169results about How to "Improves wall thickness uniformity" patented technology

The invention discloses a useful wrinkle prefabrication method for improving the internal high-pressure forming limit in a pipe, and belongs to the technical field of pipe hydraulic forming. The useful wrinkle prefabrication method can solve the problems that control difficulty and mutual restriction of wrinkles exist in the useful wrinkle high-pressure forming high-expansion-rate pipe fittings made of low-plasticity materials. An induction heating device is used for locally heating a wrinkle-required position of a low-plasticity pipe blank, and after the local temperature of the pipe blank meets the requirement, bending and plastic instability occur in the pipe blank at the heated position under the action of axial material supplementation or under the combined action of internal pressureand axial material supplementation, thus forming the local wrinkles, and the forming continues in such manner until the preforming of all the wrinkles are completed. A useful wrinkle pipe blank is placed into an inner high-pressure forming die, and then pressurized and shaped until the prefabricated wrinkles are completely ironed, attached to dies and formed into final pipe fittings. According tothe useful wrinkle prefabrication method, the dependence on the die structure is avoided, materials are pre-gathered in the inner high-pressure forming areas through the useful wrinkle prefabricating, the limit expansion rate of the pipe fittings is larger after the wrinkles are ironed, and accordingly the distribution of wall thickness is more uniform.