CAJ | 학술논문

利用热膨胀仪研究了合金元素硅和铬对C-Si-Mn-Nb系与C-Cr-Mn-Nb系超高强双相钢连续冷却相变规律的影响；采用单向拉伸试验，以及OM、SEM和TEM等方法对比研究了2种DP钢的组织性能与断口形貌。结果表明：硅元素能够提高Ac1和Ac3点温度，扩大两相区，促进铁素体相变，并能提高马氏体的回火稳定性，改善其形貌和分布；铬元素的添加导致了奥氏体中碳的分布不均匀，使得马氏体内部同时出现了孪晶与板条状精细结构，而且快冷过程中出现了残余奥氏体和马奥岛组织，部分马氏体会在时效过程中发生分解；两钢的抗拉强度均超过1000 MPa，伸长率超过15%，且含硅的双相钢各项力学性能均要优于含铬的双相钢。
이용열팽창의연구료합금원소규화락대C-Si-Mn-Nb계여C-Cr-Mn-Nb계초고강쌍상강련속냉각상변규률적영향；채용단향랍신시험，이급OM、SEM화TEM등방법대비연구료2충DP강적조직성능여단구형모。결과표명：규원소능구제고Ac1화Ac3점온도，확대량상구，촉진철소체상변，병능제고마씨체적회화은정성，개선기형모화분포；락원소적첨가도치료오씨체중탄적분포불균균，사득마씨체내부동시출현료련정여판조상정세결구，이차쾌랭과정중출현료잔여오씨체화마오도조직，부분마씨체회재시효과정중발생분해；량강적항랍강도균초과1000 MPa，신장솔초과15%，차함규적쌍상강각항역학성능균요우우함락적쌍상강。
The effects of Cr and Si on the transformation of C-Cr-Mn-Nb and C-Si-Mn-Nb ultra-high strength dual phase steels were analyzed by using thermal dilatometer. The microstructure properties and the fracture surfaces of the steels were tested by tensile tests,optical microscopy,scanning electron microscopy and transmission electron microscope. The results show that the addition of Si can increase the temperature of Ac1 and Ac3 ,enlarge the two phase region,promote the ferrite transformation,increase the aging stability of martensite and improve its morphology and distribution;the addi-tion of Cr leads to the uneven distribution of C in austenite,the appearance of lamellar and parallel twin microstructure, as well as the appearance of residual austenite and the M/A in the fast cooling stage and the decomposition of some mar-tensite in overaging stage. Although tensile strength and elongation of the two steels both exceed 1 000 MPa and 15%re-spectively,the comprehensive mechanical properties of DP steel containing Si are superior to that containing Cr.