304/316 portable tester

http://metals.lincdigital.com.au/files/ASM_Tech_Notes/TN1-0506-qualitative%20sorting%20tests.pdf

You pretty much have three options:

1) Get a hold of a hand-held x-ray alloy analyzer (fairly expensive units)

2) Try to determine from spark-testing (a little touchy-feely)

3) Use a chemical spot tester such as "Moly Drop 960" as in link below:

http://www.avestawelding.com/1899.epibrw

Also see previous thread on distinguishing SS:

http://cr4.globalspec.com/thread/14704/How-to-tell-different-grade-of-stainless-steel

I think SS316 is non-magnetic and SS304 is magnetic. If I'm right, a piece of magnate could be your tool

This is not right. Both of them are non megnetic.

He has it in reverse.

304 is non-magnetic.

316 is slightly magnetic.

We use both in my machine shop and the 316 is magnetic enough that you can feel the magnet hold to it slightly.

meaning no disrespect, but 304 is an low nickel austenitic stainless, and if sufficiently cold worked will exhibit a slight magnetic response due to martensite created during the cold work. (magnetic response means attracted to the magnet...)

316 is a higher nickel austenitic and the additional nickel in the matrix is supposed to prevent the formation of martensite out of the austenite during cold work. I just helped a client in California sort this issue out last week.

Heres an independent non technical reference which confirms what I just typed:

Cold Working

Many cold drawn and/or polished bars have a noticeable amount of magnetism as a result of the previous cold work. This is particularly the case with grades 304 and 303, and much less so for the higher nickel grades such as 310 and 316. Even within the chemical limitations of a single standard analysis range there can be a pronounced variation in the rate of inducement of magnetic response from cold work.

http://www.azom.com/details.asp?ArticleID=1140

You can rent a niton hand held xay spectrometer here:

http://www.niton.com/Rentals-and-Leasing/rentals.aspx

Very expensive.

milo

I know 304 sometimes has some magnetic properties to it.

We use stainless steel pump shaft, which is 316 and it is magnetic.

I have to assign new part numbers to materials that don't already have a part number. I also have to do for one of our divisions in Washington. They had something come up that required using cold rolled stainless steel sheets. I have to send off to France to get the part number because their system of part numbers and ours have to match.

While looking up for data on the cold rolled stainless I came across a table listing the grades of stainless steel and it listed both as being slightly magnetic.

What you need is a spectrometer. They can be expensive so hopefully you are doing a lot of testing to justify the cost. There are many types of spectrometers out there. Some are large units and some are hand-held. Look at www.thermo.com for a nice portable unit that my company uses in Sweden.

Yes,

The simplest possible tool - a small magnet.

Stu.

As a friend pointed out --"Go SPectroscopic" if you need . For any/all Steelsin the shop.

Info@OceanOptics.com

Orders@OceanOptics.com

Use an OHM meter, The conductivity of 304 vs 316 is measurable different given the same sample size. to see the difference move the contact points as far apart as you can

Hi Andrew

can you specific tell what kind of tool to visual distinguish 316 from 304

Thanks, Norberto