welding casr iron

[fabio manno]

i need to weld some brackets on the cast iron houseing of my rear end. a friend of mine gave me special electrode for the cast iron and told me to preheat the all housing before welding. is it mandatory?

[MMW]

Are you sure it is cast iron & not cast steel? I have welded on cast steel housings & used 7018 with preheat & also used mig with preheat. All successful.

[Aerometalworker]

i need to weld some brackets on the cast iron houseing of my rear end. a friend of mine gave me special electrode for the cast iron and told me to preheat the all housing before welding. is it mandatory?

No offense, but if you have to ask a basic question like that, maybe look to have someone else do the repair. You also must know what your working on, is it cast iron? cast steel? malleable iron? ductile iron? ???
Do your homework first, especially on a part like that. Remember a good number of rear ends from pre 1960's were malleable iron, and therefore not fusion weldable.
SO find out what your working with, research the process needed ( treat it like school, not cheating on a test ) and see if you want to tackle it.
-Aaron

[DDA52]

If it is cast iron, preheat and post heat are mandatory if you want it to hold.

[fabio manno]

Are you sure it is cast iron & not cast steel? I have welded on cast steel housings & used 7018 with preheat & also used mig with preheat. All successful.

i am sure it is cast iron. and i also know for sure that 7018 is not recomand for that, but you confirm that it has to be preheated. thanks

[fabio manno]

If it is cast iron, preheat and post heat are mandatory if you want it to hold.

thanks a lot to confirm it

[fabio manno]

No offense, but if you have to ask a basic question like that, maybe look to have someone else do the repair. You also must know what your working on, is it cast iron? cast steel? malleable iron? ductile iron? ???
Do your homework first, especially on a part like that. Remember a good number of rear ends from pre 1960's were malleable iron, and therefore not fusion weldable.
SO find out what your working with, research the process needed ( treat it like school, not cheating on a test ) and see if you want to tackle it.
-Aaron

yes, it is cast iron and it is not pre 60. the reason why i ask is because i had somebody welding previously on my rearend with regular mig and not special wire and no preheat and it did very good.never had problems. then i had somebody else stick welding and no preheat and again never had problems,then again mig welding and preheat with great resultes. the rear end belong to an off road rig always under big stress. so i think that the limit is the sky and asking around always different opinions. so wich one is your answer after all those infos?

[MMW]

If you are in doubt, preheat it. If it doesn't have to be it won't hurt but if it does and you don't preheat it will matter. Good luck. As far as your original question --- yes, you should preheat cast iron although I don't know the exact temperature recommended. After preheating then welding it you should post heat to even out the temperature & then cover it for slow cool down. Sometimes when it cools to fast it will crack especially something with varying thicknesses that will cool at different rates.

[Steve]

If you insist on welding cast, 7018 is second rod of choice. Arc welding on cast is not recommended however.

[burninbriar]

yes, it is cast iron and it is not pre 60. the reason why i ask is because i had somebody welding previously on my rearend with regular mig and not special wire and no preheat and it did very good.never had problems. then i had somebody else stick welding and no preheat and again never had problems,then again mig welding and preheat with great resultes. the rear end belong to an off road rig always under big stress. so i think that the limit is the sky and asking around always different opinions. so wich one is your answer after all those infos?

Is this three different rear ends or is all this welding on the same one?
The reason I ask is that if its all on the same rear end, then your statement that you never had any problems my not be correct. The fact that the latter breaks were not in the same place does not mean that they were not caused by stress from the first repair job.

[FusionKing]

It would be nice if he would give us some ACTUAL info because some of us here speak fluant automotive terminology
This WAS the motorsports forum before it got reformated.
What kind of rear end is it? What did it come out of? Dana? GM? 1/2 ton? 3/4ton?
It is ALL hypothetical at this point unless maybe we talk to your buddy