Carbon structural steel plate refers to carbon steel with carbon content less than 0.8%. This steel contains less sulfur, phosphorus and non-metallic inclusions than carbon structural steel, and has better mechanical properties. It mainly refers to steel with carbon content less than 2 and 11% and without specially added alloy elements. Sometimes also called plain carbon steel or carbon steel. Carbon steel is also called carbon steel, which refers to iron carbon alloy with carbon content less than 2 or 11%. In addition to carbon, carbon steel generally contains a small amount of silicon, manganese, sulfur and phosphorus