SPCD深冲板冲压成形中裂纹的萌生及扩展观察  

Investigation on crack generating and expanding of SPCD deep-drawing sheet during stamping deformation

作　　者：周乐育[1,2] 崔田灏 何建中[2] 张朝磊[1] 刘雅政[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]包头钢铁(集团)公司技术中心,内蒙古包头014010

出　　处：《材料热处理学报》2015年第6期88-92,共5页Transactions of Materials and Heat Treatment

基　　金：中央高校基本科研业务费专项资金资助(FRF-TP-12-046A);北京高校"青年英才计划"(YETP0355)

摘　　要：借助SEM和EBSD对SPCD深冲板冲压成形过程中裂纹的萌生及扩展行为进行观察,分析了影响其成形开裂的主要原因。结果表明,在微观织构有利于塑性潜能发挥的情况下,析出碳化物先于铁素体发生断裂,铁素体与析出碳化物交界处为微裂纹最先萌生的位置;由于铁素体基体与析出碳化物塑性不同,协调变形不良,两相界面处容易产生应力集中,这为裂纹扩展提供了通道,碳化物对扩展中的裂纹有吸引作用;尺寸超过20μm大尺寸析出碳化物的存在严重影响深冲板的塑性;铁素体晶粒尺寸的不均匀导致晶粒之间在拉深过程中变形协调能力下降,造成拉深后深冲板表面呈现波浪状局部失稳、粗糙度增大,从而引起"橘皮状"特征出现。The crack initiation and propagation in process of SPCD steel plate stamping was observed by SEM and EBSD,and the main reason leading to the cracking was investigated. The results show that in situation that the micro texture is advantageous to the plastic potential,the carbide separates out cracks early than the ferrite,and micro crack first occurs in the junction of the ferrite and separated carbide; because of the plasticity of ferrite matrix and the carbide precipitation is different as well as uncoordinated deformation,stress concentration is easy to occur on the interface between two phases,which provides a channel for crack propagation,and carbide is attractive for the crack propagation. Separated carbide whose size is bigger than 20 μm has a strong impact on the plastic of deep drawing sheet and the nonuniform size of ferrite grain causes the local buckling along a wavy path and bigger roughness on the surface of deep drawing sheet after deep drawing,and then causes the 'orange peel'characteristics.

关 键 词：深冲板 析出碳化物 微观织构 取向分布函数 

分 类 号：TG386[金属学及工艺—金属压力加工]