喷射成形超高碳钢的自超塑化现象  

Self-Superplasticization of Spray Formed Ultrahigh-Carbon Steel

作　　者：林一坚[1] 章靖国[1] 李小军[2] 史海生[3] 周灿栋[3] 

机构地区：[1]上海市金属功能材料重点实验室,上海200092 [2]上海交通大学材料科学与工程学院,上海200030 [3]宝钢研究院前沿技术研究所,上海201900

出　　处：《钢铁》2007年第7期59-63,共5页Iron and Steel

摘　　要：用喷射成形工艺制备的无宏观偏析、组织为均匀细密珠光体的超高碳钢,无需任何热的或机械的预处理,即可具有伸长率达380%的超塑性,并且在2×10-1s-1的应变速率下仍有122%的伸长率。这是由于在此变形过程中发生了碳化物由片层状向颗粒状的转变并形成细小等轴晶粒的组织超塑化;而且高应变速率可促成高度细化的球化组织。由此开发的喷射成形结合大压下量热轧的方法可以简捷有效地使超高碳钢获得很好的超塑性,并且可以应用于高速钢等其它高碳钢铁材料。1.25C-2.8Si-1.5Cr ultrahigh carbon steel （UHCS） with a carbide-network-free and fully fine pearlitic microstructure,prepared by spray forming technology, exhibits fairly good superplasticity with elongation up to 380% without any thermal and/or mechanical pretreatment. An elongation of 122 % was reached when the strain rate was raised to 2 X 10^-1s^-1. It was found that the unique superplasticity is resulted from microstructure evolution during the deformation, from the pearlite to fine-equiaxed-grained structure with the lamellar cementite turning into spheroidized particles. High strain rate could facilitate utrafine spheroidized structure. Based on the above result, a method combining sprayforming and hot rolling with high-deformation rate was developed to make UHCS super- plastic more effectively. The method was proved to he effective for other high-carbon steels such as highspeed steels.

关 键 词：超高碳钢 喷射成形 超塑性 高速钢 

分 类 号：TG142.12[一般工业技术—材料科学与工程]