To insure the spinning temperature,the interspace of pipe blank and mold is less than or equal to 0.8 mm,the temperature of preheating the mold is less than or equal to 600℃,the pyramidal number of mold is greater than or equal to 1/1000,the mold length is within the bound of 1.5 times pipe blank extension coefficient.
Through adopting the phosphate lubricate to make an acid - zinc coating on the sur-face of the pipe the drawing speed, to and the extension coefficient are increased the times of drawing, intermediate annealing and acid pickling are reduced.
This paper as well advanced the mathematical model of the hydraulic components life estimation mechod and established the relations of the system target cleanliness to the life extension coefficient The theory basis were provided to decide target cleanliness of contamination control for hydraulic and lubrication systems.
The results showed that the tensile strength and tear strength reached the maximum 27.64 MPa and 90 kN·m~(-1) when the chain extension coefficient(f) was 0.8,and the tensile strength at 100% reached the maximum 6.23 MPa when f = 0.6,the elongation at break and the hardness(shore A) increased with the increase of f.
This review includes mainly negative or positive Riemann mapping theory correspondence of boundaries, convergence theorems, parameter representation, growth theorems, distortion theorems, quasicnformal extension, coefficient problems and variation formulas of biholomorhic mappings, and univalence of holmorphic mappins.