Determing existing steel grade

[LPPE]

Does anyone know of a way to determine the grade of steel used in an existing structure, besides cutting a coupon and testing it? I have heard of taking a grinding wheel to the steel and observing the sparks. However, I understand that that method only determings whether it is mild or high carbon steel (for determing the weldability).

 

[Rich2001]

Texas Nuclear? make an nuclear alloy tester that is portable and can determine alloy content. If however can not determine carbon content. You might be able to find a local NDE company that can do this for you.

A portable hardness tester can be used to determine yield strength, (hardness is a function on yield strength). Querry the Automotive group many body plants check the hardness of the incoming steel prior to fabrication.

Good Luck,

Rich

 

[dik]

If there's enough of it, you might check for rolling mill marks embossed on the web of beams. Might give you a lead on the manufacturer...

Also, if the building is recent enough, there might be drawings available and possibly shop drawings if the consultant/building department still has this information. You might be able to make an informed guess...

Otherwise, it's a metallurgical process... and no easy way around it that I'm aware of.

FWIW, Grinding and sparks is not always positive.

 

[LPPE]

The buildings about 12 years old, and I have tried an exhaustive search for the structural drawings. None of the consultants have them and I appear to be at a dead end. Also, there is a hung ceiling, and it is PACKED with electrical, mechanical, plumbing, etc. Access to the beams is very restricted.
The beams are just about at maximum capacity as is, and the additional load the client wants to apply makes or breaks depending on what grade of steel.

 

[dik]

If it's yield only, and you have an idea of what the various yields should be, a hardness tester will likely give you a close approximation.

I don't know what your jurisdiction is, but we are required to keep documents 'forever'.
I assume you have checked with the local building inspector. Towns and cities also keep drawings (if they can locate them) for extended periods of time.

Is the contractor available; they might be able to point you to the fabricator who may be able to help.

 

[JAE]

Why can't you cut a coupon?

 

[LPPE]

Follow up - Town Hall had the structurals in their archive. The original consulting engineer did the mech and elec and struct plans. We only recieved the mech and elec plans. I contacted them for the structs and they said they did not do the structural plans. I get to Town Hall, and there is the stamp on the drawings by the consultant. Nice to share info with your peer group, eh?!