Electric pulse treatment method for lowering fatigue crack spreading rate of steel materials

A technology for fatigue crack growth and steel materials, which is applied in the field of fatigue life of high-strength steel materials, can solve the problems of easily changing the microstructure and mechanical properties of materials, and achieve the effect of prolonging fatigue life and reducing the expansion rate

CN109338093AInactive Publication Date: 2019-02-15INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2019-02-15
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses an electric pulse treatment method for lowering the fatigue crack spreading rate of steel materials, and belongs to the technical field of fatigue life of high-strength steel materials. Through the method, the steel materials with fatigue cracks are subjected to electric pulse treatment, the fatigue crack spreading rate of the steel materials is lowered, and thus the fatigue life of the materials is prolonged. In the electric pulse treatment process, the electric pulse discharge waveform is in a damped waveform, the discharge period is 400 ns, treatment is conducted twice, the first treatment working voltage is 9-10 kV, and the second treatment working voltage is 10.5-12 kV. The method can be used for research and engineering application of crack arresting, crack healing and fatigue damage repair and fatigue life prolonging of the high-strength steel materials.
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Description

technical field

[0001] The invention relates to the technical field of fatigue life of high-strength iron and steel materials, in particular to an electric pulse treatment method for reducing the fatigue crack growth rate of iron and steel materials. Background technique

[0002] Most failures of engineering metal components originate from damage caused by fatigue behavior. The fatigue process includes two stages: fatigue crack initiation and fatigue crack growth. The occurrence of cracks in the service process of components is an important issue affecting the safety and reliability of components. How to suppress fatigue cracks is a realistic and critical issue in the service process of engineering components. So far, researchers have tried a variety of methods to increase the threshold of fatigue crack growth to inhibit crack generation and growth, thereby prolonging the service life of components. A common method is to improve the surface quality of the material to suppr...

Examples

Embodiment Construction

[0022] The present invention is described in detail below in conjunction with accompanying drawing.

[0023] The present invention utilizes high-energy pulse current equipment to pass the compact tensile (CT) sample ( figure 1 ), to stop the crack, reduce the crack growth rate, and achieve the purpose of crack healing to a certain extent. The electric pulse technology can be used for research and engineering applications such as crack arrest and crack repair of high-strength steel materials and their components.

[0024] Using the above-mentioned device to conduct electric pulse treatment on the compact tensile sample (AISI 4340 steel), and compare and analyze the effect with the sample without electric pulse treatment (AISI 4340 steel), the specific process is as follows:

[0025] (a) Prepare compact tensile (CT) specimens of AISI 4340 steel with dimensions such as figure 2 shown.

[0026] (b) Prefabricate cracks on compact tension-CT specimens by means of tension-tension...