Question for the experts..

[arnon]

Reading about knives, I bump into that :
"It is very important to ensure that the blade is kept cool at all times during welding, as one could harm the temper".
Now, I don't really understand all this steel chemistry and I don't do any welding .... BUT, I am wondering, how hot -besides welding - can a knife blade become without harming the blade and the tempering?
Thanks Arnon?

[Joshua J.]

I think around 400-500 degrees Fahrenheit is the limit for the average steel. Some steel types used in drill bits and such (some knives now days) can take up to 800F.
If you want to learn a whole whack about steel and the inner workings of it I suggest reading this

http://swordforum.com/metallurgy/ites.html

[butch]

yep things start goinig wrong at around 400F for most knife steels
some of the real wild stuff is tempered around 1000F
the trick is knowing what the tempering temp. was so you dont go past it and make the steel softer
butch

[arnon]

Thanks, Arnon

[Piet.S]

For not messing with the hardness of your blade it must be kept well under the temperature at which it has been tempered.
This is usualy around 200 degrees Celcius.
There are steels, like ATS-34 that have a peak in the tempering diagram.
ATS-34 has it at about 510 degrees Celcius and it is quite narrow.
This means that it can also be tempered at this high temperature instead of the lower.
This can be a benefit if the blade must endure high temperatures later.
Like there are some makers who prefer to grind there blades in the hardened state.
They don't have to be too carefull about overheating the blade while grinding.

[HoB]

Welding????? I will open my big mouth here and risk that I am putting my foot into it, but there is no way in hell you are going to weld any blade without screwing up your temper. Welding requires to locally heat the steel to its melting temperature...that is way BEYOND the austenization temperature! And if you want to get a weld with maxium strength you have to aneal the workpiece at a temperature which is also around or beyond the austenization temperature.....either way you are screwed.

[dialex]

Welding????? I will open my big mouth here and risk that I am putting my foot into it, but there is no way in hell you are going to weld any blade without screwing up your temper. Welding requires to locally heat the steel to its melting temperature...that is way BEYOND the austenization temperature! And if you want to get a weld with maxium strength you have to aneal the workpiece at a temperature which is also around or beyond the austenization temperature.....either way you are screwed.

Just my idea too. Maybe it was not about welding but grinding?

[yablanowitz]

When they say "welding", they may very well be refering to soldering, I have seen quite a few fixed blades with silver soldered guards and pommels. It is not correct, but it is common to refer to the process as welding.

[severedthumbs]

brazing? ?