- Thread starter Mr shiney
- Start date
antonio costa
Member
- Messages
- 327
- Location
- Portugal
For alloy wheels or for other aluminum casts where the common 4043 doesn't work well I would go with the 5356 rod (5% magnesium).
For cast magnesium or magnesium in genereal for that mater I don't have experience with welding it, the only info I could give you would be textbook one, but that you can find easily by yourself. I hope that someone with experience welding cast magnesium can give an insight.
For cast magnesium or magnesium in genereal for that mater I don't have experience with welding it, the only info I could give you would be textbook one, but that you can find easily by yourself. I hope that someone with experience welding cast magnesium can give an insight.
Digger6135
New Member
- Messages
- 251
- Location
- North west England
Try Lumi weld rods They work with just the heat from a blow torch.. Google them.
Digger6135
Digger6135
Thanks, I have used them in various flavours. However it's TIG rods I am specifically after.
You need magnesium filler wire for mag castings, have a stiff drink and sit down before pricing the stuff! Trying to weld magnesium with aluminium wire results in a mess that's more brittle than glass. If you suspect the part is mag can either try and set fire to some shavings or use a drop of vinegar which reacts quickly with magnesium (fizzing as the reaction produces hydrogen) but not with ally including AlMg flavours like a 5xxx series
While the fire risk with a largish chunk or mag is no greater than welding in general any swarf (and even the end of the filler wire if you melt a blob off) do burn very well and very easily. NEVER throw water on a mag fire
Aluminium castings are virtually always alloyed primarily with silicon making 4043 or 4047 the two correct choices most of the time. While 5356 physically works and sometimes even appears to work better it's far more prone to liquation cracking... https://www.aws.org/wj/supplement/04-2005-CAO-s.pdf
Not all aluminium castings are weldable*, for example AlSiCu is fairly popular for a lot of things and as the copper content goes up, weldability goes down. 4145 is a specific filler alloys for some of the AlSiCu castings and some 2xxx series wrought alloys but it's virtually unobtainable or at least difficult to get hold of... http://www.alcotec.com/us/en/support/upload/a4145tds.pdf
Welding cast aluminium wheels (or anything structual) is not the best idea unless you know EXACTLY what you're doing. For one thing alloy wheels are virtually always heat treated and welding a heat treating aluminium ALWAYS softens it locally- partial to full anneal in the HAZ. Some are cast from AlSiCu alloys and many cast wheels these days are also 'flow formed' which is kinda a half way house between casting and forging. Like forging, flow forming refines the grain structure improving mechanical properties and this grain structure is locally destroyed by welding as welding is, in effect, casting
* not always that they can't be physically welded without cracking, sometimes their mechanical properties are just ruined
While the fire risk with a largish chunk or mag is no greater than welding in general any swarf (and even the end of the filler wire if you melt a blob off) do burn very well and very easily. NEVER throw water on a mag fire
Aluminium castings are virtually always alloyed primarily with silicon making 4043 or 4047 the two correct choices most of the time. While 5356 physically works and sometimes even appears to work better it's far more prone to liquation cracking... https://www.aws.org/wj/supplement/04-2005-CAO-s.pdf
Not all aluminium castings are weldable*, for example AlSiCu is fairly popular for a lot of things and as the copper content goes up, weldability goes down. 4145 is a specific filler alloys for some of the AlSiCu castings and some 2xxx series wrought alloys but it's virtually unobtainable or at least difficult to get hold of... http://www.alcotec.com/us/en/support/upload/a4145tds.pdf
Welding cast aluminium wheels (or anything structual) is not the best idea unless you know EXACTLY what you're doing. For one thing alloy wheels are virtually always heat treated and welding a heat treating aluminium ALWAYS softens it locally- partial to full anneal in the HAZ. Some are cast from AlSiCu alloys and many cast wheels these days are also 'flow formed' which is kinda a half way house between casting and forging. Like forging, flow forming refines the grain structure improving mechanical properties and this grain structure is locally destroyed by welding as welding is, in effect, casting
* not always that they can't be physically welded without cracking, sometimes their mechanical properties are just ruined
just assumed you ment car or motorcycle wheels. Obviously nothing to lose and you won't know until you strike an arc on them but i wouldn't be suprised if the trolley wheels are virtually impossible to weld... either cast from old cat food tins or something with LOTS of zinc in it. If you get loads of white 'soot' and no weldpool to speak of (just a scummy mess that collapses into a hole if you perservere) that'll be zinc boiling off and vaporising. If that's the case those self fluxing aluminium "brazing" rods would be the ticket. Regardless of brand name they're all mostly zinc with a little aluminium and copper and they're also cheaper if bought as a self fluxing aluminium solder (SIF 555 for example) from a proper welding supplier although you don't get any BS sales claims that way
antonio costa
Member
- Messages
- 327
- Location
- Portugal
Thanks hotrodder for the amazing info! It proves once again that because you did something a lot of times and it worked it may not be the correct way to do it.
I actually printed the aws article, amazing amount of info.
Since english isn't my primary language when Mr. shiney said wheels I thought about pulleys, it's something I come across quite often since at work when the "real" work is slow the boss accepts small repair jobs like that for farmers and such, pulleys from compressors and whole lot of cast things to repair, engine mount's, gearbox cases,sumps and so on.
I wasn't even thinking of car alloys, I would never mess with that. It's one of those things that unless it's something unreplaceable (if that's the case it should be done by a wheel specialist that has the knowledge to weld, machine and heat tem) it should be scraped.
I only use 5356 when the usual 4043 doesn't work and now thanks to you I know the name of the alloy that sometimes pops up and none of those fillers work, AlSiCu, it makes sense the higher the copper content the less weldable it is.
I never experienced comebacks because of failure of things welded with 5356 but I will avoid using it as much as I can in castings after what I just read (sometimes I have no choice but to do what the boss wants). It will remain for it's intended use.
I've came across some magnesium parts that I had to say that I could't do them, lack of knowledge on how to correct weld it and no filler material to even try it.
Regards,
Antonio Costa
I actually printed the aws article, amazing amount of info.
Since english isn't my primary language when Mr. shiney said wheels I thought about pulleys, it's something I come across quite often since at work when the "real" work is slow the boss accepts small repair jobs like that for farmers and such, pulleys from compressors and whole lot of cast things to repair, engine mount's, gearbox cases,sumps and so on.
I wasn't even thinking of car alloys, I would never mess with that. It's one of those things that unless it's something unreplaceable (if that's the case it should be done by a wheel specialist that has the knowledge to weld, machine and heat tem) it should be scraped.
I only use 5356 when the usual 4043 doesn't work and now thanks to you I know the name of the alloy that sometimes pops up and none of those fillers work, AlSiCu, it makes sense the higher the copper content the less weldable it is.
I never experienced comebacks because of failure of things welded with 5356 but I will avoid using it as much as I can in castings after what I just read (sometimes I have no choice but to do what the boss wants). It will remain for it's intended use.
I've came across some magnesium parts that I had to say that I could't do them, lack of knowledge on how to correct weld it and no filler material to even try it.
Regards,
Antonio Costa
Cheers. Magnesium is quite similar to welding aluminium castings in most respects, not difficult just slightly different weldpool behaviour (less defined pool, dirty/sooty). I was gonna say there's several good pdfs covering welding/metallurgy/heat treatments etc on http://www.magnesium-elektron.com/ but they're redoing their site at the moment. Hopefully they'll reappear, if they don't i saved a few of them a while back (learnt that lesson when Alcotec redid their site and a load of great stuff vanished to be replaced by a virtual clone of their parent ESAB site)
Dunno what availability is like outside of the UK but SIF magnesium #23 (AZ61A)* is available in packs of 12 rods which is handy for the occasional repair as mag wire is typically around or over £200/kg
* AZ61 = aluminium ~6%, zinc ~1%
Dunno what availability is like outside of the UK but SIF magnesium #23 (AZ61A)* is available in packs of 12 rods which is handy for the occasional repair as mag wire is typically around or over £200/kg
* AZ61 = aluminium ~6%, zinc ~1%
Richard.
Member
- Messages
- 18,344
- Location
- Cambridgeshire
I recently did a kwack cases with 4047(12%si). I ran out of 4043 and needed it done. I was not 100% confident it was suitable but some wise and informative words from Hotrodder helped out loads and the consumable worked really well (as well as you'd expect from a bike case alloyed with everything unfriendly mind).
