CLOSE-TOLERANCE HEAT-TREATMENT OF GEARS

Heat treatment distortion still conjures up images of gross and uncont rollable twisting, bending and warpage combined with growths and shrin kages striking fear and apprehension into designers and manufacturers. Gears are critical artifacts because even the smallest variations can severely undermine load-carrying capacity end noise abatement. Even A SM Handbook Volume 4 defines distortion as ''an irreversible and usual ly unpredictable change of size and shape''. By developing a methodolo gy for a wide range of shapes and sizes for carburise case-hardened ge ars, we can demonstrate predictability of distortion and growth which is not always irreversible.