Corrosion Fatigue Evaluation Method for Die Cooling Holes
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Solution Overview
Problem
Conventional methods for evaluating corrosion fatigue damage in components under repeated loads in corrosive environments, such as internal cooling holes of dies, face limitations in reproducing actual stress ranges and are time-consuming, requiring specialized testing machines.
Innovation Solution
A method involving a test piece with an internal space filled with a corrosive medium, where a load is repeatedly applied to the surface, allowing observation of the internal space to simulate and evaluate corrosion fatigue damage, using existing fatigue testing machines without the need for heat stress generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heating and cooling cycles are used to generate heat stress in the internal cooling hole, then fatigue can be reproduced in the internal cooling hole, but the test time becomes excessively long and acceleration testing becomes difficult
Solution Approach 1:
The patent replaces the thermal stress generation method (heating and cooling cycles) with a direct mechanical loading method. By applying repeated mechanical loads directly to the internal cooling hole using a testing machine, the fatigue damage is reproduced without requiring time-consuming thermal cycles, thus reducing test time while maintaining reproducibility
Solution Approach 2:
The patent changes the stress generation mechanism from thermal (heat stress) to mechanical (applied load). By controlling the magnitude and frequency of mechanical loads applied directly to the internal cooling hole, the fatigue damage can be reproduced in a controlled manner without the time constraints imposed by thermal cycling
2Reliability
If heating and cooling cycles are used to generate heat stress, then fatigue can be reproduced, but specialized testing machines are required
Solution Approach 1:
The patent replaces complex thermal testing systems with simple mechanical loading systems. By using a standard fatigue testing machine to apply repeated mechanical loads directly to the internal cooling hole, the need for specialized heating and cooling equipment is eliminated, simplifying the testing setup
3Ease of operation
If conventional stress corrosion crack test methods are used, then constant load testing is simple, but the test methods cannot reproduce the actual fatigue damage state caused by repeated loads
Solution Approach 1:
The patent transitions from static constant load testing to dynamic repeated load testing. By applying loads repeatedly to simulate the actual operating conditions of the internal cooling hole, the method accurately reproduces fatigue damage while maintaining operational simplicity through the use of standard testing procedures
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
This method enhances the reproducibility of actual use conditions, reduces test time, and eliminates the need for specialized equipment, enabling efficient evaluation of corrosion fatigue damage in dies and other fatigue members.
Implementation Method 1
a corrosive medium 5 which is sealed in a space 3 of a material piece 2 by seals 4 at both ends
Data Source
Figure 1~2
Figure 3~4
AI summary
Provided is a method for evaluating a corrosion fatigue damage wherein a corrosion fatigue damage occurring in various members such as the internal cooling hole of a die is reproduced easily by using a test piece. The method for evaluating a corrosion fatigue damage is carried out in such a manner that a load is applied repeatedly to the surface of a test piece having an internal space into which a corrosive medium is introduced, and the surface and/or the cross-section of the internal space in the load-applied test piece is observed. The method for evaluating a corrosion damage is carried out preferably in such a manner that a test piece, where a space simulating the internal cooling hole of a die is formed in a material piece consisting of the material of the die, and a corrosive medium simulating the cooling medium of the die is introduced into the space, is provided, a load is then applied repeatedly to the surface of the test piece, and the surface and/or the cross-section of the space in the load-applied test piece is observed.