本发明公开了一种低温输气钢管承压能力及韧脆转变行为全尺寸试验方法，在试验钢管表面预制缺陷，并在钢管两端焊接堵头，考察低温条件下含缺陷钢管的承压能力；将钢管放置于管沟内，并采用钢筋混凝土对钢管两端堵头位置进行锚固来构筑试验管路；在钢管上安装应变片、夹式引伸计、表面温度传感器等测量装置；通过在试验钢管的管体中注满液氮和酒精冷却液来实现对整根试验钢管的低温控制；在试验钢管注满低温液体后，通过注入氮气达到爆破压力，通过采集管内压力、管体壁温、管体应变、预制裂纹处裂纹嘴张开量及影像资料信息，来来分析确定钢管的断裂阻力曲线及韧脆转变温度。本发明经济、简单、易于操作，可精确控温，更加安全。

The invention discloses a full-scale test method for pressure bearing capacity and ductile brittle transition behavior of low-temperature gas transmission steel pipe. Defects are prefabricated on the surface of the test steel pipe, and plugs are welded at both ends of the steel pipe to investigate the pressure bearing capacity of the defective steel pipe under low-temperature conditions; Place the steel pipe in the pipe trench and anchor the plug positions at both ends of the steel pipe with reinforced concrete to build the test pipeline; Install strain gauge, clamp extensometer, surface temperature sensor and other measuring devices on the steel pipe; The low temperature control of the whole test steel pipe is realized by filling the pipe body with liquid nitrogen and alcohol coolant; After the test steel pipe is filled with low-temperature liquid, nitrogen is injected to reach the burst pressure. The fracture resistance curve and ductile brittle transition temperature of the steel pipe are analyzed and determined by collecting the pressure in the pipe, pipe wall temperature, pipe strain, crack mouth opening at the prefabricated crack and image data. The invention is economical, simple, easy to operate, can accurately control the temperature and is more safe.