mig welding cast iron

[darrenh]

item in question is a mcpherson strut from a car, it has a cast iron knuckle at the bottom and a steel tube at the top which houses a damper. these two parts are joined/welded at the factory and not related to my question.

i wish to apply steel box/bracing between the two items so one end will be welded to the steel, the other to the cast iron knuckle.

will i be able to do this with a mig welder with c02/argon and steel consumables?

many thanks

 

[stormin]

If it's welded at the factory it won't be cast iron, but cast or forged steel. Even if the existing joint isn't welded I can't see a piece of brittle cast iron being used on suspension components.

I'm guessing you are wanting to weld a flitch plate in place to strengthen the existing joint between the pieces. Shouldn't be problem strength wise as any strengthening piece even if the weld is poor will add to the strength of the existing assembly.

My only concern would be deformation caused by weld stresses on cooling possible altering the alignment of the existing components. Could put our steering and suspension geometry slightly out. If there's room for adjustment afterwards it shouldn't be too much of a problem.

I assume the above modification is aimed at a motorsport application rather than for road use. Have you checked with the scrutineer and the regs that modifications to such safety critical components are allowed?

 

[darrenh]

i'm using a build manual which adhered to FIA group A regulations, so its a legitimate recognised modification on that component. however, the vehicle wont be used competatively so i have no regulations to worry about (its for track days basically)

in the text it says "because of the steel/cast iron connection special electrodes must be used for welding"

its a translation from german though so might be something lost there.

thanks for your advice, so you think it would be within the realms of a mig welder with just the usual decisions for penetration etc

 

[stormin]

Well I would not go against the word of the recognized build manual but I am VERY surprised there is cast iron involved in a steering / suspension component. Can you reveal the make of car and provide a photo of the component?
If it is as described then I would follow advice as for cast iron welding on other threads on here. Pre-heat if possible to minimise chances or cracking on cooling. A high nickel content rod is one of the recommendations although there are specific cast iron filler rods.

 

[darrenh]

its a vauxhall astra (opel kadett in europe, or pontiac lemans in north america)

couple of pictures, the first a standard leg, the second an example of this modification

original

modified one