Abstract: A ball bearing has an outer circumferential surface of an inner ring subjected to a surface treatment by laser cladding in a circumferential direction, forming an annular first build-up layer with which a plurality of balls 4 is brought into contact so that the balls are rolled in the circumferential direction (first build-up layer formation step). An inner circumferential surface of an outer ring is subjected to a surface treatment by laser cladding in a circumferential direction, thereby forming an annular second build-up layer with which the plurality of balls contacts so that the balls can be rolled in the circumferential direction (second build-up layer formation step).

Abstract: A ball bearing has an outer circumferential surface of an inner ring subjected to a surface treatment by laser cladding in a circumferential direction, forming an annular first build-up layer with which a plurality of balls 4 is brought into contact so that the balls are rolled in the circumferential direction (first build-up layer formation step). An inner circumferential surface of an outer ring is subjected to a surface treatment by laser cladding in a circumferential direction, thereby forming an annular second build-up layer with which the plurality of balls contacts so that the balls can be rolled in the circumferential direction (second build-up layer formation step).

Abstract: Metal-containing ores are extracted by a process and apparatus which avoid contaminating the product with fuel gas components. In a rotary kiln, a heat shock-resistant ceramic pipe is subjected to indirect high temperature heating, thereby allowing the extraction reaction to be conducted without heat producing fuel gases.