Positive Material Identification

What's wrong with getting a mill certificate from the supplier?

MTC s are compulsory for all material received. But can you trust all of them? We have evidence of forged certificates from suppliers. Even the originals. We have shortlisted suppliers and even manufacturers from certain countries, but still do not feel comfortable.

Most of the developed world uses them.

The pharmaceutical industry depends on them.

Unlike many other industries we cannot take a chance as our products are highly flammable and toxic.

The pharmaceutical industry's products are as well.

This is possibly a thorny issue. I don't know of a simple instrument to distinguish these grades; you might need to send samples to a metallurgical lab for analysis, or to conduct tensile stress and impact tests.

See also the controversy on counterfeit electrical plugs.

What we are looking for is a non-destructive on-site analyser

No such thing.

Hi ciperera,

I found this fairly quickly:

http://www.spectro.com/pages/e/p0101.htm

I'm sure there are others out there.

Type "steel grade analyzer" into a search engine.

Wow, had a GA on this yesterday. Who's the a$$hole?

I don't know of any instrument to distinguish grades of carbon steel.

Grades of carbon steel are not determined by ASTM numbers though. I can't tell from your question if you know this or not so let me know and I'll shut up. For instance, A516 is plate metal while A106 is seamless pipe.

If you don't trust the MTR's you get from vendors then I would assume the lower stress values for calculations.

Thanks for your comments. A 516 is used mainly for our pressure vessels and Most piping are API grades. We ARE depending on MTCs upto now. The issue is that we have suspicious MTCs from certain vendors and we have already shortlisted genuine suppliers, but if any instrument is avialable to distinguise between carbon steel grades we would feel very much more comfortable. Our insurance brokers too have raised this issue. PMI would satisfy them too if possible.

PMI won't do it. A PMI gun will tell you what elements are in the material (C, Al, Mg, Ni, etc.) but it can't distinguish between grades. Mostly because the grade difference comes from the manufacturing process.

I'm not sure exactly what you need the material identification for though. If you're chemicals are compatible with carbon steel then grade won't make a difference. If you're concerned that you are getting a weaker grade of carbon steel than the vendor is telling you, then calculate for less and don't buy from that vendor.

What I mean by calculating for less is that the only difference in these grades (A516 Gr. 60 or Gr. 70) is the allowable stresses. Essentially, that will result in thicker vessels or pipe.

I guess you're at the point now that I would need a more specific question to give you a better answer.

You are spot on. Our concern is whether the material supplied conforms to the order. A completely defferent material may come with the MTC for the specified material. We need to identify these culprits and blacklist them.

I would give Mikerho's spectro.com suggestion a try (GA). If it doesn't turn out to be what you need, they may have other suggestions--or they may tell you that such a device is not economically feasible, and why. If nothing else, you could gain information. Good luck in solving this problem, and please keep us posted.