identifying stainless

[norsa]

Guys, been given a job lot of fixings. Some obviously high tensile some brass some steel etc but im more interested in finding the stainless. Q; would all stainless hardware be non magnetic, is there another home method of sorting them??
Nick

 

[bigbadbugga]

Leave them all in the garden for a week, chuck away the rusty ones.

Sorry, I have no idea apart from some grades of stainless being magnetic.

 

[norsa]

cracking answer mind
Flaw. some could be plated

 

[500e]

No not all SS is non magnetic, cheaper mixes are mag & some specialist ones to.

http://www.mceproducts.com/knowledge-base/article/article-dtl.asp?id=18

 

[pedrobedro]

Some grades of stainless do rust as well, 431 and 416 will both get surface rust if left exposed.

 

[Engineer1964]

Some grades of stainless do rust as well, 431 and 416 will both get surface rust if left exposed.

Yes, I agree with that, There are some new flats in Brightlingsea in Essex, pretty expensive and have Glass Balconies with Stainless Handrails etc, Been up there a couple of years now and every single Balcony is Rusty, It looks terrible.

 

[hotrodder]

The balconies could be the result of sloppy workmanship i.e. made from austenitic but contaminated with iron etc. Similar story with some of the other flavours... 430 is a ferritic flavour that apparently was used a lot for 'chrome' trim on classic cars. Many would declare 430 'cheap' or poor quality based on a magnet test but i've straightened and cut n' shut a bunch of 50 + year old magnetic trim that showed little to no signs of corrosion...

I'd sort it with a magnet, unless you're in the cutlery business austenic grades are far more common than other flavours. Fixings, hardware... are we talking screws/nuts & bolts etc? Cold working austenitic stainless can make it very mildy magnetic in that you can detect a slight pull but very weak compared to mild steel and the ferritic grades etc. In bolt speak grade A2 is 304 and A4 is 316, heads of bolts etc will usually be marked often something like A2-70 where the 70 is a strength class

 

[Engineer1964]

You can also Test for stainless using a Nitric Acid Reaction test, this will sort out your Stainless steels from non-stainless steels.

1. Place a piece of the steel in strong nitric acid (20% to 50%) at room temperature, or a drop of the acid on a cleaned surface of the steel.

2. Test standard samples in the same way, ie stainless and non-stainless steel samples.

3. Non-stainless steels will quickly be attacked, a pungent brown fume is produced. Stainless steels are not affected. Compare result with standards.

4. Wash samples thoroughly afterwards.

But Be careful

Wear safety glasses. Strong nitric acid attacks skin and is very corrosive. Handle carefully. Use minimum quantities. Wash off immediately if skin contact occurs. Do not breathe brown fume.

keep a Bucket of Clean Cold water Handy, just in case

You can get Nitric Acid on the web in general and even on Ebay, But at £24 a litre on ebay, its best to buy direct from the wholesaler http://www.reagent.co.uk/nitric-acid about the same price but for 2.5lt

Not really worth it unless your sorting tons of stainless or Test loads of weld penatration tests