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4340 "forged" vs "billet" (and EN40B)

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Re: 4340 "forged" vs "billet" (and EN40B)

Postby Mark O'Neal » Wed Jul 25, 2012 12:24 pm

Forging dies are very, very expensive. Billets are not.
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Re: 4340 "forged" vs "billet" (and EN40B)

Postby Ratu » Fri Jul 27, 2012 2:31 am

What about a cast steel instead?
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Re: 4340 "forged" vs "billet" (and EN40B)

Postby clshore » Fri Jul 27, 2012 1:50 pm

Or maybe one of the nodular cast iron materials?
I have heard that some of these can have comparable properites to forged steel.

3D printing can now create cores and forms with excelent quality.

That still leaves the skill and experience of the foundry, to employ casting and processing technique that yields good parts.
(ie it might take several attempts before a 'good' one is created).

The Saturn 'lost styrofoam' crankshafts were a good example of what could be achieved.

None of these approaches appears to be inexpensive.

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Re: 4340 "forged" vs "billet" (and EN40B)

Postby Schurkey » Fri Jul 27, 2012 2:18 pm

Ratu wrote:What about a cast steel instead?

Folks that advertise automotive "cast steel" parts are lying to you. "Cast steel" is a fancy and expensive way of saying "cast iron" which SHOULD result in lawsuits and recalls, but doesn't.

Very much like General Motors "Armasteel" of years ago--a fancy grade of cast iron.

When someone tries to sell you "cast steel" parts, ask them what the carbon content is. Either you'll never get an answer, or they'll admit that it's over two percent--which is cast iron territory.
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Re: 4340 "forged" vs "billet" (and EN40B)

Postby DaveMcLain » Fri Jul 27, 2012 2:52 pm

I always thought that "cast steel" or "arma steel" was really a fancy way of saying nodular iron. The cast iron used in crankshafts is not the same stuff as is used in blocks, heads etc...
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Re: 4340 "forged" vs "billet" (and EN40B)

Postby Schurkey » Fri Jul 27, 2012 2:59 pm

DaveMcLain wrote:I always thought that "cast steel" or "arma steel" was really a fancy way of saying nodular iron. The cast iron used in crankshafts is not the same stuff as is used in blocks, heads etc...

Armasteel is (was?) a GM trademark for several grades of malleable iron.

"Cast steel" may or may not be a high-quality grade of cast iron. You're at the mercy of Communist integrity on that. Maybe it is, maybe it isn't. Maybe it was last week, but this week's shipment isn't. Maybe the prototypes were, but the production pieces aren't. For the most part, the consumer won't have the material tested...and so the suppliers of "cast steel" can produce whatever they want.

If our government cared about citizens instead of being owned by the Corporate World, the FTC would jump all over "cast steel". The fact that they haven't proves they aren't looking out for OUR interests.
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Re: 4340 "forged" vs "billet" (and EN40B)

Postby CREngines » Fri Jul 27, 2012 6:18 pm

I would say this question would really come down to the grain structure, orientation and purity of both raw pieces. Obviously any billet is superior to the old gm forgings as stated earlier. If the billet has been suitably hot worked (rolled or however they do it) to produce a denser grain that is more elongated and compressed similar to a forging then i would say the diffrence between it and high grade forging with no inclusions or other defects is minimal. If the billet crank is produced from a very poor quality feed stock like a poured ingot or continually cast piece then obviously it is going to be compromised in my opinion. Depends on the use of the word billet. In theory the forging should be stronger because the grain orientation follows the form of the crankshaft better. However i would be willing to bet that a good quality billet crank with like dimensions may be more rigid because it doesnt possess some of the springyness and residual stress of the forging.
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Re: 4340 "forged" vs "billet" (and EN40B)

Postby abu-hadhood » Thu Jul 24, 2014 8:22 pm

Hello, great information, i have 2 question
how long would a 454 chevy v8 billet crankshaft take on a cnc machine?
when using the 4340 material should it be forged first?
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Re: 4340 "forged" vs "billet" (and EN40B)

Postby wyrmrider » Thu Jul 24, 2014 10:28 pm

On the turbo Rambler indy project we had the choice of ARMASTEEL (TM GM)
OR
52,000 PSI nodular Iron (which I remember as being "high")
both worked well, no problems
but they ground and machined differently
you can google ARMASTEEL
these were stock 199 AMC 6 cranks, 3" STROKE
GENEROUS CRANK PIN OVERLAP
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Re: 4340 "forged" vs "billet" (and EN40B)

Postby pdq67 » Thu Jul 24, 2014 10:55 pm

Mark is right because years ago before I got kicked off the two T/C's and NastyZ28, I priced manufacturing 1st Gen Camaro 1.5" taller STOCK shaped forged front spindles, (not dropped 2"s), to raise our 1st gen's bad front roll center and the forging die costs were too high!

I can't believe Fatman doesn't already make them in this time!!!

I don't know if I still have the forged spindle material spec's or not somewhere?? I would have to dig deep!

I ended up going with spindle extenders against Pozzi's thoughts!! (Dr. Gas??/MacFarland??). He told me that 1-15/16" is too tall, but I couldn't get 1.5" raised ones. Onna these days before I die, I will see if it raises on each side hard when pushed to the limits in the front!! I figure 525/550 pound cut way down front springs with a 1" front swaybar and WIDE tires will get me by??

Years ago, I had my car sprung so hard that it almost skidded sideways taking a 90 degree corner at 45 mph in town!

Sorry to get off topic here but what the hey....

Just as always trying to add something here..

I guess my point is that if you have the MONEY, then spend it!!

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Re: 4340 "forged" vs "billet" (and EN40B)

Postby pdq67 » Fri Jul 25, 2014 3:07 am

Back again, there are REAL cast steels. Look at investment cast steel rocker arms for one application.

I want to say ASTM 8640 or some such real cast steel designation.

Heck, look it up!!

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Re: 4340 "forged" vs "billet" (and EN40B)

Postby Kevin Johnson » Fri Jul 25, 2014 5:57 am

pdq67 wrote:Back again, there are REAL cast steels. Look at investment cast steel rocker arms for one application.

I want to say ASTM 8640 or some such real cast steel designation.

Heck, look it up!!

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Cast steel crank or new yacht? Decisions, decisions.

Cruise to Scotland with the new yacht and sail home with the new cast steel crank. Bingo.
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Re: 4340 "forged" vs "billet" (and EN40B)

Postby pdq67 » Fri Jul 25, 2014 7:02 am

Out of School, ('74), I worked for a short time at AB Chance, (Now Hubbel Sp?.), in Centralia, MO and they perfected spin-cast hot-line tool tech. It was something to watch as they made their hot line tools out of electrical grade FG and either poly or epoxy resins, I forget!

Jack Knight, (Emerson), bought them out and 6 months later, 30 percent of the staff was GONE, including me!!

I went up to WA Schaeffer Pen in Fort Madison, IA and learned how to make high end writing instruments so it ended up OK, BUT I lost about a $1,000/year!

Couldn't live on that so we came back to Moberly, MO and I got back in Construction at another $1,000/yr drop, but at least we were living in our house we couldn't give away back then. Talking like '75 and '76/7, what with two babies and a 3rd on the way!!

Boy the GOV. interest policies back then really sucked! Ended up destroying construction...

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