Rolling Contact Hydrogen Assessment for White Structure Damage

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Solution Overview

Problem

Accurately assessing hydrogen environment severity and predicting white structure damage in rolling devices is challenging due to difficulties in measuring room temperature diffusible hydrogen, which is often discharged before measurement, and the complexity of quantifying hydrogen gas concentration and lubricant decomposition in actual machine operations.

Innovation Solution

A method involving the measurement of room temperature non-diffusible hydrogen in rolling fatigue regions, where an increase rate is calculated and used as an index to assess hydrogen environment severity and predict white structure damage likelihood, utilizing a database of operating conditions to determine critical values for damage occurrence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If room temperature diffusible hydrogen measurement is performed to assess hydrogen environment severity, then hydrogen environment severity can be assessed, but the measurement accuracy deteriorates because hydrogen is discharged from the rolling member before measurement

Engineering Contradiction:

Improvehydrogen environment severity assessmentVSAvoidroom temperature diffusible hydrogen quantification

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the measurement parameter from room temperature diffusible hydrogen to rolling fatigue hydrogen (non-diffusible hydrogen trapped in dislocation structures). This parameter change allows accurate measurement because the hydrogen remains trapped in the metal structure and does not discharge before measurement, while still providing reliable assessment of hydrogen environment severity and white structure damage likelihood

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses rolling fatigue hydrogen as an intermediary indicator to assess hydrogen environment severity. Instead of directly measuring the problematic diffusible hydrogen, the method measures the trapped hydrogen in rolling fatigue regions, which serves as a reliable proxy indicator for the hydrogen environment the rolling member experienced during operation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If measurement methods are simplified to enable practical use, then ease of operation improves, but measurement precision deteriorates due to inability to measure hydrogen gas concentration and lubricant decomposition directly

Engineering Contradiction:

Improvehydrogen environment assessment in actual machinesVSAvoidhydrogen gas concentration and lubricant decomposition quantification

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The rolling member itself serves as the measurement medium. The rolling fatigue regions within the rolling member naturally trap hydrogen during operation, and these trapped hydrogen amounts can be measured directly from the rolling member without requiring separate sensors or complex external measurement systems. This self-service approach enables practical application in actual machines while maintaining measurement capability

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables effective assessment of hydrogen environment severity and prediction of white structure damage likelihood, even in actual machine operations, by correlating the increase rate of non-diffusible hydrogen with operating conditions, thereby improving the reliability of rolling device maintenance and lifespan estimation.

Implementation Method 1

metal structure of steel sometimes changes due to interaction between shear stress exerted on the inside of steel caused by rolling contact and hydrogen. This change in metal structure is a phenomenon in which martensite that is matrix structure of steel transforms into fine ferrite grains

Methodology Applied

Scientific EffectPhase transformation: Phase Change

Implementation Method 2

Quantifying the amount of room temperature diffusible hydrogen among hydrogen having penetrated into a rolling member during operation of a rolling device

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS11828698B2Ambient-hydrogen-level assessment method and white-structure-damage-likelihood prediction method

Publication Date: 2023.11.28 NSK LTD

AI summary

Provided are a method for assessing hydrogen environment severity of a rolling device during operation and a method for predicting likelihood that white structure damage occurs to the rolling device as a result of operation. A hydrogen environment severity assessment method is a method for assessing, among operating conditions of a rolling device including two rolling members coming into rolling contact with each other and having at least one of the two rolling members being a steel rolling member, hydrogen environment severity, the hydrogen environment severity being an index representing magnitude of influence exerted by hydrogen. The hydrogen environment severity assessment method includes a measurement step of measuring the amount of room temperature non-diffusible hydrogen contained in a rolling fatigue region, the rolling fatigue region being a region where rolling fatigue has been produced by rolling contact, within the steel rolling member of the rolling device operated under the operating conditions and an assessment step of assessing the hydrogen environment severity, based on a measurement result in the measurement step.