4340 rectangular bar supplier
4340 rectangular bar supplier
(OP)
We are developing custom high performance billet conrods for racing engines in Colombia. Our first prototype was developed for a sr16 Nissan engine and is working up to 9000 RPM. The material used in this development was bholer v155, and for future development we want to look for a better suited material in terms of cost and maintaining the mechanical properties. Can you suggest any low volume supplier for 4340 AQ in the states.





RE: 4340 rectangular bar supplier
This would require you to get it heat treated correctly.
There are specs for this material Q&T, but they tend to be used for aerospace and there is a significant price increase.
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P.E. Metallurgy, Plymouth Tube
RE: 4340 rectangular bar supplier
https://www.metalsupermarkets.com/metals/
RE: 4340 rectangular bar supplier
RE: 4340 rectangular bar supplier
It is likely that material in stock is soft, and you will need to have it Q&T before you use it (if you really want it pre-hardened).
People usually buy this material soft (either normalized or annealed) and then rough machine it, heat treat (Q&T), and then final machine.
I don't know why you want 4340, you parts are not very thick are they?
4140 will heat treat to uniform hardness in parts less than 2" thick easily.
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P.E. Metallurgy, Plymouth Tube
RE: 4340 rectangular bar supplier
je suis charlie
RE: 4340 rectangular bar supplier
RE: 4340 rectangular bar supplier
The as quenched hardness will be the same for the two alloys.
However the 4340 will be harder deeper. The Jominy curves for 4140 show a 2pt hardness drop at about 7/16", while 4340 doesn't show that drop until about 1".
If they are tempered at the same time and temperature the 4340 will be harder, but they can both be tempered to the same properties, just pick the correct temper.
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P.E. Metallurgy, Plymouth Tube
RE: 4340 rectangular bar supplier
RE: 4340 rectangular bar supplier
RE: 4340 rectangular bar supplier
I have contacted carrillo, wiseco, omega, venolia, saenz... and the reply is always the same "We do not sell blank forgings".
RE: 4340 rectangular bar supplier
If you want to purchase some alloy steel bar, give a large US supplier like EMJ metals a call. I don't believe there is currently US restrictions on exporting non-proprietary alloy steel raw materials to Columbia, but you should check with them to make sure.
If you decide to use wrought steel bar, I'd recommend spending a bit extra for vacuum melt quality 4340 VAR (AMS 6414). Just remember that high-performance steel conrods typically start with a hot die forged blank, that then gets 100% machined all over to remove the hot forged surface material. You'll probably need to do the same if you start with hot rolled bar stock.
Lastly, don't forget you will also need a source for high strength (Al bronze or similar) bushing stock, high strength bolts, shot peening, heat treating, etc.
Good luck with your project.
RE: 4340 rectangular bar supplier
In the normalised condition 4340 has 25% higher UTS and Yield than 4140. Link Link
In the quenched and tempered condition 4340 has 20% higher UTS and yield. Link Link
("Normalised" makes for a better comparison since the properties can be achieved throughout the bar.)
je suis charlie
RE: 4340 rectangular bar supplier
I'd want to consider principal stresses in addition to the Von Mises stress commonly displayed by FEA program defaults.
https://youtu.be/uTpRfREYa9Q
RE: 4340 rectangular bar supplier
The two grades do respond differently, so if you used the same times and temps you might get different properties, but in thin sections I can make them the same.
But if I am going 1" or thicker section I would use 4340 in order to get more uniform properties through the section.
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P.E. Metallurgy, Plymouth Tube
RE: 4340 rectangular bar supplier
As far as availability, I checked my local metal supplier, Fry Steel, and they have AMS 6414 (vacuum melt quality 4340) HR/N+T 1.5" x 4" rectangular bar in stock. Perfect raw material for machining conrods. I have an account with them and FedEx will deliver to my house as long as the material is cut to 6' and weighs less than 70lbs, typically within 4 business days after ordering. Their website says they ship all over the world by major carriers.
RE: 4340 rectangular bar supplier
https://www.ryerson.com/en/stocklist/detail/0c5d73...
Ted
RE: 4340 rectangular bar supplier
RE: 4340 rectangular bar supplier
i know with crankshafts the billet are said to be better than forged.
does the better material mechanical properties make up for the difference grain orientation? are there some materials that cant be forged and you are forced to use billet or could the best material be forged to to create the best of the best?
RE: 4340 rectangular bar supplier
In reality, the "best" crankshaft material choice is usually the one that meets design/performance/quality/manufacturing requirements at lowest cost.