2022

large flange

Author：

Details of large flanges:
Large flanges are also called rolled flanges, spliced flanges, large diameter flanges, and wind power flanges.
Large flanges refer to flanges that exceed the size specified by the relevant state departments. Generally refers to the flange size above DN2000. Such products are all welded products without threaded buttons. The specifications often used for threaded products are DN15-DN100. In the national flange standard GB/T9119-2010, the largest size among the pressure standards of 0.25MPa to 1.6Mpa is DN2000. When it reaches the 2.5MPa pressure standard, the maximum is DN800. The production of such flanges must be produced by the construction party providing drawings. There are three production processes: forging, rolling and splicing. If the product size is too large, it can only be rolled and spliced.
Large flanges are divided into threaded (wired) flanges and welded flanges. The low-pressure small diameter has a wire flange, and the high-pressure and low-pressure large diameter use welded flanges. The thickness of the flanges and the diameter and number of connecting bolts are different for different pressures.
For the flanges connected to the head used on some large pressure vessels, in order to ensure the flatness and machining accuracy of the flange sealing surface, the above-mentioned flange processing technology is adopted to complete the flange body processing, and the flange and the head are processed. After welding together, the flange sealing surface should also be finished on a large vertical lathe.
There are many factors affecting the service life of large flanges. Due to the high viscosity of large flange materials and poor chip breaking performance, it is easy to cause chips to scratch the workpiece thread or tap chipping during the tapping process of large flanges. and other phenomena, affecting the processing efficiency and thread quality. In order to prolong the service life of taps and improve the quality of thread processing, the thermo-mechanical history of large flanges changes significantly over the entire length of the furnace coil mill, especially in the production of small and large flanges, which will strongly affect the recrystallization generated on the finishing mill. degree, grain growth and precipitation, and lead to dramatic changes in ultimate microstructure and properties over the entire length of the large flange. When grinding, the original geometry of the front guide must be maintained, and it is best to use a tap shovel grinding machine for grinding. The best way to solve the long base of the tap is to customize the tap with a short base according to the specific requirements of the thread being machined.