Material anticorrosion function of concentric pipe fittings reducer

　　The preparation method of concentric pipe fittings reducer is to use a plurality of grading dies to directly conduct concentric pipe fittings reducer on the metal pipe, first leave the main pipe section in the middle of the whole metal pipe, and then use a plurality of grading dies to press the die step by step according to the requirements of the reducing angle.

　　The concentric pipe fittings reducer processed by the method of the invention has no weld on the whole concentric pipe fittings reducer; the concentric pipe fittings reducer is used as a special pipe, The utility model can prolong the service life of the concentric pipe fittings reducer in the highly corrosive liquid, especially the shell of the downhole eccentric water distributor, because there is no weld, it will not corrode and crack at the welded junction; the production process is flexible, and the concentric pipe fittings reducer with any diameter and any length of the concentric straight pipe section can be processed.

　　The middle of the concentric pipe fittings reducer is the main pipe section, and the two ends are the concentric straight pipe section. There is an concentric reducing transition section between the main pipe section and the concentric straight pipe section, and the bottom line of the concentric pipe fittings reducer is kept in a straight line.