Test for Type 316 vs. 304 Stainless Steel

A. According to ASTM STP 550, possibly available from the ASTM, the test for molybdenum in 300 series stainless is to

a) Place equal drops of concentrated hydrochloric acid and concentrated nitric acid on the metal surface. Allow 3 to 4 minutes for reaction and transfer 2 drops to a spot plate.

b) Add 2 drops of 10% potassium thiocyanate [on eBay or Amazon] .

c) Add 25% sodium thiosulphate [on eBay or Amazon] drop-wise stirring until the red color begins to disappear. A violet color will appear if molybdenum is present.

However, I think your best course of action is to get a chemical spot test kit from Koslow Scientific Testing Instruments [a finishing.com supporting advertiser] or Systems Scientific Labs or some other company that makes them. A quick web search under "chemical spot test" should show manufacturers if they foolishly aren't already listed on finishing.com, and I know the two mentioned above offer small kits just for 304 vs. 316 resolution. Good luck!

Ed. note: Aww, shucks, you're just trying to embarrass us :-), but thanks! - finishing.com

A. Ziya,
Surely you can get the name of the 'green' chemical for identifying molybdenum somewhere in a local city. Try first a major supplier of chemicals and ask to speak to the lab technician first of all!

Failing that, contact a major supplier of stainless. OK? There's Henry Wiggin, too. Highly competent Company but specializing in the ultra high Ni.Mo alloys.

Mind you, had you a 'magnetometer' I'd guess that 3l6 would show a lower reading than 304. But that's pretty esoteric. Stainless does, yes, DOES contain some magnetism albeit of a low order.

Cheers !

A. Hi, Harvinder.

If you have the money, a alloy sorter / scrap sorter [on eBay or Amazon] hand-held XRF machine will instantly tell you exactly what each piece of unknown metal is -- but you're talking about $30-45,000 or so.

Regards,

A. Hello I have the answer for you I think over here it's named CELMO MOLYBDENUM REAGENT We are testing lots of 4301 and 4401 materials and have bought a small electrical tester MOLYTESTER. Look for Corrocean. I Hope you can use this information. Good Luck !

A. I know of a way to tell the difference tween 304 and 316. this method has been used in recycling for years. It's called "spark test". With an angle grinder [on eBay or Amazon] , grind 304 and look at the sparks; they will fork out at the end of their flight. 316 will spark but each spark will stay intact till the end of its flight. Try it out, it's cheap and better for the environment.

A. There are two basic issues that requires solution.
Separate 304 and 316 and secondly how to avoid mix up of costlier 300 series SS with 200 series.

To name a few as Lee pointed out companies like Koslow Scientific Testing Instruments [a finishing.com supporting advertiser] and Systems Scientific lab have been segregating 304 and 316 for a few decades now through their kits. However, to do a cost effective segregation of 200 series which might get mixed up with costlier 300 series of SS has been a bit of a challenge. Also, both series, 300 as well as 200 series are non-magnetic.

However, The Indian Stainless Steel Development Association mentions one of the company in India i.e. Met Associates, Navsari who has a portable, economical and Non-Destructive method kit developed for both the issues mentioned above.

Please contact ISSDA for more assistance. Hope my response helps.

A. I believe that Lee Gearhart's initial response answers your question, Mostafiz. The spot test book he mentions, ASTM SP550, is available from ASTM. Good luck.

A. 1. Clean the steel surface; use abrasive paper, and if necessary degrease and dry.
2. Use "Decapoli 304/316" solution shake well, then place one drop on the steel.
3. Place similar drops on standard 304 and 316 samples.
4. Darkening of the yellow drop in 2 to 4 minutes indicates significant Mo. Compare with indications on standard samples.
5. Wash or wipe samples clean.

A. The reader is looking for Damac 635 (or possibly 625) reagent to tell the difference between 304 and 316.

With regards,

adv.
The Koslow Scientific Company has a spot test kit called 304 vs. 316 Kit is an easy method to sort 316 from 304 stainless steel that we have been using this kit for years.

A. Go to search word "electrolyte for detection of molybdenum"

Ed. note: Unfortunately, that search won't lead you to the generic chemical names you seek, Mostaviz -- it is a "cherry-picked search term" to lead you to one particular proprietary product :-(
But I think Lee Gearhart has answered your question already.

A. Hi Ziya,

Yaa, your doubt is correct. The element is "Molybdenum". And this is the difference between Gr 304 and 316 materials. Use "Elite folw findr" to identify the grade. The test is very simple. Clean the metal surface with emery paper and tissues and apply one drop of chemical on it. If it is Gr - 316 the colour of the liquid will turns to Brown within 3 minutes. And if it is Gr - 304 the colour will remains same as yellow.

TRILOK CAN BE USED TO FIND THE SS GRADE.

A. Hi Muhammad.

Ziya last posted here a decade ago, so probably doesn't monitor this thread. But the question appears to have been answered by Lee Gearhart and others. If I'm misunderstanding, or if they haven't answered the question you have in mind, please re-state it.

adv.
Please remember that this free forum can only exist with support from advertisers like Koslow; suppliers who won't support the site with their advertising dollars but try to steer you towards themselves and away from our supporting advertisers are working towards making sites like this non-feasible :-)

Thanks!

Regards,

A. Molybdenum electrolyte is the chemical, I use to check it.

The chemical reaction is the development of a bright pink color.

A. Hi. Inox 316 has a reddish tint whereas inox 304 has a whitish tint.

A. Hi Vishal. Lee Gearhart points us to the ASTM procedure for the test above, and vendors like Koslow Scientific Testing Instruments [a finishing.com supporting advertiser] instruct you in the suggested procedures for their kits. Good luck.

Regards,