Question on tempering

Hello I’m fairly new to Blacksmithing and I hope no one minds me asking, but I figure this is the best place to ask.

I was just wondering if there is a reason my knives keep breaking when I test them? I have done everything possible to ensure a good quench and temper. I’ve even used a microscope to look for cracks before going into a quench. I temper my knives with blue on the spine and straw yellow on the cutting edge. When I went to test the flexibility of my latest knife by pressing down slightly on the middle my knife broke.

I am just wondering what I am doing wrong. I was using a file at the time that wasn’t case hardened for my metal. The knife was about seven inches long and one inch wide. the only thing that I didn’t take much care to do was check if the metal was non magnetic before going into the quench, however because the color was orangy yellow I knew the knife was none magnetic or above.

I would deeply appreciate any suggestions or pointers on where I’m going wrong or things I can improve so as to get the best quench and temper that I can.

Multiple tempering is preferred when differential tempering is used. This will overlap and create a more uniform temper.

Thank you so much for the response!

How would I go about doing a multiple temper?

just redo your temper three or four times, its supposed to relax the fractures that you get when you quench,try preheating your quench oil so that it cools down a bit slower so that it doesn’t go so brittle. hope it helps:+1:

Ok, thanks again! I’m new here so thank you for replying to my question