[专利]
Cold rolled steel sheet and process for production thereof
申请号:
2013IN-DN01890
申请日:
2013-03-01
公开号:
IN1890/DELNP/2013 A 2014-10-31 [IN2013DN01890]
公开日:
2014-10-31
申请人:
NIPPON STEEL; SUMITOMO METAL
专利权人:
NIPPON STEEL; SUMITOMO METAL
发明人:
HATA Kengo;TOMIDA Toshiro;IMAI Norio
国家:
IPC:
C21D-009/46;C22C-038/00;C22C-038/60
(IN2013DN01890) A cold-rolled steel sheet having a refined structure in which grain growth 1 during annealing is suppressed has a chemical composition containing, in mass percent, C: 0.01 - 0.3%, Si: 0.01 - 2.0%, Mn: 0.5 - 3.5%, Nb: 0 - 0.03%, Ti: 0 - 0.06%, V: 0 - 0.3%, sol. Al: 0 - 2.0%, Cr: 0 - 1.0%, Mo: 0 - 0.3%, B: 0 - 0.003%, Ca: 0 - 0.003%, and REM: 0.003%, and a microstructure which contains at least 50% by area of ferrite as a main phase and has a second phase containing at least 10% by area of a low temperature transformation phase and 0 - 3% by area of retained austenite and which satisfies the following Equations (1) - (3), in addition to a particular texture. dm <2.7 + 10000/(5+300xC+50xMn+4000xNb+2000xTi+400xV)2 (1), dm <4.0 (2), and ds < 1.5 (3), wheren dm is the average grain diameter (um) of ferrite defined by a high angle grain boundary having a tilt angle of at least 15°, and ds is the average grain diameter (um) of the second phase.