Blade tempering

[KELTOI]

I was wondering, What is the BEST way for tempering blades and the like?

[Mills]

You ask a specific question Best but for general use.

In general an oven at 400 degree will take care of most issues for many steels. If it is to be struck maybe 500 degree draw, if for wood work maybe 300 degree. if a thin section time in the oven is fairly short depending on the steel. if fairly thick longer depending on the steel.

Rich Hale and others have given the best advice. PICK the steel you want to use and then learn it in a methodical way.

Hope that doesn't come across as snippy.

[dablacksmith]

a good oven with a fairly accurate temprature control ..the rest depends on steel

[KELTOI]

Thank you both. I have done some tempering before, but I don't know that my steel is, as I just get random steel from scrap and such. The little that i have read on tempering hasn't really indicated what each type of steel requires. Although, I did read that 400 is roughly the right temperature for knife blades and such to get the light stray temper colour. Is there a minimum time for tempering for different steels?

[MetalMuncher]

Do you use leaf springs? Knowing which kind of steel and what you will use it for will determine the proper temper.

[KELTOI]

no, for this knife especially, I have just used a piece of round stock that I found somewhere.

[Steve Sells]

each steel has its own hardness for various temps. 400F for one steel is way too hard for another, or too soft for yet another. Read about the various additives steel can have to get an idea of why some steels like 1075 temper at 350 to get the same hardness as H13 tempered at 950F.

Another reason to know your steel, is that while hardening can many times be done with a magnet to get the temp. Tempering temperatures are best targeted using the steels Spec's sheet. that is different for every steel.

[Woody]

1. Know what type of steel you are dealing with either by purchasing new stock, or by consulting a junkyard steel list like the one on this site which will give you a fairly good idea of the steel type if the original use of the steel can be identified, ie. car leaf spring etc.

2. Go here Principal Metals click on property data, then on the type of steel from the drop down menu, ie tool steel, alloy steel, then from the drop down menu pick the type of steel that you have, ie 1085, 5160, A-2, D-2 etc. The information for that particular steel will come up telling you forging temperatures, annealing temperatures and tempering temperatures. Be advised that the tempering temperatures will be given as a range of temperatures with the lower temperature resulting in the hardest with the steel becoming progressively softer as the temperature increases.

[KELTOI]

thanks I appreciate the input. That is what I am here for: to learn!

[Rich Hale]

I hope not to offend and if you know this then great There may be others that do not know. Tempering is done as a way of easing the hardness off of steel that has been hardened by heating to non magnetic and quenching. The temperature and what it is quenched in depends on the steel That process maks the steel too hard and a bit brittle for most uses. Tempering brings the hardness down to a usaeable level. As above knowing the steel is really important. Have fun.

[markb]

Principal Metals
This link isn't working for me. I get a blank page.

Is it me or anyone else having the same problem?

[Woody]

It works for me, must be something wrong with your computer. You could always do it the old fashioned way and type principalmetals.com into your browser bar and hit the enter key.

[KELTOI]

Thanks Woody, the link should help!