Q345A welded steel pipes belongs low-alloy high-strength steel pipe which under GB/T 3091-2008 standard, Q345A welded steel pipes mainly for boilers, heat exchangers, petroleum, aerospace, chemicals, electricity, military. The surface can be polished finish, black, paint, oil, galvanized, PE coating, PVC coating, anti-rust oil, anti-rust paint, color pre-coating for protection.