Production of High Carbon Chromium Bearing Steel by Vertical Type Continuous Caster

Abstract

Rolling contact fatigue life of bearing steel is improved with a decrease in oxide nonmetallic inclusions. The oxygen content of high carbon chromium bearing steel has been reduced to an average level of 5.8 ppm. This is accomplished through the combined processes of an electric arc furnace, a ladle furnace, an R-H vacuum degassing vessel and a continuous caster.
Rolling contact fatigue life of high carbon chromium bearing steel thus manufactured and tested on the thrust type machine has accordingly doubled to tripled if compared with the conventional vacuum degassed, ingot cast steel.
From an operational standpoint, the supply of extremely low oxygen steel to the caster has resulted in the elimination of such troubles as nozzle clogging and has been the main contributor to a record 10 000 tons of continuous cast high carbon chromium bearing steel from one tundish without interruptions.
It has been demonstrated in the life tests that neither sulphur nor titanium influenced life when the levels of these elements were held down to a minimum in the high carbon chromium bearing steel. Life is further extended by the cold working inherent to cold pilgered tubes. The improvement in life has been found out in the tests to double to triple that of hot worked hollow tubes.