摘要
某冲模正常使用中发生早期异常断裂,借助直读光谱仪、金相和扫描显微镜、洛氏硬度计等工具对其材料M42模具钢的断口形貌、化学成分、非金属夹杂物、显微组织和表面硬度进行检测与观察,分析并讨论了造成模具零件断裂的影响因素。结果表明:材料的化学成分、硬度指标、非金属夹杂物级别和大块碳化物最大尺寸均符合标准要求,但共晶碳化物不均匀度和组织平均晶粒度级别较高,碳化物沿晶界呈不连续网状分布,与锻造工艺不当、材料变形不充分、铸态组织遗传共同导致碳化物不均匀度超标;其次淬火温度偏高时会使模具钢的显微组织粗大,这都会降低其强韧性,增大脆性,缩短模具使用寿命。因此,为了防止模具过早失效,一方面要控制锻造工艺,保证共晶碳化物的不均匀度,另一方面要根据模具零件的外形尺寸,选用适当的淬火温度避免晶粒粗大。
The early abnormal fracture of a stamping die occurred in normal use. The fracture morphology, chemical composition, non-metallic inclusions, microstructure and surface hardness of M42 die steel were detected and observed by means of direct reading spectrometer, metallography and scanning microscopy, and Rockwell hardness tester, and the influencing factors of die fracture were analyzed and discussed. The results showed that the chemical composition of the material,hardness index, non-metallic inclusion level, and large carbide maximum size all met the standard requirements, but the non-uniformity of eutectic carbide and the average grain size of the microstructure were higher, and the carbide was distributed in a discontinuous network along the grain boundary, and the non-uniformity of the carbide exceeded the standard due to improper forging process, insufficient material deformation and the genetic of the as-cast structure. Secondly, when the quenching temperature was high, the microstructure of the die steel was coarse, which reduced its strength and toughness, increased brittleness and shortened the service life of the die.Therefore, in order to prevent premature failure of the die, on the one hand, the forging process should be controlled to ensure the uniformity of eutectic carbide, on the other hand, according to the shape of the die, appropriate quenching temperature should be selected to avoid coarse grain.
作者
杨礼林
徐祺昊
秦晨
赵莉萍
YANG Li-lin;XU Qi-hao;QIN Chen;ZHAO Li-ping(School of Materials and Metallurgy(Rare Earth Institute),Inner Mongolia University of Science&Technology,Baotou,Inner Mongolia 014010,China)
出处
《模具工业》
2022年第1期55-60,共6页
Die & Mould Industry
基金
内蒙古自治区科技创新引导奖励项目(0902062001)
内蒙古科技大学创新基金项目(2019QDL-B05)。
关键词
冷作模具钢
碳化物
晶粒粗大
脆性断裂
cold working die steel
carbide
coarse grain
brittle fracture
