[TDubs]

The building that I weld in is a 1920's structure that is going through some reconstruction. I'm basically replacing the roof. The section that I weld in is water tight but the main section has some leaks. Thus it is cold in the mornings lately. This morning it was about 35 degrees.

So onto my question. Will room temperature affect welds on steel? I know that steel will heat up once you start welding it, but what about that first bead after tacking. If the steel is cold, will that affect the penetration of the weld?

I have another shop building that is finished and heated. I could store steel in there until I finish the reconstruction of the building that I weld in. Would that be a good idea or does temperature not matter?

Thanks,

[noddybrian]

I would say yes ambient temp will effect welds - how much depends a bit on material / process & just how cold it is - if gas welding or Tig welding the heat input is controlled by the operator & any amount of heat can be applied prior to adding filler & moving so is not such a problem - Mig & stick are however limited as metal is deposited regardless of parent metal temp so cold starts are always a problem - the colder the metal the worse it is - with stick it's common here to use a remote amptrol so you can up the amps a bit over normal welding amps to compensate to a degree - I've never welded anywhere with heat & am lucky if it's inside but even so it will only be a barn or lean to roof to keep the rain off so in cold weather on anything important I preheat with a torch - I think this is normal practice - I would'nt worry too much about your buildings temp unless your in like the arctic circle ! just give the piece your welding on a general warm & the start point a bit more unless this is some critical part for which the WPS has stated preheat or the material is especially crack sensitive.

[Poland308]

For most mild steel there is a 50F required preheat. Below this can mean that your weld may be subject to stress cracks or hydrogen precipitation. IE more cracks. But this is also directly related to metal mass or thickness. Other metals also have required preheat.
http://www.tempil.com/assets/1/31/weldi ... _chart.pdf
Here is a chart someone posted earlier about it.

[MarkL]

http://www.tempil.com/assets/1/31/weldi ... _chart.pdf
Here is a chart someone posted earlier about it.

Great chart, I had no idea how high a preheat temp is recommended. That company also posted this chart on temperature and metallurgy.

[TDubs]

Thanks for the charts guys. It looks like the powder coating oven that I'm building just found another use. I love when that happens.

For the time being, I'll store my steel in the main shop which is usually 60F at night and 68F plus during the day.