Method for testing cracking toughness of materials by orthogonal cutting process

Abstract

The invention discloses a method for testing the cracking toughness of materials by an orthogonal cutting process. The method comprises the steps of: 1) pre-processing a material sample to be measured; 2) mounting a force measuring instrument below a workpiece and fixedly connecting the force measuring instrument with a working table of a machine tool for measuring a cutting force Fc and a cutting thrust force Ft obtained by the force measuring instrument; 3) cutting the sample to be measured on the machine tool; 4) calculating or measuring the chip thickness ach under different cutting thicknesses ac; and 5) calculating to obtain the cracking toughness Gc of the cut material. The method has the beneficial effects that the stress state of the material in the orthogonal cutting process is a plane strain state, the sample to be measured does not need to be made into a specific shape, and the test process is simple and easy to implement; and a no-layer material and a basic body can be quickly cracked by a cutting tool, the problem of crack blunting of a high-toughness and low-yield-strength material can be effectively solved, and the conventional test method can be completely replaced with the method for measuring the cracking toughness of the material by the orthogonal cutting process.

Description

technical field [0001] The invention relates to the technical field of cutting processing and material performance testing, in particular to a method for measuring fracture toughness of materials by an orthogonal cutting method. Background technique [0002] Fracture toughness is an important performance parameter of materials (including metal materials and non-metal materials), which can characterize the ability of materials to resist fracture. When the crack in the machine part gradually expands, the stress field intensity factor K at the crack tip I increases accordingly, when K I When the critical value is reached, the crack in the machine part will produce unstable expansion, and the critical value of the stress field intensity factor is the fracture toughness of the material. When the crack tip is in the plane strain state, the value of fracture toughness is the lowest, which reflects the ability of the material to resist brittle fracture. Therefore, when measuring ...

AI Technical Summary

Problems solved by technology

The sample preparation process of this method is complicated in the early stage, and the production of equivalent defect cracks is relatively random and artificial, which makes it difficult to guarantee the measurement accuracy, and the measurement process takes a long time

[0004] For some materials with high toughness and low yield strength, when testing their fracture toughness, it is more difficult to test with existing methods due to the large plastic deformation area at the crack tip, which leads to crack passivation

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