| 摘要 |
PURPOSE:To manufacture the titled steel pipe superior in high temp. creep strength and corrosion resistance, by applying heat treatment, hot extrusion, cold working, etc. under specified conditions to billet of austenitic stainless steel contg. specified quantities of C, Nb, Ti, etc.. CONSTITUTION:Austenitic stainless steel billet contg. 0.04-0.10wt% C, 2XC%-1.0% Nb+Ti total of 1 or 2 kinds of Nb and Ti is heated to about 1,300 deg.C to dissolve giant carbide in solid state, then blooming rolled and air cooled. The rolled billet is then heated and hot extruded at >=1,230 deg.C to dissolve again relatively large precipitated carbides in solid state, and the material is cooled under the condition in which carbide is not precipitated or formed in fine particles even in case the precipitation, preferably at >=0.2 deg.C/sec average cooling rate up to 500 deg.C. Next extruded material is cold worked, further solid soln. heat treated, to obtain the titled pipe having high temp. creep strength and water vapor oxidation resistance. |
