Quenching fluids

Heat Treatment

In the field of heat treatment, quenching fluids and quenching oils play a crucial role in improving the mechanical properties of metals. The choice of quenching fluid is essential to ensure optimal performance and consistent quality. 

Quenching is a thermal process that involves heating a metal (such as steel or aluminium) to a high temperature and then rapidly cooling it in a fluid, typically a quenching oil, water-based solution, or polymer. For steel, this operation alters the crystal structure, increasing hardness and wear resistance. Quenching is fundamental across many industries, including automotive, forging, railway,  transmission, agriculture,  aerospace, fasteners, cutlery & blades, steel manufacturing, and tool production. 

The quality of the quenching fluid directly affects the cooling rate and uniformity of heat treatment: two critical factors in achieving the desired mechanical properties and consistency. Selecting the right quenching oil or polymer helps reduce deformation or cracking and ensures targeted performance characteristics such as: 

  • Hardness 
  • Resilience 
  • Wear resistance 
  • Tensile strength 
  • Elongation to fracture 

Several types of quenching fluids are available, each suited to specific heat treatment processes (quenching, tempering, annealing, superficial or mass quenching, vacuum quenching) and furnace types (batch furnace, rotary retort furnace, pit furnace, tunnel furnace, vacuum furnace, etc.). The most commonly used solutions include quenching oils, polymers, and synthetic water-soluble fluids.

Quenching Oils

Quenching oil remains one of the most widely used solutions in heat treatment applications. Quenching oils provide thermal stability and controlled cooling rates, helping manufacturers achieve consistent hardness while limiting internal stresses. 

Depending on their composition (mineral or synthetic base stocks), quenching oils can vary in viscosity, which directly influences cooling speed and metallurgical transformation. These fluids enable effective heat treatment of steels with low to high hardenability. 

MotulTech has developed a comprehensive range of quenching oils covering applications from cold quenching to hot quenching up to 200°C. Our solutions are designed to meet technical, safety, and regulatory requirements. 

With our expertise, we can assist in implementing quenching oils that help: 

  • Reduce energy consumption 
  • Improve site safety 
  • Minimise fumes 
  • Extend bath longevity 
  • Eliminate zinc, sulfur or heavy metals 

Motultech offers the following range :

  • THERMIC 100

Accelerated hot quenching oil specifically formulated for quenching parts with complex geometries or variable cross‑sections, which are sensitive to distortion, internal stresses, and quench cracking. Ideal for the quenching of carburized gears.

  • THERMIC 15

Accelerated semi‑hot quenching oil with a high flash point and excellent oxidation stability, designed for the heat treatment of carbon steels and alloy steels, including those with complex geometries.

  • THERMIC 30 R

Highly accelerated quenching oil with very high cooling capacity, formulated from highly refined base oils. Its quench severity profile provides fast yet controlled cooling, making it ideal for carbon steels and low‑alloy steels requiring the formation of a homogeneous martensitic microstructure.

  • THERMIC EVO 120

Accelerated cold quenching oil, formulated from highly refined base oils, designed for the quenching of carbon steels and alloy steels, including parts with complex geometries.

  • THERMIC EVO 130

Highly accelerated cold quenching oil with high flash point, formulated from highly refined base oils, designed for the quenching of carbon steels and alloy steels of low hardenability.

  • THERMIC EVO 140

Extremely accelerated cold quenching oil formulated from highly refined base oils. Its quenching profile is characterized by an extremely short vapor phase, ensuring ultra‑fast cooling, particularly well suited for steels with low or poor hardenability, while maintaining excellent control of internal stresses and distortion risks.

  • THERMIC EVO 230

Highly accelerated semi-hot quenching oil, formulated from highly refined base oils, intended for quenching distortion-sensitive steels of low hardenability.

  • THERMIC EVO 310

Highly accelerated hot quenching oil for quenching distortion-sensitive steels., formulated from highly refined base oils. Ideal for the quenching of carburized gears.

  • THERMIC EVO 415

Accelerated semi-hot quenching oil, formulated from highly refined base oils, intended for quenching distortion-sensitive steels.

  • THERMIC EVO 420

Accelerated quenching oil specifically developed for vacuum quenching of carbon steels and alloy steels, including parts with complex geometries.

  • THERMIC EVO 430

Highly accelerated quenching oil specifically developed for vacuum quenching of steels with low or poor hardenability.

  • THERMIC INO 130

Highly accelerated cold quenching oil with high flash point, formulated from synthetic base oils derived from natural gas (GTL).

  • THERMIC INO 430

Highly accelerated quenching oil for vacuum quenching, formulated from synthetic base oils derived from natural gas (GTL).

  • THERMIC TO 10

Cold quenching oil for heat treatment of steels with good hardenability.

  • THERMIC TO 19 R

Accelerated cold quenching oil with high flash point, designed for the quenching of carbon steels and alloy steels, including parts with complex geometries.

  • THERMIC TO 26 R

Highly accelerated cold quenching oil with high flash point, designed for the quenching of carbon steels and alloy steels of low hardenability.

Polymer Quenching Fluids

Polymer quenching fluids, supplied as water-soluble concentrates, are often used as alternatives to quenching oil where reduced heat emissions or improved safety conditions are required. 

These solutions are increasingly adopted to lower environmental risks and operating costs. Polymer quenching fluids are commonly used in superficial induction heating applications and for mass quenching, replacing traditional quenching oils. 

MotulTech supports customers in implementing quenching polymers to : 

  • Reduce fire risks 
  • Limit fume emissions 
  • Avoid hazardous compounds such as PAHs (Polycyclic Aromatic Hydrocarbons) 

 

Motul product offer :

  • THERMIC FGP

Water‑based quenchant polymer formulated with synthetic polymers (PVP), specifically designed for high‑volume mass quenching operations in serial production. It is intended as a replacement for cold quenching oils.

  • THERMIC SH 620

PAG polymer quenching medium, specifically developed for induction, conduction, and flame hardening operations of steels and cast irons. It significantly reduces the risk of distortion and cracking, while minimizing bath maintenance operations.

Water-Soluble Quenching Fluids

Water-soluble quenching fluids provide faster cooling rates than quenching oils or polymers. However, this higher cooling capacity can increase the risk of deformation or cracking if not properly managed. 

To mitigate these effects, these fluids incorporate specialised additives and are typically used for induction hardening or tempering processes. 

MotulTech offers water-soluble quenching solutions that: 

  • Enable effective heat treatment 
  • Protect parts and machine components (inductors, frames) from corrosion 
  • Provide optional blackened surface finishes 

 

Motul product offer :

  • THERMIC B

Tempering stop and steel blackening fluid, supplied as a concentrated product. It produces a deep and uniform black finish, forming a temporary protective barrier against oxidation, providing 2 to 4 weeks of corrosion protection under indoor atmospheric conditions.

  • THERMIC SP

Water-soluble synthetic fluid designed for surface hardening operations by induction or conduction, as well as tempering processes.

 

Choosing the Right Quenching Fluid

The selection of a quenching oil or alternative quenching fluid depends on several technical parameters, including: 

  • Steel composition 
  • Part geometry and size 
  • Required mechanical properties 
  • Customer specifications 
  • Heat treatment process type 
  • Installations (type of furnace, agitation...) 

MotulTech is a recognised supplier in the field of quenching and heat treatment fluids, with proven expertise and validated product performance. Our solutions are tested by industry professionals to ensure compatibility with demanding production environments. 

Whatever your industry (automotive, aerospace, metallurgy, or tool manufacturing) we provide quenching oils and quenching fluids designed to ensure consistent heat treatment results, part reliability, and long-term process stability. 

By choosing MotulTech, you benefit from:

  • High-quality quenching oil solutions 
  • Technical support tailored to your process 
  • Fluid monitoring throughout service life 
  • Responsive customer service 

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