harden 1144 steel shaft

[NIKT1]

I want to harden an 1144 shaft spline to 32-38 Rc. The shaft spline is 0.875 diameter and 2.12 inches long at the end of a 16.00in. ling shaft.
Using available charts, I specified induction harden at 1500 deg F with oil quench and draw (temper) at 900 deg F for 1 hour. Does this sound OK?
I would appreciate opinions and comments from more experienced minds out there. We will have a hardness tester available to quality check the spline hardness.

Thank you!

 

[swall]

Normally, induction hardened shafts are water quenched. And SAE 1050 would be a more typical steel than 1144 for this purpose.

 

[mfgenggear]

Hi Niki

Because gears and splines require extra care during heat treating for these reason
1) prevent distortion
2) prevent dimensional change.
3) post process after quench and temper such as bead blast will cause detriment size change.
especially on splines. hardness test will be required as a micro section
there should be a case depth specified. and a section will be require to measure it.
4) martemper oil or salt

check out the following specs ams2759/1 & /2, mil-s-12515

Swall all due respect but gear engineers dislike quenching in water. almost never

 

[swall]

I understood the original poster to be inquiring about a splined shaft, not a gear. At one of my previous places of employment, we turned out splined axle shafts for automotive use. All 1050 steel, all induction hardened, water quenched. Some also received straightening.

 

[Tmoose]

https://bergsen.com/key-considerations-1144-stressproof-carbon-steel

"Maximum Attainable Rockwell Hardness: B97" less than HRC 20.

 

[mrfailure]

Since this is a splined shaft made from resulfurized steel, I wonder if loading on the shaft might be parallel to the sulfide inclusions in such a way that would induce cracking. Not a problem with loading perpendicular to the sulfides. Just don't know enough about the application to suggest whether this is an issue.

 

[NIKT1]

Thank you all for your comments. We will consider all of these comments before finalizing the process specs.

Thanks again!

NIKT1