Pre-heat for stick weld?

[Soundguy]

i never preheat on mild steel.. but do on picky stuff like cast iron. have had great results with that. must have at least 4 CI welds here recently with no ill results..

one of em was a repair cleaning up someone else's hack welding job where they really mauled a loader bracket.. spider webbed it everywhere..

soundguy

 

[R W]

Certain machinery manufactures used steel of a higher carbon content, this could sometimes be prone to cracking, preheat may be advisable in this situation although I have seen a great amount of this steel welded with a
7014 rod, the only preheat would have been from the goughing/grinding in the joint preparation.
Welded worn slip down chisel plough points together to make one a great many times, the only preheat was from grinding the V joint (they were 1/2"
thick), used a 7016 rod.

 

[jake98]

Is there no practical way to determine the carbon amount? You know, other than asking old carbon-credit-Al to take a look at it?

 

[Shield Arc]

You can send in your material to a lab and pay for a Spectro Analysis.
Or you can read this.

Guide to Buying Steel Online | Online Metals Guide to Selecting Metals for Your Project

 

[spo307]

being a welder, I never preheat steel, unless it is cover with snow, ice, or rain, most important is that the area 2 b welded is clean, and your welding rods are not stored where they can get moisture in them, when stick welding aluminum I do pre heat with a torch 2 get moisture out.

 

[Jstpssng]

Yeah that pre-heating is a wife's tale. Nobody really does it! :laughing:

Dumb question; in the second (right hand) pic is he preheating because of the difference in steel thicknesses?

 

[NC tractor driver]

For most of the stuff we do it's not necessary to preheat. I used to work in a power plant and sometimes doing repair on big drums and headers we required a significant amount of preheat followed up with UT and X-ray inspections.

 

[Shield Arc]

Jstpssng I really don't know the reason why he is pre-heating, I stole that picture off the AWS site. According to the thread he was getting ready to take a 6-G open root, test w/ restriction ring, with dual shield and SMAW. There could be a multitude of reasons for the pre-heat. I don't remember him mentioning why either, could be as simple as too take the chill off the pipe. Some guys like to pre-heat before a test, especially a bend test. Depending on the type of material the WPS may specify a certain degree of pre-heat. Like I said a multitude of reasons.

 

[Jstpssng]

Jstpssng I really don't know the reason why he is pre-heating, I stole that picture off the AWS site. According to the thread he was getting ready to take a 6-G open root, test w/ restriction ring, with dual shield and SMAW. There could be a multitude of reasons for the pre-heat. I don't remember him mentioning why either, could be as simple as too take the chill off the pipe. Some guys like to pre-heat before a test, especially a bend test. Depending on the type of material the WPS may specify a certain degree of pre-heat. Like I said a multitude of reasons.

Thanks, I was just curious.