以不同管线钢为研究对象,比较了图像分析法、游标卡尺法、侧膨胀仪法测量侧膨胀值的差异,验证了用侧膨胀值测定韧-脆转变温度的准确性及稳定性,并对X80钢实心焊丝自动焊环焊缝进行不同温度的夏比冲击试验。结果表明:对于韧性较差、韧性不均匀的材料,以及冲击断裂后发生扭曲的试样,宜采用侧膨胀仪法测量其侧膨胀值;对于管线钢,采用侧膨胀值测定其韧-脆转变温度结果的准确性和稳定性较好;X80钢实心焊丝自动焊环焊缝韧-脆转变温度对应的侧膨胀值为0. 90 mm。

Taking different pipeline steels as the research object, the differences of lateral expansion values measured by image analysis method, vernier caliper method and lateral expansion meter method were compared, and the accuracy and stability of determining the ductile-brittle transition temperature by side expansion value were verified. The Charpy impact test of X80 steel solid wire automatic welding girth weld at different temperatures was carried out. The results show that for materials with poor toughness and uneven toughness, as well as samples with distortion after impact fracture, the lateral expansion value should be measured by lateral expansion instrument. For pipeline steel, the accuracy and stability of the results of the ductile-brittle transition temperature determined by the side expansion value were good. The lateral expansion value corresponding to the ductile-brittle transition temperature of X80 steel solid wire automatic welding girth weld was 0. 90 mm.