China Manufacturer Produces ASTM A36 Hot Rolled Carbon Steel Plate is an alloy consisting of iron and carbon. The percentage of carbon in steel affects the hardness, elastic strength and ductility of carbon steel. As the carbon percentage increases, the steel becomes harder and stronger, but less ductile. China Made ASTM A36 Hot Rolled Carbon Steel Plate has high hardness, toughness and strength, and is relatively cheap compared to other steels.