Ambient-hydrogen-level assessment method and white-structure-damage-likelihood prediction method

Abstract

Provided are a method for determining the degree of hydrogen environment during operation of a rolling device, and a method for predicting the likelihood that white tissue damage occurs in the rolling device due to operation. The method for determining the degree of hydrogen environment is a method for determining the degree of hydrogen environment, which is an index indicating the magnitude of the influence on hydrogen, in the operating conditions of a rolling device having two rolling members in rolling contact with each other and at least one of the two rolling members being a steel rolling member. Furthermore, the method for determining the degree of hydrogen environment comprises a measurement step for measuring the amount of normal-temperature non-diffusible hydrogen contained in a rolling fatigue region, which is a region where rolling fatigue occurs due to rolling contact, in a steel rolling member of a rolling device operating under the operating conditions; and a determination step for determining the degree of hydrogen environment on the basis of the measurement result in the measurement step.

Description

technical field [0001] The invention relates to a method for judging the degree of hydrogen environment and a method for predicting the possibility of white tissue damage. Background technique [0002] When hydrogen penetrates into the steel forming the rolling parts of the rolling gear, the metal structure of the steel may change due to the interaction between the shear stress acting on the inside of the steel due to rolling contact and the hydrogen. This change in metal structure is a phenomenon in which martensite, which is the matrix structure of steel, changes into fine ferrite grains. If etching is performed to observe the structure change part, it looks whitish, so the metal structure changed by the intrusion of hydrogen is called "white structure". If white structures are formed in the steel, fatigue cracks will occur at the interface between the structure-modified part and the normal part (structure-unchanged part) and peel off, so the rolling fatigue life of rolli...

AI Technical Summary

Problems solved by technology

[0004] However, in the case of a rolling device used in an actual machine (for example, an automotive alternator), even if it is intended to quantify the amount of normal-temperature diffusible hydrogen contained in the rolling parts, hydrogen may be released from the rolling parts before the measurement. Diffusion hydrogen at room temperature, so accurate quantification is difficult

Therefore, it is difficult to determine the hydrogen environment degree of the rolling device when used in an actual machine, or to predict the possibility of white texture damage such as white texture peeling in the rolling device when used in an actual machine.

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