Abstract
Carbide segregation in ball-bearing steel has been said to be harmful in their life. But unfortunately there is no concrete experimental data on this problem. In order to see the effect of this segregation, flattening test which proved the strength at room temperature, and a life test were performed. Test pieces were taken from each ingot belonging to the same heats. These ingots were heated at high temperature for different durations. Concequently the grades of segregation in each ingot were found different. The ring made of the ballbearing steel were quenched, tempered and flattened between the two arms of a physical test machine. Carbide segregation slightly affected the flattening strength of the ring. But from the practical point of view, these effects could be neglected.
A life-test machine was invented by the Government Mechanical Laboratory. The small needle cut from the tube were rolled between three rolls. Their life was proved by the noise caused by the flaking on the suface of the needle. Microscopic segregation did not affect on the life of the ball-bearing steel.
