Identification of Steel

[stillfan]

I am reading through the AISC360 Section M5.5 Identification of steel and it states that "The fabricator shall be able to demonstrate by a written proceduer and by actual practice a method of material identificaion, visible at least through the fit up operation, for the main structural elements of each shipping peice."

Reading this I have a question
1. What do they mean by "Fit up operation"?


Thank you

 

[qcrobert]

Not familiar with AISC360 Section M5.5 but logical sequence of events of the fabrication of a weldment (i.e., pressure vessel, boiler, tank, etc) where material identification must be processed and controlled dictates that the material will be identified (1) purchase order, (2) receiving dept (MTRs), (3) material physically marked with heat number or some type of ID, (4) material is cut, sheared, burned, formed with ID transferred to each piece, (5) material with ID on it is "fit-up" (i.e., weld tacked in place ready for weld out), (6) a log or record of each ID material is recorded on a Weld Map.

At this point, the welding operation or later cleaning or painting operation my obliterate the ID but the ID was traceable throughout the process.

 

[stillfan]

Thank you qcrobert,

So the Id doesn't necesarly have to be a grade, it could be a code that the fabricator has on record. For example, they could use F for the ID and as long as they have a log of what the F represents ie; grade A500 steel. They would be compliant?

 

[dhengr]

Stillfan:

The whole part ID numbering system ties a plate or shape back to a purchase order number for a particular grade and size of material; and/or a mill cert. from a particular material grade and heat of steel from a particular producer. From that I can tell you a number of the mechanical properties of that material and its chemistry, weldability, etc. There are a number of mech. props. and quality items which we can request be covered by a mill cert. but you pay extra for some of these guarantees, Charpy values come to mind. We ID’ed raw stock when it was received. We didn’t always number every cut piece, but we knew that all of the stiffener plates for that girder were cut from this particular plate, which we could produce documentation on. We could trace all the flange plates back to a couple plates which they were cut from, again with proper paper work. Depending upon the specs. we were working with we might actually ID the various flange plates if they came from different heats or if the mech. props. or chemistry was not essentially the same. Some industries do req’r. ever cut piece to be ID’ed. so it can literally be located on the finished product. I don’t think this is usually the rule in building and bridge structures, but it certainly is an admonition to the fabricator that he better have traceability, so he’s not using A36 steel where A514 is called for.