Alu Rod question

[bc30se]

Hi

Some week ago I finally realised my order for an AC/DC tig and would like to buy some Alu rods right now...

I looked here and there, and it seems that you guys have different rods available on your marked... I read about 4xxx 5xxx and 6xxxx series most often....


However, as I live in POland, the only commercialy available rodsa are ALMg and ALSi


Any clarification on that? Their uses?

 

[wheresmejumper]

4xxx has silicon,5xxx magnesium
ALSi, ALMg

 

[bc30se]

OK, is there a way to differentiate between these while welding? some visual hints?? I mean, the right choice of the rod for the work...

what about 6xxx alu?? any rod suitable here?

 

[hotrodder]

6xxx series ally contains both Si and Mg, the two ingredients together are what make it 'stronger' and heat treatable (formation of magnesium silicide). There is no 6xxx filler wire* as magnesium silicide is quite sensitive to solidification (hot) cracking... all the major aluminium alloying elements have a range where they're crack sensitive. This is one of the reasons why the two common flavours of filler wire are 4043 (5% Si) and 5356 (5% Mg), to dilute the Si or Mg and take it out of the crack sensitive area

The 6xxx series can be welded with either AlSi or AlMg depending on application...
AlMg is both stronger and more ductile/less brittle than AlSi but, on paper at least, not recommended for service temps above 65C as above ~3% Mg ally is susceptible to stress corrosion cracking (googling '5356 stress corrosion cracking' will get more indepth info).
AlSi filler wires are 'easier' to use in that silicon lowers the melting temp some i.e. they wet out better and are less prone to solidification cracking but not as strong or ductile and don't anodise well as the higher Si content results in a manky grey colour

Pure aluminium (1xxx series) and the 3xxx series (ally + manganese) are best welded with a 1xxx series filler wire when it's available.
Castings are almost always high in silicon making AlSi filler the one to reach for.

There's a very good filler wire selection chart and more indepth data sheets on different filler wire flavours here... http://www.alcotec.com/us/en/support/alloy-selection-chart.cfm Looks at things from an ease of welding, ductility versus strength, anodising POV etc. It's American so some of the alloy designations differ a little compared to what we have in Europe

Visually the different wires have a slightly different appearance, touched on in this thread... http://www.mig-welding.co.uk/forum/showthread.php?t=24510&highlight=grainy

* there is a kinda special 6xxx wire called 4643 which contains both Mg and Si, there's a data sheet in the Alcotec link.

 

[bc30se]

great again,

I found this one, very good but unfortunately in Polish

http://www.dostal.com.pl/metale-kolorowe-aluminium.html

 

[hotrodder]

They're data sheets for the various flavours of ally commonly found. Not laid out as nicely but in English here... http://www.aalco.co.uk/datasheets/?gId=1&sgId=36 and there's also http://aluminium.matter.org.uk/aluselect/ which is a mine of info and has international designation charts so things can be cross referenced where the same stuff has slightly different names around the world and equivilants when a slightly different flavour is available like 3003 versus 3103 or 5052 versus 5251 for example