Lower bainite alloy steel article and method of making same
AssigneeCaterpillar Tractor Co.
InventorStuart L. Rice
Life of this patent
Estimating the term…
Abstract
A lower bainite alloy steel article particularly suitable for gears, bushings and the like includes carbon in the range of 0.60 to 0.80 Wt.%, manganese in the range of 0.45 to 1.00 Wt.%, silicon in the range of 0.15 to 2.20 Wt.%, molybdenum in the range of 0.40 to 0.70 Wt.%, and the balance substantially iron. A process of heat treatment of the article includes the steps of quenching it from a first temperature at a preselected rate and of holding it at a second temperature for less than about two hours to complete transformation of the alloy directly from an austenite morphology to a substantially complete low temperature bainite morphology.
Claims20
A bainitic steel alloy article consisting essentially of carbon in the range of 0.60 to 0.80 Wt.%, manganese in the range of 0.45 to 1.00 Wt.%, silicon in the range of 0.15 to 2.20 Wt.%, molybdenum in the range of 0.40 to 0.70 Wt.%, boron in the range of about 0 to 0.004 Wt.%, a plurality of residual elements individually limited to less than 0.30 Wt.% and the balance substantially iron, said article having a substantially complete low temperature bainite morphology including less than 10 Vol.% retained austenite in the microstructure.
Dependencies are inferred from the claim text.