The failure tube was analyzed. The results show that fracture was caused by hydrogen induced cracking initiated at brittle inclusion in the surface, though the sulphur content was only 0.003 wt %.

• 通过对开裂的渣油加氢冷高压分底排污水管线大小头的综合分析；结果表明在高硫化氢含量、高压力下；即使碳钢的含硫量达0.；003%25(质量分数)；也可以由脆夹杂物引起氢致开裂