C150 quenchant?

[Andi B.]

Hello ,

 

I'm currently thinking about, how to quench a tanto sized stock removal blade made from carbon steel (C105, 1.05% carbon) creating a detailed and designed hardening line by using clay.

[Probably I won't cover the back with clay to minimize the bending by creating a "martensite opponent" to the edge.]

 

I waver between

 

1) quench completely in warm water

Will the blade crack? How big is the risk? Is it calculated risk or suicide?

I have quenched steel with 0,75% C successfully but never tried C105 in water.

 

2) quench completely in oil

Oil will not crack the blade but the hardening line will be not detailed enough and too near to the edge.

I tied this with a C105 blade three times and the line was nonsatisfying.

 

3) quench first in water, than quick change to oil

This is what I have finally done with the first C105 blade. The result was a kind of double line - hard to describe and not really what I want. Maybe not long enough quenched in water? How long?

 

Any suggestions?

 

Or can it be, that steel with C > 1% is not suitable for detailed hardening lines because it requires oil as quenchant?

 

Thank you!

[kb0fhp]

I think that quenching 1.05%C steel in water is asking for cracking. As a general rule, steels with a carbon equivalent greater than 0.52 are prone to cracking unless special precautions are taken.

 

What oil did you quench in? I would recommend a very fast oil - but even then the risk is large that the part will crack.

[Doug Lester]

It depends on what else is in the steel. If it's a plain steel (just iron, manganese, and carbon) or a shallow hardening low alloy steel you could get by with water. I prefer brine, however, because it prevents bubbles of steam holding on to the blade causing uneven hardening, although brine is a harsher quenchant.

 

Doug Lester

[Jeremy Vaught]

I know a lot of more experienced guys/gals do it, but I have never been successful in water. Crack 'em every time. I've been doing nothing but vegetable oil for quite some time now and get a real nice quench line. I'm not familiar with your steel. Is there something else in C105 that might prevent the line from showing as well?

 

If I was going to go with water, I'd probably want to bring it up to just below boiling before the quench. The most frustrating thing in knife making for me has been being happy/excited about a design and then cracking the damn thing.

 

Good luck!

JV

[matt venier]

Hey Andi

I've done a a decent amount of W2 and W1 blades in the warm water for three to five seconds then into hot oil (300-400F) for an hour. I have cracked one or two blades out of maybe thirty so it isn't 100% safe but I have gotten some pretty detailed hamon.

http://www.bladesmithsforum.com/index.php?sh...pic=9419&hl

 

I also try to keep my austinizing temp low and soak for 10 minutes or so if you have the capability

[jake cleland]

i would go with the two stage quench, hot water then a fairly slow oil. do you have a TTT diagram for your steel? the way i see it you want to get past the pearlite nose, and preferably to ms (the martensite start point) in the water and then straight into oil for the transformation. my guess is that if the hamon is low in oil, then you'll want about 3 seconds in the water. i quench 1095, which has almost as much carbon, nearly exclusively in water, without much of a failure rate. if you do water quench, you should shoot for the lowest possible astenising temp, and a long soak, to get a detailed hamon. you should also find out if your water supply is soft or hard, and if it's hard use rain water. obviously, get everything smooth and even, normalise thouroghly etc. it sounds like you're trying to get the hamon to follow a specific clay line? if so, and you're not bothered about surface phenomena like ashi or yo, you could try leaving your edge very thick, 3.5mm say, and hope this inhibits its desire to crack.

 

alternitively, go with an oil quench, and bump the temperature up quite a bit - 75 to 100f. you want to soak at the lower temp and then go hotter for the shortest possible time, to try and prevent too much grain growth. i've had some success with this on 1095 and a couple of other steels which produce a low hamon in oil, but it never turns out as nice, and i only do it when i cant have sori. (oil will cause the blade to curve down, not up.) in oil, i leave off the clay wash on the edge, it doesn't seem to speed up the quench as it does in water, and ( i havent tried this, because it just occurred to me, but i plan to ) you could try just putting a bead of clay where you want your habuchi and not covering anything above it - the steel seems shallow hardening enough that it wont harden on the spine in oil no matter what you do, and i think the thermal mass of the clay is what stops it hardening as high as you want.

 

these are only suggestions, and i am by no means an expert, but they might help.

 

and remember that producing hamons is never guaranteed; embrace the fear, enjoy the process, never fall in love with a blade before the second temper, and have a couple of beers chilling for after the quench, however it turns out. good luck.

Edited December 11, 2008 by jake cleland

[Mike Krall]

Have any of you who want very fast quench mediums tried ultrasonic vibrators on fast quench oil? Supposedly eliminates vapor stage. Would it be of any help?

 

Mike

[Andi B.]

@ Jeremy:

 

C105 is (www.metallograf.de):

 

Material number 1.1545 - C105W1 / C105U

 

Composition in % :

C 1,00 - 1,10

Si 0,10 - 0,25

Mn 0,10 - 0,25

P max. 0,020

S max. 0,020

 

Range of application and heat treatment :

Unalloyed Tool steel : stamp , planing tools , stamping dies , shear blade

Hardening : 770 - 800 °C (water)

Soft annealing : 680 - 710 °C

 

 

Here some of my results:

 

CK75 in hot water:

 

 

CK75 in oil (or maybe water/oil - I'm not sure):

 

C105 in oil:

 

and same C105 blade in water, then oil:

Edited December 11, 2008 by Andi B.

[GEzell]

Have any of you who want very fast quench mediums tried ultrasonic vibrators on fast quench oil? Supposedly eliminates vapor stage. Would it be of any help?

 

Mike

I was planning something along those lines next time I quench 1095, Tai Goo has been doing it for awhile I believe. I have an old electric toothbrush, taped to the quench tank it should keep the oil agitated, at least.

[jake cleland]

well, it looks to me like it'll quench well enough in oil, with a thinner clay coat (1/16th to 1/8th inch) and a slightly longer soak time. nice blades by the way, i really like the sugata on the 1st and 3rd.

Edited December 11, 2008 by jake cleland

[Greg H.]

Noob question:

 

What about just pouring the oil on the water.

 

Then plunge the blade through the oil into the water, then pulling it up into the oil as needed?

[Mike Krall]

I was planning something along those lines next time I quench 1095, Tai Goo has been doing it for awhile I believe. I have an old electric toothbrush, taped to the quench tank it should keep the oil agitated, at least.

 

I'd love to hear about that when it happens...

 

Mike

[B. Norris]

Composition in % :

C 1,00 - 1,10

Si 0,10 - 0,25

Mn 0,10 - 0,25

P max. 0,020

S max. 0,020

Most of what we get here in the States has higher manganese than your C105.

1095 C .90/1.04 Mn .60/.90

1075/1080 C .70/.88 Mn .40/.90

The least Mn I've seen has been around 0.25 - 0.30 but, you have to search to find it that low.

 

~Bruce~

[Eastvillage]

In Europe we have more low manganese steels. A very easy obtainable steel is 1.2210 (silver steel):

 

C - 1.10-1.25

Si - 0.15-0.30

Mn - 0.20-0.40

P - less than 0.030

S - less than 0.030

Cr - 0.5-0.8

V - 0.07-0.12

 

Although it has added ingredients compared tot C105 it also produces some nice hamons. I water quench it.

[John Smith]

Maybe it is me but I quench all my blades in water, except O-1 and 5160 which go into oil. I have never done a double quench in water then into oil. I think where some go wrong when using water is they get the steel to hot. And this will lead to cracking and large grain growth. I really try hard to control my temps keeping the heat treat oven around 1550 F.

 

Maybe I am just lucky, I do warm the water a bit to take the edge off so I am not quenching in 30 F water.

Edited March 3, 2009 by John Smith