A ring integrator with reflective optics utilizes the precise control and repeatability of laser heat treating to harden high alloy steel components of valve assemblies with no back tempered region at any point on the circumference of the part. Conventional case hardening methods such as furnace, flame, and induction hardening do not provide the precise control necessary to meet these requirements.
AISI alloy 52100 steel was selected for this application because of its high strength, fatigue resistance, and hardenability properties. To achieve the desired hardened case properties without quench cracking requires a process with a very high heat input rate and subsequent internal quenching. Laser heat treating provides a very tough, hard microstructure with compressive residual stresses on the surface of the case.
This method of rotationally integrating the laser beam can be used to harden the outer or inner diameter of many cylindrical structures with no back tempering. Correct design and manufacture of the optical system will deliver the laser beam to the work surface at any desired angle.