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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

Any of the large distributors should have this (EMJ), but it will likely be annealed or normalized.
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

(OP)
Thank you guys, Ed could you be more specific, we are from Colombia and we don't not which are the large distributors. As for metalsupermarket, they only seem to sell 4130 and 4140.

RE: 4340 rectangular bar supplier

Do you have any friends in Houston TX? Lots of good distributors and HT shops there.
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

4340 is stronger than 4140.

je suis charlie

RE: 4340 rectangular bar supplier

You might be able to purchase raw 4340 alloy steel conrod die forgings from a vendor like Carrillo. A forging would be better than using wrought bar stock.

RE: 4340 rectangular bar supplier

gruntguru, How is that????????????
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

I concur with contacting an existing manufacturer to purchase forged blanks.

RE: 4340 rectangular bar supplier

I'm sure they do sell 4340 it is so common.

RE: 4340 rectangular bar supplier

(OP)
Guys remember that we are in Colombia , not the states, we have a PO box and we can source the material from Texas but unfortunately i don't know the name of any supplier there.

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

You might try looking around on ebay for raw conrod forgings that are a suitable size. I'm sure you can find someone that sells raw alloy steel conrod forgings if you keep looking. Try some US aftermarket/race component manufacturers like Crower, Manley, Lunati or Eagle Specialty. Even if they won't sell you forgings they can probably tell the name of someone who will.

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

EdStainless.

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

If I was machining a con rod from a billet I'd want to orient the billet to take best advantage of the generally higher fatigue endurance limit in the longitudinal direction. And especially to be mindful of the significantly lower transverse endurance limit in steels.

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

Sorry grunt, I rely on data from a steelmaker like Timken, and I stand by my numbers.
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

Actually, with a component like a connecting rod, material fatigue strength is probably your primary concern. So S/N curves (like the example attached from MMPDS) are probably more useful.

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

(OP)
Thanks for your help, it looks like Fry Steel has it, i just send the quote request, as for ryerson, i didn't found 4340 flat bar (round bar is available),they only have 4140 flat bars.

RE: 4340 rectangular bar supplier

here is a question are billet rods better than forged? where absolute strength and fatigue are concerned.
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

Die-forged and 100% machined is likely best for fatigue performance. Assuming the same quality raw material is used for both. If you can afford the tooling cost, any material suitable for a crankshaft can be hot die-forged. To get the best result, a hot die-forged crankshaft would need to be 100% machined, carefully heat treated, and have finish processes applied like fillet rolling, shot peening, ISF, etc. to improve fatigue and journal bearing performance.

In reality, the "best" crankshaft material choice is usually the one that meets design/performance/quality/manufacturing requirements at lowest cost.

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