How they are made - the laminated (cladded) blades

Z

Zagorov

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Jan 2, 2015
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Guys - have you ever wondered how are the laminated (cladded) blades made (the SuperBlue and HAP40 blades for instance)? I am just curious...

Noticed on several ones that between the core and the sides there is a very thin bright layer, looks like nickel... How are the layers joined? Any ideas?
 
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There are different methods used by different factories. It does require that both steels be comparable in heat treat.

sal
 
When making damascus, i.e. pattern-welding, they basically heat the layers and squeeze them or hammer them together. I'm not sure if there is anything else they do to make the layers bond. I recall seeing a documentary where they created layered steel using explosives- they put the 2 layers of steel together, put explosives on top of the top layer, and detonated it. I don't recall if this was a specialized manufacturing technique or something experimental.
 
Sal Glesser said:
There are different methods used by different factories. It does require that both steels be comparable in heat treat.

sal
Click to expand...

Can you share what is the process for your blades, if that's not too much to ask, and you will not give away any trade secret?

I am particularly interested in HAP40/SUS410 and SuperBlue/420J2 since I have these :D
 
bdmicarta said:
When making damascus, i.e. pattern-welding, they basically heat the layers and squeeze them or hammer them together. I'm not sure if there is anything else they do to make the layers bond. I recall seeing a documentary where they created layered steel using explosives- they put the 2 layers of steel together, put explosives on top of the top layer, and detonated it. I don't recall if this was a specialized manufacturing technique or something experimental.
Click to expand...

Bill Moran discovered the secret of bonding layers of damascus using Borax when forging.

sal
 
Zagorov said:
Can you share what is the process for your blades, if that's not too much to ask, and you will not give away any trade secret?

I am particularly interested in HAP40/SUS410 and SuperBlue/420J2 since I have these :D
Click to expand...

I don't know their particular method for that particular combination. Hitachi makes the HAP-40, but I don't know if they they do the bonding.

sal
 
I am presently retired from a international company that designed steel rolling mills, mainly for cold rolling stainless and other very tough alloys.
World wide, approx. 95% of stainless steel strip is cold rolled on our equipment.
Hitachi owned a 10% interest in our Tokyo division and we designed most of the rolling mills for Hitachi Metals.

The process is done in strip rolling and can be found with Google search for "steel rolling mill bonding" most of the references are for aluminum or copper bonding to steel however, the basic process is identical. The coils of steel are cleaned and then introduced into a rolling mill and rolling pressure/heat is the basic bonding process.
There are also hot rolling mill processes for bonding however, these are usually large heavy steel plates for special applications.

The steel coils are next processed in a machine called a leveler which flattens the steel and then it is cut into sheets for manufacturing into the end use product.

Regards,
FK
 
Thanks for the input :)

My guess was more or less the same - 3 sheets of steel, the core being the one that will hold the cutting edge, get heated red-hot, then pressed in roller mills and bonded into a single steel sheet, that gets cut into blade blanks. I was wondering if there are actually 5 sheets, two more inside, from nickel or chromium, that helps the bonding process in some way.

I have seen san mai blades that use copper in the bonding process:
14444988_540894539429844_5927126119331421507_o.jpg

And wondered if Spyderco uses something like that.
 
Sal,

I recall for ZDP, Hitachi is the one doing the HT. In that case, why Caly is laminated and Endura is not, if both are HT by them?
 
In my experience in the steel industry, the maker of the steel, does not actually perform the heat treatment.
It usually is done by smaller independent shops which must have quality control and inspection certificates available to satisfy the steel makers standards.
Only then will Hitachi sell the steel to the end user in Japan for manufacturing the product in this this case, knife blades.
Hitachi then controls the quality and reputation of their proprietary steel formula.

I believe this is the reason we do not see Hitachi exporting the steel to international markets. If the heat treatment is done poorly the reflection is on Hitachi and not he end user manufacturer.

I believe the laminated ZDP-189 was first used in Japanese kitchen knives, the Caly series most likely used the same raw material stock which was available.
Solid stock ZDP-189 is less expensive due to not having the additional expense of laminating three coils in another rolling process.

We see the same concept with laminated HAP-40 and the Blue Steel limited run used in many Japanese kitchen knives.

Regards,
FK
 
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I believe the knives made in zdp are solid or clad depending on the maker. Moki makes the Caly and cannot handle solid zdp because they do not have a laser cutter.
 
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