Cutting Constitutive Equattion Establishment And Processing Analysis Of AZ31B Magnesium Alloy

Compared to other metal structure materials, magnesium alloy has series of advantages and is rich in resource, so it is increasingly attached by each country. At present, it has become a worldwide issue and a universal focus on magnesium alloy materials in its research, development and application. There are plenty of magnesium resources in our country. However, because of late beginning on magnesium and its alloys, we have a wide gap with developed countries, especially in magnesium alloy deep-processing technology and applications.Magnesium alloy cutting processing is a further processing against its material when it is made into machine components. It has the same essence with the metal cutting processing that the redundant metal of workpiece is cut off under the action of the tool. And it always accompanied by varieties of physical phenomena, such as cutting force, cutting heat, stress, strain etc.. However, magnesium alloy cutting processing has its particularity for its own characteristics. The ignition point of magnesium alloy is low, and it is easy to react with water to release hydrogen and cause an explosion. In addition, the application of magnesium alloy has become increasingly widespread; the researches of domestic and foreign scholars on its cutting processing are relatively few. Therefore, it turns to a significant topic to research the proper tool geometric parameters and cutting conditions in the current magnesium alloy cutting processing. At the same time, along with the development of numerical simulation technology, setting up the mechanical model of cutting of magnesium alloy and then using the finite element method to analyze the problems of magnesium alloy cutting processing can replace the actual cutting experiment in order to make it more effectively to analyze magnesium alloy cutting processing.In this paper, based on the analysis of the characteristics of magnesium alloy and its cutting processing requirements, the constitutive equation of AZ31B magnesium alloy is established by combining cutting experiment with finite element software when it is being processed. Then, the problems which occurred during the process of magnesium alloy cutting processing are analyzed by finite element software, and tool geometrical parameters and cutting processing conditions are also further optimized. The main contents are as follows:Firstly, in view of the analysis to the characteristics of magnesium alloy and the security problems that appeared during machining process, the tool geometric parameters and cutting conditions are selected. Moreover, the cutting processing type is determined lying on the Oxley theory.Next, Orthogonal cutting experiment is carried on to measure cutting forces through using the measuring system of cutting force, and the influence law of feed, depth of cut and cutting speed to cutting force are analyzed lately. OXCUT program is made to predict constitutive equation by using MATLAB software, and it utilizes the cutting force data that obtained in cutting experiment condition to calculate the parameters of Johnson-Cook in corresponding condition. The cutting process is simulated under the same condition as per mentioned experiment with the help of the finite element software. The experimental data and the predictions are compared to determine the error. If the total errors of the main cutting force and feed force are in a reasonable range, it will continue to simulate the cutting processing under other conditions by using this group of constitutive parameters. It’ll eventually describe the deformation regular of magnesium alloy if they have the similar results under several other conditions.Finally, with using finite element software, preliminary studies are made on the changing law of cutting forces during magnesium alloy turning processing, the distribution laws of cutting temperature, stress and strain, the respective influence law of tool rake angle and corner radius to cutting force and cutting temperature, and the distribution law of residual stress. Furthermore, the tool geometrical parameters and cutting conditions are optimized as well.