Clamping tool for conveniently machining grading ring

The utility model relates to the field of grading ring machining structures, in particular to a convenient and fast grading ring machining and clamping tool which comprises a machining platform, a middle limiting piece and an opening positioning piece, the opening positioning piece enables the other sides of two positioning rods to synchronously move on a sliding rod face to face or back to back by shifting the sides, close to a positioning cylinder, of the two positioning rods at the same time. The center line of the V-shaped positioning piece is collinear with the transverse center line of the rectangular bottom plate, so that accurate limiting at the opening of the grading ring is realized, the positioning accuracy of the follow-up fixed pressing plate and the grading ring bracket is improved, and the welding accuracy is further improved; the first machining groove is used for achieving positioning and supporting of the lower ends of the two grading ring supports which are close to each other so that preci