PRODUCTION OF BUILT-UP PRESSURE VESSEL FOR HIGH TEMPERATURE SERVICE

摘要

PURPOSE:To reduce the weight of a vessel and to facilitate production by constituting an inside cylinder of a clad steel consisting of a Cr-Mo steel and stainless steel and using a high-strength Cr-Mo-V-Nb steel for build-up materials. CONSTITUTION:The inside cylinder 11 is formed of the clad steel consisting of the Cr-Mo steel and the stainless steel and many layers of build-up materials 12 each consisting of the high-strength Cr-Mo-V-Nb steel are wound on the outside circumference thereof. An outside cylinder 13 is further fitted onto the outside circumference thereof to form a built-up body part 14; at the same time a nozzle 16 and manhole 17 consisting of the Cr-Mo steel are joined to both ends. The inside cylinders 13 and the materials 14 are welded respectively of the same welding material in this stage and thereafter the entire part of the vessel is subjected to a post weld heat treatment in such a manner that the cylinder 11 has the required hardness or below. The resistance to hydrogen attach and strength of the cylinder 11 are improved by the above-mentioned method and therefore the reduction of the thickness and weight of the vessel is made possible.