SUPERFINE-GRAINED STEEL OBTAINED BY FORMING MECHANICALLY MILLED IRON POWDER INTO BULKY STATE, AND ITS MANUFACTURE

摘要

PROBLEM TO BE SOLVED: To inexpensively mass-produce an iron and steel material excellent in mechanical properties by forming a superfine-grained mechanically milled iron powder into bulky state while keeping its crystalline grain size. ;SOLUTION: The superfine-grained steel prepared by forming a mechanically milled iron powder into bulky state can be obtained by forming a mechanically milled iron powder of 0.005-1.0 μm crystalline grain size into bulky state by means of hot rolling under inhibition of grain growth. As to its manufacturing method, a space formed in a steel ingot or a steel slab is filled with a mechanically milled iron powder of 0.005-1.0 μm crystalline grain size and hot rolling is performed at 600-1,200°C heating temperature and then the steel ingot or the steel slab is removed, by which a steel plate having the crystalline grain size of the iron powder can be obtained.;COPYRIGHT: (C)2000,JPO