摘要
为了系统研究临界区退火和全奥氏体区退火对中锰钢性能的影响,为中锰钢的实际应用提供理论基础,在650~900℃范围内系统研究了冷轧中锰钢的显微组织和力学性能,并通过断口形貌观察分析了试验钢的断裂特性。结果表明,试验钢在临界区退火的综合力学性能明显优于全奥氏体区退火。650~750℃退火时,抗拉强度在1 000MPa左右,强塑积超过30GPa·%,发生韧性断裂,宏观上可以观察到明显的层状裂纹,微观下为大量韧窝;在800~900℃退火时,抗拉强度在743~1 154MPa范围内波动较大,强塑积不足10GPa·%,断口平整,发生脆性沿晶断裂;退火温度为650℃时,组织为片层状和等轴状的奥氏体、铁素体双相及大量渗碳体;随着退火温度的升高,渗碳体逐渐溶解消失,等轴状组织所占体积分数明显增加,奥氏体体积分数也不断增加,在750℃时达到52.2%;退火温度为800℃时,有马氏体产生,奥氏体体积分数下降;退火温度为900℃时,组织基本为马氏体,残留奥氏体体积分数仅为14.6%。
To systematically study the effects of intercritically annealing and austenite reverted transformation annealing on the properties of medium-Mn steel and provide the theoretical basis for its practical application,effects of annealing temperature in a range of 650-900℃ on microstructures,mechanical properties and fracture behavior were studied for a cold-rolled medium-Mn steel.The results show that the comprehensive mechanical properties of specimen after intercritical annealing were obviously superior to the specimen by austenite reverted transformation annealing.When annealed at 650-750℃,the tensile strength of about 1 000 MPa and product of strength and ductility of above 30 GPa·% were obtained.The fracture exhibits distinct layer-like cracks and massive dimples.When the annealing temperatures were 800-900℃,the tensile strength fluctuates greatly in the range of 743-1 154 MPa while the products of strength and ductility were below 10 GPa·%.Meanwhile,the brittle inter-granular fracture occurred due to the poor elongation and the fracture surfaces were flat.Annealed at 650℃,the microstructures consist of equiaxed/lamellar ferrite and austenite,as well as abundant cementite.With increasing temperature,the cementite gradually dissolved and disappeared,and the volume percent of austenite and equiaxed grains increased.When the annealing temperature was 750℃,52.2%austenite was obtained.Martensite was generated at 800℃.With further increasing annealing temperature,austenite volume percent decreased,and only 14.6%austenite was retained at 900℃.
作者
杨丽芳
魏焕君
孙力
信瑞山
马成
潘进
YANG Li-fang;WEI Huan-jun;SUN Li;XIN Rui-shan;MA Cheng;PAN Jin(Technology Research Institute,HBIS Group,Shijiazhuang 050023,Hebei,China;Technical Center,HBIS Group Tangsteel,Tangshan 063000,Hebei,China)
出处
《钢铁》
CAS
CSCD
北大核心
2019年第11期80-87,100,共9页
Iron and Steel
基金
国家自然科学基金资助项目（51775298）
深水油气管线关键技术与装备北京市重点实验室开放课题资助项目（BIPT2018006）
关键词
冷轧中锰钢
退火工艺
微观组织
力学性能
断口形貌
cold-rolled medium-Mn steel
annealing
microstructure
mechanical property
fracture morphology
