Abstract: This invention relates to a capsule for pressings pressed by isostatic pressure and to these pressings used for extruding metallic objects, particularly tubes, of stainless steel, the outer and inner wall of the capsule consisting of thin-walled sheet metal, and at least the outer wall having substantially the same strength properties in the axial direction over its circumference and particularly consisting of a spiral-welded tube and being preferrably provided with a bulge which is directed outwardly against the shrinkage occurring during isostatic pressing, and at least on the front end of the capsule an insert being provided, which consists of one or more pieces of a ductile solid material or a ductile material pressed from powder. The invention further relates to a process for the production of such capsules and pressings and to a process for extruding tubes and to the tubes obtained according to this process.

Abstract: A method of pickling metallic material particularly for the continuous treatment of material in strip or wire form and especially such material consisting of stainless steel, wherein the material after annealing is subjected in a first step to the chemical attack of a first aqueous solution which is heated to a temperature above room temperature, preferably to between 55.degree. - 60.degree. C, and which contains HF in contents of from 7 to 25%, or which contains HF in the contents mentioned above and H.sub.2 SO.sub.4 over 2%, or which contains HF in the contents mentioned above the NaCl up to 10%, but especially from 0.5 to 2.5%; or which contains HF in the contents mentioned above and H.sub.2 SO.sub.4 in the contents mentioned above and NaCl in the contents mentioned above, and in a second step the material is subjected to the chemical attack of a second aqueous solution heated to a temperature above room temperature, preferably to between 55.degree. - 60.degree. C, and containing HF and HNO.sub.3.