A process for forming a low silicon rapid-carburizing wear resistant steel
article includes selecting an article formed of a steel material having
less than about 0.05% silicon by weight, and carburizing the article for a
preselected time and temperature to form an austenitic surface and attain
a carburized case depth which is at least 5% greater than the carburized
case depth of a similar article formed from a steel material having a
range of about 0.09% to about 0.25% silicon by weight and being carburized
at substantially same conditions of time and temperature. After quenching,
the as-carburized surface transforms into a microstructure of martensite
and retained austenite, being substantially free of intergranular oxides.
A low silicon rapid-carburizing wear resistant steel article formed
according to the present invention is particularly useful for making
gears, couplings, shafts, bearings, and similar articles subjected to a
combination of high bending loads, surface wear and contact fatigue.