熔覆工艺：激光熔覆按熔覆材料的供给方式大概可分为两大类，即预置式激光熔

Cladding process: Laser cladding can be roughly divided into two categories according to the cladding material supply method, namely preset laser cladding and synchronous laser cladding. [17] <br>(1) Synchronous laser cladding is to directly feed the cladding material into the laser beam, and simultaneously complete the feeding and cladding. The cladding materials are mainly supplied in the form of powder, and some are also fed by wires or plates simultaneously. The main technological process of synchronous laser cladding is: pretreatment of substrate cladding surface-feeding-laser melting-post-heat treatment. <br>(2) Preset laser cladding is to place the cladding material on the cladding part of the surface of the substrate in advance, and then scan and melt with laser beam irradiation. The most common is in powder form. The main technological process of preset laser cladding: pretreatment of substrate cladding surface-preset cladding material-preheating-laser cladding-post heat treatment. This method can solve the problem of the reflectivity of the matrix material to the laser, but the thickness of the coating is controllable. <br>(3) Through multiple experiments, it was found that if the copper substrate is properly preheated, a smooth continuous cladding layer can be obtained at a lower laser power and a higher moving speed, and the cladding process is stable. Therefore, the laser cladding in this paper is carried out on the substrate preheated at 300 ℃. In order to meet the application requirements of the guide rails, the preparation of thicker coatings was studied using multi-layer multi-pass lap methods. It was found that the laser cladding process will vary with the size of the substrate, the cladding area and the number of cladding layers. When continuous lap cladding is performed on a substrate with a small size, the temperature of the substrate will rise rapidly as the cladding proceeds, so the required laser power will be reduced; however, the actual guide rail cladding process At this time, due to the rapid heat dissipation of the substrate, the overall temperature of the substrate is difficult to rise, and no power adjustment is required; while in the multi-layer cladding process, due to the surface roughness of the deposited material and the change in the composition of the material, the laser absorption rate increases, which requires appropriate reduction Laser power or increase the speed of movement.

Cladding process: Laser cladding according to the supply of the material can be divided into two categories, namely, pre-set laser cladding and synchronous laser cladding. [17]<br>(1) Synchronous laser cladding is the direct feed of the cladding material into the laser beam, while completing the feed and cladding. The cladding material is mainly supplied in the form of powder, and some are also supplied synchronously using wire or sheet. The main process of synchronous laser cladding is: pretreatment of substrate cladding surface - feeding - laser melting - post-heat treatment.<br>(2) Pre-set laser cladding is the pre-positioned cladding material placed on the surface of the substrate, and then with the laser beam irradiation scanning and melting, the cladding material is added in the form of powder, silk, plate, the most common form of powder. The main process of pre-set laser cladding: pretreatment of substrate cladding surfaces - pre-set cladding materials - preheating - laser fusion - post-heat treatment. This method can solve the problem of laser reflectivity of the substrate material, but the thickness of the coating is controllable.<br>(3) Through a number of tests, it is found that if the copper substrate is properly warmed up, a smooth continuous cladding can be obtained at a lower laser power and a higher motion speed, and the cladding process is stable. Therefore, the laser cladding in this paper is carried out on a substrate that is preheated by 300 degrees C. In order to meet the application needs of the rails, the preparation of thick coatings is studied by multi-layer multi-way connection. As a result, the laser cladding will vary with the size of the substrate, the area of the cladding and the number of cladding. When continuous cladding on a smaller substrate, the temperature of the substrate will rise rapidly with the chum, thus the required laser power will decrease;

Cladding technology: laser cladding can be divided into two categories according to the supply mode of cladding materials, i.e. preset laser cladding and synchronous laser cladding. [17]<br>(1) Synchronous laser cladding is to send cladding materials directly into laser beam, and complete feeding and cladding at the same time. Cladding materials are mainly supplied in the form of powder, and some are also supplied synchronously by wire or plate. The main technological process of synchronous laser cladding is: surface pretreatment of substrate cladding - feeding - Laser Melting - post heat treatment.<br>(2) Preset laser cladding is to place the cladding material on the surface of the substrate in advance, then scan and melt it by laser beam irradiation, and the cladding material is added in the form of powder, wire and plate, the most common of which is in the form of powder. The main technological process of laser cladding: pretreatment of the cladding surface of the substrate - preset cladding material - preheating - laser cladding - post heat treatment. This method can solve the problem of laser reflectivity of matrix material, but the thickness of coating is controllable.<br>(3) Through many experiments, it is found that if the copper matrix is properly preheated, a smooth and continuous cladding layer can be obtained at a lower laser power and a higher moving speed, and the cladding process is stable. Therefore, the laser cladding in this paper is carried out on the substrate preheated at 300 ℃. In order to meet the application requirements of guide rail, the preparation of thick coating was studied by multi-layer and multi-channel lapping. It is found that the laser cladding process will change with the matrix size, cladding area and cladding layers. When the continuous lap cladding is carried out on the smaller size of the substrate, the temperature of the substrate will rise rapidly with the cladding, so the laser power required will be reduced; however, in the actual rail cladding process, because of the rapid heat dissipation of the substrate, the overall temperature of the substrate is difficult to rise, and the power does not need to be adjusted; while in the multi-layer cladding process, Due to the surface roughness of the deposited material and the change of material composition, the absorption rate of laser increases, so it is necessary to reduce the laser power or increase the moving speed.