Welding Problem

O

outline

Joined
Aug 18, 2004
Messages
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Hey everyone, I just started to mess around with forge welding and I
stuck a couple of welds with plain high carbon steels such as 1095 and 1080
but I'm having a ton of trouble welding mild steel. Right now I'm
not sure I am getting the tempurature in my forge hot enough. I am using
a forced air horizontal gas forge from Darren Ellis which was at 7psi when
I was trying to weld. Is that a typical pressure for welding mild steel
for this type of forge or is it to low? I feel like if I raise the gas
and air pressure any more my forge will start acting more like a flame thrower
 
what is your temperature?
gas pressure is only relevant to someone with the same forge
mild steel has a higher welding temp than high carbon steel

try making your welds a couple hundred degrees hotter, you don't have to worry about decarb with mild so cook it

-Page
 
If you straighten out a coat hanger you can easily tell when the steel is ready to weld. Heat the wire and dip it in the flux can ( to put a bit of flux on the tip).
Bring the steel up to heat and when it looks right, touch the wire to it. If it immediately sticks and fuses, the metal is ready to weld. If it doesn't stick, heat some more, and try again.
Of course, use flux when making the welds.

Stacy
 
Page, are you sure that's right? "try making your welds a couple hundred degrees hotter, you don't have to worry about decarb with mild so cook it"

I can understand the decarb, but the part about "so cook it", was interesting to me. I have had mild steel in my forge many times, and all of a sudden I get the 4th of July show, with sparklies flying everywhere, meaning it overcooked, or so I thought anyway.
Is that what you meant?
 
I don't think it would be wise to burn any steel, however sometimes the sparkler show can be the effects carbon. High carbon steel will melt and also burn quicker than low carbon, so the low carbon stuff can take more heat, and may indeed require more heat to weld.

I mention this sparking point only because of a couple of things that gave me a new incite recently. First when consolidating a bloom from a smelt the stuff will spark like crazy in the first few welds in ways that would cause me the throw normal steel into the trash. However this sparking subsides as the bloom becomes solid, you will then have to work a little harder to spark it again and if you do you will immediately notice that this time the steel really resents being sparked, while the first time it almost seemed necessary. This is all due to the burning out of the excess carbon and reducing things to a workable level steel, (so much for the old "you can't make steel in a bloomery furnace, you have to make iron and then carburize it!" argument :rolleyes:).

The other time I encountered this is in recent experiments I have done with incorporating silicon carbide powder into the welding process- you want to see sparklers...WOW! :eek: You won't notice it inside the forge but as soon as you pull steel coated with silicon carbide out into the air it is the 4th of July right there in your shop!
 
I have been using anhydrous borax as flux which I figured should be fine for low allow steels. The thing is, I forge outside so judging the tempurature by color is hard because these higher temps still look orange as opposed to yellow or white. However Stacy's coat hanger idea should help alot, it seems similar to judging the hardening tempurature with a magnet. Ill try it again soon and let you guys know how it went. Thanks for all of your advice I really appreciate it.
 
Well, I finally made successful welds when I raised the pressure. The coat
hanger trick really helped me find the right welding tempurature.
 
outline said:
Well, I finally made successful welds when I raised the pressure. The coat
hanger trick really helped me find the right welding tempurature.
Click to expand...

FWIW, I have one of Darren's forced air horizontals as well and I regularly weld at 3PSI. When I "turbocharge" my blower (by blowing a blower into a blower....don't ask, the main blower pushes enough CFM, but not enough pressure...the backpressure causes inefficiency) I can hit 2500F+ at 3PSI. I can also control the atmosphere well enough to melt steel without burning it. You may be able to get more complete combustion with some more air and a little fiddling.

-d
 
fwiw I meant get it a whole lot hotter than where you weld blade steels, not to sparkler level (althoughthat seems to be where blacksmiths like to weld mild)
-Page
 
Deker, I had no idea I could get to those kinds of tempuratures with only
3psi. Do you know a way to raise the pressure of a blower without adding a
second one? The one I am using now is from Kayne & Son and blows about 112 CFM. I like Page's idea of raising the temperature in my forge to a higher level so all of my welds have a better chance of sticking.
 
Don't let pressure and CFM throw you. 3PSI through a 1" pipe is not the same as 3PSI through a 1/4" hose ( huge difference for example). Every forge and burner setup will have its own parameters. Decker's gauge may not even read the same as yours ( you might both be running at 5PSI?). As far as air flow goes. 112 CFM is plenty for all but a big forge. The thing you want to do is adjust the air/fuel mix to get a balanced atmosphere. To raise the temp,increase the air and gas. Just increasing the air will make the forge hotter, but it will be rough on the steel, and rougher on the forge lining.
Stacy
 
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