steel? - SKH40...

D

dirc

Joined
Jan 31, 2018
Messages
2,970
You know you've been spending too much time reading metallurgy when:
(...this can get to be an addiction :p (And I don't even spend thousands on knives like some of us))

So I came across this steel, just reading random stuff, and thought, wow. The numbers look good, but no one seems to use it for knives... maybe I'm wrong?

http://www.steel-grades.com/Steel-Grades/Tool-Steel-Hard-Alloy/SKH40.html
or
http://zknives.com/knives/steels/skh40.shtml

it has a LOT of tungsten and cobalt (not to mention vanadium)... so I'm guessing it's rather expensive?
 
I have a few home made knives in M3, which is similar to skh40 minus the 8% cobalt.
 
Thanks for pointing that out... I thought it looked somewhat familiar. However, 8% cobalt is big change... esp for the yield strength: M3 is 274 Rp0.2 (MPa) vs 744 in SKH40

it's interesting that these types of steels are used for high temperature areas like turbine blades, and also used in prosthetics as the cobalt is said to help wear resistance

from cobalt's wiki page:

Cobalt-based superalloys have historically consumed most of the cobalt produced. The temperature stability of these alloys makes them suitable for turbine blades for gas turbines and jet aircraft engines, although nickel-based single crystal alloys surpass them in performance. Cobalt-based alloys are also corrosion and wear-resistant, making them, like titanium, useful for making orthopedic implants that don't wear down over time. The development of wear-resistant cobalt alloys started in the first decade of the 20th century with the stellite alloys, containing chromium with varying quantities of tungsten and carbon. Alloys with chromium and tungsten carbides are very hard and wear-resistant. Special cobalt-chromium-molybdenum alloys like Vitallium are used for prosthetic parts (hip and knee replacements). Cobalt alloys are also used for dental prosthetics as a useful substitute for nickel, which may be allergenic. Some high speed steels also contain cobalt for increased heat and wear-resistance. The special alloys of aluminium, nickel, cobalt and iron, known as Alnico, and of samarium and cobalt (samarium-cobalt magnet) are used in permanent magnets. It is also alloyed with 95% platinum for jewelry, yielding an alloy suitable for fine casting which is also slightly magnetic.
 
I also have home made knives in m35 (5% co), m42 (8% co), and T42 (10% co). Spydercos hap40 and maxamet have cobalt, 8.5 & 10%.
I would welcome any hss, cobalt or not. It's by far my favorite class of blade steel.
 
HSS ................ Like ! They cut and cut and cut .............they never get tired :) I just grind this one ..... 3mm thick M42 and 68 HRC ....it is almost stainless , too ;)

Ja7fkE6.jpg

G28OpIt.jpg

EKMzuiY.jpg
 
Natlek said:
HSS ................ Like ! They cut and cut and cut .............they never get tired :) I just grind this one ..... 3mm thick M42 and 68 HRC ....it is almost stainless , too ;)

Ja7fkE6.jpg

G28OpIt.jpg

EKMzuiY.jpg
Click to expand...
GET A HANDLE ON THAT BABY! :D

Cool knife Natty
 
nice, how much does one of those sawblades cost you? I'm guessing you do a full HT regime after shaping?
 
dirc said:
nice, how much does one of those sawblades cost you? I'm guessing you do a full HT regime after shaping?
Click to expand...
I get them for free from my friend , he cry when they break but I m happy :( I don t think that it is easy to HT HSS steel .I grind them as they are , hard. Ceramic belt and crazy fast speed eat this steel like cake .It take me one hour for this knife , to cut ,shape ,drill holes and to grind blade bevel ;)
You can buy power hack saw blade 575 x 50 x 2.50mm. HSS Cobalt (AISI M35) for about 70 euro .M2 HSS is much cheaper .You can buy new circular saw blade from M42 HSS steel / not sharpened / for good price .
 
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