Did these temper too hot? Can I re-HT 1075?

[boy&hisdogs]

I think they did. I quenched them in canola and tempered in the toaster oven. I set the toaster oven to 450 assuing that it would error on the side of cool being in the open air and on a granite counter top.

Between quench and temper I scrubbed the blades pretty well with scotchbrite and dish soap, then steel wool for what was left. The metal was pretty clean going in so I believe that these colors are true.

I have tempered other knives cut from the same piece of stock at the 400 setting and they came out a good straw color.

The steel is 1075, would it be be ok for me to anneal and re-ht them? These knives aren't really "for" anything besides learning experience but I would still like to save them if I can.

 

[Natlek]

I think you do not have to anneal blade if you you decide to re-HT . And whether you have to re-HT , someone else will respond

 

[redbate]

If you do decide to re HT you have to normalise first not anneal.

 

[S.Alexander]

I would say 450 degrees would be to hot to temper 1075 at. I do that temperature for my 1075 hatchets.

You should not believe the temperature of your toaster oven. You should buy an oven thermometer to verify your oven temperature. They are about $5 at your supermarket.

You can just reheat and quench again. There is no need to normalize or anneal the blade.

 

[kuraki]

Not only is my toaster ovens temperature not accurate, setting it to 400 one day will get 450 and the next 375. So I do as Shane recommends, because it will hold a temp quite well, once you find it.

 

[boy&hisdogs]

I went and got a thermometer and have them in the oven now at just a hair above 350. According to a chart I found for 1075, this should put me at about 60 hrc. Thanks for the advice, you've all been such a great help as always. :thumbup:

 

[PaMtnBkr]

Once you figure out where your setting is for the temp you want, you may want to add some thermal mass to your oven as they lose heat and spike up and down pretty quickly. Some use a tray of sand to add mass. I used 3 3x.5 thick SS bars that were cut-offs of some bar stock. Really helped to stabilize the temp in the toaster oven.