armour plate welding

[David Ellery]

Hi there, I,m about to start repairing rusty sections of my carrier lp2, as well as adding top armour, which will be fabricated out of mild steel, whats the best welding type with old armour steel, mig, arc ? and what wire type is needed ? Thanks David... PS.. Go the ALLBLACKS !!!

[Alex Blair (RIP)]

Originally posted by David Ellery
Hi there, I,m about to start repairing rusty sections of my carrier lp2, as well as adding top armour, which will be fabricated out of mild steel, whats the best welding type with old armour steel, mig, arc ? and what wire type is needed ? Thanks David... PS.. Go the ALLBLACKS !!!

Hi Dave..
Mig is fast and messy,TIG is slow and clean..Stick is the way I would go...If it dosen't have to be certified...
7018,7024 or 6013...in that order would be my preference....
Play with the amperage and grind a bevel on your weld joints before welding..
disconect your battery before welding on any vehicle...

[Tony Smith]

Now this poses a really interesting question! Normally, Armour plate has a high Nickel content which makes it difficult to
A): Find welding stock which will weld effectively, and
B): weld properly as weld will embrittle the armour.

Australian carriers were manufactured from a heat treated steel alloy called ABP3 (Aust Bullet Proof, No3) which contained no nickel, as this was unable to be imported in sufficient quantities. It was still difficult to weld, but less so than normal nickel content armour plate. This makes problem A less of an issue, but problem B is accentuated (by the heat treatment) and Aussie carriers are prone to cracking after welded repairs. Now, the question! Where did NZ source it's armour plate for it's LP2 programme? Is it Aussie ABP3 or is the armour plate supplied from another source?

[Snowtractor]

To reduce warping of the metal from welding, which is worse in armour plate I am told, try button welding.
Start by prepping the metal as you would for a normal weld. Then when the sheet is in proper alignment tack weld both ends. Now get out your tape measure ( the thingy with the numbers on it ) and mark every two inches front start to end. Okay, so now you have a line of marks starting at 1 then 2 then 3..etc .
Now tack weld all of the marks.
Now go to tack number two and weld back to number one, then go to tack number three and weld back to number two and then 4 to 3 and so on. Make sure you stop and peen each weld before proceeding and if the temperature starts to build up in the metal , go for coffee. You will get an incredibly straight twp pieces of metal with no need to start with straightening techniques, though it does take considerably longer.
Sean

Oh, and high nickel rods are common but more expensive on this side of the pond. So are stainless rods and they would likely do a nice job too.

[Lynn Eades]

Tony, I suspect the Aust pattern carriers built in N.Z used Aust steel. -This is just a guess and I have no basis for it. Does Jeff Plowmans book say where it came from. I remember seeing photos of piles of finished cut steel plate at G.M. but nothing of it being rolled here in N.Z
David, I understand the Aussies had a lot of trouble with welding armour plate and it stopped production for a while, while it was sorted out. The English O.P. carriers were welded with stainless electrodes. I realize that we are probably talking a different sort of armour plate, but technology has moved along a lot and I think you will find stainless to be your least troublesome direction to take. I,m a dummy on this subject, but I replaced a section of my hull division plate, replaced the rear panel from the guards up, replaced the sides from the guards up. All the welds to armour plate was stainless, all the rest was done with the mig. (my replacement steel is all mild steel) You would need to do some test runs, taking some advice from a good welder, as there is a range of different stainless rods for different applications.
You will have to be careful as I know the LP2/2a (N.Z.) steel is prone to cracking as Tony says. Lastly us Kiwi,s were issued with the Aussie mechanization pamphlets( manuals/partsbooks) in which they went into hull repairs, via welding. I have not seen one of these books in N.Z. with any extra notes in them saying to repair N.Z. carriers any differently.

[chris vickery]

In my humble opinion, go with the SMAW (stick) and use Ni rod.
Depending on the location, thickness and size of the weld, it may be prudent to pre-heat the joint several hundred degrees to reduce the chance of thermal cracking. A rosebud head on the end of your oxy-acetylene torch should do the job. It is especially effective if you can clamp the torch handle into a stand of some sort and apply it directly to the area you intend to weld.

[rob love]

Welding on armour plate calls for exactly what Chris just mentioned; preheating the work. Especially if you find that it is cracking after the weld.
I treat the armour plate like I would treat cast metal. Cast calls for the metal to be warmed up to 400 degrees before welding.
I used mig on some of the front armour repair on my UCmk1, and the only real problem after dressing the welds is that the welded area ended up looking nicer than the rest of the armour plate. Nothing a couple of strikes with the chisel won't fix, mind you.

[David Ellery]

Thanks for the feed back guys, I've taken it all on board, so we'll see how we go!

[Alex Blair (RIP)]

Originally posted by Alex Blair
Hi Dave..
Mig is fast and messy,TIG is slow and clean..Stick is the way I would go...If it dosen't have to be certified...
7018,7024 or 6013...in that order would be my preference....
Play with the amperage and grind a bevel on your weld joints before welding..
disconect your battery before welding on any vehicle...

Dave

If you are using mild steel to replace armour these methods are good for mild steel..If you are welding armour plate then I agree with Chris...Bevel,preheat and stainless or Ni rod..