Looks like the main difference between the buzzken downpipe and the other contenders is:
Buzzken DP: T409
Rawtek: T304
Diesel Dubs: T304
What is the difference between 304 and 409 stainless steel?
You may wonder why with some stainless steel products become rusty after a year, while the others remain in the perfect condition they were in when you bought them. You may also think that it may have something to do with the price and quality because the stainless steel products you bought at a low price are the ones that became rusty right away, while the more expensive stainless steel products are the ones that are still rust-free. Your assumptions are partly true because different stainless steels were used in those products.
Generally, regular steel becomes stainless when chromium is added to it. Chromium is an element that allows it to produce a filmy texture. This film serves as a buffer that prevents corrosion and even scratches and cuts. The more chromium is added to steel, the more stainless it becomes. This means that it becomes even more resistant to corrosion or oxidation. The addition of nickel content to the steel also enhances its resistance. Obviously, stainless steel products that turn rusty right away have less chromium content in its material and they are mostly constructed with t409 stainless steel.
To get your money's worth when buying stainless steel products, you have to know the difference between t304 and t409 stainless steel.
Stainless steel systems
The t304 and t409 are stainless steel production systems. The t304 system is more expensive because it is made to be more durable and it is a higher quality of stainless steel. The t304 system is generally used in equipment that requires more strength and durability like in cars and machines.
Chromium content
The difference between t304 and t409 stainless steel lies in their chromium content. T304 has more chromium than t409, between 18% to 20%. It also has a nickel content between 8% to 10%. T409 has chromium content of 10.50% to 11.75%. Its nickel content is only 0.50%. Because t304 has so much chromium and nickel content and very little ferrous material, magnets will not stick to it, whereas magnets will stick to t409.
Getting the right one
Knowing the difference between the t304 and t409 stainless steel will help you when you buy stainless steel products. The t304 system will not oxidize or rust. However, it can develop a golden color when exposed to high heat over time. The t409 stainless steel has a lot of ferrous material in it and can show surface oxidation after a while, especially when exposed to calcium chloride or salt. However, this can be prevented by applying stainless steel cleanser using a scouring pad.
If you are concerned about long-term appearance, then you should get the t304. If you are more concerned about the price but want something that is fairly durable, then the t409 will work just as well. So the next time you buy a stainless steel product, make sure you ask about t304 and t409 stainless steel options.
Stainless steel info from:
http://www.summitracing.com/expertadviceandnews/professoroverdrive/answer/3932
