SGCC Chemical Elements

SGCC Chemical Elements
SGCC is a hot-dip galvanized steel sheet defined by the Japanese Industrial Standard (JIS G 3302). Its chemical composition is primarily determined by the base material (cold-rolled steel sheet). The primary component of the galvanized layer (zinc layer) is zinc (Zn), and the base material's elemental composition determines the steel's fundamental properties.
According to the standard, the base material for SGCC is ordinary-grade cold-rolled steel sheet. Its primary chemical elements and common ranges are as follows:
Carbon (C): ≤0.12%
Carbon is an essential element of steel, affecting its strength and hardness. As an ordinary-grade steel, SGCC has a low carbon content, ensuring good plasticity and stamping properties.
Silicon (Si): ≤0.05%
Silicon improves strength in steel, but excessive levels can affect coating adhesion. The silicon content in SGCC is strictly controlled to ensure a good bond between the zinc layer and the base material during the galvanizing process.
Manganese (Mn): ≤0.50%
Manganese improves the strength and toughness of steel. A moderate addition can improve the workability of cold-rolled steel sheet. Phosphorus (P): ≤0.035%
Phosphorus is a harmful element. Excessive levels can cause cold brittleness in steel, so its content in SGCC must be strictly controlled.
Sulfur (S): ≤0.035%
Sulfur is also a harmful element. Excessive levels can cause hot brittleness in steel, affecting weldability and workability. Therefore, its content must be strictly controlled.
Iron (Fe): Balance
Iron is a base element in steel and accounts for the vast majority of its content.
In addition, the primary component of the galvanized layer is zinc (Zn), which is of high purity (typically ≥98%) and may contain small amounts of impurities (such as lead and cadmium, but modern processes strictly limit these harmful impurities). During the hot-dip galvanizing process, a very thin zinc-iron alloy layer (including Fe-Zn compounds) forms between the zinc layer and the substrate surface, but the overall composition remains primarily zinc.
In summary, the chemical composition of SGCC is based on the iron of the substrate, supplemented by small amounts of alloying elements such as carbon and manganese, while the galvanized layer is primarily zinc. The composition is designed to balance the workability of the steel sheet and the adhesion of the galvanized layer.