【摘要】 现行压力容器标准中奥氏体不锈钢疲劳设计曲线均基于常温疲劳试验数据拟合得来,并未考虑低温对奥氏体不锈钢强度、疲劳寿命的影响。本文提出一种基于常温疲劳设计曲线和深冷力学性能,获取奥氏体不锈钢深冷疲劳设计曲线的方法。首先,在试验研究基础上整理分析了文献中77 K和4 K温度下的奥氏体不锈钢疲劳试验数据,并按ASME BPVCⅧ-2采用的Langer模型表征疲劳试验曲线;其次,根据低温对奥氏体不锈钢强度和塑性的影响规律,分别对Langer模型中的疲劳极限和塑性应变项系数进行修正,建立低温下Langer模型系数与温度的关联关系,提出了深冷疲劳试验曲线计算公式;最后,通过对比文献中110 K温度下材料疲劳试验数据,初步验证了深冷疲劳曲线计算方法的有效性。更多还原

【Abstract】 Design fatigue curves of austenitic stainless steel(ASS) in current pressure vessel standards are based on fitting of fatigue test data at ambient temperatures, without considering the effect of low temperature on strength and fatigue life of ASS.In this work, a calculation method is proposed to obtain cryogenic fatigue design curves of ASS based on its conventional design fatigue curve at room temperature and cryogenic mechanical properties.Firstly, fatigue data of ASS at 77 K and 4 K in the literature were statistically analyzed and fatigue curves were characterized by Langer model as per the criteria and commentary of ASME BPVC Ⅷ-2;Secondly, according to the influence rules of low temperature on tensile strength and ductility of ASS,coefficients of fatigue limit and plastic strain in Langer model are modified respectively, relationships of Langer model coefficients with temperature at low temperature are established, and the calculation formula of cryogenic fatigue curve is put forward; Finally, by comparing fatigue tests data of ASS at 110 K in literature, the effectiveness of the proposed calculation method of cryogenic fatigue curve is preliminarily verified.更多还原