Metal temperature question

[Trip59]

Presently, this relates to MIG, but will relate to TIG later... When in the Navy, all the welding I did was under shelter, in moderate temperature. A year or two ago I had some outdoor work on relatively heavy metal, 1/4"+ thickness, it was cold, freezing temps (yes, in FL) and I seemed to have nothing but trouble. On a whim, we decided to hit all the joints with a MAPP torch, thinking the cold was messing with things. It might have been a coincidence, but it started going much easier, easier starting, cleaner welds, better penetration.

Well, we're hitting 30-40 temps now and I'm wondering if there's a point where it makes sense to warm the metal before welding for better welds. Thoughts?

[geezer]

Yep, warming the metal will make a difference, after all you are trying to make the metal hot enough to melt, so any heat added improves the process. 30 to 40 degrees may seem cold in 'florida, that's still Tee shirt weather where I come from. Uphill welding at those temps will allways produce better penetration due to the heat rising and preheating a head of the weldbead.

[DaveO]

Makes you wonder how those guys on the Alaska Pipeline did it- stick welding in all types of conditions.

[Trip59]

I've paid my dues, I was in NY for the blizzard of 77, I was in Chicago for two of the last coldest winters in the last 100 years. Most of what I'm doing is flat clamped to the table. Would hitting it with a torch be a benefit under what temp? For now, I'm running a 110v MIG and .024 wire, so it's not dumping a ton of heat.

[geezer]

I've paid my dues, I was in NY for the blizzard of 77, I was in Chicago for two of the last coldest winters in the last 100 years. Most of what I'm doing is flat clamped to the table. Would hitting it with a torch be a benefit under what temp? For now, I'm running a 110v MIG and .024 wire, so it's not dumping a ton of heat.

metal preheated at any temp is a benefit for welding, after all we want the heat from the electrode to melt the metal not get wicked off to heat it up.

[Trip59]

Ok, that makes sense. I think I'll play with it a bit on some scrap to see if there's a significant difference. I will add that most of the welding I've done this year was unintentionally pre-heated. Sat out in the sun long enough to get hot to the ungloved hand, didn't even make the connection

[jerky]

as everyone else said preheat in the cold will greatly help the weld. if you cant preheat, try turning your heat up 2-4. welding in the cold sucks, but sometimes its just gotta be done.

[Spike]

pre-heating for a Mig weld can help out alot. It will not only get the molecules in the metal warm so that they are easier to bond together, but will also help keep heat warping down in your part. And since heat warpage is a much bigger problem in MiG welding over TiG welding, the pre-heat helps that much more in making a finished product.

With aluminum, preheating makes welding an order of magnitude easier. Either in a MiG or TiG process. When i'm cold welding aluminum, i'll run the TiG torch back and forth a couple of times over the joint to pre-heat it before i start welding. Makes a whole heap of difference.