海洋泊链用钢大尺寸试样CTOD试验研究

RESEARCH OF CTOD TEST OF LARGE DIMENSION SPECIMENS FOR ANCHOR CHAIN STEEL IN SEA

设计制作了大尺寸试样裂纹尖端张开位移(CTOD)试验用低温环境箱和相关的卡具。依据英国BS7448断裂韧性试验标准,分别对海洋泊链用钢母材及焊缝进行了-20℃的CTOD试验。结果表明,母材试样的CTOD特征值δm普遍很高,均在0.77mm以上;所有焊缝试样都发生了脆性断裂,其中,两块试样的PV曲线图及其所对应的宏观断口异常,另两块焊口试样在弹性区就发生了脆性断裂,导致了它们的CTOD特征值δc小于设计指标0.15mm的要求。试验分析结果为评价焊接工艺及焊后热处理规范提供了依据。

The environmental chamber and related clamps used for crack-tip opening displacement test at low temperature were designed. According to the test method on fracture mechanics toughness tests of British Standard 7448, two series of CTOD test at -20℃ on matrix and weld of anchor chain steel used in sea are performed. Results showed that CTOD eigenvaluesδm for matrix were generally big and above 0.77mm, while all weld specimens had brittle fracture, and theP-V relationships and macro-fractographic appearance for two specimens were abnormal, and the other two specimens occurred brittle fracture within elastic region and their CTOD eigenvaluesδc were less than 0.15mm which is the minimum designed target. The results provide reference for assessing weld procedure and heat treatment norm.