The invention belongs to the technical field of
metal machining, and particularly relates to a preparation
machining method of a large-
diameter pipe material and a special-shaped
pipe fitting. The preparation
machining method comprises the following steps of prefabricating a hollow blank by
punching, carrying out isothermy or hot mould combined
extrusion on the hollow blank, machining the inner and outer surfaces of an extruding tube blank, and carrying out multi-pass cold or hot power cone
spinning on the machined tube blank; carrying out intermediate heat treatment (which can be annealing or
solution treatment) on a semi-finished
pipe material product; repeatedly and alternately carrying out multi-pass power cone
spinning and the intermediate heat treatment, and carrying out power
spinning on the finished pipe material product; carrying out multi-pass composite spinning forming on the semi-finished pipe material product after heat treatment so as to obtain the special-shaped
pipe fitting; and carrying out acid
pickling and cleaning on the obtained
pipe fitting and special-shaped
pipe fitting and then carrying out
thermal treatment on the finished product. The preparation machining method of the large-
diameter pipe material and the special-shaped pipe fitting provided by the invention has the advantages that the large-
diameter pipe material and the special-shaped pipe fitting are prepared and machined, the product organization is uniform, the combination property is high, the forming is effort-saving, the additional value is high, and a product has good popularization and application prospect and definite
economic benefits and
social benefits.