Material --------------------------Tensile (psi)
Wrought Iron, Hot Rolled ------------331 (48,000)
Powder Metal, 84 % density ---------- 214 (31,000)
Powder Metal, repressed, 95 % density - 283 (41,000)
I had my doubts this was wise, until I read this:
In comparison to the traditional gear manufacturing process, the powder metallurgy process offers several advantages, particularly the elimination of machining and scrap losses. Internal configurations (splines, keys, keyways) can also be formed simultaneously with the gear profile during molding, eliminating subsequent machining operations. General process advantages of powder metal gear manufacture include:
* Economy in mass production
* Repeatability and uniformity of part features and dimensions
* Production of multilevel gears
* Close control of density or , conversely, porosity to suit a particular application
* Reduction or elimination of secondary operations
* Improved surface finishes on gear teeth by reducing or eliminating the machining (or "scoring") marks that can be left by conventional methods
* Self-lubricating ability from impregnation of oils and lubricants into the pores
* Noise reduction from the sound-dampening qualities of the pore structure of a powder metal component. High surface finish and tooth form consistency can also have an effect on overall reduction in noise in comparison to cut gear sets
* Weight reduction by incorporating weight-saving or lightening holes (or similar shapes) in the initial tool design