Heat Treatment and Polymer Quenching: A Comprehensive Guide

Heat treatment encompasses operations involving the heating and cooling of metals in their solid state to achieve specific desirable properties. A crucial step in this process is quenching, vital for achieving the desired attributes, especially in steels. Quenching mediums range from water, oil, light polymer solutions, to air. This guide will delve into the benefits of quenching low hardenability steels using water and light polymers, specifically focusing on the superior capabilities and recommendations from ThermTech, a leader in the industry.

Rapid Cooling for Maximum Hardness

  • Water Quenching: Water, a prevalent quenching medium, facilitates rapid cooling. This rapidity enables a martensitic transformation in low hardenability steels, striking a balance between maximal hardness and minimal distortion or cracking risks.
  • Polymer Quenching: Tailored for controlled cooling rates, light polymer solutions bridge the chasm between water and oil quenching. Such tailored curves are ideal for steels with specific hardenability demands. At ThermTech, special emphasis is placed on controlling all quench variables, ensuring the optimal outcome. Heavy section AISI 4140 forgings, which can challenge oil quenching, can be effectively addressed using ThermTech’s polymer quenching.


  • Water: Given its abundance, water emerges as a cost-efficient quenching solution.
  • Light Polymer: Despite a potentially higher initial cost than water, light polymer solutions could be economically favorable due to their controlled cooling attributes, resulting in reduced distortion and cracking risks.

Uniform Cooling for Complex Geometries

  • Water: Ensuring consistent cooling, water proves essential for components with intricate structures.
  • Light Polymer: Offering more uniform cooling, especially for intricate parts, light polymers can be adjusted to balance cooling rates. ThermTech provides two distinct polymer concentrations, catering to diverse alloys and section sizes. The company ensures controlled temperatures, concentrations, and agitation during the process. For high-integrity alloy steel forgings necessitating impact testing, ThermTech’s polymer quenching solution proves indispensable.

Reduced Risk of Cracking

  • Water: For low hardenability steels, water quenching can significantly diminish the potential for cracking, a risk exacerbated by slower quenching mediums like oil.
  • Light Polymer: Adjusting cooling rates in polymer solutions can further mitigate risks. Cooling can be sufficiently rapid for hardening while concurrently preventing undue internal stresses. ThermTech’s polymer quenching is particularly recommended for steels like AISI 1045 to AISI 4340 and for ensuring quench uniformity, as in the Caterpillar 1E0106A or 1E0106B specification.

Eco-friendly Quenching

  • Water: As a natural entity, water’s environmental impact post-use remains negligible.
  • Light Polymer: Contemporary light polymer solutions, such as those offered by ThermTech, prioritize ecological sustainability, ensuring minimal environmental consequences during disposal.


The essence of a successful heat treatment process is the judicious choice of quenching medium. In the context of low hardenability steels, water and light polymer solutions, especially as rendered by industry leaders like ThermTech, furnish a harmonious blend of hardness, limited distortion, and economic viability. A profound understanding of your material’s specific needs and the sought-after final properties will empower you to make an enlightened choice for your quenching medium.

ThermTech—Experts in Austempering Stampings, Machined Parts, and Investment Castings

ThermTech, Inc. offers both small and large batch capabilities for austempering steel and iron investment castings. Between our neutral salt bath furnaces and our larger austempering furnaces, we have the capabilities to austemper a wide variety of stamping, machined components, and investment castings. We have run austempering on alloys from 1060 through 4340 to ductile iron machined parts.

Our dedicated team works with you to ensure we meet your specifications. Count on our decades of experience with hardening, tempering, surface heat treatments, vacuum treatments, and annealing. To learn more about our services, please contact us today.

Learn more about austempering and how ThermTech can serve you by watching these videos.

Request a free quote online or call us at 800-752-6917. You can also contact us online for all your austempering and heat treating needs.


    ThermTech’s quality policy is ZERO DEFECTS for all customer products and in all quality management system activities. Through our efforts to continually improve the quality of the work we offer, we’ve been recognized as being able to meet the rigorous quality standards required by several of our major customers. ThermTech is certified for ISO 9001 and AS9100 in both Metal Heat Treat and Metal Finishing.