In the past 20 years, the production technology of stainless steel pipe, whether seamless or welded, has been greatly improved. Stainless steel pipes produced by some domestic manufacturers have reached the level of completely replacing imported products, and the localization of steel pipes has been realized.
In petroleum and petrochemical industry, stainless steel pipes are mainly used in pipeline transportation system, including high pressure furnace pipes, piping, petroleum cracking pipes, fluid delivery pipes, heat exchange pipes, etc. Stainless steel pipe is required to perform well in wet and acid service.
In order to meet the requirements of processing low-quality crude oil and environmental protection, domestic refineries constantly optimize the processing structure and adjust the product structure of refinery units. In recent years, high-pressure hydrogenation units such as hydrocracking and hydrotreating have developed rapidly, and the processing capacity of the units has been continuously improved. The main characteristics of Hydrogen-facing pipeline are large diameter and thick wall.
For the choice of high-pressure Hydrogen-facing materials, because of its high temperature and high pressure conditions, TP321/H and TP347/H are generally used as materials for high-pressure Hydrogen-facing tubes at home and abroad. The above two stainless steel materials have good high temperature corrosion resistance and high temperature mechanical properties due to the addition of stabilizing elements such as Ti and Nb.
At present, domestic hydrogen pipelines with large diameter and thick wall are mainly manufactured by hot piercing, cold rolling and cold drawing.
Compared with steel pipes manufactured by other methods, the pipes manufactured by hot piercing, cold rolling and cold drawing have the characteristics of good surface, high dimensional accuracy and uniform wall structure.
Because of the particularity of working medium, the requirement for raw materials of high-pressure Hydrogen-facing steel pipe is higher. Therefore, the requirement of Design Institute for high-pressure Hydrogen-facing steel pipe is as follows: S ≤ 0.015%, P ≤ 0.030%, non-metallic inclusions A, B, C and D are not higher than 1.5 grade. Ultrasound inspection is required for finished pipes. The artificial contrast defect is not more than 5% of the nominal wall thickness of pipes.