EQ70钢焊接接头CTOD允许值概率迭代修正

摘要

In order to solve the problem that relevant technical standards have given the allowed value in a high degree of conservation and they are not suitable for application,the CTOD (crack tip opening displacement) test on weld joints of high strength steel EQ70 has been carried out at low temperature.Combining with the probability distribution of the CTOD values,a new method is presented which uses probability iteration to modify the allowable value of CTOD,and the APIRP 2Z norm′s allowable value of CTOD (δmin=0.13mm) is corrected.The EQ70 steel′s allowed value of the fusion-line can be set as 0.069 mm,the allowed value of the weld joint center can be set as 0.072 mm.The failure assessment curve of SINTAP is used to assess the allowed value after the iterative correction.The studies show that the value derived from probability iterative correction method is in the acceptable range of the failure assessment curve,sufficient to ensure the safety of the structure.%针对规范所设定的允许值偏保守,不符合"合于适用"原则的问题,对高强钢EQ70钢焊接接头进行低温裂纹尖端张开位移(crack tip opening displacement,CTOD)韧度试验,并结合CTOD试验值的概率分布规律,提出了CTOD允许值概率迭代修正法,对APIRP 2Z所设定的CTOD允许值δmin=0.13 mm进行修正.EQ70钢焊接接头允许值通过迭代修正后熔合线处允许值δmin=0.069 mm,焊缝中心处允许值δmin=0.072 mm,并应用SINTAP的失效评定曲线对修正后的允许值进行安全性检验,结果表明,通过概率迭代修正法求出的允许值对应的评定点均在失效评定曲线的可接受区域内,足以保证结构的安全性.