A4140 steel

Hi, Is any one familar with A4140 steel. I was at the scrap yard and most of the metal was misterium but there was one pile that had a
label on it. A4140.
What are its charasteristics and common uses? Al
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4140 is also known as chrome-moly. It is a non hardening high strength steel used for things like air frames, bike and race car frames. Lots of other applications too. Very useable in rod, sheet and tube shapes. It's a bitch to forge and machine. It's tougher than the hubs of Hell and welds very well. It is also very pricey. If it's at scrap price I'd get me some pardner.
Glen G. P.S. sorry about the "off topic rebuff" dude. Can we still be friends?
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GSG wrote:

I will have to go back and double check it. This number was on a lable but it was unclear if this was the material type or just some other number that happens to mean something to us but some paper pusher is using it as a invoice or po number.
If I remember right the stuff had a dark almost a smooth rusty layer on it but it might have been dust. I think it was about 1" solid rod about 10ft long. I'm use to thinking of chrome-molly as a tube used in bike etc.
I'll look tomorrow and report back. I most likily will just have a few more questions:-( I'm still learning what is important to look for.
Thanks for all your help. Al
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Alpinekid wrote:

Well, if it's SAE 4140, then it's a molybdenum alloy with one percent 'moly' and .4 of one percent carbon. It's commonly used for structural apps and fasteners such as bolts. It is a deep-hardening oil quench steel. In the past in aviation it was used for tubular airframe structures, but there were cautions on it concerning hydrogen embrittlement after welding. I have also encountered problems in hammer welding as the alloy tends to form an oxide skin with a very high fusion temperature. I use it normalized for pressed-in pin stock for its wear characterists against hardened 5160 blades.
Hope this helps...
Charly
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Lots of power hammer dies are made from it.
I think you'll find that 4130 is more often used in tubular form for frames. It would be a little LESS hardenable and that would be desirable for welded structures.
Pete
Alpinekid wrote:

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4140 is a high hardenability chrome/moly alloy steel. Its as quenched (oil) hardness is 601 Brinell. Compare that with 1095 which is 601Brinell water quenched and 4130 which is 495 Brinell oil quenched.
601Brinell is about 58 Rockwell C and 495 Brinell is about 51 Rockwell C.
My guess would be that 4140 hardens deeper than 4130 in larger sections, maybe above 1" diameter. 4340 is through hardening in pretty large sections, so it's reasonable that 4140 is something between 4130 and 4340.
4140 is a good tough steel, not as tough as 4340 and not as weldable 4130. I think it would be great hammer material.
Cheers,
Kelley
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