at what tempeture would you ruin the temper on a production knife?

[durbanposion]

like if you left your knife on a really hot stove or too close to the campfire, or on a radiater? would temps that dont burn your hand be able to ruin the temper? or is the temp required to do damage alot hotter?

 

[J.Wade]

Most Knife steels need to reach at least 425 to temper. I don't think if you can hold it you will do any damage.



cya
jimi

 

[Jeff Clark]

Around 140 F a metal surface is too hot to hold for more than a few seconds. At 150 it burns you almost immediately. Tempering is usually at a hot oven temperature around 400 F and the duration is usually around an hour. You can ruin a temper with a grinder, but you will see the metal discolor when you get there. Generally you are talking flames or hot coals if you are going to damage a temper around a campfire. It isn't going to happen at boiling water temperature.

 

[Cliff Stamp]

Some of the low alloy steels are tempered lower, ~325 F, still way hotter than you can handle by hand - however the main body of the blade can be cool to touch and the edge easily burnt if it is thin enough. This is usually a grinding problem rather than poking in the fire problem.

-Cliff

 

[Gollnick]

The general rule-of-thumb that I tell people is that if the knife isn't hot enough that a drop of water put on it sizzles, it's ok. Water boils at nominally 212F. As has been pointed out here, the lowest final heat-treatment temperatures in general use are around 325 and 450 is even more common. So, if a drop of water won't boil off, the knife is no hotter than 212F which is at least 100F below any affect on temper, plenty of margin. It's not perfect, but it's a handy rule-of-thumb.

 

[x39]

Just out of curiosity, which steel is tempered at 325 deg.?