Materials 101: 304 vs 409 Stainless vs Mild Steel for Exhaust Systems

Why Material Choice Matters

Durability, cost, and appearance are set at the material decision. This primer compares 304, 409, and mild steel for common duty cycles and environments.

304 Stainless

High corrosion resistance and clean aesthetics; ideal for harsh conditions or visible components. Higher material cost, but extended life can offset total cost of ownership.

409 Stainless

Balanced corrosion resistance and value; widely used in OEM exhausts. Good weldability and service life.

Mild Steel

Cost‑effective with excellent formability. With coatings and smart design, it serves well in many applications.

Choosing for Your Application

Consider temperature, road salts, vibration, and lifecycle expectations. We can advise on mixed‑material strategies.