针对超临界直流锅炉过热器、再热器钢所采用的新型耐热钢T23在使用过程中出现的焊接接头裂纹缺陷，分析了射线检测和超声检测的局限性，并根据其铁磁性材料特征及缺陷特点，确定对该类焊接接头采用磁粉探伤工艺，检出含裂纹缺陷焊接接头302只，缺陷检出率显著高于射线探伤、超声探伤方法。检测结果表明对T23钢焊接裂纹缺陷采用磁粉探伤检测方法，工艺可靠且方法简便高效，也为其他类似结构铁磁性材料焊接接头探伤提供了借鉴和参考。

The newly employed heat resistant steel T23 material in supercritical once through boiler superheater/ reheater shall be easily subjected with welded joint crack defects in operation. By analyzing the limitation of radiographic testing and ultrasonic testing of ferromagnetic materials and being based on defect characteristics, it is determined to use magnetic particle inspection technology for the welding joint crack detection. 302 flaws were detected and the rate of detection was much higher than that of ultrasonic testing and radiographic testing. Test results showed that the magnetic particle testing of T23 material welding crack is reliable,simple and efficient,and it also provides reference for other similar structure in ferromagnetic materials welded joint flaw detection.