how to choose the steel grade material for stainless exhaust system

Families of stainless steel

Stainless steels are primarily used when corrosion or oxidation is a problem. The function that they perform cannot be duplicated by other materials. The development of stainless steel was the start of a family of alloys which has enabled the advancement and growth of chemical processing and power generating systems upon which our technological society is based. 
Subsequently several important sub-categories of stainless steels have been developed. 

Stainless steel falls into four distinct families:

• Austenitic Stainless Steel
• Ferritic Stainless Steel
• Duplex Stainless Steel
• Martensitic & Precipitation Hardening Stainless Steel

Stainless steel series and typical grade

• 200 Series Austenitic – Typical grades are 201 and 202
• 300 Series Austenitic – Typical grades are T304 and T316
• 400 Series Martensitic – Typical Grade: 410
• 400 Series Ferritic – Typical grade 409, 430

Stainless steel for auto exhaust system

As the development of the stainless steel, it’s good performance of high temperature characteristics and high corrosion resistance attracted Europe and Japan to take the lead in putting Ferrite stainless steel in automobile exhaust system.
The 2 main grades of stainless steel used for exhaust parts are 304 and 409.
The difference between the grades of stainless steel is the amount of chromium and nickel found in each. 304 stainless steel contains a much higher percentage of chromium and nickel. This makes it much more resistant to rust. 409 stainless steel is still more rust-resistant than Aluminized Steel. However, neither grade type of material is 100% rust-proof.

	409 Stainless Steel	304 Stainless Steel
Chromium	10.5% - 11.75%	18% - 20%
Nickel	0.5%	8% - 10%

Besides 304 and 409, there are still many other stainless steel grades used for auto exhaust system, like 321, 316L, 441, 429, 444, SUS409L, SUS 436LM, SUS 439L, SUS 436L, SUS 436J1L, SUS 432L, SUS 429LM, SUS 441L and SUS 430J1L.

AHL steel can supply all the above stainless steel grades for auto exhaust system. Both steel strips and steel pipes are professional manufacture.