Cast iron welding clip. Anyone ever tried it?

[hooda]

I've made a few cast iron weld repairs over the years, using nickel based stick, brazing with brass rod, and yes, even welded a cracked exhaust manifold on the truck with 7018 and it held for 10 more years till the truck was sold. But as a tig noob, I was pleasantly surprised to find this clip.
http://www.youtube.com/watch?v=-uqi9wCmBgw
This guy has posted a few videos using unconventional methods, including using flux-coated aluminum stick rods with DC TIG. I hever thought of using piston rings for filler metal, but think about it, once the carbon is cleaned off, It's probably some of the cleanest cast iron a guy can find.

[sportbike]

Piston rings for filler when welding cast iron is an old farm repair trick. Tractors have alot of cast iron (at least old ones) and when stuff breaks, you can't afford to buy new or pay someone.

[Canada]

I always thought you had to heat up the whole cast, weld and then ensure it cooled slowly and evenly. Is this incorrect?

[welderdude]

Here is another interesting method from Jody's website. He uses AC TIG with Aluminum Bronze filler metal.

http://www.weldingtipsandtricks.com/...cast-iron.html

[hooda]

OH CANADA... Always wanted to say that. To answer your question, yes, preheat is generally accepted as a necessary. Cast iron is some real funky stuff. As Jody correctly says on his site, there are so mant different situations that affect the properties of the metal, that sometimes it goes like a dream, sometimes not. There was another clip on youtube of a guy repairing a notorious crack on a cummins diesel truck block, that involves running the engine, draining the coolant, preheating the metal, doing the weld, then immediately refilling the engine with the still warm coolant and restarting the engine, all to keep the thermal properties in a range where by the stresses built up during the welding process are allowed to properly dissipate. Enormous pain, but by the looks of it a successful technique. This is the type of stuff I would like to get into.

[sportbike]

Sometimes the part can be placed in vermiculite after welding to make it cool very slowly.

Silicon Bronze filler is a good choice for some items, including hardened tool steel that may otherwise crack. I have seen it used on tooling adn machine compontnes (tailstocks for lathes for example) that are hardened. Not going to get the same strength as original, but it helps to prevent cracking.

[jakeru]

I tried some cast iron welding on a gray cast iron automotive intake manifold, without much regard for pre or post heating. I just cut some slices partway through the manifold, and tried welding them back up closed using a variety of methods. Let them air cool, waited for it to be cool enough to touch in between weld attempts.

I had a very nice result TIG weld/braizing in AC mode using aluminum bronze filler rod. The bronze seemed to be quite crack resistant, even without any serious pre or post heating. The AC mode seems to help keep the puddle a lot cleaner, and may prep the base metals for welding better than DCEN as well.

TIG welding with DCEN and 309L stainless filler rod resulted in a crack forming while part was cooling, right where the base metal joined to the weld deposit. Apparently there was poor fusion between the two.

Stick welding with 6013 electrode showed some promise, although I need stick welding more practice to really determine how it works when done properly. I think I was running it way too hot and just blowing through. Although I noted there was some cracking tendencies, the cracks didn't form along the edge of the deposit, I only noticed them in the middle of the deposited material. Which tells me the weld metal to parent metal interface was sound.

I picked a small quantity of nickel rods, which I'd like to try next. They are supposed to work well for cast iron welding, but boy are they pricey. I paid $3 per stick.

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Edit: here are some pics of my cast iron experiments.

I hacked up a 1960's era, gray cast iron automotive intake manifold with the cutoff wheel as shown, for cast welding experiments as described above.
Attachment 1650

This joint, which I didn't prepare very well at all, (also didn't bevel at all) worked pretty well with TIG aluminum bronze. There is one small discontinuity in the weld if you look close it will be obvious, but considering the "quick and dirty first attempt", I'd say it did pretty well overall. This is shown after flap-wheel grinding the weld bead down to see what's underneath the surface. It's kind of interesting how "TIG weld-braizing" melts some of the parent metals, yet if you look closely, you can see "islands" of parent metal (silvery color) that have not mixed with the bronze braze material (yellowish color.) I could probably use some more practice/development of my TIG weld-braizing on cast technique, but I'd say that is a pretty promising result for a first, very "quick and dirty" attempt.
Attachment 1651Attachment 1652

I tried using 309L stainless on a pretty well prepared area with a fairly large "Vee". It was dirty (oily) on the back side of the joint, which I'm sure did not help. (Possible hydrogen embrittlement.) I was doing a multi-pass weld. The initial tack welds and first "root pass" were holding up, but on the final pass, I got a crack right along the fusion zone of the earlier weld, a little way into it, and stopped to check it out. You can see the crack, along the bottom edge of the fusion zone, as shown in the pic. (Disregard the "spatter BB's" from subsequently attempted nearby stick weld.)
Attachment 1653

I'm not going to post my stick weld attempts because I need way more practice stick welding before being able to know what its capable of. I am really more of a two handed process (TIG/oxy-fuel) welding guy. I did just pick up 5 lbs of Lincoln 6013 3/32", I might do some practicing with. Those would be much better to learn the process with than using the $3/stick Ni-rod, I was thinking.

[hooda]

Hey Jake, the welds that you posted are pretty cool. I was wondering if you had a particular spec on the bronze rod, or was it just your garden variety brazing rod?

[jakeru]

It's "Aluminum Bronze A2":
https://weldingsupply.securesites.co...:terms::PE#E05

I tried laying some more 6013 stick beads on the cast iron yesterday and realized, the cast is indeed very crack sensitive. I can see why people to go great efforts to reduce the expansion and contraction forces with this material.

I am still working my confidence up to trying the expensive Ni-Rod, but learned it is Harris "NIC-L-WELD 59", basically 59% nickel and the rest essentially Iron.

[jakeru]

OK guys - I had a break through just now with my cast iron welding experiments I wanted to share.

I tried Harris "NIC-L-WELD 59" 1/8" diameter stick electrode (the only NI-ROD my local welding supply had in stock), TIG welded with the flux scaped off, using a clean prepped cast iron surface, and (not sure if this is necessary) AC welding mode (with 20%EP AC balance) just for a little extra insurance towards getting good fusion.

To scrape off the flux, I just used a utility knife and scraped it off similar to how you'd peel a carrot. I didn't go crazy getting every last bit of flux off there, and didn't solvent wash the scraped electrode or anything either.
Attachment 1746
I didn't do any pre-heating. Welded the same piece of gray cast (old automotive intake manifold) I did as in above experiments, in one welding pass. I just sliced through the wall using a cutoff wheel, did not bevel for this experiment. I did prep the front side clean and bright with a flap wheel. Back side was left rusty/dirty.

No pre-heating, no post-heating, no cracking. On the back side, I fully penetrated near the end of the weld bead, and it even looked decent (no notable porosity on the back side)
Attachment 1745

And here is what it looked like underneath the surface - if you held it against the light just right, you can tell the weld material wasn't a perfect color match. (But it was pretty close)
Attachment 1748
Attachment 1747
No discontinuities underneath the surface were noticed.

[welderdude]

That looks awesome Jake! I have played around with welding ductile iron with dcen tig and 312 stainless filler. it seemed to work pretty well. It took a large hammer to get it to break. It broke in the HAZ though. I didn't do any post heat treatment either.

[worntorn]

I've stick welded cast with ni-rod quite a bit over the years. I have always done the preheat and post heat tho, just didn't want to chance going without.

I find ni-rod very easy to stick weld with, it flows beautifully.

Glen