Rolling component and manufacturing method thereof

Abstract

A rolling component formed by carrying out spheroidizing annealing, processing, carbonitriding, and finishing on steel material containing, by mass, 0.90% to 1.10% carbon, more than 0.35% and up to 0.70% silicon, less than 0.80% manganese, 1.85% to 2.50% chromium, and oxygen in the amount of 12 ppm or less. On the surface, the mean quantity of carbon is 1.20% to 1.50% by mass and the mean quantity of nitrogen is 0.10% to 0.60% by mass. There are at least 700,000 deposits with particle diameter of 0.1 [mu]m or more per square millimeter of the surface. Said deposits have a mean particle diameter of 0.6 [mu]m or less and a surface area ratio of 10% or more. The volume fraction of retained austenite on the surface is between 25% and 45%. The surface hardness is Hv 750 or more. The volume fraction of retained austenite inside the rolling component is 20% or less.

Description

technical field [0001] The present invention relates to a rolling part and a manufacturing method thereof, in particular to a rolling part suitable for use in an impurity-containing lubricating environment and lubricating oil, such as a drive transmission unit for an automobile, and a manufacturing method thereof. [0002] Incidentally, in this specification and claims, the term "rolling member" refers to a member subjected to rolling contact alone or a combination of rolling contact and sliding contact. Background technique [0003] As rolling parts used with lubricating oil containing impurities, for example rolling / sliding parts are known. The rolling / sliding parts are manufactured through a carburizing process, a rapid cooling process, and then an annealing process in which bearing steel (high carbon chromium bearing steel) such as JIS SUJ2 is treated by machining so that It has a predetermined shape to obtain a component raw material, which is heated at 870° C. for 3 h...

AI Technical Summary

Problems solved by technology

[0007] However, among these measures, the amount of alloy components of the steel is too much, which increases the material cost of JIS SUJ2, which causes a problem of impairing economic versatility

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