Abstract: Fatigue assessment of pressure vessel welded joints is a critical process to ensure the long-term safe operation of the equipment. With the release and implementation of the GB/T 4732.1~4732.6—2024 (hereinafter referred to as GB/T 4732) standard, China's fatigue design methods for pressure vessels has made significant progress based on the ASME standard system. However, it still differs notably from the European EN 13445—2021 (hereinafter referred to as EN 13445) standard in welded joint assessment. Based on existing theoretical research, this study systematically compared the technical differences between GB/T 4732 and EN 13445 in fatigue assessment of welded joints, focusing on design methods, stress calculation and engineering applicability of the assessment results. Using tank welds as a case study, the computational results showed that the allowable cycle count for identical welded joints assessed under EN 13445 was significantly higher than that under GB/T 4732. By further analyzing the reasons for this discrepancy, the study has revealed the technical characteristics of different standard systems and provided references for standard selection and design optimization in engineering practice.

Key words: welded joint, fatigue assessment, GB/T 4732, EN 13445, structural stress, hot spot stress method