kjbarth

What kind of steel?

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So I picked up some new 2lb bolts as scrap.  The seller gave me some info that was on the box but didn't know much about them.  He did not give me the box.

Unbrako brand, the box they were in had A2LA (which I think is a certification group), vendor code on the box - 66245. ANSI B18.3.1M A574M, Stock no 40418, size M30 - 3.5 x 120mm.  Pics below...

I googled Unbrako, "A2LA", the vendor code, ANSI code, etc but, unless I didn't read far enough, didn't see anything to indicate what type of steel unless I'm misinterpreting the "A2LA".

I was thinking I could make some hammer heads or some other tooling out of these.  If they're crap steel, I can just practice hammering on them - I've got 26 of them.

If anyone has any ideas what they're made of or how I can figure out what they're made of, please let me know.  I was going to bring one down to the grinder to see how the sparks fly.

Thanks, Ken.

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Grinder and the forge-quench-break test will tell you enough to know if they will make hammers.

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Ditto Thomas, maybe add a spark test. Nice score, lots of potential tools you have there.

Frosty The Lucky.

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That type of bolt from Unbrako has a material spec of 190,000 psi tensile strength, and they are heat treated to RC 38-43. With numbers like that I believe it might be 4340, or a modified version. That said, it’s very good material for tooling, it will be able to get harder than 4140 and be more impact resistant at a given hardness. Your bolt is the metric equivalent to a grade 8 bolt, made to exceed grade 8 specs. Other lesser grade 8 bolts (all grade 8 bolts are good quality) are made of 4140, 5140 and other high strength alloy steels.

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Metric grade 12.9. 170,000 psi tensile strength alloy steel. Bout a $10.00 dollar bolt! Info from McMaster Carr catalog

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Yes sir they’re top quality. Unbrako have an even higher tensile of 190,000psi. We used other versions of their fasteners in high stress areas of a robot we used to make years ago. They are one of the best fastener makers out there.

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Thanks guys.  My spark test last night indicated high carbon steel.  So I lucked out and made a good deal.

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