Carburized component and manufacturing method therefor

Abstract

Provided is a carburized component having excellent fatigue strength in the "low-to-mid-cycle regime." Said carburized component comprises a steel having a chemical composition as follows: the base steel contains 0.15-0.25% carbon, 0.03-0.50% silicon, more than 0.60% and up to 1.5% manganese, no more than 0.015% phosphorus, 0.006-0.030% sulfur, 0.05-2.0% chromium, no more than 0.10% aluminum, no more than 0.03% nitrogen, and no more than 0.0020% oxygen; the steel also contains specific amounts of molybdenum, copper, nickel, boron, titanium, niobium, and / or vanadium as necessary; and the remainder comprises iron and impurities. The surface hardened layer of the carburized component fulfills the following conditions: (a) the mean carbon concentration up to a depth of 0.2 mm from the outermost surface is between 0.35% and 0.60%; (b) the surface roughness Rz is at most 15 [mu]m; and (c) the compressive residual stress at the outermost surface of the component is no more than -800 MPa, thecompressive residual stress 100 [mu]m from the outermost surface of the component is no more than -800 MPa, and Ir is at least 80,000, where Ir is the integral of sr(y) dy from 0 to 100, y being the depth in [mu]m from the outermost surface of the component up to a depth of 100 [mu]m and sr(y) being the residual stress at a depth y.

Description

technical field [0001] The present invention relates to a carburized part (hereinafter referred to as "carburized part") and a method of manufacturing the same. More specifically, it relates to high-strength steel carburized parts that can be used as various shafts of automobiles, construction machinery, industrial machinery, etc., power transmission parts, and the like, and a manufacturing method thereof. More specifically, it improves the strength, especially the fatigue strength in the so-called "low to medium cycle region" that occurs with the impact load, that is, "when repeated impact loads are applied to impart plastic deformation, at 10 3 ~10 4 A high-strength steel carburized part and a manufacturing method thereof. Background technique [0002] Automobile parts such as axle shafts, drive shafts, outer races for constant velocity joints, or gears for power transmission, construction machinery parts, and industrial machinery parts are usually machined into a prede...

AI Technical Summary

Problems solved by technology

However, in this method, two treatments of "carburizing and quenching" and "induction quenching" are performed at the same time as the surface hardening treatment, so the manufacturing cost increases

In addition, there is no disclosure about the fatigue strength in the low to medium cycle range

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