| 摘要 |
PROBLEM TO BE SOLVED: To lengthen the period of time required for the inspection and maintenance of a roll supporting equipment, and reduce the expenditure of inspection and maintenance. SOLUTION: An inner race 5a, outer races 5b and 5c, and a tapered roller 5d, are made out of cemented steel (SNCM 815, SNCM 420, SCM 420, SCr 435, SCM 435 or the like) containing 0.12 to 0.40% carbon content, preferably 0.12 to 0.35% carbon content, 25 to 35% remaining austenite by volume, and a carbonitriding layer A which contains at least 0.80% carbon content, and has Rockwell hardness HRC 58 and greater, is formed over the surface of the parts 5a, 5b, 5c and 5d. It is preferable that the texture size of remaining austenite in the carbonitriding layer A is not more than 10 μm, and the quantity of remaining carbide is not more than 10%. |
