Forged file falling apart!

[Jan Ysselstein]

Your water may be too cold or temp too high on those blades? The one with the sheared edge looked like my little tanto but add about 4 more shears on it. As for the water getting too hot, for water quenching the waters temp doesn't matter as long as its not cold. And the hot water also seems to be a plus for sori compared to cold water. I quench all mu blades except for my 5160 and 9260 in water because thoae seem to be finicky in water compared to 52100. And my clayed blades so far have been a disaster. I may have to sacrifice to the god of heat treating or catvh the water gremlins. :unsure:/>/>/>/>/>/>/>

 

 

Steven,

The water temperature of about 75 F should be about .75 the rate of cold water (1.) as the temperature goes up the effective cooling rate goes down. The reason for the cracking in the picture seems to be a hesitation when quenching the steel..I went in to about 1/3 of the front of the blade , paused, and finished..only to make Aldo smile....after that the rest went well. At this point it is 4/6 successful quenches..I have no idea as to how well the hamon on this steel will develop..I do not have time to play with it. By the way there is some sori noticable.

 

The three blades in the picture seem ok, a file skids off the edge and grabs at the back....this is a bit of a subjective test..the blades are not glass hard but the file does not want to grab. I worry about grinding a hardened blade and not softening it by heat. Below is a photo of the quench line on one of the clayed blades...the back still has to have the clay removed. I will grind the 3 blades this evening. I am hoping those ( especially beginners) who want to try an old file as a blade will get something from this and not be afraid to forge a file, should they like to take a risk, quench it in water.

Jan

 

Edited December 22, 2012 by Jan Ysselstein

[Jan Ysselstein]

Steven,

The water temperature of about 75 F should be about .75 the rate of cold water (1.) as the temperature goes up the effective cooling rate goes down. The reason for the cracking in the picture seems to be a hesitation when quenching the steel..I went in to about 1/3 of the front of the blade , paused, and finished..only to make Aldo smile....after that the rest went well. At this point it is 4/6 successful quenches..I have no idea as to how well the hamon on this steel will develop..I do not have time to play with it. By the way there is some sori noticable.

 

The three blades in the picture seem ok, a file skids off the edge and grabs at the back....this is a bit of a subjective test..the blades are not glass hard but the file does not want to grab. I worry about grinding a hardened blade and not softening it by heat. Below is a photo of the quench line on one of the clayed blades...the back still has to have the clay removed. I will grind the 3 blades this evening. I am hoping those ( especially beginners) who want to try an old file as a blade will get something from this and not be afraid to forge a file, should they like to take a risk, quench it in water.

Jan

 

 

 

Just to review the causes of thew two failures ( I think )

One blade cracked because it was heated to too high a temperature, and the blade was too thin for quenching (blade 1)

One blade cracked because the quenching motion was not smooth and rapid (blade 4)

 

The blades are not finished ground yet..... I am a little surprised at the hardness and strength of pearlite ( rapidly formed pearlite). The backs of these blades are pretty hard ..one blade is especially hard (edge and back) ( I am not sure if it is the one which was heat treated twice or not). I will do a multiple quenching/tempering cycle test soon as I still have about 6 blades to begin processing. During the hardening heat, I made sure the back was fully heated to help absorb the shock of the martensite transformation.

 

? Is this the normal structure of a clay quenched blade? ? Do people soften the back edge after quenching?

 

Jan

Edited December 24, 2012 by Jan Ysselstein

[Steven Gillespie]

The blades are not finished ground yet..... I am a little surprised at the hardness and strength of pearlite ( rapidly formed pearlite). The backs of these blades are pretty hard ..one blade is especially hard (edge and back) ( I am not sure if it is the one which was heat treated twice or not). I will do a multiple quenching/tempering cycle test soon as I still have about 6 blades to begin processing. During the hardening heat, I made sure the back was fully heated to help absorb the shock of the martensite transformation.

 

? Is this the normal structure of a clay quenched blade? ? Do people soften the back edge after quenching?

 

Jan

 

This should be discussed on another post so its easier to find. But, I don't soften the back, the spine should be rather soft compared to the edge, for my clayed blades, I've never done more than a flash temper, sometimes twice for a real hard blade, or if it curves too much. I've been using hot water now for my blades, and my luvk has changed. I have yet to clay a blade again, but I will soon.

[Jan Ysselstein]

This should be discussed on another post so its easier to find. But, I don't soften the back, the spine should be rather soft compared to the edge, for my clayed blades, I've never done more than a flash temper, sometimes twice for a real hard blade, or if it curves too much. I've been using hot water now for my blades, and my luvk has changed. I have yet to clay a blade again, but I will soon.

 

 

The list of reasons why the blades have cracked has been edited.

 

Aldo,

The steel in question ( we are not 100 % sure of the composition) will produce a very nice hamon. I was able to rough polish one side of a blade and it allowed me to see which clayed blade in the photo above I was handling....the steel is very fine grained and it was quenched from a low temp, but the hamon will be very nice . The remaining question for the steel is performance.....performance is the main criterion here, so if you have a testing suggestion ( for knife blades) let me know. Right now all I have a Japanese knife maker at a Japanese flea market (youtube) . I will post a link when I find it again.

 

 

Steven,

I find this topic the ideal place to find file steel metallurgy, both you and Scott have a lot of experience here why not post about it .....this is one steel the manufacturer must tightly test for compliance to spec and it is available to many of us in our sheds or flea markets. There are a lot of why?s associated with the selection of this steel by Nicholson.( and us) .and these will be fun to explore. Why does it behave as it does... How did Nicholson heat treat this steel?

 

Jan

Edited December 24, 2012 by Jan Ysselstein

[Steven Gillespie]

I learn mostly the hard way, more or less what to do and what not to do, and then research how and why it will happen. I just thought it would be easier to surf around on the beginner's section, but you have a good point, I thinking requirements of the steel are mostly high hardness, with a good toughness for the small teeth, while keeping heat treating very quick, cheap and simple. I've seen some files made before, and they appear to be using brine, with a very slight temper afterwards. I'm still looking for a better source for the steel of this composition to mess with and look at how well it forge welds to wrought or mild, as well as longer blade lengths, and hamon appearance.

[Jan Ysselstein]

I learn mostly the hard way, more or less what to do and what not to do, and then research how and why it will happen. I just thought it would be easier to surf around on the beginner's section, but you have a good point, I thinking requirements of the steel are mostly high hardness, with a good toughness for the small teeth, while keeping heat treating very quick, cheap and simple. I've seen some files made before, and they appear to be using brine, with a very slight temper afterwards. I'm still looking for a better source for the steel of this composition to mess with and look at how well it forge welds to wrought or mild, as well as longer blade lengths, and hamon appearance.

 

Steven,

I do a bit of learning that way myself...but at times I pay dearly for it..I like to go to the books because steel has been so well studied.

 

Aldo,

I am not sure you will ever get this steel produced, in any case, the hamon it produces (water quench under 800 Deg C 10 min. soak , into 25 Dec C water) is beautiful, attached is a sample of a roughly polished blade.. Once I tune into how to photograph them and produce them I will post another picture. I need to make a smaller knife or recreate the form from a file to an ingot as I find the file too limiting.

Jan

 

Edited January 4, 2013 by Jan Ysselstein

[Steven Gillespie]

You can always forge weld multiple files together of the same shape, size and brand.

 

Also, its not a matter of getting it produced, more of a matter of sourcing the steel for our uses. The steel is actually everywhere, but has been made into files.