best grade stainless anyone

[markbigears]

Sorry for "another" exhaust question, but can anybody tell me the best grade of SS, and what the differences are? specing the exhaust tomorrow so any advice appreciated, cheers mark

[simpo one]

From my very limited knowledge (eg the Demon Tweeks catalogue and Mikalor clamps in particular, the ordinary ones are in '430' stainless steel and the 'pro' ones in '304 marine grade' stainless steel. I suppose you get what you pay for.

[mel]

Tube and sheet come in totally different specs and usually reflect their suitability for a job e.g machinable,weldable,suitable for cold forming etc etc The 430 grade is a tube grade normally used for downpipes etc and the 304 is mid grade sheet spec usually used as the outer sleave on expansion boxes etc. These grades are used by most manufacturers and it is unusual for a manufacturer to scrimp using a lesser grade, what is more common and must be looked at is the wall thickness of tubes and gauge of sheet as this is a more common place to cut corners and save money. IMO downpipes should be ideally be 2mm and sheet for expansion boxes 1.2mm (18Swg). Don't accept the cheaper shite using 0.7mm Eastern European crap often badged as being decent stuff, if in doubt chuck a magnet on it, it should fall off.

[MajorClanger]

It might be worth have a look at the ACT website with some info on Silencers

I'm not an exhaust expert but have used various alloys in the past in my work. There are basically two types of stainless, Ferritic and Austenitic. Type 430 is ferritic and types 304 and 316 are austenitic. There are other grades but 430 and 304 are the main grades used in exhaust systems.

So, what's the difference? Ferritic SS is slightly easier to work i.e. bend and weld, than Austenitic. But ferritic SS is less corrosion resistant than Austenitic, especially a high temperatures and in presence of chlorides e.g. road salt.

I would choose 304 and you will probably get a life time guarantee from the supplier which I doubt you would get from one supplying 430 (or if they do they won't be around to honour it when you need to repair it in 5 years time!).

MC