Laser heat treating, a form of case hardening, offers substantial advantages when distortion is a critical concern in manufacturing operations. Traditional heat treating processes often lead to metal distortion, necessitating additional post-finishing operations like hard milling or grinding to meet dimensional tolerances.
This Technical Tuesday article was originally published in first published in Heat Treat Today’s January/February 2024 Air & Atmosphere print edition.
In laser heat treating, a laser (typically with a spot size ranging from 0.5″ x 0.5″ to 2″ x 2″) is employed to illuminate the metal part’s surface. This results in a precise and rapid delivery of high-energy heat, elevating the metal’s surface to the desired transition temperature swiftly. The metal’s thermal mass facilitates rapid quenching of the heated region resulting in high hardness.
Key Benefits of Laser Heat Treating
Consistent Hardness Depth
Laser heat treatment achieves consistent hardness and hardness depth by precisely delivering high energy to the metal. Multiparameter, millisecond-speed feedback control of temperature ensures exacting specifications are met.
Minimal to Zero Distortion
Due to high-energy density, laser heat treatment inherently minimizes distortion. This feature is particularly advantageous for a variety of components ranging from large automotive dies to gears, bearings, and shafts resulting in minimal to zero distortion.
Precise Application of Beam Energy
Unlike conventional processes, the laser spot delivers heat precisely to the intended area, minimizing or eliminating heating of adjoining areas. This is specifically beneficial in surface wear applications, allowing the material to be hardened on the surface while leaving the rest in a medium-hard or soft state, giving the component both hardness and ductility.
No Hard Milling or Grinding Required
components (Source: Synergy Additive Manufacturing LLC)
The low-to-zero-dimensional distortion of laser heat treatment reduces or eliminates the need for hard milling or grinding operations. Post heat treatment material removal is limited to small amounts removable by polishing. Eliminating hard milling or grinding operations saves substantial costs in the overall manufacturing process of the component. Our typical tool and die customers have seen over 20% cost savings by switching over to laser heat treating.
Applicable for a Large Variety of Materials
Any metal with 0.2% or more carbon content is laser heat treatable. Hardness on laser heat treated materials typically reaches the theoretical maximum limit of the material. Many commonly used steels and cast irons in automotive industry such as A2, S7, D2, H13, 4140, P20, D6510, G2500, etc. are routinely laser heat treated. A more exhaustive list of materials is available at synergyadditive.com/laser-heat-treating.
Conclusions
Laser heat treatment is poised to witness increased adoption in the automotive and other metal part manufacturing sectors. The adoption of this process faces no significant barriers, aside from the typical challenges encountered by emerging technologies, such as lack of familiarity, limited hard data, and a shortage of existing suppliers. The substantial savings, measured in terms of cost, schedule, quality, and energy reduction, provide robust support for the continued embrace of laser heat treatment in manufacturing processes.
For more information:
Contact Aravind Jonnalagadda at aravind@synergyadditive.com.
