Preheating question

[camshawn]

I am about to weld some ears for mounting a hydraulic cylinder on my back blade. The welder at work recommender to preheat them before welding (1" thick onto 1/2" backing plate). I did not think to ask him how hot to get them before welding.
Thanks, Cam

 

[Shield Arc]

That can be a loaded question, but most of us here welding mild steel anything over 50-degrees is enough. But here is a good article on pre-heating.
What is Preheat?

 

[camshawn]

Thanks for the quick reply. One of the things I love about this site.
I will read the article. Everything I am using is mild steel. I think that preheating gives better penetration on the thicker pieces. Is that correct?
Cam

 

[Shield Arc]

I think that preheating gives better penetration on the thicker pieces. Is that correct?

If your welding machine is under powered, it sure can't hurt! Proper joint prep is key also!

 

[camshawn]

If I manage to stop procrastinating, I will grind off the mill scale, preheat until warm (100 deg F) weld 3 passes (t joint), with 035 wire, about 430 inches, 23 volts, 85/15 gas.
It is. Hard to get moving when it is raining out and the coveralls are going to be damp. Inside is warm and dry and has the internet. Thanks for the preheating link Shield Arc
Cam

 

[Shield Arc]

Oh wow! Is .035 the biggest wire your machine will run? The 85/15 gas is a big help. Any chance your welder can produce more volts so you can get into spray?
Put your numbers into the this calculator, and you'll see my concerns!
Miller - Welding Calculators

 

[camshawn]

I see what you mean. I would be better to use stick and 7018 for this heavy material. My thermal arc 211i maxes out at 210amps
Cam

 

[Shield Arc]

The .035 wire sends up red flags to me! I wouldn't think twice about 1/8-inch 7018, 5/32-inch would be better.

Here is some spray I did with my V350-Pro with .035 wire, and C/10 gas.

 

[camshawn]

I will use the 7018. 1/8 is what I have here. With the cold coming next week in southern BC, snow may come with the warming and I need to get this back blade finished. Off to clean and weld, Cam

 

[Shield Arc]

OK, now we'll need pictures!