409 stainless steel round bar

Grade 409 is a stabilized ferritic general-purpose stainless steel containing 11% chromium. It is particularly beneficial for applications that require oxidation or corrosion protection beyond what carbon steel and some coated steels can provide. While 409 stainless steel round bars offer good oxidation resistance and formability, they exhibit lower corrosion resistance compared to grades like 304, 430, or 439. However, they are significantly more resistant than mild carbon steel.

The 409 stainless steel round bar can be formed through processes such as roll forming, stretch bending, deep drawing, or pressing. In its annealed condition, 409 does not harden when cold worked using mild roll forming techniques, including pressing or stretch bending. Welding performance for grade 409 is considered fair. It's important to note that this stainless steel material should not be used in impact-loaded structures, as grain structure growth in heat-affected zones may adversely affect mechanical properties.

General Properties

Alloy 409 is a general-purpose, chromium, and titanium-stabilized ferritic stainless steel primarily used in automotive exhaust systems. With its 11% chromium content, it forms the passive surface film that grants stainless steels their corrosion resistance. Alloy 409 combines good elevated temperature corrosion resistance with medium strength, excellent formability, and overall cost-effectiveness. It serves as a robust alternative to carbon steel in mildly challenging environments, where its high resistance to corrosion and high-temperature oxidation provides an advantage. Typically, it is used in applications where appearance is secondary to mechanical properties and corrosion resistance.

Applications

While Alloy 409 is designed primarily for the automotive exhaust industry, it is also successfully employed in various other industrial applications. Examples include:

• Automotive exhaust systems
• Catalytic converters
• Mufflers
• Tailpipes
• Farm equipment
• Structural supports and hangers
• Transformer cases
• Furnace components
• Heat exchanger tubing

Standards

• ASTM/ASME: UNS S40900
• EURONORM: FeMi35Cr20Cu4Mo2
• DIN: 2.4660

Overall, 409 stainless steel round bars are an excellent choice for applications requiring a balance of performance and cost in mildly corrosive environments.