几种球铁应变疲劳特性的研究(Ⅰ)

对珠光体球铁、铁素体球铁、奥—贝（A－B）球铁的应变疲劳特性进行了研究。结果表明，所研究的几种球铁都具有循环硬化特征。在高应变区，延性较高的铁素体球铁具有较高的循环应变疲劳寿命；而在低应变区，强韧性较高的A－B球铁具有较高的循环应变疲劳寿命。分析了球铁的循环硬化原因，探讨了A－B球钦在循环硬化中的奥氏体转变、断口形貌、循环变形特性和应变疲劳寿命的关系。

Investigation of Strain Fatigue Characteristics of Nodular Cast Iron

The strain fatigue characteristics of perlitic, ferritic and austennitic- bainitic (A-B)nodular graphite cast iron are investigated. The investigated results show that all of investigated nodular cast iron has the cyclic hardening characteristic. In the higher strain area, ferritic nodular cast iron with higher ductility appears a longer cyclic strain fatigue life, while in the lower strain area, A-B nodular cast iron with higher toughness appears a longer cyclic strain fatigue life. This paper analyses the reasons of cyclic hardening and explores the austenization, morphology of fracture, the reletions between cyclic strain characteristic and strain fatigue life in cyclic hardening of A-B nodular cast iron.