What Is Quenching Oil? Basic Guidance

Oil is often used for quenching because it transfers heat rapidly and does not cause extensive deformation. Usually, quenching oil has two primary functions. During quenching, it facilitates the hardening of steel by controlling heat transfer.

Besides this, it increases the wetting of steel to reduce the formation of unwanted thermal and transformational gradients. It’s because this can build distortion and cracking. However, let’s know more about quenching oil below:

What Is Quenching Oil?

Quenching oil is a heat-treated oil mixed with a solvent-refined base oil and selected additives. Notably, it comes with fantastic chemical and oxidation stability. This oil also has outstanding thermal properties, high flash and fire points, and low volatility.

Also, this high-quality oil is produced in various quenching operations to heat-treat ferrous metals. They can provide deep and uniform gardening for a soft surface finish.

 Quenching Oil

Quenching Oil Specifications:

Typical PropertiesQuenching Oil 22 Quenching Oil Special 22           Quenching Oil 32Quenching Oil Special 32Quenching Oil 68
Kinematic Viscosity at 40°C., cSt22 to 2422 to 2432 to 3432 to 3466 to 70
Viscosity Index, Min.           9090909090
Flash Point, °C, (COC), Min.    190190190190190
Pour Point, ºC, Max.            -6            -3            -6            -3            -6

Check: Viscosity & Flash Point

What Is Quenching Oil Used For?

Quenching oil is necessary for various operations to quench multiple metal parts. You must use these oils to control metal quenching to increase flexibility, hardness, and strength. Besides this, you can use these oils to ensure the surfaces are clean and free from patches and spots.

You can use these oils to decrease the building of adverse temperatures and modification gradients because they can increase cracking and deformation. Moreover, quenching oil can increase the wetting of steel during quenching.

It can decrease the risk of breaking down in metal and is safer than polymer quenching. They can protect against oxidation and have excellent heat resistance.

Types Of Quenching Oil:

Although many different types of oil are used for quenching, the two most commonly used classifications are hot and fast oils. As their name suggests, fast oils can calm items very quickly. Subsequently, they can decrease the vapor phase’s length and extend the boiling phase’s length. They are excellent for low-carbon steels and low-hardenability alloys.

You can use hot oils at high temperatures. And it ensures that a part’s core and surface temperatures do not change too much during quenching. Thus the risk of deformation and cracking is low. They work great with very-hard alloys. Nevertheless, other types of quenching oils are:

Canola Oil:

The budget-friendly choice is canola oil. However, it’s slower than Parks 50 but can provide a proper quenching speed. Likewise, it contains high smoke points and reduces the risk of fire. Yet, it is readily available in grocery stores, making it a convenient choice.

Peanut Oil:

Accordingly, another punching oil is peanut, which has a high smoke point. Peanut oil can provide moderate quenching speed. If you are looking for an oil that gives safety in terms of fire, they can choose it. Usually, this oil is also affordable and provides the best balance between performance and price.

Mineral Oil:

The most exclusive option for quenching oil is mineral quenching oil. One of the best versatile performer oil typically comes with moderate quenching speed. Hence, this oil is perfect for use in a variety of projects. The most important fact is that it contains fewer smoke points than peanut and canola oil. Mineral oil is generally cheap, although prices vary depending on grade and Viscosity.

Parks 50:

Parks 50 quench oil provides a consistent and controlled cooling rate. Also, it’s crucial for achieving optimal hardness in your workpiece. The cooling pace is slower than water but faster than other oils.

In addition, it keeps the perfect balance for hardening various steel alloys. With a flash point of 425°F (218°C), Parks 50 has a lower fire hazard, making it a safe choice for your workshop. Thus, Parks 50 is versatile and suitable for various steel sheets, including high-carbon, stainless steel, and alloy.

In particular, its versatility makes it the best quenching oil for knife makers and blacksmiths performing with various materials.

How To Make Quenching Oil?

They are formulated of petroleum oils or base mineral oils. And they often contain polar lubricants such as fats, esters, vegetable oils, and extreme pressure additives like chlorine, phosphorus, and sulfur. Straight oils give the branching oils the best lubrication and the poorest cooling properties.

What Is the Purpose Of Oil Quenching?

Oil quenching is a general process of hardening alloy steel forgings. Basically, this is suitable for acquiring the stiffness and strength of characteristics needed in many alloys. During the oil quench on steel forgings, there is no risk of cracking than polymer or water quenching.

An essential step in the heat treatment of metals is the quenching process. It is a method of quickly cooling a metal part to modify specific properties such as hardness, strength, or toughness. Rapid cooling reduces the time the metal spends at high temperatures and resists defects that would occur.

Traditional media are air, oil, water, and saline solutions. Metals can be modified in specific ways depending on the application process and medium. This Oil has been a popular metalworking fluid throughout history and remains so today.

What Quenching Oil For Steel?

Mineral oil emulsifiers are excellent for oil-hardened steels and steels that need quick emulsification rates. They are on the expensive side, but they are highly efficient. Likewise, they have a greater cooling capacity for steel alloys.

Additionally, they have a huge environmental impact because they are not biodegradable. Similarly to motor oil, mineral oil releases toxic substances into the air when heated to extreme temperatures.

What Quenching Oil For Blacksmithing?

Quenching is an essential step in the blacksmithing process when working with hot metal. A standard medium in which to quench a blacksmith’s workpiece is oil. There are many types of quenching oil for blacksmithing available. But not all oils are better for all applications.

Common quenching oils for blacksmithing are motor oil, mineral oil, food-grade oil, commercial quenching oil, and automatic transmission fluid (ATF). The properties of these oils can vary widely. That’s why it’s also crucial to consider their price, compatibility, availability, and the grade and steel you want to quench.

Final Word:

On the other hand, you need to use the best quenching oil for the quenching process. Hence, quenching oils or heat-treated oil comes with undergone solvent refining and carefully selected additives. Furthermore, it enables rapid quenching through proper cooling.

Ultimately, this fluid is suitable to use appropriately and rapidly to cool steel and other metals during tempering and hardening. Quenching oils are versatile, so you can easily change them thanks to their consistency.

Read About: Punching Oil


Emon is Lubricants specialist who studied on Petroleum Engineering in UAE. He have more than 10 years experience on different kinds of lubrication including automobile troubleshooting.