material for drive axle
material for drive axle
(OP)
I would like to have some feedback on some material we are considering for half shafts in a custom car application.The app.is a shaft 24" long with a 1.2"spline journal diam.with 29 splines 45 degree pressure angle 24-48 pitch angle.The axle is exposed (visually)and I didn't want corrosion.I would also like to avoid any paint.Ford uses a necked down or waisted area of 1.437 down to the 1.2 spline diam.My concern is that if I make these shafts from 17-4 or 15-5 and use H-900 cond.Would it compromise the spline area in a torsional shock load? The parallel would be 4340 material which is used in the aftermarket and is presumably stronger than stock.





RE: material for drive axle
I would not recommend 17-4 in the H900 condition, due to potential SCC. 15-5PH or 13-8 would be better choices for that strength level.
Hope that helps.
Terry
RE: material for drive axle
RE: material for drive axle
RE: material for drive axle
RE: material for drive axle
Mike Halloran
Pembroke Pines, FL, USA
RE: material for drive axle
RE: material for drive axle
Or Ferrium 53 or 54.
C300 doubled fatigue life in one case for splined shaft of (4340 with most sophisticated surface hardening and core treatments available including shot peening and electro-polishing). Also these maraging steels have excellent corrosion and SCC resistance.
But these are not cheap alloys. How custom is it?
Design for RELIABILITY, manufacturability, and maintainability
RE: material for drive axle
RE: material for drive axle
I think that the most important issue is to understand the contact stress in the spline area, as that should determine the strength that is required, and hence the alloy and heat treatment that can meet it. Based on your further clarification, as long as the contact stresses are not so high that surface hardening (case carburizing or induction hardening) is required, one of the PH stainless steels should be ok. 17-4 PH is somewhat cheaper than 15-5, and certainly more readily available. I would suggest using the H1100 temper rather than the H900, if you want this to be a bullet-proof part that doesn't require extensive inspection, replacement, etc. Shot peening or roller burnishing will go a long way toward improving durability, and are not that costly, especially if you can do the latter in house.
RE: material for drive axle
RE: material for drive axle
RE: material for drive axle
RE: material for drive axle
RE: material for drive axle
RE: material for drive axle
RE: material for drive axle
I think you should look strong and hard at this suggestion --ALL OF IT including :
Because if TVP says, "bullet proof" he must have looked at impact values for H1100 condition and this could be the simple answer to:
mechanodan, Have you gone thru the numbers? This can be calculated and if the shaft couples with the CV joint, you need to calc bending load (stress) from the CV joint. This is a complex stress pattern including torsion, bending, and spline root stress, which I think requires Mohrs Circle analysis with contact stress as an adjunct .
Dana Convel is the largest automotive aftermarket CV joint supplier and designers/builders of humongous special CV joints if you desire some technical expertise in that area.
I am also a machinist/Toolmaker and a metallurgist and I have great confidence in TVP's expertise on this forum.
Please keep us informed on this fascinating project!
Design for RELIABILITY, manufacturability, and maintainability
RE: material for drive axle
Race engineer Carroll Smith doesn't think using maraging steels for drive axles is a good idea, due to load reversals.
http://bo
Regards,
Terry
RE: material for drive axle
RE: material for drive axle
300M is a good material for driveshafts. But it's not the same as C300. I couldn't find any published fatigue data for maraging steels.
RE: material for drive axle
Design for RELIABILITY, manufacturability, and maintainability
RE: material for drive axle
The measured stresses on the oscilloscope and print out verified calculated stresses. However, because MSHA (Mine Safety Health Administration)requires a max limit on inrush current of underground Coal machines during startup (an electric motor can develop 300% Full load current during start up), the LH motor had to have a 3 second time delay after the RH motor was energized.
The drum drive motors on this machine were located on the chassis with a long drive train of two drive shafts and several CV joints besides the CV joints connected to the notorious FAILING 4340 SPLINED SHAFTS. Inside of and upstream of the SHAFT was more drive train including a planetary, bevels etc.
This long drive train would wind up like a spring during start up on the RH side and by the time that the LH drive was energized, the RH side was UNWINDING and Powww! Reverse loading fatigue from START UP LOADS. Of course cutting loads added significantly to the fatigue history but the REVERSE loads were discovered during this dynamic testing which solved the mystery.
Maraging was a temporary solution -- the M shafts increased the fatigue life but still eventually failed because it was a geometry problem where the shaft had to pass thru the sun gear of the planetary to drive the center drum and later a second generation drum drive was designed to allow for a larger diameter splined shaft.
To reiterate and because cost is a factor for mechanodan's project, Maraging Steels are prohibitively expensive -- the shafts used to temp solve the above problem cost about $700 each -- no problem for Formula One folks.
Look at TVP's 17-4 suggestion!
Design for RELIABILITY, manufacturability, and maintainability
RE: material for drive axle
Carroll Smith had some definite technical deficiencies, and this mistruth illustrates one of the worst ones.
RE: material for drive axle
RE: material for drive axle
CoryPad,
Appreciate the correction and reference.
Terry