Welding mild to unknown cast steel...

[BrokenBiker]

Need to weld a few lugs on a cast steel frame to allow one part to pivot...no idea what composition the cast steel is but will need to weld some mild steel to it for the pivots.

What would be a good rod choice? I have about 15 312 rods that would be more than enough to do the job but don't know if it's a good choice

 

[Tom Orrow L]

I believe 312 is what your typical dissimilar rod would be which is what I would personally use. IIRC a guy at work did a job at home the other week of welding some mild steel to some cast (a old bench needed some supports or something like that), he used some 312 dissimilar but we were chatting and he playing with the idea of using 7018's, don't know if thats an option you could consider?

Of course whatever you use would depend on what the exact composition the cast is.

 

[BrokenBiker]

I have to cut a section of the frame out to make it fit it's new purpose before welding the pivots in so will give an off ur a blast with a 312 and see if anything happens. It's non weight bearing and the only rotational force will be given by a quick nudge to pivot the frame around so strength isnt too much of an issue

 

[Bill Edwards]

The fact it's cast doesn't tell you much about the kind of steel used, only that it's unknown...

What is the frame?
I have found that 7018 tends to be fine on cast steel (or at least all that I've used them on) but the correct rod to use is a 312, as that will work.

 

[TechnicAl]

If youre sure its cast steel and not cast iron 312 will be fine

 

[Welderpaul]

Cast steel to steel isn't a problem to weld?

 

[BrokenBiker]

It's definitely steel. No idea what it used to be for but with some slight modification it will work well for my brother to put canvasses on to paint. It was free from a house clearance he helped with

 

[Welderpaul]

'Cast' is only the method how it was formed. It's still steel then. Just weld it with normal welding consumables?

 

[TechnicAl]

Cast steel isnt a grade its the means used to shape it
Its like saying rolled steel or forged steel

It could be mild, low alloy or stainless

However, they usually add more silicon when casting as it helps it flow better........its like adding fairy liquid to water.........unfortunately the silicon progressively embrittles steel

 

[BrokenBiker]

I know casting is just a process in order to make the steel the right shape, but my concern is not knowing the composition so I don't know if it's going to have issues being welded so looking or a fail safe rod

 

[Welderpaul]

a fail safe rod

I don't think there is is there if you don't know the composition, is there?

 

[TechnicAl]

If 312 wont weld it..........nothing will

 

[BrokenBiker]

Will try the 312 and see what happens

 

[Bill Edwards]

I don't think there is is there if you don't know the composition, is there?

Probably, in that it could be completely unweldable. But I've welded up plenty of unknown cast steels with 6013 and 7018 rods and so far have had a 100% success rate - and since then I have learnt a little about these things so will go for a 312 if there is any doubt.

I think that in practical terms most of the cast steel you need to weld is probably weldable, even though technically there may be some where it's just about impossible.

 

[sardine]

If you need any dissimilar or other unusual electrodes I have shed loads I never use. I'd be glad to post a few out to forum members to get rid of them.

 

[Freddy0309]

If you don't mind me being cheeky what rods are they?

 

[Richard.]

If you don't mind me being cheeky what rods are they?

312?
They are part of the dissimilar family, like 309 they are commonly used to join mild to stainless but they are also used to weld difficult to weld material too. They offer a higher strength joint than a 309 does because of the higher ferrite content but I believe lower ductility. They are quite expensive I have some in the form of tig rods.

 

[Freddy0309]

Sorry Richard that was aimed at sardine although I didn't know that so in a way it was worth not quoting the post, I like yo hoard all these little facts even if I don't ever need to know it.

 

[Richard.]

Sorry Richard that was aimed at sardine although I didn't know that so in a way it was worth not quoting the post, I like yo hoard all these little facts even if I don't ever need to know it.

Ah I see. You wanted to know what consumables sardine has on offer! Makes sense lol.

 

[BrokenBiker]

312?
They are part of the dissimilar family, like 309 they are commonly used to join mild to stainless but they are also used to weld difficult to weld material too. They offer a higher strength joint than a 309 does because of the higher ferrite content but I believe lower ductility. They are quite expensive I have some in the form of tig rods.

It's things like this that make me want to learn more about metallurgy