Call for Charpy toughness samples

OK I will check the hardness after it is broken. Will test them this week sometime, hopefully.
 
I did vanax at 1975f and 2000f, cryo, and 400f tempers. I also did a cross grain condition.
 
I was looking for it in the chart missed the to be done list my bad.

Warren thoughts on vanax compared to z wear?
 
Tin.Man said:
I was looking for it in the chart missed the to be done list my bad.

Warren thoughts on vanax compared to z wear?
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I’ve only made a couple blades. It reminds me of S35VN in terms of grinding, I've got a test blade I’m grinding to a zero-edge to test fine edge stability, I just need to put a handle on it now.
 
There is a new toughness champion: 8670 with 400°F temper gave 59.7 Rc and 51 ft-lbs. The 175°F temper gave 63.9 Rc but a drastic reduction in toughness to 6.1 ft-lbs, lower than CruForgeV at the same hardness. M2 was similar with 6.2 ft-lbs at 64 Rc, difference between 400 and 1000°F temper was small but 1000°F was slightly better (5.4 vs 6.2 ft-lbs). 52100 was 19.7 ft-lbs at 61.9 Rc (1475°F-300°F), similar to CruForgeV. N690 the worst steel yet at 3.7 ft-lbs though heat treated to 62.6 Rc with likely too low temper of 175°F. Z-Finit keeps giving me high variability in toughness testing for unknown reasons, it got 27.8 ft-lbs at 59.5 Rc but the scatter was extreme.
 
Interesting. That hardness is a tad higher than what I normally think of as the sweet spot for max toughness with that "L6 type" nickel bearing steel. Wonder what the number would be at 57-58? I have seen one chart that had moly bearing L6 like Champaloy at its toughest at 58 with a 500F temper but with kind of a "secondary toughness hump" at 61 with a 400F temper. that looked like it was at least 85% of the 58Rc high. The drop going from 58-61 seemed to be less drastic that some of the numbers we see for say 3V at 58 vs 60-61 using the standard high temper.
Larrin said:
There is a new toughness champion: 8670 with 400°F temper gave 59.7 Rc and 51 ft-lbs. The 175°F temper gave 63.9 Rc but a drastic reduction in toughness to 6.1 ft-lbs, lower than CruForgeV at the same hardness. M2 was similar with 6.2 ft-lbs at 64 Rc, difference between 400 and 1000°F temper was small but 1000°F was slightly better (5.4 vs 6.2 ft-lbs). 52100 was 19.7 ft-lbs at 61.9 Rc (1475°F-300°F), similar to CruForgeV. N690 the worst steel yet at 3.7 ft-lbs though heat treated to 62.6 Rc with likely too low temper of 175°F. Z-Finit keeps giving me high variability in toughness testing for unknown reasons, it got 27.8 ft-lbs at 59.5 Rc but the scatter was extreme.
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It could be that it reaches yet higher toughness at lower hardness. However, the toughness at ~60 Rc was very impressive. I haven’t seen so much deformation in other steels.
 
I’m not surprised! It tested as one of the best from what I’ve done so far. That steel is extremely tough stuff. Ztuff will definitely unseat it though! I made a warranty replacement blade for one of my friends, he works at the mine here where I live. He broke a through hardened blade in 15n20, cutting through some mild metal with a small hammer, snapped the blade in half. I replaced it with 8670, tempered at I think 375, with the spine drawn back. He has yet to break this one!! Larrin, was this one austenized at 1525?
 
Larrin said:
There is a new toughness champion: 8670 with 400°F temper gave 59.7 Rc and 51 ft-lbs. The 175°F temper gave 63.9 Rc but a drastic reduction in toughness to 6.1 ft-lbs, lower than CruForgeV at the same hardness. M2 was similar with 6.2 ft-lbs at 64 Rc, difference between 400 and 1000°F temper was small but 1000°F was slightly better (5.4 vs 6.2 ft-lbs). 52100 was 19.7 ft-lbs at 61.9 Rc (1475°F-300°F), similar to CruForgeV. N690 the worst steel yet at 3.7 ft-lbs though heat treated to 62.6 Rc with likely too low temper of 175°F. Z-Finit keeps giving me high variability in toughness testing for unknown reasons, it got 27.8 ft-lbs at 59.5 Rc but the scatter was extreme.
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I’ll do more N690 with 350, 400, and 450f tempers.

I should do M2 at lower aust temp too.
 
Larrin said:
It could be that it reaches yet higher toughness at lower hardness. However, the toughness at ~60 Rc was very impressive. I haven’t seen so much deformation in other steels.
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I didn’t temper higher than 400f, as the charts suggest it should be Rc56 at that point, not Rc60. I’ll do more samples at lower hardness to see how tough it gets.
 
rodriguez7 said:
I’m not surprised! It tested as one of the best from what I’ve done so far. That steel is extremely tough stuff. Ztuff will definitely unseat it though! I made a warranty replacement blade for one of my friends, he works at the mine here where I live. He broke a through hardened blade in 15n20, cutting through some mild metal with a small hammer, snapped the blade in half. I replaced it with 8670, tempered at I think 375, with the spine drawn back. He has yet to break this one!! Larrin, was this one austenized at 1525?
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Yes, aust @1525f.
 
I found a chart from Crucible for Champaloy that seems to show that "dip" at 59-60, Their numbers said the 400F temper would give you that 61 or so and a Charpy notched reading of 43 lb ft. At 500F, which was 58-60 Rc, it was down to 37 lb ft, but at 600F they said it was at 56-58Rc and 58 lb ft. Interesting stuff.
 
jdm61 said:
I found a chart from Crucible for Champaloy that seems to show that "dip" at 59-60, Their numbers said the 400F temper would give you that 61 or so and a Charpy notched reading of 43 lb ft. At 500F, which was 58-60 Rc, it was down to 37 lb ft, but at 600F they said it was at 56-58Rc and 58 lb ft. Interesting stuff.
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That’s the tempered martensite embrittlement range where the dip is. There is usually a peak in toughness around 400-450F and then you have to get past the TME region to further increase toughness.
 
I was under the impression that L6 did not suffer from TME.
Larrin said:
That’s the tempered martensite embrittlement range where the dip is. There is usually a peak in toughness around 400-450F and then you have to get past the TME region to further increase toughness.
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I will try to make a new chart of some kind. The current one is getting too busy.
 
Larrin said:
There is a new toughness champion: 8670 with 400°F temper gave 59.7 Rc and 51 ft-lbs. The 175°F temper gave 63.9 Rc but a drastic reduction in toughness to 6.1 ft-lbs, lower than CruForgeV at the same hardness. M2 was similar with 6.2 ft-lbs at 64 Rc, difference between 400 and 1000°F temper was small but 1000°F was slightly better (5.4 vs 6.2 ft-lbs). 52100 was 19.7 ft-lbs at 61.9 Rc (1475°F-300°F), similar to CruForgeV. N690 the worst steel yet at 3.7 ft-lbs though heat treated to 62.6 Rc with likely too low temper of 175°F. Z-Finit keeps giving me high variability in toughness testing for unknown reasons, it got 27.8 ft-lbs at 59.5 Rc but the scatter was extreme.
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Can’t remember, Larrin, did Warren went down to 57hrc with 8670, where it has even more toughness?

How amused I’ll be if this “simple” steel reveals to be tougher at 60hrc than 3v at that same hardness, no matter the way it is tempered (high or low temper)!
 
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