高强热轧卷板TQ700MCD拉伸层状断裂形成原因分析  

Analysis of Formation Cause of Tensile Lamellar Fracture of TQ700MCD High Strength Hot Rolled Coil

作　　者：付培茂 曹永录[1] 马瑞[1] 

机构地区：[1]太原钢铁集团有限公司技术中心,山西太原030003

出　　处：《热加工工艺》2017年第5期240-242,247,共4页Hot Working Technology

摘　　要：为了分析铁素体型高强热轧卷板TQ700MCD层状断裂的成因,本文使用OM和SEM观察了断口组织和形貌,并研究了裂纹萌生扩展的过程。结果表明:层状断口由多个小平面组成,为典型韧窝状的韧性断口;层状断裂的裂纹起源于缩颈阶段;裂纹是在(Nb,Ti)(C,N)析出带、夹杂物的边缘萌生扩展;层状断裂的发生与钢种的成分、组织及拉伸过程中复杂的应力状态有关。In order to analyze the causes of TQ700MCD ferritic hot-rolled high strength coil lamellar fracture, the microstructure and morphologies of fracture were observed by using OM and SEM. And the process of crack initiation and propagation was studied. The results indicate that, the layered fracture surface is composed of many tiny planes, which is the ductile fracture with typical toughness; the microcracks originate from the necking stage, the initiation and propagation of the cracks are in the edge of the （Nb, Ti）（C, N） precipitates and the inclusion; the occurrence of lamellar fracture is related to the composition and microstructure of the steel and complex stress state in tensile process.

关 键 词：TQ700MCD 层状断裂 裂纹扩展 

分 类 号：TG335.56[金属学及工艺—金属压力加工] TG111.91