Welding Tips and Tricks

I'm a maintenance technician and have been doing a lot of repairing water leaks lately. Any tips on repairing cracks and choice of rod for regular mild steel. Any tips would be great. Thanks

I'm going to assume you're welding steel, and I don't care whether it's "stainless".

I'm going to also assume you can't take it out of service to "quick" fix it. This is the nature of the beast.

Use 6010 rod at high amperages. Again, don't care if it's stainless or carbon.

1/8" @ 115+ amps to close a leak is not unusual. 5/32" at 160 A. Just put a cork in it, and record the leak for repair during the next shutdown.

Steve S

kurtdsmith wrote:I'm a maintenance technician and have been doing a lot of repairing water leaks lately. Any tips on repairing cracks and choice of rod for regular mild steel. Any tips would be great. Thanks

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Kurtdsmith.

What type of leaks?

Alexa

We can take machines down to repair them but they are big mixers. The water jackets around the body get clogged up and build steam as they run on 250 degree water. Once the steam builds up they crack the welds on the outside edge. They are 1" square bar stock welded to the body and a 1/2' plate fillet welded to these. They always seem to crack the weld that at the 1/2" plate. Also these machines are about 60 + years old. Not sure of the grade of steel, but with the constant heat and cooling of them it may be hardened from that? Is it good to use a needle scaler to peen after each pass to stress relieve? i have done some research in my old lincoln welding hard back book. Since it is 1" welded to 1/2" should it be preheated? Says anything over 3/4" requires preheat. Also says to use low hydrogen rod (7018) to reduce cracking as well. I have been using 1/8 6010 up hill about 100amps, and just running stringers. Thanks for the replys

Frankly, I think 6010 is the better choice. The "60" kpsi tensile strength comes from higher ductility/less hardness.

If you think age hardening (from the multiple cycles over the years) is an issue, though, it might be worth considering a high-nickel rod for the repairs. The high-nickel alloys will not harden from cooling or quenching, so the heat apsortion on the heavy sections you weld will not promote cracking or "interface" hardening.

Hastalloy W comes to mind.

I'd expect Alexa, and perhaps Werkspace, to chime in on this, as they both know the metallurgy better than I do.

Steve S

I agree that the 6010 would be the more common choice. Here's a bit of literature from Lincoln Electric.
http://www.lincolnelectric.com/assets/g ... /c2420.pdf

Kurtdsmith.

Do you have a couple photos? One of the over all joint (drum plate-to-square stock-to-half inch plate) and one blow up shot of the cracking?

Is the cracking consistently along the fillet welds or only in the locations that corresponded to the blockages?

Tanks.
Alexa