我厂800吨水压机高压罐是五十年代末、六十年代初期的产品。罐体的材料为19Mn5,内径900毫米、壁厚90毫米,罐体的纵、环焊缝均为电渣焊。在今年全厂设备大检查中,经超声波探伤,发现该罐纵缝和环缝交接的丁字接头处沿环缝方向有长100毫米的树枝状裂纹群(见图1)。裂纹从内壁表面沿厚度方向延伸,其深度达60毫米。经从内表面取样化验(取样部位见图2),含铜量最高处达12.8％(1点2％、2点3.4％、3点 1.83％、 Our factory 800 tons of hydraulic press high pressure tank is the late fifties, early sixties products. The material of the tank is 19Mn5, the inner diameter is 900 mm and the wall thickness is 90 mm. The longitudinal and the ring welds of the tank are electroslag welding. In this year’s large-scale inspection of the entire plant, ultrasonic flaw detection found that there was a dendritic crack cluster of 100 mm in length along the direction of the ring seam at the T-junction where the longitudinal seam and the girth of the cannel were handed over (see Fig. 1). Cracks extend in the thickness direction from the inner wall surface to a depth of 60 mm. Samples from the inner surface of the sample test (sampling site shown in Figure 2), the highest copper content of up to 12.8% (1 point 2%, 2 points 3.4%, 3 points 1.83%