海洋平台结构钢焊缝金属解理断裂的评定

ASSESSMEMT ON CLEAVAGE FRACTURE OF WELD METAL USED FOR OFFSHORE STRUCTURAL STEEL

介绍了由法国Ｂｅｒｅｍｉｎ提出的局部法理论基础和基本参量─威布尔指数ｍ和临界解理应力σｕ的确定方法。并结合海洋平台用钢Ａ５３７采用ＬＢ５２ＮＳ施焊的接头焊缝金属进行了局部法的探讨。给出了在低温下缺口半径分别为１．２５，２．５０和６．４０ｍｍ拉伸试件的断裂载荷及通过有限元程序计算所得的威布尔应力σω，最后通过统计分析确定出经验与理论分布拟合良好的ｍ值和σｕ值，可用于焊接结构的防断设计和安全评定。

Theoretical basis of local approach developed by Beremin is first reviewed,then the methodology determing two parameters of Beremin model-Weibull exponent and critical cleavage stress σ_u are described. Based upon investigation on weld metal in the welded joints prepared with A537 steel welded electrode LB52NS the local approach is discussed. Later, the values of the Weibull stress at cleavage fracture are derived from tensile tests of axisymmetrically notched specimens R=1.25, 2.50 and 6.40mm) at low temperatures and finite element calculation. Finally good fit for the parameters m and σ_u between experimental and theoretical distribution are defined in accordance with statical analysis. The parameters obtained can be used in design against brittle failure and safety assessment of welded construction.