Guessing the grade of stainless from how it looks? 1

[antknee]

If I had some dull grey stainless, not shiny or bright or silvery like 316 or 302, what grade might it be? Any guesses? Thanks. Ant.

 

[moltenmetal]

Are you kidding? Surface finish determines colour, not the alloy grade!

 

[antknee]

Why would I be kidding? I'm now laughing because I'm wondering if it was a stupid question or an incredibly stupid question lol.

 

[moltenmetal]

If it matters, "look" at the surface with an XRF gun. That will tell you something your eyes are unlikely to see.

 

[antknee]

I've finished laughing. For some reason I had it in mind that there would be some grades with for example more carbon making them a bit darker.

 

[SJones]

Try tasting it - that should be more helpful!!!

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[swall]

I had an uncle that was an industrial electrician--he claimed he could tell stainless by the smell.

 

[antknee]

I've just broken a tooth, where do I send the bill? lol

 

[moltenmetal]

Superman probably doesn't need the XRF gun, or the new teeth for that matter. Then again, he's probably got better uses for his x-ray vision than looking at lumps of stainless!

 

[EdStainless]

In mill products with identical surface conditions you do see color differences, but not enough for identification.

I used to cast alloys and could separate grades by smell, we added S to some and not to others.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[MiketheEngineer]

Good luck - like asking where the sugar I had on my cereal came from??

 

[antknee]

The sugar bowl?

 

[SJones]

Yes - a stainless one.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[qcrobert]

Introduce me to the person that can discern the type/grade of stainless by its color because I wish to take him with me on my next trip to Las Vegas.....

 

[bhollands]

Is it magnetic? Take a piece of known 304 and a piece of carbon steel and see how strong each pulls. Then try the mystery piece. How strong it pulls in relation to the knowns can give you an idea. If it is strongly magnetic hit it with a grinder to get an idea of the carbon content.

Bob

 

[antknee]

How does precipitation hardened stainless look after aging (with no added finish) ? I'm 99% sure that's what it is.

 

[MiketheEngineer]

How long did it age?? Two days or two hundred years??

Even SS will corrode after a while.

 

[redpicker]

While not what the OP in interested in, you can, in some instances, tell the grade by looking at it.

For example, take a forging operation that produces the same valve in carbon steel, 410 stainless, and 316 stainless. I could tell by looking at the as-forged valve bodies and determine which was which because of the differenes in the appearance of the scale. Now, this is a result of education and experience so I could spot and understand what caused the scale to take on different appearances, along with knowing that they had to be one of those three grades. This was also years ago; today I might be able to tell if one was A105 or stainless by appearnace, but I wouldn't trust myself.

rp

 

[MiketheEngineer]

I challenge you to "eye-ball" ALL grades of SS. Sure - a couple, yes - but after that - good luck

 

[redpicker]

I challenge you to "eye-ball" ALL grades of SS. Sure - a couple, yes - but after that - good luck

And, I might add, you'll need a lot of luck. My point was that, under controlled situations, it is possible to differentiate between CS, martensitic SS, and austenitic SS. I'd be very suspicious of anyone who said they could tell a 316 from a 321 or a 347 Stainless just by the way it looks.

rp