设计了一种 C- Si- Mn 系(0.14C-1.4Si-2.72Mn)实验钢．采用热膨胀仪测定并研究了实验钢的 CCT 曲线和相变规律;通过 OM、SEM、TEM、EBSD 分析了经热轧、退火后钢板的微观组织、相分布等;用 XRD 测定了实验钢中的残余奥氏体含量．结果表明:0.14C-1.4Si-2.72Mn 实验钢具有较好的淬透性，临界冷速为 10.00℃ /s;退火后微观组织主要由马氏体、铁素体和少量残余奥氏体组成，其中部分马氏体发生回火，残余奥氏体主要以薄膜状分布在马氏体板条间，部分分布在铁素体晶粒内部，含量为 4%～6%;退火后钢板的抗拉强度可达 1333MPa，总伸长率为 13%，强度和塑性匹配较好．

A kind of C- Si- Mn series (0.14C-1.4Si-2.72Mn) tested steel was designed,and the CCT curves andphase transformation rules of the steel were measured by using a thermal dilatometer.Then,the microstructure andphase distribution of the tested steel sheet after hot- rolling and annealing were analyzed by means of OM,SEM,TEM and EBSD.Finally,the retained austenite content of the tested steel was measured by means of XRD.Theresults show that (1) the designed 0.14C-1.4Si- 2.72Mn tested steel possesses good hardenability and is of a criti-cal cooling rate of 10.00℃ /s; (2) the microstructure of annealed tested steel sheet is mainly composed of martens-ite,ferrite and a little amount of retained austenite; (3) the martensite is partially tempered,and the retained aus-tenite accounts for 4% ～6% and mainly distributes among martensite laths but partially distributes in the ferrite;(4) after the annealing of the tested steel sheet,the tensile strength and the total elongation reach 1333MPa and13%,respectively,and the tensile strength accords well with the ductility.