| 摘要 |
The invention relates to the production of long articles from powders of various materials, as well as from plasticized masses, by means of extrusion. A device for forming long hollow articles comprises an extruder and a forming attachment consisting of a die, a mandrel and an assembly for securing the mandrel inside the die. The working surfaces of the forming attachment are provided with one or more rows of profiled deformation elements disposed with an equal circumferential pitch on the working surfaces of the die and/or the mandrel. A blank of a plasticized material is forced through the mandrel securing assembly into an annular axisymmetric deformation region formed by the working surfaces of the mandrel and the die. In said region, the material undergoes additional drawing and deformation treatment prior to sizing. The design features of the device make it possible to realize cyclic drawing and compressive strains in an axial direction and in surfaces enveloping the working surfaces of the die and the mandrel across the entire length of the annular region, and cyclic compressive strains in a radial direction, as well as cyclic oppositely signed shear and flexural strains, resulting in uniform, intensive deformation treatment of the entire volume of material prior to the sizing of the blank. The invention provides improved physical and mechanical properties of the long hollow articles produced and an increase in the yield of finished product by virtue of an increase in the uniformity of the properties of the material across the cross-section of an article. |
