摘要
φ3.3 mm 60Si2Mn A油淬火回火弹簧钢丝生产的拉簧拉钩折弯处出现断裂。采用扫描电镜、金相显微镜、显微硬度计对拉簧拉钩折弯处断口及其附近内侧表面和表层进行检测分析。结果表明：用油淬火回火弹簧钢丝卷制拉簧时,由于模具状态不良或设备不稳定,在弹簧内侧表面产生严重刮蹭,形成一条带有横向裂纹的白亮带。该白亮带金相组织为回火屈氏体冷变形组织,深度约15-20μm。拉钩折弯时局部严重扭转变形引发白亮带处产生微裂纹。白亮带处微裂纹或原有微裂纹在剪切或扭转应力作用下迅速扩展,导致拉簧断裂。
Hook bending of tension spring produced with diameter 3. 3 mm 60Si2 Mn A oil quenched and tempered spring steel wire occurs fracture. The tension spring hook bending fracture and its nearby inner side surface and outer layer were inspection analyzed by adopting SEM,microstructure and micro hardness. Results show that when tension spring was coiled with oil quenched and tempered spring steel wire,for mold condition was bad or device was unstable,serious scratch occurred on spring inner side surface and formed a white band with transverse crack. The microstructure of white band is tempered troostite cold deformation structure,depth is about 15 - 20 μm. Micro cracks occur at white band caused by part serious torsional deformation as hook bending. The micro cracks of white band or original micro cracks spread quickly under shear or torsion stress,cause tension spring fracture.
出处
《金属制品》
2015年第2期37-40,共4页
Metal Products
关键词
拉簧
冷变形组织
横向裂纹
断裂
扫描电镜
tension spring
cold deformation structure
transverse crack
fracture
SEM
