This article mainly introduces the high-efficiency processing method of large-scale metal tube sheet hole groups used in large-scale reaction vessels and heat exchangers in the petroleum and chemical industries. Choosing traditional boring and milling machines and radial drills has not been able to achieve the requirements of high efficiency, let alone the requirements of accuracy. BOSM large-scale heavy-duty CNC drilling and milling machines are specially developed and produced in this industry. At present, it has obtained the first set of BOSM-DS8585 in the country, which can realize the maximum workpiece diameter of 8500mm, and the smaller models are 6000×6000, 5000×5000, 4000×4000, 3000×3000, 2000×2000 and 1000×1000.
Clamp the tube plate on the CNC drilling and milling machine, install the pilot hole drill on the CNC drilling and milling machine, start the CNC drilling and milling machine, and use the CNC drilling and milling machine to process all the tube holes on the tube plate with the pilot hole depth of 20 ～ 30 ㎜ , In order to ensure the position accuracy of the tube holes on the large metal tube sheet.
The method for processing large-scale metal tube sheet hole groups according to requirements, characterized in that the diameter of the tube sheet is 5000 mm ~ 8000 mm, the thickness is 50 mm ~ 250 mm, and the material is GB150.2 “Material of the second part of pressure vessel” Specified metal materials; thousands to tens of thousands of reaction tube holes or heat exchange tube holes are arranged on the tube plate to form dense holes arranged according to a certain rule.
In the processing process, if a radial drill is used, the depth dimension processing becomes more difficult, and the reaction force cannot be satisfied with the increase in the feed rate. Due to the poor rigidity of the lengthened drill bit, if the lengthened bit is directly used for the initial hole, the reaction force of the tube plate test piece will easily cause the lengthened bit to bend, and the lengthened bit will easily bend under the rotating force, and the lengthened bit is rotating. Circumferential jitter begins to appear in the state of, although the amount of jitter is reduced after drilling to a certain depth, the direction of travel of the front end deviates from the expected downward linear trajectory, resulting in the end hole being drilled in the tube hole of the larger and thicker tube sheet The bridge width exceeds the standard. On the contrary, if you use a CNC drilling and milling machine, use a U drill, which has good rigidity and water out of the center. During the initial drilling, as long as the feed rate is controlled, the drilling will not bend or break.
The BOSM CNC drilling and milling machine replaces the traditional radial drill to process super-large tube sheets. The processing time of the CNC drilling and milling machine is only 23.5% of that of the radial drill. CNC drilling not only liberates the labor force, but also greatly improves the production efficiency. Radial drills cannot process thicker tube sheets. For example, if the thickness exceeds 300mm, it must be equipped with a CNC drilling and milling machine with U-drills. Because the radial drill cannot overcome the disadvantages of the upward-returning iron cutting, the quality of the tube sheet will also be greatly affected.
Post time: Nov-20-2021