Gray cast iron material has the advantages of low price, excellent casting performance, easy cutting and good wear resistance. It is a raw material widely used in industrial production. The improvement of its different properties can be applied to different fields, which is unmatched by other materials. When gray cast iron is used as the working surface of rolling guide rail, the external load is transmitted to the surface of gray cast iron through very narrow contact line, and alternating stress is generated in the process of reciprocating movement, resulting in fatigue wear failure of gray cast iron surface. Therefore, improving its surface anti fatigue wear performance is the key factor to determine whether gray cast iron material can be used in rolling guide rail. Aiming at the disadvantages of soft, poor mechanical properties and poor fatigue wear resistance of gray cast iron, based on the bionic coupling theory, this paper selects the biological prototype with excellent fatigue resistance in nature, and uses laser to carry out bionic coupling treatment on the surface of gray cast iron, so as to improve its surface mechanical properties and fatigue wear resistance. According to the concept of bionics, the selection of the form of coupling unit (point, strip and mesh) is particularly important to the improvement of different properties of materials, and the characteristic quantity of coupling unit has a great impact on the improvement of its properties. In addition, by artificially adding carbon element, the difference in the microstructure of the treatment area caused by the uneven distribution of graphite in gray cast iron can be overcome; At the same time, wear-resistant alloy elements are added to further improve the strength of the unit body, so as to improve the fatigue wear resistance of gray cast iron to a greater extent. Accordingly, the main research contents are as follows:
- Analyze the feasibility of Laser Biomimetic Coupling processing method, and calculate the theoretical maximum depth of defects, so as to guide the minimum processing depth of biomimetic unit in the experimental process.
- Under the same laser processing parameters, the effects of different biomimetic coupling element combination forms, including point, strip and mesh, on the fatigue and wear resistance of Biomimetic Coupling samples and the improvement mechanism are studied; By controlling the laser processing path, the influence mechanism of bionic unit orientation on the fatigue and wear resistance of materials is explored; Adjust the spacing of bionic units, compare the fatigue and wear resistance of materials under different spacing, and find out the best soft hard ratio under laboratory conditions.
- Through laser carburizing treatment, the microstructure and properties of the laser treated area are more consistent. On the premise of laser carburizing, the effects of different pre coated carbon layers on the microstructure, mechanical properties and fatigue wear resistance of the whole material were investigated; In addition, the effects of different laser energy on the fatigue wear resistance of Biomimetic Coupling samples with the same thickness of precoated carbon layer were studied.
- Through laser alloying treatment, break through the barrier of limiting the content of alloying elements in gray cast iron and improving the degree of unit body. Add Cr + W mixed alloy elements to the processing area, study the strengthening degree and strengthening mechanism of different elements on the coupling unit, and compare the advantages and disadvantages of bionic samples added with mixed elements and single alloy elements in fatigue wear resistance.
- Analyze the mechanism of improving the fatigue wear resistance of gray cast iron treated by laser bionics, simulate the stress distribution on the sample surface under laboratory conditions by using ABAQUS finite element analysis software, and further explain the mechanism of improving the fatigue wear resistance combined with the wear surface of bionic sample.
- Based on the manifestations of fatigue wear failure of gray cast iron under different treatment methods, the forms and mechanism of fatigue wear failure of gray cast iron are explained.