作　　者： ; ; ; ; ; (董杰）;

机构地区： 东北大学材料与冶金学院轧制技术及连轧自动化国家重点实验室

出　　处： 《机械工程学报》 2007年第9期145-150,155,共7页

摘　　要： 在MMS-100热力模拟试验机上,采用热膨胀法结合金相法,建立Mn-Cu耐候钢未经变形和变形奥氏体的连续冷却转变曲线,分析比较它们的组织演变规律。利用光学显微镜、扫描电镜和透射电镜分析研究冷却速度、变形条件对显微组织的影响。试验结果表明,变形使铁素体+珠光体相变区向左上方移动,获得铁素体+珠光体组织的临界冷速增大,随着冷却速度的增加,晶粒细化,抗拉强度提高。变形奥氏体的位错缠结,抑制贝氏体长大,细化相变后的显微组织。在20～30℃/s冷速范围内获得的板条状组织主要由贝氏体铁素体组成,贝氏体的第二相是渗碳体。在5～10℃/s的冷速范围内可以获得粒状贝氏体,第二相为基体上分布的马氏体/奥氏体岛或退化珠光体。 The continuous cooling transformation （CCT） curves of austenite non-deformation and compressively deformed for a weathering steel are constructed by means of a dilatometry in combination with metallography measurement by MMS-100 thermomechanical simulator, and the microstructure evolution of the steel is analyzed and compared. Optical microscope, scanning electronic microscope （SEM） and transmission electronic microscope （TEM） are employed to investigate the influence of cooling rate, deformation process on the transformation behavior and microstructure. Experimental results show that the deformation promotes the area of polygonal ferrite and pearlite to move to-wards top left corner, leading to the increase of critical cooling rate obtained ferrite plus pearlite. With cooling rate increasing, the grains refine and the tensile strength increases. The deformation on austenite stifles the growth of bainitic ferrite by tangled dislocations resulting the refinement of microstructure. Lath-like microstructure observed at the cooling rate ranging from 20-30℃/s is mainly revealed to consist of bainitic-ferrite with cementite. Granular microstructure observed at the cooling rate ranging from 5-10℃/s is characterized to be martensite-austenite constituent islands or pseudopearlite in matrix.

关 键 词： 耐候钢 连续冷却转变曲线 奥氏体变形 残余奥氏体 透射电镜

领　　域： [金属学及工艺] [金属学及工艺]