Device and method for testing metal corrosion fatigue crack extension

Abstract

The invention discloses a device and a method for testing metal corrosion fatigue crack extension. The device comprises a pedestal and a corrosive medium accommodation container, wherein a fatigue machine clamping piece is designed on the lower surface of the pedestal and used for clamping the lower chuck of the fatigue machine; a testing specimen locking piece is designed on the upper surface of the pedestal and used for fixing the lower end of a fatigue testing specimen; the upper end of the fatigue testing specimen is clamped by a fatigue machine upper clamp; the alternating load of the fatigue machine can be transferred to the testing specimen through the fatigue machine clamping piece; the corrosive medium accommodation container adopts a cylindrical structure; the bottom end of the cylindrical structure is fixedly mounted on the upper surface of a circular table in the pedestal; the testing specimen locking piece in the pedestal is positioned in the corrosive medium accommodation container. The device is used for testing according to the test fatigue testing parameters until the working section of the fatigue testing specimen is broken; in the process, a microscope is utilized to record and shoot the producing-extending-fracturing process of the crack. The device disclosed by the invention has the advantage of realizing the corrosive fatigue performance test of the metal material in the corrosive medium under the standing 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...

AI Technical Summary

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

Images