HIGH MANGANESE STEEL HAVING SUPERIOR HOT WORKABILITY, AND PROCESS FOR MANUFACTURING HIGH MANGANESE HOT ROLLED STEEL SHEET WITHOUT ANY CRACK

摘要

A high manganese steel having superior hot workability is disclosed, in which small amounts of the alloying elements are added into a high manganese steel of Fe-Mn-Al-C system, so that the rupture strength of the grain boundaries of columnar crystals can be improved, thereby realizing an improved hot workability. Further, a process for manufacturing a high manganese hot rolled steel sheet is disclosed, in which the above-mentioned high manganese steel is subjected to be controlled in the initial hot rolling conditions during a hot rolling, so that large cracks would not be generated on the edges and on the surface of the hot rolled steel sheet. The process for manufacturing a hot rolled high manganese steel without any cracks includes the following steps. That is, the process includes the steps of: preparing the ingot or the continuous casting slabs of the conventional Fe-Mn-Al-C steel with one or more elements selected from a group consisting of 0.0005-0.04 % of B, 0.0005-0.050 % of Ti, 0.0005-0.050 % of Zr, 0.0005-0.040 % of La, 0.0005-0.040 % of Ce, and 0.0005-0.030 % of Ca; heating the into or the continuous casting slab to a temperature range of 1150 - 1300 DEG C; carrying out a hot rolling by applying a low reduction ratio below 7 % per pass and an average strain rate below 2.0 sec<-1> per pass, until a total reduction ratio reaches 40 %; and carrying out a hot rolling by the high reduction ratio after reaching the total reduction ratio of 40 %.