带环形裂纹的微试样小冲杆试验法测试材料断裂韧性探讨

火电、核电、石油化工行业中有大量的在役压力容器、管道和构件,准确评价在役设备材料的脆化和结构完整性,对于保证装置的安全运行具有重要意义。为适应这一需求,小冲杆测试技术得到了发展,但对小冲杆试样评估在役容器材料的断裂韧性时,仍然只是依靠经验方法和标准的断裂韧性值进行关联,缺乏理论依据。该文提出了在小冲杆试样上开一环形裂纹,以反映裂纹体的断裂韧性测试要求。

Determination of material fracture toughness by circular pre-cracked small punch test specimens

The mechanical properties of pressure vessels and pipes operated at thermal power,nuclear power and petrochemical industry deteriorate drastically during a long period of service.Consequently,there is an increasing need for the development of a procedure for assessing structure integrity and remain life of these parts.Small punch test(SPT),a new miniature specimen test technique to adapt to the above requirement,can assess the mechanical characterization of materials from in-service components with non-destructive manner.Now the fracture toughness assessment by SPT is empirical correlation between standard fracture toughness test and SPT without pre-cracked sample.The O-type pre-cracked sample was used in this paper to evaluate fracture toughness.The O-type crack meets with plane strain condition in the crack length direction with axi-symmetric state.The research applied the fracture mechanism to determine the fracture toughness with pre-cracked samples.