ISO 15653:2018规定了根据应力强度因子(K)、裂纹尖端开口位移或CTOD(δ)和金属材料(J)焊缝J积分的实验等效值确定断裂韧性的方法。 ISO 15653:2018补充了ISO 12135，涵盖了母材断裂韧性测试的所有方面，需要与本文件一起使用。本文件描述了测定断裂韧性点值的方法。它不应被视为获得有效R曲线（抗裂扩展曲线）的一种方式。然而，当确定焊缝的R曲线时，可以有效地采用本文档中描述的样品制备方法。这些方法使用疲劳预裂纹试样，这些试样在焊接后在焊缝中的特定目标区域被缺口。描述了评估焊缝在目标区域内切口放置的适用性的方法，目标区域是在焊缝金属内或焊接热影响区(HAZ)内，然后在适当的情况下，评估疲劳裂纹在对这些区域进行取样时的有效性。

ISO 15653:2018 specifies methods for determining fracture toughness in terms of stress intensity factor (K), crack tip opening displacement or CTOD (δ) and experimental equivalent of the J-integral for welds in metallic materials (J). ISO 15653:2018 complements ISO 12135, which covers all aspects of fracture toughness testing of parent metal and which needs to be used in conjunction with this document. This document describes methods for determining point values of fracture toughness. It should not be considered a way of obtaining a valid R-curve (resistance-to-crack-extension curve). However, the specimen preparation methods described in this document could be usefully employed when determining R-curves for welds. The methods use fatigue precracked specimens which have been notched, after welding, in a specific target area in the weld. Methods are described to evaluate the suitability of a weld for notch placement within the target area, which is either within the weld metal or within the weld heat-affected zone (HAZ), and then, where appropriate, to evaluate the effectiveness of the fatigue crack in sampling these areas.