How does heat treatment affect the properties of metal?
The temperatures metals are heated to, and the rate of cooling after heat treatment can significantly change metal’s properties. It softens metal, making it more workable and providing for greater ductility. In this process, the metal is heated above its upper critical temperature to change its microstructure.
What happens to the grain structure when you heat a metal above the recrystallization temperature for an hour and why is it advantageous for some applications?
When a cold-worked metal is heating above a certain temperature, rapid recovery eliminates residual stresses and produces the polygonized dislocation structure. new small grains the nucleate at the cell boundaries of the polygonized structure eliminating most of the dislocations.
What is the process of heat treatment?
In simple terms, heat treatment is the process of heating the metal, holding it at that temperature, and then cooling it back. During the process, the metal part will undergo changes in its mechanical properties. This is because the high temperature alters the microstructure of the metal.
Does annealing increase toughness?
Annealing can increase ductility and alleviate internal stresses that contribute to brittleness. Annealing can also increase toughness and homogeneity of metals. Physically, the annealing process involves diffusion of particles within a material.
Why is it bad to quench a blade in water?
Water is one of the most efficient quenching media where maximum hardness is desired, but there is a small chance that it may cause distortion and tiny cracking. When hardness can be sacrificed, mineral oils are often used.
What kind of oil do Bladesmiths use to quench?
There are many food-grade quenching oil options available to use for blacksmithing. Among these options are vegetable, peanut, and avocado oil. Some commonly used vegetable oils are canola, olive, and palm kernel oil. Vegetable oil is very cheap and comes from renewable sources.
Can you quench a blade in vegetable oil?
Quenching Oil. Realistically, just about any kind of oil would work for this. Vegetable oil, olive oil, peanut oil, motor oil, used motor oil, etc. It will all work. You do not want to use water, however.
Why do you quench in oil?
To get a grip on why oil is a popular quenchant, it’s important to understand what happens in a quench. The succession of heating and then quickly cooling parts via quenching is a way to achieve added hardness to a part that otherwise wouldn’t have been possible.
How do you quench steel in oil?
One way to do this is to make the steel red-hot, then plunge it into motor oil. The carbon in the motor oil bonds with the top layer of red-hot steel molecules and forms a tough outer covering on the steel. One last step is necessary, however, before your hardened steel is ready to work with.