Curtiss-Wright’s Surface Technologies Division, a global provider of highly engineered surface treatments and analytical services, announced their newly issued US Patent Number 10,619,222 entitled “High Fatigue Strength Components Requiring Areas of High Hardness”.
For applications in gears, splines, and torqueing devices where wear and bending fatigue strength are critical, metal components are typically hardened to levels as high as HRC 60. This minimizes the wear of the contact surfaces. Although high hardness generally means high yield strength, and thus high fatigue strength, as the material hardness exceeds HRC 50, ductility begins to decrease, thereby actually reducing fatigue strength. Component features, such as the teeth of gears and the splines of drive shafts, need high hardness in areas of wear, but also critically need high fatigue strength in the roots of a gear tooth or spline.
To develop components with optimum wear and fatigue strength, Curtiss-Wright has invented a hybrid manufacturing approach where gear teeth are hardened to the highest levels in faces and flanks, but root areas are only hardened to the level optimizing ductile yield strength. Then, laser or shot peening is applied to optimize overall fatigue strength. This process provides a gear or other component with characteristics of the highest level of wear while attaining superior fatigue strength.
For more information: Curtiss-Wright Surface Technologies
