Uses of A4140

Hi, I was at my local scrap yard and they had a pile of steel rod with a label of A4140. 30, I just noticed that my keyboard does not have the cents symbol, $0.30/lb

Is this good for anything special or is it just "regular steel".

Can it be machined, harden, forged etc? Al

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ALT +155= ¢


This is not just "regular" steel. What you found is what is commonly referred to as aircraft quality material. Of course, without certs (certification) you can't use it that way, but chrome-moly (that's what you found) is one of the better alloys available, depending on the properties you need for your projects.

It can be worked in all ways with proper techniques. It is heat treatable and develops considerable strength Welding on 4140 requires exacting procedures, but is possible, so don't weld on that stuff, it has too high a carbon content to weld routinely.

It's not fun to machine, tends toward tearing, similar to mild steel, but is much harder on tooling. The A designates annealed, so it's readily machinable (as good as chrome-moly gets, anyway). 4140 is also available heat treated in a range around 28 Rc, so it is also machinable. It tends to cut slightly better heat treated, but is correspondingly harder on tooling, too.

Great find if you need the stuff.


Reply to
Harold & Susan Vordos

Reply to
James P Crombie

It's tough, it can be hardened, it can be forged. It is sometimes classed with the tool steels, used in places where extreme strength is needed, but can be rough to machine if you try to hurry it. It's a chrome-moly alloy, very strong. Good stuff.

Reply to
Lennie the Lurker

Everybody stresses how tough this stuff is. It aint really all that hard to machine. Use carbide for best results. In the heat treated (28-32Rc) condition it is a little tougher to machine but the finish is much better. Be careful if using in a situation where it may be used as body protection-such as a roll bar. Though stronger when it does fail it tends to break rather than bend. A mild steel roll bar will bend and absorb energy along the way. ERS

Reply to
Eric R Snow

Skipping the rest, which translates into it being a very nice steel for certain purposes, though it isn't anywhere near as nice to machine as 12L14. :-)

My primary reason for bothering to follow up to this is that while the above key sequence will generate the character in question on a Windows box, (and it happens to show up correctly on my Sun unix box), it is not a sure thing to work properly across the range of all computers which might be reading the postings on usenet. It is one of several extended character sets which go beyond the standard 7-bit ASCII character set (which is pretty much limited to what you can find on the keycaps on your keyboard, plus control characters). As such, there is no certainty that everybody will see it properly, so it is best to avoid the extended characters, and work around (as the $0.30 did in the original posting).

We had an experiment here a few years ago, in which I posted a set of extended characters, followed on each line by a text description of what it looked like on *my* screen, and got back an interesting collection of ways in which some few of the characters varied on other systems, with lots of variations on Windows boxen, depending on which characterset was being used by that particular system. (I'm using ISO-8859-13 I think at the moment. I was probably using ISO-8859-1 at the time.)

¢ -- Ah -- there we are, on *my* keyboard, it requires a '' (solid diamond key) plus shift plus the "'" to get that character. Good luck finding a '' key on a Windows keyboard. :-)

Oh yes -- another reason to avoid the extended characterset with some systems -- it is likely to trigger sending the article in HTML, which will make it even harder to read for some of us. :-)

Enjoy, DoN.

Reply to
DoN. Nichols

I just thought it was funny that all these years of using the computer and this is the first time I remember needing that key. I guess that is why it is not on the keyboard. I knew it could be generated it is just my brain is getting filled up and I have to be carefull what I put in it now. My days of finding all the strange randomly used computer code interesting is behind me. I have been a computer engineer for 25 yrs, during the golden years of software engineering, IMO. but these large corporation have made me feel like roadhill on the information superhighway. I could use and would take a cube job again, I can do the work in my sleep but that is the problem.

Just for fun the following key is alt 155, which on my system tonight generated nothing. Was it netscape, or xFree86 or the linux OS that didnt have that mapped. I could figure it out, I know where the keyboard map file is, and being linux unlike M$ I could change it. I just dont care.

Thanks for your help, Al

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There are 'funny' things in windows - there are two alt keys.

The right hand one is called altgr it is useful in Word for symbols of all types and languages......

The left one is the standard alt for what ever... . Not the std alt commands.


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ALT 0162 (the numbers on the numeric keyboard will do it) on a PC, usual caveats about cross-system stuff.

Other useful ones- ALT 0176 , ° the degree symbol ALT 0177 , ± ALT 0169 , © copyright symbol ALT 0174 , ® trademark symbol ALT 0181 , µ mu, for micro

But usually on usenet it's best to avoid the above.

4140 is nice tough stuff. IIRC, Machinery's says it's used for axles and such like.

Best regards, Spehro Pefhany

Reply to
Spehro Pefhany

I can't imagine anything about Word (ultra-bloat) that is useful.


Reply to
Ted Edwards

We use it for small race car axles. Heat treats very nicely to the 140kpsi range while maintianing decent ductility. Or you can push it to 265kpsi (!!!!!) at 11% elogation.

Go here

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search on 4140

It also has uses in the annealed state for machinery run in exptremely cold temps. At -40 F it has a charpy test several times that of equivilent mild steel. Translation: MUCH less brittle.


Alp> Hi,

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