The effect of nitrogen (N) on the properties of S355JR carbon steel is similar to that of carbon and phosphorus. With the increase of nitrogen content, the strength of steel can be significantly improved, especially the plasticity, especially toughness, and the weldability will be decreased, and the cold brittleness will be intensified. At the same time, aging tendency, cold brittleness and hot brittleness will be increased, which will damage the weldability and cold bending property of steel. Therefore, the nitrogen content in S355JR carbon steel should be reduced and limited as much as possible. Generally, nitrogen content should not be higher than 0.018%.
Ordinary S355JR carbon steel mainly refers to the steel whose mechanical properties depend on the carbon content in the steel, and generally does not add a lot of alloy elements. Ordinary carbon steel is the abbreviation of ordinary carbon structural steel. Carbon content is less than 0.38%, and less than 0.25% is the most commonly used. It belongs to low carbon steel. In the Chinese standard, each metal grade indicates the low yield point of the steel when the thickness is less than 16mm. Compared with high-quality carbon steel, the limitation of carbon content, performance range, phosphorus, sulfur and other residual elements is wider for ordinary carbon steel.
In recent years, the application of pressure swing adsorption oxygen generation technology in blast furnace oxygen enrichment in the iron and steel industry has become more and more mature, and the scale of oxygen generation per hour has also expanded from thousands of cubic meters to tens of thousands of cubic meters. The active steel market has strongly promoted the development of PSA oxygen generation technology to intelligent, large-scale, and refined.
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