Soaking Time for HT 1.2519 steel

N

Natlek

Joined
Jun 9, 2015
Messages
6,182
This data in bold text is from shop where I get this steel . BUT we don't HT plate we bye from them ...in the name of god :mad: We HT knive with specific geometry . Blank on picture is ready for HT , but HOW long to soak ??? It's 5 mm. thick on spine and about 0.6-0.7 mm on edge . So , how long I need to soak this blank for hardening ?? I would / not only I / be very grateful if someone explain this problem . Which thickness we take for reference in determining the soak time ?? Spine or edge ?


Hardening: 830 ° C (holding time 2-3 minutes per mm thickness) / annealing at 170 ° C for 1 h = ca. 62-63 HRC.

332nzow.jpg

8wmqs8.jpg

2gwckma.jpg


PS . Several times I send them email with a question, but they does not answer to me . I'll never get anything out of them again !
 
Yes, 5-10 minutes will do, insert the blade in your furnace only after it reached the target temperature and it is stable; start counting the time after the blade reached the target temperature (you see, it doesn't matter the thickness, soaking time starts with the whole blade in temperature!). I suggest lowering the temperature to 805 °C, try not to go hotter than 815-820 °C. Final HRC after tempering to 175-180 °C should be around 64, and that steel will work wonders at that hardness, but will work very well even at 62 HRC if you feel more comfortable and plan to abuse the blade, in that case rise the tempering temperature to 190-200 °C.
If you have an hardness tester you could confirm it by treating some samples at different temperatures and different soaking times.
 
Thanks a lot Stezann :thumbup: Seems 800 celsius is the magic number for many steel ? Last month I HT blade from Japan made /NSK/ extra clean 52100 chrome steel on 800 celsius + 3 normalizing /book say HT on 840 celsius / It's amazing how good is that steel for knive . And Yes , I'll use a digital oven from friend in the mechanical workshop , they have a Rockwell tester too .. Thanks again !
 
It is indeed a magical number for those steels that have more than .84% carbon and not many alloy elements hungry for it ;)

If the alloy become consistent (think just for example Stainless Steels with a lot of Chromium) then the temperature needs to be way higher since you need to snatch away your needed amount of carbon from the hands of the Chromium carbides...that's roughly why austenitizing temps for stainless are so high.

But if your carbon steel is a simple one, the carbon will be free to go readily where to you guide it, and 800 °C is just about the magic temperature to put in solution just about the eutectoid level of carbon, the amount you need to get maximum hardness from the steel, with negligible retained austenite, and the rest of carbon left in shape of finely dispersed small carbides to aid in strenghtening the matrix and contributing to wear resistance.
 
Finally ................... thanks for the advice guys :thumbup: File skates , no warp ... ... Now I have a work for the winter :) First three from top are 52100 , next one is 80Crv2 and last one is 1.2519


hur1j9.jpg

24v2r1y.jpg

k9e3jd.jpg


PS . I have a question ......HT oven in the picture .... I can not see the heater coil inside? How was it resolved?
 
Last edited:
stezann said:
Yes, 5-10 minutes will do, insert the blade in your furnace only after it reached the target temperature and it is stable; start counting the time after the blade reached the target temperature (you see, it doesn't matter the thickness, soaking time starts with the whole blade in temperature!). I suggest lowering the temperature to 805 °C, try not to go hotter than 815-820 °C. Final HRC after tempering to 175-180 °C should be around 64, and that steel will work wonders at that hardness, but will work very well even at 62 HRC if you feel more comfortable and plan to abuse the blade, in that case rise the tempering temperature to 190-200 °C.
If you have an hardness tester you could confirm it by treating some samples at different temperatures and different soaking times.
Click to expand...

Here it is after one hour on 170°C and file still skates .... I'm good ? I'm afraid little , this one is for me ..... :) There's only a little pale yellow color ...?

oizu6x.jpg
 
Last edited:
The colors on the blade mean nothing. They are just surface oxides. I often get rainbow colors. That is for "drawing a color" when torch tempering blades and tools. It is very inaccurate. A file should skate on most hardened blades, even after temper. SAt 170C you have arely tempered it at all. It is probably only a point lower than as-hardened. I would temper at 190C as a minimum.
 
Stacy , is it okay if I tomorrow do another tempering at 190 °C ? I have some spray -70°C which I use in the service and I sprayed blank .....It is now in deep freeze in the fridge . I have no idea whether I do right thing with that ? Sorry to bother you :(
 
170C or 350F temper should give Rc62-64, about right for this steel. 190C would work, but the beauty of this steel is how well it behaves at high hardness. I have two 4"(100mm) blades I am testing in the kitchen now that were tempered to Rc64-65(12 point check, no readings lower than 64.5). Sharpen to a thin edge and slice almost anything all day long. I would suggest if doing a kitchen knife, get some 1.5mm or 2.0mm thickness stock.
A visit to the freezer won't hurt a thing, just let warm to room temperature before putting in a 150C oven for an hour or so.
I wish Aldo or Chuck at AKS would sell this steel, it is imported by Bestar. It is comparable to Aogami 1 and Aogami 2 in that it has similar carbon and tungsten but double the chrome and 0.25 vanadium as a cherry on the top. Typical composition C:1,15%/Mn:0,4%/W:1,4%/Cr:1,3%/V:0,25%

scott
 
If you don't intend to abuse the blade (and you shouldn't with 1.2519) go and sharpen it with stones and water...then see if the edge chips, only in that case bake it at 198-200 °C.
Consider that especially in the edge you have a lot of decarburation to dig into before the actual performance surfaces
 
Thanks Scott , thanks Stezann , I'll do as you say :thumbup: Now I have a lot to hand sanding from both side to get 0.3mm on the edge . I tried a bit and it looks like that will be no easy task .....
 
Natlek said:
Thanks Scott , thanks Stezann , I'll do as you say :thumbup: Now I have a lot to hand sanding from both side to get 0.3mm on the edge . I tried a bit and it looks like that will be no easy task .....
Click to expand...

rather than hand sand to get the edge down, use a coarse silicon carbide stone like Norton Crystolon
 
I finally finished this knive .I left as it is in hardness . I decide to do hard chrome so I sandblasted blade . . . . but then I change my mind and here we are............. wood is a black ebony and for bolster I use combination of bronze - stainless- copper . Thanks again for your help and I like to hear what do you guys think about this knive ? I'm making progress in this new hobby or . . . :)

q5SehI3.jpg

jG9FGzS.jpg

0OOsyjT.jpg

QCZ4UlV.jpg

MeeGjLY.jpg
 
Thank you ! The total length of knive is 25.5 centimeters . From tip to bolster is 13.5 centimeters which mind handle is exactly 12 cm. /bolster + wood / It s lying good in my hand . . .
And if anything means,balance is exactly on the bolster ?
 
It is a beautiful knife! It is difficult to tell from the pictures, but if you are going to keep it for yourself as a user, i'd thin the edge with whetstones down the road, blending it into the main bevel. The steel you used would allow it.
I really like the line you gave to your knife, it's really craving for the hunting season!!
 
Thanks stezann ,I'm glad you like it :thumbsup: Yes , this one is for me .The first plan was to hard chrome this blade . that s why I grind full flat.But I change my mind ...... I would have grind it convex if I know that will not do hard chrome . Now is about 0.30 - 0.35 mm. behind edge , angle is 15-16 degree per side . When needed in future I'll sharpen it as if it's convex grind :)
PS. For the hunting season I am buying Strasser RS 05 .... 7mm. Rem.Mag. or .30-06 . I just wait for approval ;)

ic6n02s.jpg
 
You must log in or register to reply here.
Back
Top