forging temp vs welding temp

[hardheart]

why is welding temp bad when forging monosteel? I mean when the steel is at a uniform thickness, so not a question of ruining the tip or edge. The max forging temps seem lower than the 2200-2300 I've seen mentioned for pattern welding.

 

[Jared Stenoien]

you get a lot of decarburizing at higher temps, and it also causes grain growth, which will make your knife a lot weaker if not properly dealt with

 

[hardheart]

Yes, but these would also be issues with the pattern welded steel as well, would they not? Leaving it thicker to grind away the decarb, and normalizing cycles should work either way, shouldn't it?

 

[Jared Stenoien]

as far as I know it would, but most makers that forge try to bring the profile to as close to finished as possible, theoretically they should be able to do a quick swipe on the grinder to knock the scale off when they're done and it's done, but some of us (me) leave something to be desired with our forging technique and that's not quite how it goes

 

[deker]

I think you've pretty much got it. You can save some time and work by running at lower temps since you needn't be AS concerned with resetting grain size. I'm personally one of the "forge thick grind thin" types so that I don't have to worry about decarb as much. I normalize everything 3 times just to be safe as well. I used to forge very close to final shape, but I find I spend a lot more time straightening things and getting it perfect than I do taking off the extra 1/8" of steel at the grinder. I also like the piece of mind of knowing that I'm a lot less likely to have a soft spot on the edge due to decarb. I do try to use reducing heats as a finish my forging though...So, really what I'm saying is that I'm just contradicting myself a lot in this little diatribe.

Forging temps are VERY important however if you're dealing with wootz. If you've done a wootz smelt and everything went well, forging your billet at too hight a temp will destroy the dendrites you worked so hard to grow in the smelt.

-d

 

[Stacy E. Apelt - Bladesmith]

Every steel has its forging temp range. Go above it or below it and you will run into trouble. The welding temps are for making the billet, then you work at the forging temp. Usually between 1650 and 2200.
Stacy