What Is Heat-Treating? A Quick Guide for Businesses New to the Process

If your business works with metal components—whether manufacturing, machining, or engineering—you’ve likely come across the term “heat-treating.” But what exactly does it mean, and how can it benefit your operations?

Heat-treating is a controlled process used to alter the physical and mechanical properties of metals without changing their shape. Through carefully regulated heating and cooling cycles, manufacturers can improve hardness, strength, durability, and resistance to wear and corrosion. It’s a foundational part of the production process for everything from aerospace components to automotive parts to industrial tooling.

Why Businesses Use Heat-Treating

Even if your business doesn’t perform heat-treating in-house, chances are the parts you rely on have gone through it. Understanding the process helps you make better sourcing decisions, ensure product quality, and communicate effectively with suppliers or customers.

Here are a few common goals of heat-treating:

• Hardening: Increases the surface or core strength of metals, making them more resistant to abrasion and deformation.

• Tempering: Balances hardness and toughness by reducing brittleness after hardening.

• Annealing: Softens metal, improves machinability, and relieves internal stresses.

• Stress Relieving: Minimizes residual stress from welding, machining, or forming—especially useful before final machining.

• Normalizing: Improves uniformity in microstructure and mechanical properties, often used for carbon steels.

Who Uses Heat-Treating?

Heat-treating is a critical process across a wide range of industries:

• Aerospace: Structural components must withstand extreme stress and temperatures.

• Automotive: Gears, axles, and engine parts require strength and wear resistance.

• Tool and Die Makers: Cutting and forming tools are hardened to ensure long service life.

• Defense and Government: Specifications often require military-grade heat-treating procedures.

• Job Shops and Machine Shops: Even small shops benefit from in-house heat-treating to reduce lead times and gain control over quality.

In-House vs. Outsourced Heat-Treating

For companies new to heat-treating, outsourcing is a common first step. However, as production needs grow, bringing heat-treating in-house offers key advantages:

• Faster Turnaround: Eliminate the delays and logistics of working with third-party processors.

• Greater Quality Control: Monitor results and adjust processes in real-time.

• Cost Savings: Reduce per-part costs over time, especially for frequent or high-volume needs.

• Flexibility: Respond quickly to engineering changes or short-run demands.

Installing an in-house heat-treating furnace is often more accessible than many assume. Equipment ranges from compact bench-top models for small parts to fully automated systems

designed for larger-scale production. Many manufacturers—including Lucifer Furnaces—offer turnkey solutions tailored to specific part sizes, workloads, and atmosphere requirements.

*If you're wondering if in-house heat treating will work for you, check out our article Benefits of Industrial Heat Treating In-House to learn more

What You Need to Get Started

If your team is considering heat-treating in-house, here are a few things to consider:

• Part Material & Size: The alloy and geometry of the part will determine the heat-treating method and equipment needed.

• Process Requirements: Does your application require hardening, annealing, or stress relieving? Some processes require specific atmospheres (like inert gas or endothermic gas) to prevent oxidation.

• Industry Standards: Certain applications must meet certifications such as AMS2750 for aerospace or CQI-9 for automotive. Your equipment and process controls should be capable of compliance if required.

• Facility Setup: Ensure proper electrical and safety accommodations are in place. Most small to mid-size heat-treating furnaces can be installed with standard utilities and minimal footprint.

Final Thoughts

Heat-treating might sound technical, but it doesn’t need to be intimidating. Whether you're looking to improve turnaround time, reduce costs, or gain better control over part performance, bringing heat-treating in-house can offer a strategic advantage.

If you're not sure where to begin, talking with a furnace manufacturer or consulting a metallurgical engineer can help you understand what's involved and what solution best fits your operation. We are happy to help; feel free to contact us with any questions or to explore your options for heat treating.