SPA-H is a high-strength weathering steel with excellent corrosion resistance and high strength. It is mainly used to manufacture steel structures that require extremely high strength and corrosion resistance, such as highway guardrails, railway Bridges, vehicles and ships. In the chemical composition of SPA-H, the carbon content is low, while containing a small amount of nitrogen, hydrogen and phosphorus and other elements, the content of these elements can effectively improve the strength and corrosion resistance of steel. In addition, SPA-H also contains small amounts of elements such as titanium and niobium, which can refine the grain and increase the strength and hardness of the material. In the manufacturing process, SPA-H needs to be hot-rolled to obtain better material properties. After hot rolling treatment, the grain size of SPA-H is finer, the strength and hardness of the material are improved, and it has good plasticity and toughness.