Rock Toy

Sorry, but I don't know what 1540 is, I've never ran across 1540 shafts I have had 1040 carbon steel, 1050 carbon steel,1541H alloy steel, 4140 alloy steel, and 4340 alloy steel.

The yield strength in psi for the axle steel I have found are:
1040 carbon steel = 106,000
1050 carbon steel = 146,000
1541H Alloy steel = 164,000
4340 Alloy steel = 210,000

jscusmcvet

You have a PM and an order already placed. Thanks for your help.

John

ct67_72

sorry, its 1541. The OP had 1540, and I was basically referencing the 15 part of the property, which is still a carbon steel. not an alloy.
http://www.efunda.com/materials/allo...le=AISI%201541
But 1541h would be a high alloy steel. I went by what he posted, although now all I see for shafts are 1541H.
So thats a good comparison, as stock shafts should be 1040

Rock Toy

Yes, the 1541H is a high silicon, manganese alloy steel that, as you can see by the yield strength, is about haft way between 1040 carbon steel and 4340 Chrome-moly steel.

jscusmcvet

Thanks to all for the informatiojn and opinions. I have completed an order with Frank froim Serious off road for a set of Alloy USA axle shafts.

I know the hits against the d35. I hear you all that are saying it won't hold up, but... well I made this decision about the 35, and if I regret it, I will. But I think I'll be fine. Only time will tell.

John

Pinoy59

Is that tensile strength or torsional strength?

Rock Toy

It is the point where the axle will
twist, bend or otherwise become deformed. I hope that answers your question.

thebyus

I talked with a guy in Moab at EJS about this this year. He races KoH and was complaining to the Yukon guys about breaking shafts.

Their explanation was that what makes Chromo so much better is NOT that they twist less, but rather that once they twist, they return to original better. ALL shafts twists, but it is the return that matters. The less a shaft returns to original, the sooner it will break, as each time it twists, the farther away from original it is, the less twist it has to give before breaking.

This guy said that the Yukon guys basically said, when you get a brand new shaft, either draw a straight line with sharpie down it, or scribe one into the metal. Then check it periodically. When the ends of the line are twisted 90 degrees off, your shaft has no more return left and is about to snap. This guy started doing this and hadn't broken a shaft in a couple years because when the ends were 90 degrees off, he just yanked them and replaced them.

Pinoy59

Materials have different strengths in different planes. Tensile strength is determined but putting the shaft in tension or pulling on both ends. Axial strength is determined by rotating the shaft along its axis. They can be very different. For example, Concrete is very good in compression but very weak in tension.

As for ductility, or yielding, the harder a shaft is the less it yields. There is a range (called the elastic range) where the shaft with move but always to back to its original form. If you bend/twist it enough in moves into the Plastic Range. Plastic deformation is permanent and will not go back to its original form. As this happens the material actually gets harder (work hardening), but we all know that hard materials break/shear and soft/ductile materials bend. That is why you end up breaking a shaft after it bends/twists a certain amount. If you have any questions about this you can look it up in any Mechanics of Materials textbook or google it.

Rock Toy

Yeah, I know, I just didn't want to get into that. The yield strength I think is the best way to choose what material
your shafts should be made out of.

The tensile strength: in PSI
1040 = 120,000
1050 = 162,000
1541H = 181,000
4340 = 228,000
300M = 270,000

But here are the tensile strength ratings.

Pinoy59

It would have a different yield strength for each axis. Since the shaft is in torsion you need that yield strength. There is very little tensile force on the axle when compared to the torsional forces.

Rock Toy

K whatever, I've been wheeling for 40 years, always used yield #s never broke a shaft yet. I'm done with this, good luck.