I feel kind of stupid asking this question, but here goes. I am not a newbie welder by any stretch, but it just occurred to me that I have never welded sheet metal in a building that was less than 65-70 degrees. Since the parts I am about to weld are structural sheet metal, I thought I would throw this out there. First, this is just plain old sheet metal(floor/trunk pans, quarters, frame rails, etc on a '70s GM). None of the newer high strength low alloy or anything like that. It will be MIG welded. Since fall seems to have just assaulted us in my area and there is no heat in the building I am working in, I am guessing the air temperature in the building when I weld will be in the upper 40s. So, will this colder temperature impact the strength/quality of my welds or am I concerned about nothing? Thanks in advance.
Not much difference if you start out with 40 or 80 degrees when you are going well above the 2500°F that steel melts at. That's what I'm guessing anyway.
I've welded for well over 40 years and never gave it a thought, but then the shop was 60 to 80 degrees all year round.
If you were welding @ 0°F, the difference would be ~ 50-60° colder. Simplest of % change using the 2500° mentioned would be 2%. Think except for slight increase in distortion, you're ok.
You only need to be concerned about thermal controls when welding thick members. With sheet metal, you are fine.
For significantly thicker steel, I've found that pre-heating the metal helps out with welding. But that may also be due to the fact that my MIG machine only goes to 180 amps. Seems to help create a flatter weld if the metal is already hot.
It all comes down to base material temperature. The voltage and amperage welding adjustments are based on material temps. You normally never think about it during welding, but an experienced welder will automatically adjust his machine on this factor. Example. If you are welding a thick piece of material with a 110 volt mig and find it’s not blending into the base material you will automatically turn up the voltage and amperage. Now here’s something many may not have thought about.... If you are welding and find your cheap flux core mig isn’t hot enough. And turning it up doesn’t help. You simply heat the base material and the weld will blend right into the base material. Bottom line. Doesn’t matter how cold the ambient temp is as long as you have enough experience to see your getting penetration and make changes to accomplish it.
Now here’s another idea many haven’t thought of. Your welding sheet metal, maybe a small piece that will burn up at the touch of the arc. Some piece very near and dear to you. Beside backing it with copper as a heat sink, you can stick the piece into a bucket of water. Now don’t jump to conclusions. We aren’t welding underwater. You simply hold the un-welded part of it in the water. Giant heat sink at your disposal.
I'm glad you asked this. I was wondering about this very thing recently... because I am a fairly inexperienced welder... but I'm going to be doing quite a bit in the near future. I doubt that I'll be welding in freezing temperatures, but maybe. My specific concern was if welding cold sheet metal, will the metal outboard of the heat affected area draw heat away from the weld quicker and require more hammering to control shrinkage. I like PJs answer. Whatever you're doing, in whatever conditions, you watch your results and adjust as needed. Sent from my VS835 using The H.A.M.B. mobile app
I once welded a model A box together in an unheated garage when it was minus 59 outside. The welds held up after several years of abuse so I think you shouldn't have any issues. There was a local old school bodyman that used to gas weld everything, he would wait until the coldest winter day and then push the car outside and do all his welding to avoid warpage.
I would be more concerned with condensation in the metal. But that's quickly driven out as you weld. Really more of an issue with heavy sections and alloyed steels. Sent from my SM-G965U using The H.A.M.B. mobile app
What is important is how fast it cools. I recall a "TTT" curve (Time, Temperature Transformation) that changes the molecular structure of steel, as well as warpage, if it cools too fast or too slow. Each composition of steel has a different curve. That was for heat treating / quenching, but I'd guess it would be the same for werlding. Learned that 50+ years ago, so maybe things have changed - either that or I know just enough to be dangerous.
Are you pro welder and can pass X-ray tests ? If you are you might be able to determine outside air temp effects your welds. If your not weld any temp until your finished with your project. Just be sure the PPE is in place. I found this out years and years ago, those little foam ear plugs are your real friend when cutting or welding over head. Man does it suck to hear it burning through the the ear drum and you can’t do Schmidt about it . All the time knowing you could have prevented it from happening .
Those ear plugs aren't a bad idea any time you are welding. The main thing on sheet metal is don't get in a hurry and run long beads. That is what does more damage than anything. I've seen a lot of panels that guys warped the tar out of because they tried to run a continuous bead because the welder was working so great they just kept burning wire.
You’ll not have a problem other than condensation. I generally like to warm the sweat out before welding if I can. A halogen light does that well enough
I enjoy reading all the responses. But it's nice when someone just answers the freaking question, too. LOL Thanks, 31 V. Sent from my VS835 using The H.A.M.B. mobile app
I love it Another welding question that I ignored and let the resident “experts “ try to answer. Life has been great since I learned not to respond to welding questions on the HAMB.
Watch the regulator for frost/icing up. Under some conditions the gas flow is messed up and the welds go from OK to not so good.
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