stompbox64
Professional Goof Ball
- Joined
- May 17, 2013
- Messages
- 98
So I just upgraded to the Knife Maker profile/account, waiting on email, so please bear with me.
Me and my buddy are making knives as a hobby, selling a few to get more good stuff. We just did a heat treat on a round of CPM M4. However, we saw something really strange. We appear to have "case softened" the steel. We went with the Crucible sheet on the heat treat, but when finished, we noticed the following:
1. Sand blasting won't touch the stuff.
2. Files cut the metal easily, to a point, then glide like glass.
3. A hit with a punch resulted in a divot, but the metal shot outwards (like an impact crater on the moon).
4. When we did the punch test with the cut-offs from the untreated stock, the punch simply pushed the material in, no explosive factor in move the metal out of the way.
We did a round before where the punch test resulted in a blunted punch, but no marking on the M4.
Heat Treat (with case softening) - ramp to 1500 F, hold for 30 minutes to equalize, then quick ramp to 2200 F for 20 mins. Quick quench on Aluminum plates. Then 3 rounds of tempering at 1025 F at 1 hr each. Then a 6 hour Cryo treatment with dry ice (-118 F).
Heat Treat (with no issue) - Foil wrap, ramp to 1500 F, hold for 30 minutes to equalize, then quick ramp to 2125 F for 20 mins. Quick quench on Aluminum plates. Then 1 round of tempering at 1000 F at 1 hr. Then a 6 hour Cryo treatment with at 31 F (freezer).
The only differences we can see between the 2 treatments is the foil wrap, the # of temperings, and the Cryo treatment. But our biggest thought on this is that we over-cooked the metal exposed to Oxygen, thus cooking the carbon out of the outside layer.
Anyone else seen this, or can let me know what we did wrong?
Me and my buddy are making knives as a hobby, selling a few to get more good stuff. We just did a heat treat on a round of CPM M4. However, we saw something really strange. We appear to have "case softened" the steel. We went with the Crucible sheet on the heat treat, but when finished, we noticed the following:
1. Sand blasting won't touch the stuff.
2. Files cut the metal easily, to a point, then glide like glass.
3. A hit with a punch resulted in a divot, but the metal shot outwards (like an impact crater on the moon).
4. When we did the punch test with the cut-offs from the untreated stock, the punch simply pushed the material in, no explosive factor in move the metal out of the way.
We did a round before where the punch test resulted in a blunted punch, but no marking on the M4.
Heat Treat (with case softening) - ramp to 1500 F, hold for 30 minutes to equalize, then quick ramp to 2200 F for 20 mins. Quick quench on Aluminum plates. Then 3 rounds of tempering at 1025 F at 1 hr each. Then a 6 hour Cryo treatment with dry ice (-118 F).
Heat Treat (with no issue) - Foil wrap, ramp to 1500 F, hold for 30 minutes to equalize, then quick ramp to 2125 F for 20 mins. Quick quench on Aluminum plates. Then 1 round of tempering at 1000 F at 1 hr. Then a 6 hour Cryo treatment with at 31 F (freezer).
The only differences we can see between the 2 treatments is the foil wrap, the # of temperings, and the Cryo treatment. But our biggest thought on this is that we over-cooked the metal exposed to Oxygen, thus cooking the carbon out of the outside layer.
Anyone else seen this, or can let me know what we did wrong?
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