Packaging steel strip without surface treatment

Packaging steel strips without surface treatment are generally hot-rolled and cold-rolled steel coils or steel strips. Steel plates can also be used. The size range of the raw material is from 0.1mm to 25.4mm in thickness, from 10mm to 2500mm in width, and over 12m in length. The most commonly used steel strip with a maximum coil weight of 45t is a steel strip with a thickness of 3mm or less and a width of 600mm or less.
　　The steel grades can be carbon structural steel, high-quality carbon structural steel, low-alloy structural steel and stainless steel. Generally, low-carbon steel with a carbon content of less than 0.1% is used, followed by low-carbon steel with a carbon content of 0.1 to 0.2%. Steel with high carbon content must be annealed, otherwise cracks are likely to occur during forming. Carbon steel with a carbon content of 0.9% cannot be cold-formed even after annealing. Phosphorus, sulfur and inclusions have an impact on the processing properties of carbon steel. Among them, non-metallic inclusions will form a fibrous structure along the rolling direction during rolling, and will easily cause cracks during roll forming. Roll forming generally uses rimmed steel and silicon-killed steel strips. For cold-formed steel that is prone to cracks during forming, the blank must be aluminum-killed steel. The materials of cold-formed steel in my country are low-carbon steel and high-strength low-alloy steel. The following steel grades have been used successively: Q215-A (F), Q235-A (F), Q215-B (F), Q235- B(F), 16Mn, 15MnV, 15MnVNi, 0.9PV, lOPCuRe, 12MnPV, etc. The more commonly used ones are Q215, Q235 (yield point of 240MPa) and 16Mn (yield point of 350MPa).