For the first time, the 9% Ni steel is being used in CO₂ injection units in floating production storage offloading vessels. Pipe joints welded with nickel-based superalloy 625 as the filler metal present difficulties in ultrasonic inspection owing to the sonic attenuation and deviation caused by the anisotropic and coarse-grained weld metal. This study aims to conduct a probability of detection (POD) to evaluate the discontinuity detection reliability in 9% Ni steel arc welded joints. The inspections were performed using ultrasonic phased array transducers with transversal and longitudinal waves, by using both a conventional wedge formed of Rexolite® and an adapted wedge filled with water to simulate the immersion inspection. POD curves were developed using the hit/miss and â vs a models. The inspection performed with transversal waves detected much fewer discontinuities than that performed with longitudinal waves. Furthermore, inspection performed with longitudinal waves after weld metal cap pass removal exhibited much more reliability in 9% Ni steel welded joints. The obtained POD curves were shown to be a suitable tool to evaluate the inspection of 9% Ni steel welded joints, as they confirmed that the best inspection procedure involves a combination of three different phased array ultrasonic testing configurations.

9% Ni 钢首次用于 CO ₂浮式生产储存卸油船上的注入装置。用镍基高温合金 625 作为填充金属焊接的管接头由于各向异性和粗晶焊缝金属引起的声波衰减和偏差，在超声波检测中存在困难。本研究旨在通过检测概率 (POD) 来评估 9% Ni 钢弧焊接头的不连续性检测可靠性。使用具有横波和纵波的超声波相控阵换能器进行检查，通过使用由 Rexolite® 形成的传统楔块和经过调整的充满水的楔块来模拟浸入式检测。POD 曲线是使用命中/未命中和 â vs a 模型开发的。使用横波进行的检查检测到的不连续性比使用纵波进行的检查少得多。此外，在去除焊缝金属帽焊道后用纵波进行的检查在 9% Ni 钢焊接接头中表现出更高的可靠性。获得的 POD 曲线被证明是评估 9% Ni 钢焊接接头检测的合适工具，因为它们证实了最佳检测程序涉及三种不同相控阵超声检测配置的组合。