摘要
测试分析评价了各种铸铁的疲劳裂纹扩展行为;1)铸铁的裂纹扩展速率按球铁、蠕铁及灰铁的顺序依次增大。2)铸铁的石墨形态不同,疲劳裂纹扩展行为相差很大。灰铁由于石墨片在共晶团内相互连接,疲劳裂纹沿着与外应力垂直的石墨片/基体边界连续扩展,对于球铁,当疲劳裂纹尖端扩展至石墨球中时。裂纹尖端被石墨球周围的基体钝化、需重新诱发裂纹。本文提出球铁疲劳裂纹扩展的物理模型。
In this paper, the concept of fracture mechanics is used to evaluate the fatigue crack propagation behaviors of various cast irons used for producing ingot mould and the crack propagation life is estimated. The results show that;1) The crack propagation rate increases in the sequence of nodular iron,vermicular iron and then grey iron and this is coincident with the practical observation results of mould crack propagation in situ. 2) The behaviors of clack propagation vary a lot with the different graphite morphologies of cast irons. Due to flake graphite of grey iron linked up together in eutectic colonies, fatigue cracks propagate continuously along graphite /matrices interfaces which are vertical to external stresses. As to the case of nodular iron, when the crack tip propagates near to graphite nodules, the tip is blunted by ferrite around graphite ncdu-les and the crack will be re initiated. In this paper, a fatigue crack propagation model for nodular iron is proposed.
出处
《钢铁》
CAS
CSCD
北大核心
1993年第3期26-29,19,共5页
Iron and Steel
