δ_5间接测量法测试管线钢止裂韧性CTOA试验研究

CTOA measurement experimental study on δ_5 indirect measurement method in pipeline steel

为解决多数实验室不具备δ5专用夹式引伸计而无法实现δ5间接测量法对裂纹尖端张开角CTOA的测试问题,该文另辟蹊径借鉴直接法测试CTOA中的数值图像相关方法,通过工业摄像机采集试样撕裂过程图像,然后在图像上直接测试δ5和裂纹扩展量Δa,进而求得裂纹尖端张开角CTOA。采用该方法重点测试3件X80管线钢试样的稳态裂纹扩展阶段临界CTOA值(CTOA)c,并依据试验断裂形式从原理上分析试验结果的有效性,确认被测X80管线钢的(CTOA)c为10.32°。

Since a lot of labs didn't have special δ5clip gage, the δ5indirect measurement for CTOA(crack tip opening angle) testing was hardly carried out. A new method was tried to complete the δ5indirect measurement. In the new method, industrial camera was used for photo collection during the tearing test period,in order to test δ5and Δa of each photo. By a series of δ5and Δa were achieved, the CTOA was easy calculated. In this paper, the steady-state critical(CTOA) C of three X80 pipeline samples were tested. Simultaneity,the validity of the results was inspected by the fracture modes of samples. As a result, the(CTOA) C of X80 pipeline was assured to be 13.09°.