about steel

Seasoned fabricators says to the greenhorn fabricator to taste it, because 316 is more salty.

Not visually

no.

No quick chemical spot checks either.

milo

Ask the mill to tag it for you.

All SS Plate Materials, Sheets, Filler rods, Electrodes - whether it is AISI 302, 304, 316, 307, 309, 310 Or other SS or its low carbon versions can not be identified by look of it. If any body claims, it could be self thinking. if required a spot analysis could be carried out to check it's Cr, Ni & Mo elements to determine the type immediately.

Sridhar

All SS Plate Materials, Sheets, Filler rods, Electrodes - whether it is AISI 302, 304, 316, 307, 309, 310 Or other SS or its low carbon versions can not be identified by look of it. If any body claims, it could be self thinking. if required a spot analysis could be carried out to check it's Cr, Ni & Mo elements to determine the type immediately.

Sridhar

thx to all for their view and suggestion on this discussion

yes i know composition testing is the last option to identify the material but problem is with me we genrally purchase approximate 100 shaft or pipe at a time now it is not looking physible to send all the shaft or pipe for material testing every time. however spark testing suggestion is looking intresting i will defintly go through this procedure

can anybody tell me wht is the approximate cost of material testing by outer source or how much expenditure is required to set up a lab for material testing (SS )

The only methods I was taught many years ago, but not for stainless I am afraid, was to take a known piece of each to a grindstone and note the difference in the way it sparks....various normal steels spark each in a different way.....

Whether stainless even sparks or not when ground or whether the differences are noticeable or not I have no idea as I have not really done any work worth mentioning with stainless.....that may change shortly!!

Perhaps someone else can shed more intelligent light on the idea (or not!!)

Class in Physical Metallurgy, we did that to ID carbon Steels, We has to ID 1035, 1040 and 1045, it was called a spark test, one sparK was called crows feet. That was the easiest, that others were less pronounced.

We has to ID an used existing tank we had to rebuilt, Talked to my professor, they did that for area industry, and for a non destructive test it could only give a educated guess (flip of a coin) or to be certain they could conduct a Gas chromatography-mass spectrometry (GC/MS), which they use a sample piece and basically denigrate it and ID the metals by analysing the gases. That is Pricey and probably like the original poster may not be worth the expanse.

Might the spark test work for stainless? or was I off track?

I don't know.

I haven't tried it. The number and geometry of bursts are somewhat proportional to the carbon content, the carrier streams are a function of deoxidation/ deoxidizer, and their are certain spark characteristics/attributes that are chemical constituent dependent, but if they can be seen at the low levels in regular steels, I don't know how 10-15X the level would affect their presentation, nor interact or mask their appearance.

My buddy from Carpenter Stainless had never heard of it, so it,s not something that they routinely employ.

milo

What creates the type of spark is the presence of carbon, very little carbon in stainless,

That is true, but it is not the whole story, The number and type (form) of bursts are dependent on carbon content; but the carrier lines, thickness of the lines and spark stream, and blocks or seeds along the carrier lines are a function of deoxidation (silicon, aluminum) and then other characteristics are a function of other elements- phos and moly for example. Color was an important attribute on tool steels sparks, I found, as they were all very high carbon.

I always used known samples and did my sparktesting as a comparator, rather than hit it with the wheel and proclaim its grade. That would be a fools errand.

Consistent pressure with the wheel and not streaming against sunlight were also important, though difficult to do on a line pipe job...

milo "not carnac"

Thank you Milo,

Now that you mentioned that, we did use a known as a comparator as will as the other items such as color.

milo "not carnac" ???? huh?

This is carnac.

milo

geez, I should have known that...

I have much experience with sparktesting,but its not something that can be taught via email.

My experience was limited to carbon, alloy steels, line pipe and toolsteels.

Based on my experience sorting mixes, I developed absolutely airtight product identification systems.

It's no fun explaining a grade mix to anybody in Detroit.

Niton makes a hand held xray spectrometer unit for about $4000, but you need a lot of mixed steel to "justify" that investment.

http://www.thermo.com/com/CDA/Category/CategoryFrames/1,,15526,00.html

Matchmarks samples are easy to manage and administer if product is not mixed in bundles, (im a bar and pipe guy) but I believe the original post was plate, and so they would need a coupon off each plate...

I'm thinking that these folks haven't heard of quantotester or spectrotesters either.

milo

"I have much experience with sparktesting,but its not something that can be taught via email. "

That is a more hands on demonstration.

Well can you tell by seeing it , obiviously if it looks same interms of color , appearance micro textures, or using any other human sensor , you will have to undergo tests , why not heat it red hot on gas stove and let it cool down you can observe coloration difference or other tests mentioned by experts

And just how would type 304 react noticeably different from type 316 upon heating and cooling?

These are both austenitic grades.

milo

eeny meeny minny .....................MOE...!!!!

Spark test is good for checking Carbon , Manganese percentage and like elements present in Low/Medium/High Carbon steels and Cast iron etc. Even there it will only gives an idea, but may not give actual percentage. This method does not suit for

detecting Cr, Mo etc. present in SS. Now a days spectrometers are available in the maarket as portable (handy) devices and gives instant Chemistry of any material .

Sridhar

I have come to the conclusion that all they need a simple marking system to identify the smaller pieces properly, a rubber stamp and ink pad for example, or pre-printed labels.

They obviously know what the steel is when it arrives - mark it, later that bit gets chopped off for manufacture, mark the other bit. each and every time.....it could even be the color of the ink that lets them know....

It would appear that the users are slovenly in the way they keep track of their materials!! nothing more, nothing less.....

If what you are saying this is a supplier problem, change your supplier immediately.....even if it costs more per unit!!

Hey all, We by all our steels with material certs and heat numbers as well as material and grade stamped clearly on the metal. If the heat number on the cert. matches the number on the metal then we accept it, log it and store it in a way so as not to mix the materials. I believe that hiring or training an existing employee to be a quality control manager to manage this would be the answer in most situations.

pipewelder