A device and method for testing metal corrosion fatigue crack growth

Abstract

The invention discloses a device and method for testing metal corrosion fatigue crack growth, comprising a base and a corrosive medium container; the lower surface of the base is designed with a fatigue testing machine clamping part, which is used for clamping the lower chuck of the fatigue testing machine ; The upper surface of the base is designed with a sample locking piece, which is used to fix the lower end of the fatigue sample; the upper end of the fatigue sample is clamped by the chuck on the fatigue testing machine. The alternating load loaded by the fatigue testing machine can be transmitted to the sample through the clamping parts of the fatigue testing machine. The corrosive medium container is a cylindrical structure, and the bottom end is fixedly installed on the surface of the circular table in the base; the sample locking part in the base is located in the corrosive medium container. The test is carried out according to the set fatigue test parameters until the working section of the fatigue sample breaks; during the process, the microscope is used to record the initiation-expansion-fracture process of the crack. The invention has the advantages of realizing the corrosion fatigue performance test of metal materials in corrosive media in a static state.

Description

technical field [0001] The invention belongs to the field of corrosion fatigue crack damage detection of marine metal structural parts, and specifically relates to a device and method for testing the propagation of metal corrosion fatigue cracks when marine structural parts have corrosion fatigue problems when they are serving in marine environments. Background technique [0002] During the service process, marine metal structural parts are in a state of full immersion in seawater during the entire life cycle. On the one hand, they are eroded by seawater corrosive media, and on the other hand, they are subjected to periodic stress loading, resulting in corrosion fatigue fracture failure. Corrosion fatigue is a type of stress corrosion, and the metal defects caused by corrosion can be used as crack sources and then crack propagation occurs until fracture failure. Fatigue fracture of marine metal structural parts in corrosive environment has become the focus of research, and a...

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Problems solved by technology

[0003] The crack detection of the sample is the focus of corrosion fatigue research. The crack growth rate is directly related to the fatigue life of the sample. GB / T6398-2000 "Metallic Materials Fatigue Crack Growth Rate Test Method" introduces various measurement methods of the fatigue crack length in detail , including the flexibility method, the potential method, etc., and the determination method of the crack growth rate. These methods are based on a certain physical basis and calculated through formulas to indirectly obtain the value of the fatigue crack length, which leads to a gap between the measured value and the actual value. error to some extent

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