Why do blacksmiths put hot metal in water?

Blacksmiths put metal in water because water submersion will allow the forger to control the brittleness and overall strength of the metal. This is referred to as “quenching,” and is used by many blacksmiths to decrease the risk of breakage when crafting new pieces. What is this?

Why do blacksmiths quench in water?

In materials science, quenching is the rapid cooling of a workpiece in water, oil or air to obtain certain material properties. A type of heat treating, quenching prevents undesired low-temperature processes, such as phase transformations, from occurring.

What happens when you put hot steel in water?

Water is an effective and simple option, but it also has some significant drawbacks. It cools metal very quickly and helps it reach its maximum level of hardness. However, it can also lead to cracking or distortion of the steel, compromising its utility and potentially rendering it useless.

What is it called when hot metal is put in water?

Quenching is a rapid way of bringing metal back to room temperature after heat treatment to prevent the cooling process from dramatically changing the metal's microstructure. Metalworkers do this by placing the hot metal into a liquid or sometimes forced air.

What do blacksmiths use for quenching?

Blacksmiths generally use water, oil, or compressed air to quench. These substances vary in environmental impact, cost, and effects on the metal, but the best quenching medium is usually water or quenching oil.

STEEL HEAT TREATING CLOSEUP - WATER VS OIL [Trollsky Knifemaking]

Why are knives dipped in oil?

Parts made of low-carbon steel and low-hardenability alloys quench better in fast oils. Hot oils are kept at much higher temperatures and are used to ensure that a part's core temperature and surface temperature do not vary too greatly during a quench. This controls distortion and reduces the risk of cracking.

Why do blacksmiths dip in oil?

Oil is a third traditional quenching agent, suitable for high-speed steels and oil-hardened steels, and in fact for any steel for which the required degree of hardness is achievable. Oil has a slower rate of cooling compared to either water or brine, but faster than air, making it an intermediate quench.

What is the purpose of quenching?

quenching, rapid cooling, as by immersion in oil or water, of a metal object from the high temperature at which it has been shaped. This usually is undertaken to maintain mechanical properties associated with a crystalline structure or phase distribution that would be lost upon slow cooling.

Does quenching increase strength?

Quench Hardening Steel

Depending on the carbon content and alloying elements of the steel, it can get left with a harder, more brittle microstructure, such as martensite or bainite, when it undergoes the quench hardening process. These microstructures result in increased strength and hardness for the steel.

Why do you quench metal?

Quenching improves a metal's performance by rapidly cooling the heated metal, thereby altering its molecular structure and increasing its hardness.

Why do they dip hot metal in oil?

Hot Oils. Hot oils are always used at high temperatures and prevents temperature variations during the quenching process, which protects the metal against defects, cracks, and distortions.

Is quenching the same as tempering?

The key difference between quenching and tempering is that the quenching is rapid cooling of a workpiece, whereas tempering is heat-treating a workpiece. Quenching and tempering are important processes that are used to strengthen and harden materials like steel and other iron-based alloys.

What kind of oil is used in quenching?

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.

Is water quenching better than oil?

Water-quenched steels will generally be harder than oil-quenched steels. This is mainly because the thermal conductivity of water is higher than the thermal conductivity of most oils (that I know); consequently, the rates of cooling will be less rapid (or lower) in oils compared with water.

Why does a blade warp when quenched?

When these heated parts are quenched, their internal crystal structure changes again, and that volume change is not necessarily sufficient to offset the change upon heating. This change of volume can cause dimensional distortion.

Why is water not used for quenching?

A saturated solution of air (or other gas) in water will come out of solution during quenching and create a very long vapor phase. This is one reason why is it is recommended to never agitate a quench tank using compressed air.

Can you reuse quenching oil?

Usually, the post-quench washer is used to recover the quench oil for reuse. This washer must only be used to clean parts after the quench and must not be contaminated with other coolants or other contaminants. In this process, the oil is recovered from the post-quench wash and segregated to a separate tank.

Why are steels tempered after quenching?

After being quenched, the metal is in a very hard state, but it's brittle. The steel is tempered to reduce some of the hardness and increase ductility. It's heated for a set period of time at a temperature that falls between 400° F and 1,105° F.

Why is steel tempered after being hardened?

Why Is Steel Tempered? Tempering steel after a hardening process allows for a middle ground of hardness and strength. This is achieved by allowing the carbon diffusion to occur within a steel microstructure. When steel is hardened, it can become excessively brittle and hard.

How do you make steel harder but not brittle?

To make steel harder, it must be heated to very high temperatures. The final result of exactly how hard the steel becomes depends on the amount of carbon present in the metal. Only steel that is high in carbon can be hardened and tempered.

Does quenching metal make it brittle?

Quenching results in a metal that is very hard but also brittle. Gently heating a hardened metal and allowing it to cool slowly will produce a metal that is still hard but also less brittle.

Why are swords tempered?

Tempering reduces the hardness in the steel by gradually changing the martensite into a microstructure of various carbides, such as cementite, and softer ferrite (iron), forming a microstructure called "tempered martensite".

Can you quench a blade in mercury?

In order to quench your sword in mercury, you need to displace more than one and a half times its own weight in mercury - and you need to put a corresponding amount of pressure on the blade. However, quenching is done while the metal is still hot and partially malleable.

Why are swords hammered?

When you draw out a piece of steel, you are increasing the length of the steel and reducing the thickness. In other words, you are flattening it into the basic sword shape. By hammering along one edge, the bladesmith can make the length of steel gradually curve to create a curved sword.