SAE 1050 modified Axle shaft temper time
SAE 1050 modified Axle shaft temper time
(OP)
We induction heat treat axle shafts made of SAE 1050 (mod.) and then furnace temper it. My question is does it really affect the microstructure or the hardness of the shafts if they have been tempered longer than they are supposed to be. In other owrds, if I am not sure whether the shafts were tempered or not and may have re tempered it. Is it going to affect the hardness of some other metallurgical change.





RE: SAE 1050 modified Axle shaft temper time
Rao Yallapragada
RE: SAE 1050 modified Axle shaft temper time
RE: SAE 1050 modified Axle shaft temper time
RE: SAE 1050 modified Axle shaft temper time
RE: SAE 1050 modified Axle shaft temper time
I would either rework (draw above 800F), mag particle after temper or scrap them alotogether if there is absolutely no idea when they were IH'd.
RE: SAE 1050 modified Axle shaft temper time
1) Perform mag particle inspection for cracks before re-temper.
2) Re-temper the parts above 800 deg. F, like dbooker630 has suggested.
You may also want to scrap the parts if the quantity is very small, instead of going through all the additional inspections and rework costs.
Hope this helps.
Rao Yallapragada
RE: SAE 1050 modified Axle shaft temper time
Just FYI we furnace temper shafts at 303 F. The customer print calls for stress relieving at 280 F for 75 minutes. From my experiments with the thermocouples located at several positions on the rack we came up with 303 F for three hours.
Also I want to ask dbooker630 about "tempering before the end of the four hour period" How important is that? And what are the consequences if it does not happen within that duration?
Thanks
RE: SAE 1050 modified Axle shaft temper time
In my opinion, 4 hours may be too long. I would only allow less than an hour.
Hope this helps.
Rao Yallapragada
RE: SAE 1050 modified Axle shaft temper time
It depends (metallurgist talking!) on the part configuration, if there are not many severe transitions in diameter or fillets you can allow more time.
Ideally I would temper parts within an hour also but then realize things happen in manufacturing that you have to allow for or you will have an ISO nightmare.