Welding To Hardened Steel?
Posted November 04, 2012 - 08:15 AM
I'm trying to weld a piece of mild steel, to a hardened shaft.
Posted November 04, 2012 - 08:27 AM
If you are extending the shaft, and it will be in a wearing or high stress situation, I would recommend using a raw (not been heat treated yet) shaft material (1130 is common in automotive applications and 4140C is another shaft material, but it's more expensive). Heavily bevel the ends to be joined, preheat the steel to 400 F and weld it up in layers, being sure to thoroughly clean the welds in between layers, allow it to cool slowly to under 600 F in between passes as well (to avoid tempering it unevenly at the weld site). Many also recommend a close fitting overlaying sleeve welded on both ends. Have the shaft heat treated when you're through.
And now it's time for the disclaimer. This is not recommended for high speed highway applications...period! If you're planning high stress use (such as plowing or other ground engaging work) it will also be a weak point no matter how it's done. Shaft steel is often forged and hardened at the factory. You will not be able to duplicate the original strength of the part.
- MH81, IamSherwood and Cvans have said thanks
Posted November 04, 2012 - 08:55 AM
Posted November 04, 2012 - 09:04 AM
Yes, it's in a stress stuation.
I like the disclaimer. I promise I'll go slow, when I cross the highway.
So, how do I go about checking the temp in the preheating/cooling process?
Posted November 04, 2012 - 09:24 AM
Steve, please correct me if I've been doing wrong, but here on our farm, we've always used 7018 on such welding jobs. It's always held well.
7018 is a good choice and for most applications it will do a fine job, especially if it's what you have. I recommend 7014 because it has a higher deposition rate and thus will allow less heat transfer and possible loss of strength. The "70" part of the number is the tensile strength, so the two rods are equivalent in that respect.
...So, how do I go about checking the temp in the preheating/cooling process?
You could pick up one of these:
Harbor freight has on available for about $35 Here. I'll bet that you could get one at Princess auto too.
- IamSherwood and Cvans have said thanks
Posted November 04, 2012 - 09:39 AM
- caseguy said thank you
Posted November 04, 2012 - 10:20 AM
- caseguy and IamSherwood have said thanks
Posted November 04, 2012 - 10:27 AM
- caseguy said thank you
Posted November 04, 2012 - 10:55 AM
Also nice disclaimer there as well:-)
- Cvans said thank you
Posted November 04, 2012 - 06:47 PM
I've changed my mind now, because as it turns out, I have enough space to allow me to have a
bolt together connection there. It'll be much better, for future possible service situations.
Now, the plan is to weld a flange on the stub, that mates/bolts to the splined shaft flange.
But, thanks for the info guys. I learned a few things, and next time I'm faced with this type
of situation, I'll be better prepared.