Material of super major top arms - cast iron or steel?

[Roadless63]

I have a pair of super major top lift arms, (the splined type rather than the square centred earlier type) which have the extra hole for pick up hitch linkage. Trouble is, one has got no splines left and it was held on with a coach bolt which was drilled through the cross tube....
Anyway I have got a few standard super major arms about and thought I could make up a good one by machining the centre out of the damaged unit, and turning down a new centre with good splines. With a good lead on the ends it should be possible to weld and be a good repair.
Question is, are these cast iron or cast steel? How does one tell? I'd guess cast steel as it would be less brittle - can anyone shed some light.
As an unlikely alternative dont suppose anyone has a spare LHS top arm with the built in hole for pick up hitch..

[super6954]

I seem to remember that you can tell from grinding it and the colour of the sparks or by looking at the dust from grinding and you should see the cast iron as a greyish dust . the steel will be more like filings .
I think cast iron is a redish colour and steel is a yellow/ orange spark . It has been so long since I was told i cant be real sure.
Maybe Brian or one of the other older engineers will confirm right or wrong.
They may even know from the days when they where made .im guessing cast steel as I heated a bent one and straightened it and also welded a piece on with a mig but that is not always a fool proof tell tale.You can some times get away with welding disimilar metals like that.
Regards Robert

[henk]

It's steel not iron.

[Matt 1944 N]

you might be better off to drill the standard arm and make a tubular sleve to weld on to make it look like the original and be stronger than the other approach

[nikk]

Cast has deep orange sparks and steel are more yellow in colour ! Would advise a decimilar rod such as a 29/9 they aresuitable for both and will weld cast to steel if required. If you struggle to find a 29/9 look for 312 grade stainles steel rods they are the same remember your health and safety gear dont want you down the A and E when you could be spannering

[Roadless63]

Thanks for the info. I'm pretty confident this should be a feasible project and will mean my pick up hitch is completed!