Heat exchanger, also known as heat exchanger, is a device that transfers heat from one heat-carrying medium to another. In industrial production processes, heating or cooling, that is, heat transfer, is often required. When one fluid exchanges heat with another fluid and is not allowed to mix, it is required to be carried out in a partition heat exchanger, which is used in chemical, petroleum, power, food and other industries. The main function of the heat exchanger is to exchange heat energy between hot and cold fluids. Heat exchangers in the prior art require welding during processing. Common welding techniques can easily damage the heat exchanger components and affect the processing quality.
In view of the above shortcomings in the existing production technology, a vacuum brazing process for titanium alloy heat exchangers is provided to ensure processing quality and extend service life. The technical solution adopted in this article is as follows: a vacuum brazing process for titanium alloy heat exchangers, including the following steps: Step 1: Preparation before welding, removing oxide scale and degreasing the surface of the workpiece and fixture;
Step 2: Assemble the workpieces;
Step 3: Put the assembled workpiece into the trackless hydraulic feeder, and then send it into the vacuum brazing furnace;
Step 4: At room temperature, vacuum the vacuum brazing furnace;
Step 5: Heat the vacuum brazing furnace to 850°C-1000°C at a speed of 3-8°C/min;
Step 6: Keep the vacuum brazing furnace warm for 40min-50min;
Step 7: Then raise the temperature to 1100°C-1200°C at a speed of 2-5°C/min
Step 8: Keep at brazing temperature for 15min-20min;
Step 9: Cool to 500°C;
Step 10: Keep warm for 8min-10min;
Step 11: Cool to below 100°C;
Step 12: Raise the temperature to 900°C at a speed of 3-8°C/min, then quickly cool to below 100°C, open the furnace and take out the workpiece;
Step 13: Clean up the solder droplets and accumulation. As a further improvement of the above technical solution
In the fourth step, the vacuum degree in the vacuum brazing furnace is less than 3X10-3Pa. The beneficial effects of this article are as follows: The process of this article is simple to operate. During the heating process, the parts are in a vacuum atmosphere, and there will be no oxidation, carburization, decarburization, pollution and deterioration. The parts are heated as a whole, the thermal stress is small, and the basic metal and There is low pressure around the brazing material, which can eliminate volatile impurities and gases released by the metal at the brazing temperature, and the properties of the base metal and the brazing seam are improved; vacuum brazing does not use flux, and there will be no pores or slag inclusion defects. The welding joint is bright and dense, with excellent overall performance.