Magnesium, any suggestions?

Date 04-09-2008 03:39

got to get that lincolns "the procedure handbook for arc welding" its a fukn keeper for sure!!!!! tells all for all ;) and its only $25

By motard1 Date 04-09-2008 03:56

We have looked at everything we can find. The aws welding journal, hobart institute, every magazine, and I've been searching online for a while. Still nothing. I doknow magnesium is not a very popular metal, so not a lot of people weld it. It seems to me like its contaminated, but from what. I have cleaned it with scotch-brite discs first, then MEK, and still the same results. If you've ever welded mag, or titanium, then you know that cleanliness is the most important thing. I've cleaned it every way I know how. There are other important things like, short arc length, leaving the filler in the puddle, but ??????..... I still don't know. I have tried changing the frequency, penetration, even the dcen, still nothing. The dcen is set at 105, and the dcep at about 98. This has produced the best weld. The freq is at 200 and penetration at 65, again the best bead so far. Do ineed more cleaning? It shows that I have enough. How about penetration? Maybe freq? I have also welded uphill as well as flat and horizontal.

By Lawrence (*****)

Date 04-09-2008 03:59 Edited 04-09-2008 04:02

Hey Tard :)

I spent a couple of years in a dungeon welding Mag and Aluminum castings for aircraft. Just part of being low man on the shift.

The truth is that sometimes they just won't fix no matter what you try..

We used EZ33 on cascade vanes (think of an old Ice cube rack made out of mag) The procedure demanded pre-heat and when you took them out of the oven to weld they would often start to *ping* before you could get a blanket on em.... Oh what joy. The things would come in with one crack and finally leave with 6 or 7 repairs.

But here are some things think about... But if you have been doing this for a while you prolly already have thought of them and more.
   1. 100% of any cracks or defects must be removed. This should be verified by penetrant check. It never pays off to try to weld on top of a crack and try to grind back down to if from the other side... If the crack goes deep it must be chased deep. If the depth of crack is beyond limits than EVA or Scrap..
   2. If you are building up on a flat surface or replacing a lug you might want to try DCRP, a 1/4 inch tungsten and 50% Helium 50% Argon set @ about 100 amps and a jumbo water cooled torch... This will make a wide shallow pool that will provide good fusion on a flat surface in the flat position only.. It will reduce overall heat input by quite a bit. DCRP will not work on Mag without at least 50% Helium. This procedure will not work in deep routes or out of position because the tungsten will be big and pretty close to molten at the end. This procedure will smoke heavily so resperators and ventellation are a must as well as interpass cleaning.

   3. Last resort (prolly will need an EVA) might be to remove massive amounts of material from the entire zone and rebuild on a larger scale... Sometimes silica pockets and other contaminants just need to be ground away before a good weld will come. This risks distortion that might cause further rework of faying surfaces or even worse cracking... But it might be worth a shot before throwing the thing on a campfire and getting the maximum enjoyment magnesium can give.

Keep us updated

By DaveBoyer (*****)

Date 04-10-2008 02:52

"maximum enjoyment magnesium can give" I like that. I never had a big enough piece of pure magnesium to get the maximum effect, but the little ribbons from My chemistry set were pretty impressive.

By devo

Date 04-10-2008 21:13

My uncle is a machinist and I can remember during family holiday gatherings he would bring out a cardboard box full of magnesium chips and a jug of water. What a light! Also, a few years back a company in Cleveland that recycled Mg caught fire. And as luck would have it, it rained for about a day and a half. The local fire departments just sat back and kept the surrounding buildings from catching fire. It burned for 27 hours.

By motard1 Date 04-11-2008 02:48

Well, I still haven't fixed that piece. It just won't work. I tried patching it today, no good luck. The patch welded in well, but the shrinkage won't allow the other parts to fit. I am getting tired of welding this, I have put like 75 feet of filler in it. Maybe somebody knows the magic trick.

By motard1 Date 04-16-2008 19:31

Still haven't got it fixed. it is cracking on the edge of the weld. I have cut the old material completely out, to remove any contamination, but I still end up with the same result.

By Joseph P. Kane (****)

Date 04-17-2008 01:14

Motard 1

Are you so sure it is Magnesium?

I went to weld an "Aluminum" Ferrari engine once - It was Magnesium. For years in the 80's, I welded VW engines that everyone thought were Aluminum.

I have repaired many a damaged VW engine that someone else had attempted to weld as Aluminum.

Did you try "burying" the arc? (Be sure it is not an esential variable on your WPS first.)

By welder5354 (**)

Date 04-20-2008 07:03

Try this site:

http://www.soudotec.com/englishpages/indexen.html
Go to light metals and hit 780
I have used this with brazing, it is excellent for bonding.

dan