So today I took a few hours and did a few heat treat tests before moving on with my next knife-making project
To do this, I cut out 2 test pieces each of approx. 20x50mm in size from 3 different steels and hardened them in an electric furnace.
The steels are:
- 1.2235 / 80 CrV2 / L2
- 1.2419 / 105WCr2
- 1.2842 / 90 Mn CrV8 / O2
Each piece was treated with graphite spray to prevent decarburization and slag build-up (I once read this in a US forum, I had the spray there and I thought it couldn't do any harm)
It was quenched within 3-5 seconds in approx. 80 ° C rapeseed / canola oil.
I always removed the 1st piece after 5 minutes of oven time (not holding time!), the second after 10 minutes of oven time. I hope that this is sufficient for such small and thin test pieces.
The file test succeeded with every piece, with the 1.2235 with 10 minutes of oven time I noticed that there was a slight decarburization on the edges of the sample, but with the second cut the file slipped.
Then I clamped the samples in the vice and broken them with a pipe wrench or, in the case of the 1.2235, in 3.5mm with a hammer.
Then, using the kiddies' USB microscope, I took a snapshot of each fracture as good as possible, one image each at 50x and 1000x magnification. Please click on the pictures to see a larger view.
It would be great if the specialists her could tell me something about the photos, my "test principle" and the results.
I notice that some pieces have a darker edge and a lighter core. Does that mean the holding time wasn't long enough?
steel 1.2235 (thickness 3.5mm)
Oven running at approx. 840 ° C
5 minutes oven time
10 minutes oven time
1.2419 (thickness 2.2mm)
Oven running at approx. 825 ° C
5 minutes oven time
10 minutes oven time
