The principle of magnetic inspection of butt welds on the urea reactor described,analyzed,the danger of cracks on the surface of welds and by experiments optimal MT technique drawn by experiments.

• 介绍了尿素合成塔对接环焊缝磁粉探伤的理论基础，分析了焊缝表面裂纹的危害性，并通过实验给出磁粉探伤中的最佳探伤工艺。