VG-10 temper

[Steffen Dahlberg]

A year ago I was given a kitchen knife in VG-10.
I like it in many ways, but it's a bear to hone. The alloy supposedly has great edge retention, but in my opinion the edge that "keeps" is a semi-sharp one.
Therefore I'm sharpening so often anyways that I'm thinking I don't really have any use of this alloy and its hardness. And it's wearing on my hones.
It's written 60hrc on the side of the blade.
Would I be doing a silly thing if I took it back to, say, 58hrc?
Tempering charts for this alloy seems to be kept secret, what temperature would give 58?

[B. Norris]

What angle do you sharpen this blade at? Stainless steels, in general, have lots of large carbides that will easily rip loose from an edge sharpened at shallow angles. When they do tear free, it leaves behind a dull, ragged edge. This phenomenon is why stainless steels have a reputation for not taking a keen edge. Sharpening at a steeper angle, 30 degrees is what I've seen recommended, will provide more metal at the edge to support the carbides and the edge will last much longer. Reducing the RC hardness of the steel will do nothing to change the hardness of the carbides, it will not change the steels resistance to abrasion because the carbides are mostly responsible for this property in stainless steels. Tempering the blade softer will not really make it much easier to sharpen because of all those, large, carbides that are present in stainless steels. Try put a micro-bevel on the edge that you have, at a more obtuse angle, and then use the knife for awhile and see how it does. You have nothing to loose trying this except a little bit of time.

 

Bruce

[Steffen Dahlberg]

Thanks, Bruce!
I think I'm approaching 30^o , freehand. I was actually about to grind it back to 20-25 to ease honing.
Now I'm thinking I should rather make or buy a carbon steel chefsknife, and use the vg10 one for cutting carrots.

[B. Norris]

How do you generally use your knives? Occasional use at home or professional soux chef? What motivates your desire for a sharp edge? What knife, or steel, would work best for you will depend upon how the knife will be used. For home use a plain, carbon steel will be the best value. If stainless steel is a requirement (say you fillet fish for a living) you might want to look into one of the 3rd generation powder metallurgy steels from Bohler-Uddeholm, such as Elmax. The particle size of the powder used to make the ingot is so small that it is said to prevent the formation of large carbides, thus making it capable of taking an edge like a plain, carbon steel.

 

Bruce

[Steffen Dahlberg]

It's only home use.
Daily and frequent use on vegetables, and for that it would stay sharp enough for months.
Thing is we really like sushi and fish carpaccio, so it gets a weekly tuneup to shaving mode.

Quite obvious I need another knife

[B. Norris]

One more thought. What abrasive are you using to sharpen the VG-10 knife? All those carbides that stainless steels have are just as hard, or harder, depending on the carbide, than aluminum oxide. I use diamond abrasives exclusively to sharpen stainless steels for this reason.

 

Bruce

[Steffen Dahlberg]

I use DMT mini-hones. These: https://www.lie-nielsen.com/product/blade-sharpening/dia-sharp-mini-hone-coarse?node=4203
I really like them, they are very versatile and usually long lasting. When the green 9 micron is a bit worn it will act almost like a polisher. They are not too happy about this knife, tho, even with a silk touch.
There's no way I'd put any knife to any of my bench stones, exept maybe if I forge a hollowed scissoredged sushi knife.

Edited February 24, 2015 by Steffen Dahlberg

[deker]

My guess is that with the carbide tearout at the edge that VG10 would server better for protiens than veggies. Have you tried using it on your meats? You may find that it works well and holds a "useful" edge longer for meats.