mild to cast

[deano1]

Hi guys,
my boss has asked me to do a job for him but i`m not sure i can? can you guys tell me if its possible to weld mild steel to cast iron railings it doesn`t have to look good but strength wise it`s gotta be pretty good, i have an ac/dc tig and a mig, which if any ,would you advise and what rods etc many thanks.

 

[Drains]

I'd stick weld it with a ni/fe (nickel rich) rod, and peen the weld as it cools so the cast doesn't crack. Only weld half an inch to an inch or so at a time, and allow to cool. Not cheap rods though, but it'd be the right way to do it.

Alternatively some 312 or 309 rods might work at a push.

You could stainless tig it, but that's not the proper way, and it might not work either.

I'm sure there will be other opinions to follow...

Nickel cast iron rods here £100/kilo. Ouch

 

[snowcat]

you could buy some MMA Ni/fe and chip the flux from em then TIG, around £30 for the pack.......

I'm saying knowt about S/S

 

[irondarren]

I hate them ni/fe rods, many moons ago when i work for a company we occasionally got cast iron bins to weld up from the local council, normally where the Kids had waked the bins with scaffold pole. Used to take dam ages to weld them up. 18 inch break in about 12mm thick cast. The tendancy was to try and push the run just that little bit longer than you really should. Then to hear that lovely ping sound and think to yourself should have done a shorter run and left it longer to cool.

 

[TechnicAl]

I'd stick weld it with a ni/fe (nickel rich) rod, and peen the weld as it cools so the cast doesn't crack. Only weld half an inch to an inch or so at a time, and allow to cool. Not cheap rods though, but it'd be the right way to do it.

Nickel cast iron rods here £100/kilo. Ouch

Spot on

I would expect you to be able to get rods for around £50 / Kg or a little less if you haggle well.

 

[snowcat]

Spot on

I would expect you to be able to get rods for around £50 / Kg or a little less if you haggle well.

you forgot the preheat Al (duck)

In all honesty I would tho.....

 

[TechnicAl]

You a Sheffielder......they call everyone duck (or love)

Believe it or not you are usually better advised NOT to preheat. Keep it cool, little short runs and allow to cool in between.

 

[irondarren]

Last lot i bought Al that had any form of instructions on use say. Welding in short runs, peen while hot, cool to touch between runs.

And today im weld crappy wrought iron to mild steel, and it keeps breaking, and i hate it. Well it doesnt break if you TIG it but i want ideally MIG or arc it, but ill stay safe with tig and take longer

 

[TechnicAl]

Darren

wrought iron isnt cast iron. They are very different.

To be honest proper wrought iron is very rare (its usually annealed mild steel) but if its cracking it sounds like you have "proper" wrought iron.

Wrought iron is basically thin layers of pure Iron and slag. So some of the time you are trying to weld to slag, which is impossible and usually results in porosity and/or cracks. There is no point using a NiFe rod, you are better using a 7016 or a 7018. It will still crack but its cheaper.

If you keep welding and grinding, eventually you will get a sound weld.

If you are welding to the surface you will be weldig onto pure iron and the weld will be fine but you will get lamellar tearing (the layers pull apart).

 

[Bigjoe]

Well thats another day ive come on here and learnt something

Joe

 

[deano1]

more advice on the cast to mild please!

hi guys,
So is stick welding a form of welding that can be done with a mig or a tig or is it the welding thats done with the stick attached to the hand held torch and you strike the surface with the stick to start? sorry but i`m really confused.Oh and whats the process involved with " peening" as mentioned by a couple of the lads, thanks.

 

[irondarren]

Deano stick welding is MMA or Arc welding. Using welding rods which are flux coated. All inverter based TIG units have the ability to Arc weld, but Mig machines Dont.
Peening is clipping off the slag etc whilst its hot, and tapping with a chipping hammer the weld bead.

 

[Drains]

Deano - peening is hitting the weld with a hammer (usually the round bit on the back side of an engineering hammer). It deforms the weld, spreading it as it cools (otherwise it would contract as it cools, causing the cast metal on one side of your joint to crack).

Or you could use a chipping hammer, as Darren says. Better for tight spaces, and less brutal.

Your tig welder will almost certainly be capable of stick welding too. You'll need an electrode holder, and lots of practice.

 

[snowcat]

hi guys,
So is stick welding a form of welding that can be done with a mig or a tig or is it the welding thats done with the stick attached to the hand held torch and you strike the surface with the stick to start? sorry but i`m really confused.Oh and whats the process involved with " peening" as mentioned by a couple of the lads, thanks.

stick weldings slang for arc, denno..... peening is to lightly tap the surface of the weld as it cools to relieve stress, a chipping hammers good as its not too heavy.....


Al, we've been here before, but I always use preheat, and generally work quick, keeping the work hot if I'm running multiple passes.....I know the TWI recommends preheat (again we've been here before) not a disagreement with you Iv just found it to be an affective way of working........Oh and I sometimes post heat or one better drop it in some lime for a couple of hours..... proberbly all wrong mind...

 

[snowcat]

Bravo chaps, 3 answers all the same, have it stuffed and mounted.....

 

[TechnicAl]

Snowcat

If it works.................

PS I think the TWI is wrong on this one.............there isnt a smiley for arrogant ****

 

[irondarren]

Strange a thread about cast iron welding. Last night i get a phone call is it possible for me to repair a cast iron fire Top. oh joy, cast iron thats been heated and cooled a thousand times, going to be nothing better in the world to weld up is there. One crack they say, and probally a billion micro fractures you can't see. Still i suppose it means i can get the camera out and show everyone the wrong way to weld cast iron. Perhap i can do a tutorial so malcolm can post it on the forum. How Not to weld cast iron.

 

[deano1]

What would i do without you boys, thanks guys