Laser Heat Treating

Precise Surface Modification
Laser Heat Treating Gear

Heat Treating with a Laser

Laser heat treating is a surface modification process designed to change the microstructure of metals through controlled heating and cooling. Lasers offer an advantage in this process in the ability to heat treat localized areas without affecting the entire workpiece. During heat treating, the mass of the material being processed is generally sufficient for "self-quenching" for heat removal. One example of an ideal application of this technology is heat treating hand tools. No post-machining is needed in most situations.


  • Hand tool cutting edges and jaws
  • Bearing journals
  • Thrust faces on gears
  • Sealing surfaces
  • Cylinders
  • Camshafts
  • Bending and forming dies
  • Cutting tools
  • Sliding wear surfaces
  • Gear teeth 

Efficient and effective.

The enhanced mechanical properties resulting from laser heat treating depend upon the specific composition of the metal or alloy. For example, laser case-hardening of transformation-hardening metals provides high hardness and wear resistance with minimum distortion. In addition, laser spot annealing of precipitation and work-hardened metals (i.e., aluminum alloys and 300 series stainless steels) restores ductility and improves formability in critical areas.

Laser heat treating large metal parts

Diode, Disk and Fiber lasers are commonly used for laser heat treating. These modern lasers have inherently high absorption properties allowing ease of use at a lower cost. 


  • Industrial 
  • Agriculture 
  • Automotive
  • Aerospace
  • Construction Equipment
  • Consumer Products


Some of the many advantages of Laser Heat Treating with a Preco-made machine.

  • Precision control of heat input to localized areas
  • Repeatability
  • Time-efficient process
  • Minimal distortion 
  • Minimal residual stress input
  • Self-quenching process; generally requiring no quenching medium
  • Hard-to-reach areas can be treated if line-of-sight exists
  • Internal Diameter (ID) capable 
  • Maximum hardness achieved
  • Single part flow
  • Digital/CNC process
  • Closed loop feedback

Webinar: Exploring the Endless Horizons of Surface Modification

In this webinar, you will see our practical, cut-to-the-chase discussion to discover insights about:

  • Laser light and laser types
  • Common materials processed
  • Methods used to deliver light to a part
  • The range of industries and applications where Laser Heat Treating has effective results. 

Frequently Asked Questions

Common questions for laser heat treating.

Why are some high alloy and tool steels not well suited for heat treating?

While high alloy and tool steels are generally suitable for heat treating, certain types may present challenges due to their specific properties. In the case of laser heat treating, the primary limitation arises from the speed of the heat cycle.

  • Advanced Heat Cycle Requirements: Many high alloy and tool steels require a longer and more advanced heat cycle to achieve the desired metallurgical changes and properties. This extended duration allows for proper transformation and tempering of the steel, ensuring optimal performance.
  • Time Constraints in Laser Heat Treating: Laser heat treating operates on a rapid timescale where the heat cycle is generally too fast to adequately achieve the desired results for certain high alloy and tool steels. The short duration of the heat cycle may not allow for sufficient diffusion and transformation processes to take place, leading to suboptimal outcomes.

While these materials may not be as well-suited for laser heat treating due to the rapid nature of the process, alternative heat treating methods may still be viable options to achieve the desired properties in high alloy and tool steels.

How do you determine the hardness of the heat treated area?

Determining the hardness of a heat-treated area involves several techniques commonly used in the industry:

  • Scratch Files Method: This is a straightforward technique where a set of scratch files is used to assess if a particular hardness level has been achieved. While somewhat subjective, it serves as a practical method for evaluation.
  • Superficial Hardness Test: For parts that can be brought to the lab, a superficial hardness test can be conducted on the treated surface to assess its hardness.
  • Portable Tester: If the part is too large to be brought to the lab, a portable tester such as a Leads rebound tester can be utilized when measuring the hardness of the heat-treated area.
  • Micro Hardness Test: To perform this type of test and verify the depth of the heat-treated area, a cross-section of the part needs to be made. The section is then mounted and etched. Various hardness tests, tools, and scales are employed to quantify the results accurately.

These tests are routinely conducted in our lab at Preco to ensure the quality and reliability of our heat-treated areas.

What is required to be successful if I wanted to implement laser heat treating?

Implementing laser heat treating successfully requires several key components:

  • Appropriate Part Design: It starts with having the right part design that is compatible with the laser heat-treating process. This includes considering factors such as geometry, material composition, and surface finish.
  • Suitable Chemistry: The material chemistry must be conducive to laser heat-treating. Ensuring that the composition of the material is appropriate for the desired heat treatment is essential for successful outcomes.
  • Equipment: Access to the necessary equipment for laser heat treating is vital. This includes laser systems capable of delivering the required energy levels and control mechanisms for precise treatment.
  • Quality Checks: Implementing a robust quality control process is crucial. This involves having methods in place to perform quality checks throughout the heat-treating process to ensure the consistency and reliability of the treated parts.
  • Basic Understanding: While you don't necessarily need a Materials Scientist on staff, having a basic understanding of the laser heat-treating process is beneficial. This allows for better communication with suppliers and a clearer understanding of project requirements.

At Preco, we offer comprehensive support throughout the entire implementation process, from assisting with part design to running trials and final implementation. Our expertise and resources are available to help you achieve success in laser heat-treating applications.

Can a laser head be mounted to a robot for increased application flexibility?

Yes, integrating a laser head with a robotic arm offers enhanced application flexibility, making robots valuable tools for automation in laser processing.

  • Manipulation of Laser or Part: Depending on various factors such as part size, geometry, and process requirements, the laser or the part itself can be manipulated by the robotic arm.
  • Large, Heavy Parts: For large and heavy parts like forming dies, it is often more practical to manipulate the laser head over the part. This approach allows for precise control and coverage of the entire surface area.
  • Small Parts: Conversely, for smaller parts, it may be advantageous to pick them from a bin, process them while still held by the robot, and then place completed parts in an outgoing bin. This streamlined workflow minimizes handling and improves efficiency in processing small components.

In summary, mounting a laser head to a robot provides versatility in laser processing applications, allowing for customized solutions tailored to specific part sizes and processing requirements.

How can we ensure consistent hardening/quenching temperatures and thermal profiles across all areas during laser heat treating?

Keeping in mind that lasers produce a spot source of energy they are seldom used for whole part or through hardening. The typical case depth produced by laser heat treating is between 0.010" (0.25mm) and 0.080" (2mm). If there are locations within the area to be treated that pose discontinuities in mass, like a hole or groove, then compromises may need to be made, or another hardening process considered.

Metals Laser Processing Equipment


ST Series

Multi-Axis Laser Processing Machines

These workstations are designed for multi-axis laser welding, heat treating, cladding, drilling and cutting of metallic components.


SL Series

Multi-Purpose Laser Processing Machine

The SL Series is manufactured from standard parts and integrated into a single workstation designed to fit specific customer needs.