Low pressure carburizing and annealing in aircraft industry
Due to its far-reaching responsibility, the aircraft industry forms one of the most demanding sectors for any supplier in terms of quality of the equipment, the process and eventually the end-product.
Heat treatment technology is no exception thereto; on the contrary, standards as the AMS2750 have been established and are constantly updated to categorize heat treatment equipment with regard to pyrometry. NadCap takes it further with restrictions for continuously calibrated measuring chains for all process relevant instrumentation.
Special materials call for special processes, neutral or thermo-chemical vacuum heat treatment, and recently particularly low pressure carburizing, has proven to be the preferred choice of manufacturers of aircraft gear box components. The rather small lot sizes involve small surfaces to be carburized. Whilst usually the challenge is the upper limitation as to the total surface to be carburized in one batch, the task here is to meet case depth requirements with low tolerances and realize utmost homogenous carburization in the small loads finding just the right balance between insufficient and exceeding carbon exposure.
New, complex parts entail various case depths on the same part, which makes it indispensable to get carbide formation and further distortion under control.
The furnace suppliers must go beyond providing their usual equipment and master different challenges in developing new features and processes, even furnace concepts, to enable the end-user to manufacture high quality products in accordance with its industry’s high standards.