Press phosphorus, sulfur can be divided into ordinary carbon steel carbon steel (phosphorus, sulfur and higher), high-quality carbon steel (phosphorus, low sulfur) and high quality steel (phosphorus, sulfur less) and premium quality steel.

High-quality carbon steel carbon content of their number into a low carbon steel (low carbon content between 0.25% to 0.5%) and high-carbon steel (carbon content greater than 0.5%). According to the amount of manganese and manganese content is divided into ordinary high manganese content in two categories. By impurities in the steel S, P content is divided into different quality steel, high quality steel, high-grade steel. Such steel must also ensure that the chemical composition and mechanical performance requirements of steel. Commonly used steel pressure vessel with a No. 20, No. 35, the national standard steel, these steels are GB699-99