Why are steels quenched in oil not water?

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.

Is it better to quench steel in oil or water?

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 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.

Why is oil used for quenching steel?

Oil is frequently used for quenching because it transfers heat very quickly and without causing significant distortions. While water-based caustic quenchants are even faster, but the severity at which they do it can distort or even crack some materials.

Can you quench 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.

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

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.

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 is water quenched steel harder?

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 is hot metal dipped 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.

What is special about quenching oil?

Quench oil serves two primary functions. It facilitates hardening of steel by controlling heat transfer during quenching, and it enhances wetting of steel during quenching to minimize the formation of undesirable thermal and transformational gradients which may lead to increased distortion and cracking.

Why are swords quenched in oil?

The oil in the quench tank causes the steel to cool rapidly and evenly. If the steel does not cool evenly for some reason, then the blade can warp or even fracture.

What liquid do blacksmiths use to quench?

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.

Can you use used motor oil for quenching?

Motor oils are a common type of quenching oil used in both blacksmithing and bladesmithing applications. New and used motor oils can be used for quenching and are both widely available. New motor oil is typically cheaper to use than commercial quenching oils.

Why do you preheat quench oil?

I figure preheating the oil does one of two things. It either lowers the shock for the quench, making fractures and bends less likely (hope it's this one, because it didn't happen) or it hardens better because it makes the oil less viscous, meaning it can transfer heat away from the blade better.

What is the advantage of using oil as the are quenching medium?

The oil has high dielectric strength and provides insulation between the contacts after the arc has been finally extinguished and there has been time for the oil to flow into the gap between contacts. Cooling oil presents the cooling surface in close proximity to the arc.

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.

Can you harden steel with water?

Water is an effective medium when the goal is to have the steel to reach maximum hardness. However, using water can lead to metal cracking or becoming distorted. If extreme hardness isn't necessary, mineral oil, whale oil, or cottonseed oil may be used in the quenching process instead.

Why does hardness increase after quenching?

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

Why are blades quenched in oil not water?

Oil has a slower rate of cooling compared to either water or brine, but faster than air, making it an intermediate quench.

When was oil quenching invented?

Much of the history of quenching is shrouded in mystery – especially from roughly 400 BC to approximately 1500 AD. This is thought to be a result of the general education of the people, and the desire to protect intellectual property by the many blacksmiths and guilds.

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.

How long does quench oil last?

Oil Recovery

Quenching and martempering oils deteriorate during use, although most premium quenching oils can last more than 10 years when given reasonable use and care.

What motor oil is best for quenching?

Canola, Motor Oil, and the Inconel Probe Test

I found a study on 1045 steel where they found canola to quench more rapidly than motor oil so I am going to stick with canola as my “cheap” quenching option to test.

How hot does oil have to be to quench?

Quenching into oil above 212°F (100°C) has traditionally been referred to as "hot oil" quenching. Oil temperatures in the 195°F - 450°F (90°C - 230°C) range have been used with both ends of the spectrum normally reserved for special applications.

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.