在1000 MW超超临界机组锅炉受热面中引进了新型马氏体耐热钢T92，这种钢的合金元素含量较以前的锅炉用钢更高，但具有焊接冷裂纹倾向，裂纹缺陷对机组运行的危害性严重，因此对射线探伤裂纹的检出率要求更高。针对裂纹检出率问题对射线探伤工艺进行了试验，制定出了厚壁T92钢焊接接头射线探伤工艺，并在现场射线检验过程中证实了探伤工艺符合要求。

A new type of martensite heat-resisting steel T92 was introduced in 1 000 MW ultra-supercritical units, whose alloy element content was higher than former boiler steel. T92 steel is susceptible to welding cold cracks, imposing serious harmfulness on the unit operation. Therefore, the higher detection rate of crack is requested for X-ray testing technology. This paper showed some test results for satisfying a higher demand for radiation detection of cracks, put forward X-ray inspection technology for thick walled T92 steel welding joint. Field inspection confirmed that the technology met the requirement.