Welding Tips and Tricks

We weld this kind flanges bretty often. This pic is one part todays jobs making tube connection
that hole will be grind smooth. But my queston is what is that shiny stuff on that cast i grind it wire wheel and some flab disk but still in the puddle flows all kind black spots of it. Welds are pressure tested40-50psi and some times leak can be middle of that bead/weld if there is that "contamination/ We use 5356 filler and mostly 5000 series Al(dont know about that flanges series). Is 4043 better in cast? Welds can be made for OK like this but many of them will be leave on shight and could look better and maybe have longer life in service?

have you ever cut one apart to see if you are getting proper
penetration without any hollow at the base or the two components?
craig

There is gap between to parts welded. Service time i ment that contamination shortens that weld lasting eaven longer. That cast has somekind of coating? The pic doesent show thoos (peppers) and if that coatin could not grind it shows much better.

By the looks of the texture and the sharp details I would assume it is a gravity die cast (kokill, if you know the Swedish word for it )
A very common Aluminum quality for that method is AlSi10Mg which is recomended to weld with 4043 as far as I can find.

As it's a cast part, could there be some mould release agent/coating/oil inside the casting mould that's getting embedded into the top layer of the alu in some areas as it cools and forms a surface contamination pocket that's leeching out as you try to weld on it?

If you ever get a cast piece like this that's defective perhaps it's possible to take a grinder or cutter to these 'shiny' areas that give the problem to see how deep/far the contamination goes.

Bye, Arno.

AndersK wrote:By the looks of the texture and the sharp details I would assume it is a gravity die cast (kokill, if you know the Swedish word for it )
A very common Aluminum quality for that method is AlSi10Mg which is recomended to weld with 4043 as far as I can find.

Thanks for info. Yes some other parts readed AlMg... Anyway i machined one and weld whit 4043 And it came much better..

Thanks for the feed-back

Looks like you nailed it

Forgot to ask what grade you are welding the flanges against