低碳钢冷脆特性参量——临界缺口(裂缝)尺寸的研究

本文研究了缺口尺寸对低碳钢低温断裂行为的影响,分析了断裂载荷谷值所对应的温度T_C~*(称为冷脆特征温度)附近的断裂特征,结合工程设计特点,提出了冷脆临界缺口(裂缝)尺寸α_C及其特征值α_C~*的概念,推荐作为控制冷脆的一个基本特性参量。文中推导出了α_C及α_C~*的数学表达式,该式的可行性得到了静载及疲劳载荷条件下模拟试验数据的验证。

CRITICAL NOTCH (CRACK) SIZE AS A CHARACTERISTIC PARAMETER OF CRYOGENIC BRITTLENESS IN LOW CARBON STEEL

The effect of notch depth on the low-temperature fracture behavior of a low carbon steel has been studied. An analysis was made for the fracture features at T_c~* (cryogenic brittleness-characteristic temperature) at which the fracture load reaches a valley value. Furthermore, according to the experimental results and engineering design practice, a concept of criticai notch (crack) size for cryogenic brittleness, a_c, as well as its limit Value, a_c~*, was put forward and recommended to be a basic characteristic parameter for controlling the brittleness. Mathematical derivation was carried out to give the expression of a_c and a_c~*, the reliability of which was verified by the modeling tests under both static and cyclic loading conditions.