At present, the domestic boiler water wall, economizer and other parts made in China are using 20G or ST45.8 high-pressure boiler tube. With the development of the power station, the working parameters of the boiler have been improved, especially the emergence of subcritical and supercritical boilers, which has a higher requirement for the wall thickness of the boiler pipe. Other countries in the world have adopted C-Mn steel which has a higher strength than 20G and good process performance to manufacture high pressure boilers, such as Japan's STB52, Germany's 19Mn5, American SA-210C and ASTM 106 Gr.C.
SA-210C is ASME boiler materials, a seamless carbon steel pipe widely used for water cooling wall, economizer of boiler parts. Its chemical composition is simple, except a higher carbon and manganese content, and the rest composition are similar to 20G, so the yield strength is about 20% higher than 20G while the plasticity and toughness are equivalent to 20G.Because of simple production process and good properties. It is mainly used for water cooled wall, economizer, low temperature superheater and other parts with working temperature lower than 500 degrees centigrade.
ASTM A106 Gr C is ASTM A106 steel used for large diameter and high temperature and pressure boiler and Superheater C-Mn steel. Its chemical composition is simple, similar to that of 20G steel, but the content of carbon and manganese is higher, so the yield strength is about 12% higher than that of 20G, and the plasticity and toughness are similar to 20G. Manufacturing header with A106 Gr C instead of 20G (economizer, water cooling wall, low temperature superheater and reheater header) can reduce the wall thickness of about 10%, which can save the cost of materials, but also reduce the workload of welding, improve the heat transfer condition of boiler. It’s working pressure is 6 ~ 13.9MPa and steam temperature is 450~580 degrees.
The chemical composition and Mechanical Properties of SA-210C compared with ASTM A106 C
