Many firms market their stainless steel exhaust products as nothing more than stainless steel. Most manufacturers don’t bother identifying the distinctions between Stainless Steel 409 Sheets and 304 stainless steel Sheet material in their products, and you may be fooled if you don’t know the difference. There are some significant differences between the metals, such as carbon concentration, iron content, and corrosion resistance.
The corrosion resistance of the pipe is determined by the amount of chromium and nickel in the alloy. 409 stainless is a metal created primarily for the automotive exhaust sector, though it has been utilized effectively in other industrial applications. It has good elevated temperature corrosion resistance, medium strength, moderate formability, and a low overall cost. 409 has a carbon content of.03 percent. 304, on the other hand, is austenitic stainless steel and one of the earliest types of stainless steel. It is one of the most common metal alloys available today and is commonly utilized in domestic applications. It has a carbon content of.08 percent.
The Difference is in the Numbers
The highest quality stainless steel utilized in performance exhaust systems is 304 stainless. T409 stainless steel is the most commonly used stainless steel in performance exhaust systems. This composition, which is commonly found in Flow master, Invidia, and many other aftermarket stainless mufflers and cutbacks, lack enough chromium to prevent corrosion in cold-weather states or locations where salted roads aid in corrosion growth. T409 has a chromium concentration ranging from 10.50 to 11.75 percent, but just 0.50 percent nickel.
304 stainless steel is the highest quality stainless steel utilized in the automobile industry, and it is commonly used in exhaust tips, clamps, bolts, and other minor exhaust components where strength is critical. Because the alloy contains roughly 20% chromium and 10% nickel, 304-grade stainless is strong and practically immune to rusting. Because of its high nickel concentration, 304 is austenitic stainless steel. Because of its low ferrous content, 304 can turn golden when exposed to intense heat over an extended period. The ferrous metal percentage is so low that magnets will not cling to it, making T409 and T304 easy to distinguish.
Which choice is the best?
When shopping for an aftermarket exhaust system for your performance vehicle, whether it’s an Evo 8/9/X, a Subaru WRX/STI, or a Scion FRS/Subaru BRZ, consider your global location. For regions where road salt isn’t a concern, 409 stainless exhaust systems will suffice. When compared to your northern brothers and sisters, its temperature-resistant alloy allows for higher strength, and trust is often not an immediate worry. 304 Stainless Steel is excellent for rust protection in northern/wintry climates, however, it is sensitive to heat discoloration in most southern states.
The corrosion differences after just one winter are shown above. The main 304ss piping is somewhat discolored but rust-resistant, however, the 409 stainless steel resonator part has surface rust. It’s still strong and should last a long time, although the rust can be bothersome to hardcore performance enthusiasts.
Why use SS 409 Sheets if it isn’t as durable?
Automobile makers have discovered that by employing the less expensive 409 stainless steel grade in production, they can keep prices low. Manufacturers also assess their target market and whether the advantages of a more expensive material would influence purchasing decisions.