FUNCTIONALLY GRADED COMPOSITIONAL CONTROL METHOD FOR ELIMINATING DISSIMILAR METAL WELDS DURING MANUFACTURE OF AN INTEGRATED HEADER TO REDUCE ADDITIONAL DAMAGE

摘要

PURPOSE: A functionally graded compositional control method for eliminating dissimilar metal welds during manufacture of an integrated header is provided to remove the need for heat treatment after welding.;CONSTITUTION: A method for manufacturing an integrated header comprises the steps of: preparing a reverse mold for a head assembly(21), filling a header section of the reverse mold with atomized low-alloy steel powder to form a header section, forming a tube section, and integrally melting the atomized powder in a high-temperature high-pressure atmosphere to form a header assembly. The tube section forming step comprises the steps of: filling a first portion of a tube section of the reverse mold with atomized low-alloy steel powder(22), filing a second portion of the tube section of the reverse mold with atomized steel powder, which gradually proceeds from low-alloy steel to austenitic stainless steel, to form a transition portion, and filling a third portion of the tube section with atomized austenitic stainless steel powder.;COPYRIGHT KIPO 2013;[Reference numerals] (20) Designing reproduction header assembly; (21) Preparing reverse mold; (22) Filling mold with atomized powder; (23) Evacuating and sealing mold; (24) High-temperature high-pressure processing; (26) Maintaining at sintering temperature; (27) Cooling to room temperature; (28) Thermal processing?; (29) Removing from mold; (30) Washing/Grinding; (31) Boring; (32) Chamfering