Exploring Knife Making & Steel Structure Changes

In summary, the conversation is about knife making and the potential changes in steel structure when forging a blade from a large bar of steel. Heat treatment can cause an increase in hardness and density, but in most cases, it does not significantly impact the overall performance of the knife. Forged blades have a more oriented microstructure which can have both pros and cons in terms of toughness and mechanical properties.
  • #1
flava
3
0
Hello,

I just registered to these forums but already visited this place for a while. I have a question that fits this particular subforum (I hope). It is related to another hobby of mine, which is knife collecting/making. Let me give you first some background info on the subject, in order to better explain the question.
A knife blade is usually made of steel, and brought to it's particular shape either by "stock removal" (grinder, mill, files ...) or forging. The knifemakers that forge to shape are saying this method has several advantages, like bringing the raw steel to a more homogenous state, "packing" the crystals closer and getting a crystalin structure that shows smaller "grain".
My question is: by taking a big bar of steel (like roller bearing steel 52100 or spring steel 5160) that has a diameter of let's say 20cm, getting it hot enough and forging it down to a blade size (using power hammers, repeated heat cycles), what changes in the steel structure might one expect? In particular, is there ANY change in density possible?
Thank you in advance for any clue or answer.

Flava
 
Last edited:
Engineering news on Phys.org
  • #2
Well heat treatment can cause the formation of more grain boundaries which would lead to increased hardness. Density really isn't going to change much I don't believe depending on what state it is heated to. From what I remember at I think 900K (or celsius not exactly sure) the strucure of steel changes from BCC to FCC which causes an increase in density if I am not mistaken. But I believe when it cools it begins to return to a BCC structure. Honestly, for most civil applications of knives I don't really think it matters.
 
  • #3
Thank you, omagdon7
In both cases, the blade will be heat treated (normalized, quenched and tempered) after it has reached the required shape. A forged blade is hammered to shape, which requires multiple heat cycles. A "stock removal" blade is abraded to shape.
 
  • #4
Yeah, would say the density change itself is meaningless (unless viewed really locally microstructure wise but don't think that is the case here). Due to forging you can have a highly oriented microstructure, which has both pros and cons. It can be for example a great in arresting and preventing initiation of cracks in region of ductile tearing, but due to the orientation possesses in some loading orientations poor toughness and mechanical properties, high propensity to initiate cleavage cracks etc. Naturally quantitatively as with all treatments can make a better steel for an application by forging and subsequent heat treatments or ruin the steel. Get some lose some, great if you lose something you don't really need.
 

1. What is knife making and how does it relate to steel structure changes?

Knife making is the process of creating a knife from raw materials such as steel. It involves shaping, hardening, and tempering the steel to create a functional and durable tool. Steel structure changes refer to alterations in the composition and properties of the steel, which can affect the quality and performance of the knife.

2. What are the different types of steel used in knife making?

There are several types of steel used in knife making, including carbon steel, stainless steel, and Damascus steel. Carbon steel is a popular choice for its hardness and ability to hold a sharp edge, while stainless steel is known for its corrosion resistance. Damascus steel is a type of steel that is made by layering different types of steel together to create a unique pattern.

3. How does the heat treatment process affect the steel in a knife?

The heat treatment process, which involves heating and cooling the steel, can significantly impact the properties of the steel in a knife. It can affect the hardness, toughness, and overall strength of the steel, which can determine the performance and durability of the knife.

4. What are some common techniques used in knife making?

Some common techniques used in knife making include forging, grinding, and heat treating. Forging involves shaping the steel by hammering or pressing it into the desired shape, while grinding is used to refine and shape the blade. Heat treating is the process of heating and cooling the steel to alter its properties.

5. How can I learn more about knife making and steel structure changes?

There are various resources available for learning more about knife making and steel structure changes. You can attend workshops or classes, read books or online articles, and connect with other knife makers through forums or social media groups. It's also essential to experiment and practice to gain hands-on experience and develop your skills in this field.

Similar threads

Woodworking: How I Built My Own End Tables from Scratch
    • General Discussion
2
Replies
42
Views
4K

Hot Threads

Recent Insights

Back
Top