acid or an aqueous solution of hydrochloric acid-nitric acid mixture while at least one kind of ion selected from a group comprising a platinum ion, a palladium ion and a rhodium ion is contained in a hydrochloric acid having a temperature of 50.degree. to 110.degree. C. and a concentration of 100 to 450 g/l with NO.sub.3.sup.- ion contained therein by a quantity of 300 g/l or less, as desired, or pickling treatment in the aforementioned aqueous solution by feeding a direct current between two electrodes at an electric current density of 5 to 200 A/Dm.sup.

Abstract: According to the present invention, a stainless steel thin strip and sheet having a superior surface gloss and high rusting resistance is produced by heating a continuous cast slab of ferritic or martensitic stainless steel containing 10 to 35% by weight of Cr at a temperature of 1100.degree. to 1300.degree. C. selected according to the Cr content in a combustion atmosphere having an oxygen concentration lower than 7% while adjusting the furnace staying time from preheating to extrusion to within 260 minutes, carrying out hot rolling while adjusting the rolling-finish temperature to a level higher than 900.degree. C., carrying out mechanical descaling by adding a grinding and descaling agent, such as iron sand, having a maximum particle size smaller than 400 .mu.

Abstract: High Al austenitic steels are particularly susceptible to deterioration of the hot workability and suffer from severe cracking during hot working, with working becoming impossible in some cases. The present invention remarkably improves the hot workability by strictly limiting the impurities in the steel, in particular the S, O, Mg, Pb, Bi, etc. That is, the present invention reduces the S and O by adding one or more of Ca, Y, and REM to satisfy the range of -50<(S)+(O)-0.8.times.(Ca)-0.2.times.(Y)-0.1 .times.(REM)<30 (unit: ppm) and further limits the Mg to no more than 100 ppm, the Pb to no more than 10 ppm, and the Bi to no more than 5 ppm. According to the present invention, it is possible to obtain a high Al austenitic heat-resistant steel superior in hot workability which is free from occurrence of edge cracks, surface flaws, and other surface defects during hot rolling, hot casting, etc.