METHOD FOR PRODUCING LARGE half shell forgings ball valve STEEL centrifugally cast and forged tube billets

摘要

FIELD: process engineering.;SUBSTANCE: invention relates to metal forming and may be used in forging large-sized half-bodies of ball valves from spun-cast and forged pipe billets. The billet is heated to 1150-1200°C and deformed. First, semi-finished product is directly extruded at high temperature to thickness smaller than that of initial billet by 25-30% and equals that of forged piece spherical part. Then after heating semi-finished product is stamped in second mould with spherical bottom male die. Note here that semi-finished product is simultaneously reduced and expanded to obtain the throat and the spherical part. Semi-finished product is expanded at said spherical bottom male die with OD increase by, at least, 10%. Thus, in fact all metal of pipe billet is subjected to plastic strain without breakage in uniformity.;EFFECT: lower costs and metal input, higher mechanical properties and process efficiency.;2 dwg