Cleaning Before soldering, it is necessary to carefully clean the weldment in order to remove the oily and thick oxide film on the surface of the weldment. Specifically, all the weldments were first hot-alkali-washed (NaOH solution) at 80° C., washed with clean water, neutralized with acid, and dried. The pre-assembly welding fixture is mainly to connect and position each component and solder according to the requirements of drawings; adjust the reasonable gap of each weld to promote the capillary action; prevent and reduce the deformation during the welding process. Therefore, the rationality of the welding fixture design directly affects the dimensional accuracy of the parts and the quality of the welding quality. Because the box is composed of multiple parts and has a large external dimension, it is necessary to use elastic clamps at all joint surfaces during welding. This ensures that the weld gap (that is, the range of the capillary action of the solder) at high temperatures is 0.01- 0.10mm to meet the design requirements for welding strength. On the other hand, in vacuum aluminum brazing process, the removal of oxide film on the surface of aluminum alloy mainly depends on Mg activator. For the complicated structure of the weldment, in order to ensure that the base metal is fully affected by Mg vapor, the most common method is to weld. The pieces are placed in a stainless steel box (called a process box) and then heated in a vacuum furnace for brazing. This significantly improves the brazing quality. The box welding fixture is designed with a 0.1-0.14mm layer of brazing filler metal foil between the front panel, left and right side panels, rail plates, bulkheads, and fin welding contact surfaces. When the brazing material is melted, the brazing material is brazed. Filler gaps rely on capillary action to flow through the gaps in the welds, so the size of the gap depends on its wettability to the base metal. Based on the above factors, the design of the fixture structure shown in Figure 3, the fixture and the top screw and high temperature resistant springs, pads to all parts, including solder fastening at the same time, so that parts can be accurately positioned to prevent and reduce the welding process deformation . The backing plate also acts as a shield, the top plate changes the direction of the force, and the action of the spring causes the parts to be in a stressed state to ensure that a reasonable weld gap is always maintained during the welding process. According to the measured data before and after repeated welding, it can be seen that during the welding process, the shrinkage between the left and right side plates is about 1.5 mm, which can determine the length of the blank material in the length direction of the front plate, rear plate, and guide plate: Dimensions: 310 0.30 Process dimensions before welding: 311.50 0.3C. Weld Weld pieces and tooling together into a vacuum furnace and vacuum first (vacuum level 3 or higher). Through the implementation of the process of the chassis, its main advantage is the high quality of brazing, especially those with large dimensions and complicated structure. It has great reference value for the design and processing of similar parts. At the same time there are still some defects in vacuum aluminum brazing, such as deformation, etc., which need to be continuously improved and improved. Mining Dump Trucks are Off-highway dump trucks, which are used to transport coal and sand in non-highway field sites, such as large open-pit mines and water conservancy projects. In civil engineering, it is often combined with excavators, loaders, belt conveyors and other construction machinery to form a loading, transportation, and unloading production line to carry out the loading, unloading and transportation of earth, sand, and bulk materials. Mining Truck,Massive Mining Truck,Mining Dump Truck,Electrified Mining Truck NORTH HEAVY GRYPS EQUIPMENT AND ENGINEERING CO.,LTD , https://www.nhgtunnel.com
Vacuum device fixture structure analysis
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