What happens when you heat steel?

D

DavidL41

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Oct 12, 2014
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If I took regular steel and casted the steel to form the blade shape how is this different to forging steel. Does the liquid state when casting make a difference even if you let it cool. Any difference in performance between the two or when a knife is cnc made + heat treated after.
 
DavidL41 said:
If I took regular steel and casted the steel to form the blade shape how is this different to forging steel. Does the liquid state when casting make a difference even if you let it cool. Any difference in performance between the two or when a knife is cnc made + heat treated after.
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:) stuff and things man, you know :D
Hi,
From what I understand, it doesn't really matter how you get there, forging casting cnc magic ... that only affects the heat treatment steps required/possible for the desired/optimal results, the finished product is essentially the same

Geometry (edge angle and thickness) and grit finish make more of a difference in performance than steel type, steel types just determines how low angle and how thin you can go


For some ideas see optimum knife edge angles and what they should be able to do/slice/chop and follow the links
... something like, advantage one steel has over another is at most 2:1
 
Jason B. said:
Google, its your friend.

Casting steel- https://en.m.wikipedia.org/wiki/Steel_casting

Steel Forging- https://en.m.wikipedia.org/wiki/Forging
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I know the general idea of casting steel and steel forging, but dont know how that affects the grain of the steel. If the steel is heated and hammered will the grain look the same as a knife that was casted? Im taking a guess but im thinking that when a knife is forged it may have better steel structure + be easier to sharpen? or maybe it has little difference. Can you tell a steel is properly done by the way it feels on the knife.
 
Most commercial steel is forged or hot rolled (similar to forging, but using 2 rollers instead of a hammer) after being cast. Cast structures will generally have worse strength, toughness, and ductility than wrought (hot worked, either by forging or rolling or some other process) structures. Casting is more economical for some parts and can be quite complex to reduce the mechanical property reductions. Both castings and forgings (or rolled plate/sheet shapes) can be heat treated afterward. There are some makers (Stuart Ackerman, David Boye) who make knives by casting then final grinding/polishing. I've used a Boye folding knife and found it worked fine, but just as a cutter. I carried it for many years and finally wore it out.
 
Thanks this was what I was after. Did the boye folding knife you have wore out, as in you used it till you needed a new knife, or the steel quality progressively gotten worn out.
 
No, I used that thing like I stole it. Turned into a little steel toothpick.
 
In more crude steels (common lower strength) there can be a difference between cast and worked. I know that rolled elements such as plates can be tougher parallel to the rolling direction than perpendicular to the surface of the plate due to inclusions that get rolled into the steel. I know what the end result is and what it causes, we deal with what is called "lamellar tearing" in structural steel welded parts, but I don't know exactly what causes it or if it is limited to mass produced bulk steel. Maybe the manufacturing of steels used in knife blades is much more controlled and creates better grain already. I also read about various methods for making blade material that involves powder steel, spray forming, etc. with the goal of creating better grain structure so that makes me wonder how good the grain is in the less expensive blade materials.
 
The casting and heat treatment of metals has come a long way over the past several decades. Cast steel and cast ductile iron anvils, for example, can be excellent. A cast and well finished blade would probably rival a modern forged blade. I think the process of casting, finishing and correctly heat treating such a blade does not give as much of a savings as casting a larger, low production item like an anvil. So there is probably little incentive to develop such a process.
 
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