Is Blue Super Steel Actually Super? The Facts about Tungsten-Alloyed Steels

[DevinT]

Thank you - I did read it. My question is more about damaging the steel through forging, not being hot short. I'm wondering if the multiple heats of forging could potentially create an overly coarse carbide structure that would still be there in the finished knife.

Only if you forge at too low temps. One of the charts shows the temperature at which the carbides dissolve.

Hoss

 

[scott.livesey]

Stuart, I think that the timber industry still uses those tungsten saw steels, but the metal cutting job has supposedly gone to more "standard" high speed steels. Bestar list 1.2419(?) and 1.2519 for sale.

you see more and more 'bi-metal' blades for metals and wood, a thin layer of HSS welded to other steel. 1.2419 would make an interesting knife. basically upgraded O1. 1.05% carbon, 1% manganese and chrome, 1.2% tungsten. here is a link http://steelselector.sij.si/steels/MERILOEX.html. last time I checked Bestar was still importing both, but smallest piece was 3/32"x2'x6'.

 

[jdm61]

I think that it is more accurate to say that Bestar CAN import those steels. I have been told that they will or perhaps may throw an extra couple of sheets in with an order already coming from Germany. The other steel that they have that would be of interest to Damascus makers is 02.

you see more and more 'bi-metal' blades for metals and wood, a thin layer of HSS welded to other steel. 1.2419 would make an interesting knife. basically upgraded O1. 1.05% carbon, 1% manganese and chrome, 1.2% tungsten. here is a link http://steelselector.sij.si/steels/MERILOEX.html. last time I checked Bestar was still importing both, but smallest piece was 3/32"x2'x6'.

 

[Larrin]

Thank you - I did read it. My question is more about damaging the steel through forging, not being hot short. I'm wondering if the multiple heats of forging could potentially create an overly coarse carbide structure that would still be there in the finished knife.

With steels that have carbides stable at high temperatures there is an optimum temperature range where the carbides are most effectively refined. Too high temperature leads to coarsening and too low leads to segregation. Tool Steels recommends a relatively low forging temperature of 1900F and I believe that is because there are issues with cracking at higher temperatures. So 1900F is probably a good starting point; that shouldn’t be so high as to lead to excessive coarsening.

 

[samuraistuart]

Larrin, I don't have a Rockwell tester, but as quenched 1.2442 is 65+. I do use P50, and 1490°f 10 minute soak. Interesting about the cementite vs WC. I have this thing in my head that I need more carbide % and wear resistance in a kitchen knife, but that isn't really necessary, is it? After all, our food isn't abrasive, otherwise our teeth would be little knobs. Maybe what is more important in a kitchen knife isn't wear resistance, but edge stability, because usually the wear/tear on a kitchen knife is from it's cutting board and bad storage habits (sliding against other stuff in the drawer). I guess there is a line where the carbide % and size is too great for thin edge geometries, and you're saying it's best to have little cementite %, but larger WC %. I can understand that, if I have you right. So I guess what you would recommend for a real "Blue Super" steel would be a lower carbon % (say 1.1% vs 1.45%), but with the same, or maybe higher, Tungsten count? I'm just spitballin. here.

 

[Larrin]

Larrin, I don't have a Rockwell tester, but as quenched 1.2442 is 65+. I do use P50, and 1490°f 10 minute soak. Interesting about the cementite vs WC. I have this thing in my head that I need more carbide % and wear resistance in a kitchen knife, but that isn't really necessary, is it? After all, our food isn't abrasive, otherwise our teeth would be little knobs. Maybe what is more important in a kitchen knife isn't wear resistance, but edge stability, because usually the wear/tear on a kitchen knife is from it's cutting board and bad storage habits (sliding against other stuff in the drawer). I guess there is a line where the carbide % and size is too great for thin edge geometries, and you're saying it's best to have little cementite %, but larger WC %. I can understand that, if I have you right. So I guess what you would recommend for a real "Blue Super" steel would be a lower carbon % (say 1.1% vs 1.45%), but with the same, or maybe higher, Tungsten count? I'm just spitballin. here.

Yes lower carbon for a given tungsten content. You don’t want more cementite anyway because it doesn’t add very much to wear resistance. If you want more carbide you should have WC instead.