Is forging always necessary?

In answer to the OP question - YES, forging is necessary. Every bar or sheet of steel we get has been forged down from a HUGH billet of steel weighing many tons. Whether we decide to forge it more or just grind a knife from it is optional.
 
OK I have managed to solve this problem using some of your suggestions! Softening the handle with a blowtorch, with the knife standing in water helped a lot. I also realised that some of my drill bits were worn, so someone showed me how to sharpen them on a bench grinder. Worked first time! This will speed things up considerably in future. Thanks again folks.
 
Grimp2001 said:
OK I have managed to solve this problem using some of your suggestions! Softening the handle with a blowtorch, with the knife standing in water helped a lot. I also realised that some of my drill bits were worn, so someone showed me how to sharpen them on a bench grinder. Worked first time! This will speed things up considerably in future. Thanks again folks.
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Another tip I don’t think anyone said that you may already know is after a Ceramic belt of 50-60 grit , I then go to a 120 grit belt. Then a 220-320 belt. so doubling your grit, or close to it works the best to not have to go back and chase deep scratches. Stay safe & have fun !
 
here are few advantages of forging
  • Reduced chance of voids.
  • Better fatigue resistance.
  • Improved microstructure.
  • Continuous grain flow.
  • Finer grain size.
  • Greater strength
 
So to answer the myth of forged steel;

Forging can ruin or improve a metal, depending on the process. In a sense forging is a heat treatment in of itself and the material should be annealed prior to work, thermo cycled in the first few heats and thermo cycled at the end and annealed prior to the final heat treat to remove any stesses from the forging itself. While working the steel should be kept at a temp which austonises the steel over and over and over again. (Every time steel cools the phase shift starts over). Not nessisary compared to a single soak time.

Forging in the wrong phase state depending on the metal will cause internal damage which creates hidden flaws in the steel. Which is as simple as a single hit too cold.

It IS possible for the ending steel to undogo significant changes using a charcoal forge and no longer be the steel it started off as as the chemical composition can get rearanged, (carbon can be absorbed and redistrubuted and carbides can be formed) but that is only when forge welding or sustained extreme temperatures over very long periods of time (thats hours) in a non oxygen enviroment at which point it is inaccurate to call it the starting steel because its elemental structure has changed from how it was made from the foundry. (The term for that is carbonization) and its a process very few people even deal with because the choice of metal should be sufficient to simply forge and then treat. Unless forge welding which is another animal. In an ogyginated enviroment the scale absorbs the carbon and falls off making it irrelivent.

A knife doesnt really require any of those major changes unless the metal has a working condition or it is pattern welded.

A decent smith can work quickly and shape steel, a single mistake can ruin the blade entirely, there is far less risk in pure stock removal and consistant factors offered by technology.

So the only thing a smith can offer is an altered steel and unique shaping.

I will be editting this post to add a few sources for reference when i get home.

Edit: heres a link on that.
https://www.researchgate.net/public...ron_be_Carburized_in_a_Charcoal-Fired_Furnace.
Important to know in forge welding with propane or charcoal, with charcoal the desire is to make a reducing flame which meets the requirements.
 
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vish said:
here are few advantages of forging
  • Reduced chance of voids.
  • Better fatigue resistance.
  • Improved microstructure.
  • Continuous grain flow.
  • Finer grain size.
  • Greater strength
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You’re comparing cast and forged parts. The number of cast knives is near zero.
 
Joseph Gardner said:
Most tools are injection molded and theres an aweful lot of knives made the same way.
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Sure it does, you’re just unlikely to buy it that way.

Edit: My response no longer makes sense because the comment I was replying to was completely re-written.
 
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Joseph Gardner said:
Most tools are injection molded and theres an aweful lot of knives made the same way.
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Maybe I'm misunderstanding what you're trying to say, but most tools are not injection molded and pretty much no knives are injection molded (other than, you know, disposable polystyrene plastic knives, but we're not that kind of blade forum here) . Injection molding is a process for molding thermoplastic polymers (plastic), not metal.

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Its a powder metallurgy thing https://www.parmaco.com/en/mim-micromim/mim-und-micromim-prozess-im-detail.html

Theres alot of companies that make machine and automotive and aviation parts this way as well some machinist companies like JD machinist do this in addition to stock removal. I know that from a tour.

Other things like screw drivers hex wrenches chisels ect are sometimes made from a liquid molded air hardening steel like d2, when its cool enough the mold gets removed and then it comes out as the tool it self hardens.

Tools made from that process do not forge well into knives, which is a problem for us smiths who like to use junk yard scrap, occasionally you run into a tool like that and gooooodnight.

Crucible before they went out of business designed their powders to be injection mold-able, its featured on their website still. And if they didnt go out of business it would have ended up replacing just about everything, there is hardly any wastage to the process and it cuts out a lot of the machining.

Context: Molded material - tool - scrap - knife maker.
 
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Joseph,
I don't know where you get most of your information, but the bulk of what I have read by you is bunk. Are you an actual knifemaker?
 
Traditional blacksmith, everything from creating alloys to forge work. So if by knife maker you mean someone who grinds steel into knives, yeah. Theres file work and get it hot and dunk it, and then theres understanding.
 
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Joseph Gardner said:
Traditional blacksmith, everything from creating alloys to forge work. So if by knife maker you mean someone who grinds steel into knives, yeah. Theres file work and get it hot and dunk it, and then theres understanding.
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I'm familiar with metal injection molding as applied to medical devices (a field I used to work in) and firearms (a hobby) and the parts lack the physical strength of a conventional steel (this is part of the reason Kimber isn't as good as they once were), they're simply sintered powdered metal. I can't imagine it being used in a knife blade, though I could certainly be wrong. Could you give an example?

Also, I'm plenty familiar with cast steel parts, but again they lack the physical strength of a conventional steel. I can't imagine it being used to make a knife blade. Again I could certainly be wrong. Could you give an example?

Perhaps you've seen a tool that was drop forged and mistook it as cast? They can look pretty rough? For sure there are some cast tools (cheap C clamp for example), but I wouldn't say most tools are cast and certainly I don't think very many tools are injection molded. I could certainly be wrong, can you show some examples of what you're talking about?
 
and the parts lack the physical strength of a conventional steel
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Lacking by only slight margin. Millions of highstress small parts are successfully made MiM.
Unless one wanted to blend custom alloy what otherwise be cost prohibitive from a steel mill, MiM is not economically suited to making the simple shapes of knifeblades.
Other knife parts yes. (Still, You better make thousands to be economical) but blades, no.
 
Theres a PM stamping process where the powder is forced into a mold with a piston at forge welding temps and compressed, boom instant D2 tool, or whatever steel and shape you need. The places iv seen those tools made were DoD companies.

Being close to hill air force base there is an entire set of aerospace industries in utah that fabs tools that way and they just find their way into the junk yards along with that juicy aerospace steel and other fun shit. Beowing, L3, some of the local machinist shops that do work for hill airforce base making parts but you get the point.

This was a chisel, which normally is a medium steel, except it wasnt. I am very cautious with my forge work I anneal, heat let it cool reheat let it cool reheat and then forge, started drawing it out into a large chopper and first hit on a reheat caused the end section to literally turn into hot dust and crumble at a gentle orange.
it cooled and formed martensite which tells me it was an air hardening steel, I broke off some more off the edge to get the clean grains with my fingers. (that bad)
the cracks are somewhat typical of partial cementite which suggests a higher carbon content then 1.5(ish), but it forged like it was 1045, really fricken soft and in my experience with A2, S7, CPM 3v 10v, air hardening steels are a BITCH to hit.



My cellphones photo quality is shite I Apologize for that. you can see a mixture of austenite and some decent martensite on the outside edges but only a very partial transformation, and the grains are massive as well as cementite.
Iv had about 3-4 of these experiences and I went to buying clean steel like everyone else.

You typically see this sort of thing happen when you water quench an air hardening steel at the wrong temp, except this happened WHILE IT WAS HOT.
 
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You do realize that the powder metallurgy steels that we use are subsequently rolled aka forged into usable sizes, right? It doesn't come out of the "can" in 24 x 48 x 3/16 sheets. ;)
Joseph Gardner said:
Theres a PM stamping process where the powder is forced into a mold with a piston at forge welding temps and compressed, boom instant D2 tool, or whatever steel and shape you need. The places iv seen those tools made were DoD companies.

Being close to hill air force base there is an entire set of aerospace industries in utah that fabs tools that way and they just find their way into the junk yards along with that juicy aerospace steel and other fun shit. Beowing, L3, some of the local machinist shops that do work for hill airforce base making parts but you get the point.

This was a chisel, which normally is a medium steel, except it wasnt. I am very cautious with my forge work I anneal, heat let it cool reheat let it cool reheat and then forge, started drawing it out into a large chopper and first hit on a reheat caused the end section to literally turn into hot dust and crumble at a gentle orange.
it cooled and formed martensite which tells me it was an air hardening steel, I broke off some more off the edge to get the clean grains with my fingers. (that bad)
the cracks are somewhat typical of partial cementite which suggests a higher carbon content then 1.5(ish), but it forged like it was 1045, really fricken soft and in my experience with A2, S7, CPM 3v 10v, air hardening steels are a BITCH to hit.



My cellphones photo quality is shite I Apologize for that. you can see a mixture of austenite and some decent martensite on the outside edges but only a very partial transformation, and the grains are massive as well as cementite.
Iv had about 3-4 of these experiences and I went to buying clean steel like everyone else.

You typically see this sort of thing happen when you water quench an air hardening steel at the wrong temp, except this happened WHILE IT WAS HOT.
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jdm61 said:
You do realize that the powder metallurgy steels that we use are subsequently rolled aka forged into usable sizes, right? It doesn't come out of the "can" in 24 x 48 x 3/16 sheets. ;)
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https://usaknifemaker.com/cpm-d2-powdered-metal-5lbs.html from the can...
Im saying iv seen powder shoved into a mold and then pressure welded into a crappy tool, and if you try to forge that tool it poofs and burns nice holes in you.

Added: why would you do such a thing? contractors are required to buy a hammer at 200$ a pop because of regulations.

its probably irreverent to junk yard steel somewhere.
 
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