STRECHING REDUCING MILL TYPE RACK BAR MANUFACTURING PROCESS

摘要

PURPOSE: A method of manufacturing an SRM(Stretching Reducing Mill) type of a rack bar is provided to realize light weight and save costs since an SRM type of a rack bar using a plate maintains performance equivalent to a seamless tube. CONSTITUTION: A method of manufacturing an SRM(Stretching Reducing Mill) type of a rack bar comprises next steps. A plate is rolled and welded in a hollow shape(S20). After welding, welding effect is removed through thermal treatment(S31). After removing of welding effect, a rack gear is molded as an unprocessed rack bar through a drawing process over at least first step(S32). The rack gear is processed for the rack bar manufactured through the drawing process, thus the rack bar is manufactured as a finished product(S331). The plate consists of C: 0.32~0.38, Mn: 1.25~1.45 and a slightest amount of B.