Tolerance. In steel, it’s called ASTM A484

Tolerance is in short supply with me, especially lately. Traffic, people that drive the speed limit in the “fast lane”, airport security lines Oh! and waiting for Whataburger to deliver to the driver’s side window…

You get me. These are real struggles.

Oh wait. I’m not talking about the willingness to put up with something before driving yourself crazy, I’m talking about TOLERANCE as in the allowed variation in dimensions.

My world is round, especially in bar. I have remarked over the years that I do not subscribe to that flat world theory, but I have had to play the part a few times in a pinch (insert big shout out to my Cali and Dallas sales gals that have held my hand repeatedly when I had to brave this road less travelled). In my world, those tolerances are governed by ASTM A484.

ASTM A484 is all about bar conditions and finishes. Today tho, its just conditions. I’ll get to finishes later.

Conditions are determined by the last part (or parts) of what happens when bars are made that gives an idea of what the metal will be when it leaves the mill. The big word to describe this “part” is thermomechanical processing.

Wow. That’s a mouthful. But all it means is that the bar has had some sort of temperature put to it (the thermo part) with a machine or some sort of machinery shenanigans (the mechanical part).

And here’s that laundry list of things that are considered thermomechanical processing:

Hot worked, hot worked annealed, annealed, cold worked, hot worked quenched and tempered, normalized and tempered.

EDITED… pickling is not a condition. It is a finish which is discussed in ASTM A484 part 2. My apologies for having used that in this post. I have removed it for the purpose of staying within topic.

Why’s it important to know this? Well, in a word, because conditions influence the mechanical properties of the material — hardness, yield, tensile. The widgets of the world are manufactured knowing that a specific grade of metal will hold up to the stresses of the job– whatever job that widget has to do. Think of the widgets in your life. Screws, handles, espresso machines, cars, click pens – metal has to hold up to the repetition of use.

I leave you with this–

“Success is a science, if you have the conditions, you get the result.” Oscar Wilde