公开(公告)号：US20140144559A1

公开(公告)日：2014-05-29

申请号：US14116980

申请日：2012-04-20

Applicant: ARCELORMITTAL INVESTIGACION Y DESAROLLO SL

Inventor： Kangying Zhu ,  Olivier Bouaziz

IPC: C22C38/38 ,  C22C38/32 ,  C22C38/28 ,  C22C38/00 ,  C22C38/22 ,  C22C38/06 ,  C22C38/02 ,  C21D8/02 ,  C22C38/26

CPC classification number: C21D8/0263 ,  C21D6/005 ,  C21D8/0205 ,  C21D8/0226 ,  C21D9/46 ,  C21D2211/008 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/14 ,  C22C38/22 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/38

Abstract: The present invention provides a method for the fabrication of a martensitic steel sheet with a yield stress greater than 1300 MPa. The method includes the steps of obtaining a semi-finished steel product, the composition of which includes, whereby the contents are expressed in percent by weight: 0.15%≦C≦0.40%, 1.5%≦Mn≦3%, 0.005%≦Si≦2%, 0.005%≦Al≦0.1%, S≦0.05%, P≦0.1%, 0.025%≦Nb≦0.1%, and optionally: 0.01%≦Ti≦0.1%, 0%≦Cr≦4%, 0%≦Mo≦2%, 0.0005%≦B≦0.005%, 0.0005%≦Ca≦0.005%. The remainder of the composition is iron and the inevitable impurities resulting from processing. The semi-finished product is reheated to a temperature T1 in the range between 1050° C. and 1250° C., then the reheated semi-finished product is subjected to a roughing rolling at a temperature T2 in the range between 1050 and 1150° C., with a cumulative rate of reduction εa greater than 100%, to obtain a sheet with a not totally recrystallized austenitic structure with an average grain size less than 40 micrometers and preferably less than 5 micrometers. The sheet is then cooled to prevent a transformation of the austenite at a rate VR1 greater than 2° C./s to a temperature T3 in the range between 970° C. and Ar3+30° C., is then subjected to a finishing hot rolling at the temperature T3 of the cooled sheet, with a cumulative rate off reduction εb greater than 50% to obtain a sheet, then the sheet is cooled at a rate VR2 which is greater than the critical martensitic quenching rate. Steel sheets are also provided.

Abstract translation: 本发明提供一种制造屈服应力大于1300MPa的马氏体钢板的方法。 该方法包括获得半成品钢产品的步骤，其组成包括其中含量以重量百分比表示：0.15％＆lt; NlE; C＆lt; L; 0.40％，1.5％＆amp; NlE; Mn＆nlE; 3％，0.005％ ＆lt; nlE; 2％，0.005％＆amp; NlE; Al＆NlE; 0.1％，S＆amp; NlE; 0.05％，P＆lt; I; 0.1％，0.025％＆nlE; Nb＆nlE; 0.1％和任选的：0.01％ ; Cr＆nlE; 4％，0％和nlE; Mo＆NlE; 2％，0.0005％＆amp; NlE; B＆lt; NE; 0.005％，0.0005％＆amp; NlE; Ca＆NlE; 0.005％。 组合物的其余部分是铁和由加工产生的不可避免的杂质。 将半成品再加热至1050℃〜1250℃的温度T1，然后将再加热的半成品在1050〜1150℃的温度T2进行粗轧， 以平均粒径小于40微米，优选小于5微米的方式获得具有不超过完全再结晶的奥氏体结构的片材，其累积的还原率等于或大于100％。 然后将片材冷却以防止以大于2℃/ s的速率VR1将奥氏体转变成在970℃和Ar3 + 30℃之间的温度T3，然后进行精加工 在冷却片材的温度T3下进行热轧，累积脱模率大于50％以获得片材，然后将片材以大于临界马氏体淬火速率的速率VR2冷却。 还提供钢板。