Call for Charpy toughness samples

[hugofeynman]

@Stacy E. Apelt - Bladesmith is working on some salt pot samples from a salt pot that @mete donated. We should get some interesting results from that.

Great news! Let’s throw some bainite to those charpy tests! Results will be really interesting, to say the least! It would be great to test 1095, 5160 and 52100 to full lower bainitic transformation and, of course, L6.

Never heard of PM steels heat treated to bainite. Would it, in theory, be possible and reach a useable hardness or RA would be too high to even try?

 

[Willie71]

Perfect! A8mod it’s probably the one I prefer, if I have to choose only one steel. Can’t wait for those results!

I did the one sample you sent. I’ll try a few different hardnesses. I used the slow ramp as prescribed by the data sheet, and Chuck’s experiments show its needed, to reach full hardness. I’m curious about this steel. It’s not crazy expensive like z-tuff.

 

[Larrin]

Never heard of PM steels heat treated to bainite. Would it, in theory, be possible and reach a useable hardness or RA would be too high to even try?

PM steels are almost universally air hardening meaning they would either take way too long to form bainite or never would form 100%. Forming some fraction of bainite would be possible, probably.

 

[Michael.Drinkwine]

30 pieces of AEB-L finally headed Larrin's way. HRC listed on sheet is the average of 3 tests on the end of the coupon.

I am now set up to machine samples if anyone needs me to, just PM me for my address if you are interested. If you get them to me then I will grind them and cover shipping them to Larrin.

Willie71 you might be interested to see that the 1750f Prequench/1975f Aust/300f temper gave a solid 65 HRC. I don't think there was anything more to get there. Looking forward to finding out how tough it is!

Michael

 

[jdm61]

The salt pot tests should be interesting. IIRC, Kevin Cashen did the 1475 austenizing for 52100 using high temp salt, but Parks AAA for the quench instead of low temp salt like he uses for his O1 and L6 blades.

 

[Willie71]

30 pieces of AEB-L finally headed Larrin's way. HRC listed on sheet is the average of 3 tests on the end of the coupon.

I am now set up to machine samples if anyone needs me to, just PM me for my address if you are interested. If you get them to me then I will grind them and cover shipping them to Larrin.
View attachment 1074772
Willie71 you might be interested to see that the 1750f Prequench/1975f Aust/300f temper gave a solid 65 HRC. I don't think there was anything more to get there. Looking forward to finding out how tough it is!

Michael

This is great! We are really honing in on the most we can get from steels. I appreciate your effort! Anything above Rc64 with aeb-l is worth mentioning, especially after temper. DevinT can comment on this. He is the aeb-l guru. JTKnives is also well versed in aeb-l heat treatment.

Warren.

 

[cotdt]

I'm surprised that AEBL can even get this hard. Other stainless steels have much more carbon and doesn't get as hard. It would be great to have a more wear resistant stainless steel that can get very hard and be tough like AEBL.

 

[Michael.Drinkwine]

I'm surprised that AEBL can even get this hard. Other stainless steels have much more carbon and doesn't get as hard. It would be great to have a more wear resistant stainless steel that can get very hard and be tough like AEBL.

Remember that % of carbon in steel has several jobs, making martensite (hardness) and making carbides (wear resistance). AEB-L doesn't have any excess carbide formers to lock up the carbon, so it can mostly go to hardness. Compared to 440C that has a huge amount of Chromium that locks up the carbon so doesn't have as much free for making Martensite.

 

[jdm61]

It is kind of odd. I would like to see a "carbon" steel with similar carbon levels tested. The hardness is a bit puzzling. When I think of something "comparable," like maybe 5160, I don't think of it getting that hard. Do you think that 1075 might?

I'm surprised that AEBL can even get this hard. Other stainless steels have much more carbon and doesn't get as hard. It would be great to have a more wear resistant stainless steel that can get very hard and be tough like AEBL.

 

[Larrin]

AEB-L has around 0.4-0.5% carbon in solution at peak hardness. The high chromium in solution gives it a lot of solid solution strengthening and tempering resistance that low alloy steels don't have. 1060 can reach about 65 Rc without tempering.

 

[jdm61]

if you look at "almost stainless" D2 it has 12% chromium and AEB-L has only 13%, just barely enough to be considered stainless. But D2 has other carbide formers and over twice as much carbon. What a difference.

Remember that % of carbon in steel has several jobs, making martensite (hardness) and making carbides (wear resistance). AEB-L doesn't have any excess carbide formers to lock up the carbon, so it can mostly go to hardness. Compared to 440C that has a huge amount of Chromium that locks up the carbon so doesn't have as much free for making Martensite.

 

[Kentucky]

AEB-L has around 0.4-0.5% carbon in solution at peak hardness. The high chromium in solution gives it a lot of solid solution strengthening and tempering resistance that low alloy steels don't have. 1060 can reach about 65 Rc without tempering.

We use a lot of 1060 for tool making and that’s been my exp. it has a higher as quenched hardness than most people think

 

[Kentucky]

I’d kinda like to see a comparison between say carpenter L6 and Champaloy or Republic L6 with Moly. See if that Moly makes a noticeable difference in the finished product

 

[Larrin]

I’d kinda like to see a comparison between say carpenter L6 and Champaloy or Republic L6 with Moly. See if that Moly makes a noticeable difference in the finished product

The Mo is primarily for hardenability but characterizing the difference in toughness would be fun.

 

[Kentucky]

The Mo is primarily for hardenability but characterizing the difference in toughness would be fun.

Dosnt it also have a bit higher temper hardness? I mean a bit harder at say 400 than without Moly?
Sure air hardens to a good degree

 

[Larrin]

Dosnt it also have a bit higher temper hardness? I mean a bit harder at say 400 than without Moly?
Sure air hardens to a good degree

Probably. Haven’t compared the data sheets recently.

 

[Willie71]

Finally back at it today. Dewar is full, the shop isn’t freezing. I’ve got A11, additional M2, additional 3V, additional N690, M4, Elmax, and additional z-wear in the oven.

Edit: it’s not M4, but 4V in the oven. My mistake. M4 should be Saturday.

 

[DevinT]

Finally back at it today. Dewar is full, the shop isn’t freezing. I’ve got A11, additional M2, additional 3V, additional N690, M4, Elmax, and additional z-wear in the oven.

That’s old news, you post something similar every week.

Thanks

Hoss

 

[Willie71]

That’s old news, you post something similar every week.

Thanks

Hoss

It’s been 3-4 weeks since I’ve been in the shop. I’ve been down with the flu, and it went down to -37c a few weeks back.

 

[Willie71]

Larrin , I meant to ask. I’ve heard conflicting reports regarding the need to do the pre soaks at 1250f and 1550f in thin cross sections like ours. I only have one oven. I’ve been ramping at max, but is this needed? I can do some test samples to tease this out, if needed.