Reduced pressure carburizing parts

Abstract

The objective of this invention is to stably suppress the formation of coarse grains in vacuum carburizing at high temperatures, where coarse grains are easily generated on the surface of the carburized layer, thereby providing a vacuum carburized part with excellent grain size characteristics and suppressed coarse ferrocarbon in the edge portion, and further providing a vacuum carburized part with excellent toughness. To solve this objective, this invention provides a vacuum carburized part having an edge portion of 150° or less; the area fraction of grain boundary carbides in the aforementioned edge portion is 5.00% or less, and the original ferrocarbon grain size from the surface of the aforementioned vacuum carburized part to a depth of 0.05 mm is 6.0 or more in terms of grain size number.

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