1. Manufacture of water distribution tanks for flue pipes: The headers of each section of the flue are made by medium frequency tube boring machine. Before the box tube is cut, magnetic particle inspection is performed on each header tube to ensure that the header tube has no defects such as cracks and pores. After the intermediate frequency bend is formed, the magnetic particle inspection is performed again to determine that there is no processing defect. The secondary tires are specially calibrated on all the clamped boxes, and the geometrical dimensions are strictly guaranteed to meet the drawing requirements. After the pipe end is machined to the groove, the upper butt joints are butt welded, the butt joint is controlled at 2mm, the argon arc welding is used to make the bottom, and the 507 is welded to cover the surface to ensure no deformation after welding. After the welded box weld is qualified by radiographic inspection, it can enter the next process.
2. Due to the difficulty of opening the ring header, three rows of machined holes with different angles need to be machined in the circumferential direction. We make special tires according to the different diameters and different angles of the ring header, ensuring that each hole after the drilling machine is processed is a radial hole, and the holes are reamed with a reamer to ensure the deviation and precision of the hole. Strictly remove the inside of the header without leaving any debris.
3. When assembling the flue body, firstly, according to the design and process drawings, a large number of assembled tires are produced, including the box positioning chassis, the fixed ring bracket, the connecting flange fixing bracket, and the heating surface tube positioning chuck. Strictly control the geometrical dimensions of the assembled tires, and ensure the assembly accuracy of the body with the accuracy of the tire. The material used for the tires here is about one quarter of the total weight of the body and is for single use. Although the investment is large and the labor is more, the overall manufacturing quality can be guaranteed, which we think is worthwhile.
4. When welding the body heating surface tube, use the welding process parameters reasonably, precise welding and strict inspection. The heating surface tube and the header are welded by 507. All the joints are machined and polished before welding, and after welding, the color is flawed. The argon arc welding is used for the butt joint of the heated surface tube, and the electric beveling machine is used to open the groove at the end of the pipe to ensure the welding butt joint. After positioning with a positioning card, the welding is performed, and ultrasonic testing is used after welding. The heating surface tube is made according to the drawings, and the test tires are produced to control the quality of the curved tubes. After the tube is clamped and welded, a ball pass test is performed to check the ellipticity of the tube. After the tube has passed the flaw detection, the tube and the fin are assembled and welded. The welding procedure is evaluated before welding, the section of the welded specimen is inspected, the weld fusion and penetration are checked, and the welding parameters are adjusted. The fin welding is carried out by carbon dioxide gas shielded welding. The total length of the welds of each set of flue is tens of thousands of meters, the workload is large, and the welding position is complicated and difficult. During construction, we overcome many unfavorable factors, strict process parameters, ensure the height of the solder fillet, use anti-splash liquid, reduce spatter around the weld bead, polish all welds after welding, check, and resolutely eliminate defects such as weld undercut.
5. After all the welding work is completed, the hydrostatic test is carried out. After the test pressure is passed, heat treatment is performed to eliminate the welding stress. We specially designed a heat treatment furnace for the flue for the shape of the flue and the actual conditions required for the heat treatment temperature. The volume of the furnace can be adjusted, and can be accommodated from small parts such as the lower insert inserter to the flue section of the furnace mouth section, which overcomes the excessive cost of the general annealing furnace single processing small parts, and can not accommodate the large-sized water distribution pipe. Disadvantages. The heating of the workpiece and the temperature inside the furnace are controlled by the computer to ensure the balance of the temperature gradient in the furnace and the furnace temperature increase speed is stable.