4130 AQ (Aircraft Quality) steel sheet (chromolly) is one of the most widely used in aviation and racing industries because of its weldability and ease of fabrication. 4130 steel is ideal when a strong light weight steel is needed. The weldability of 4130 steel sheet is excellent. 4130 is resistant to scaling and oxidation and has a clean, smooth finish. Our 4130 sheet is offered cold rolled in .025-.063 and hot rolled in .080-.125. The difference between hot and cold rolled 4130 sheet is cosmetic, the strength is the same. However our hot and cold rolled look the same, both have a smooth glass finish.