V-anvil with flat upper layer dabber swaging and turning method

Abstract

The invention discloses a method for elongating and turning over a mandrel with an upper flat and a lower V anvil. The divergence angle η of the large deformation zone is determined according to the reduction rate ΔH and the V anvil angle θ; there are two strong zones and one weak zone under the flat anvil, and a reasonable overturning process should give full play to the single anvil reduction effect so that the strong and weak zones can be reasonably matched. The deformation of the outer layer of the forging is equivalent to the deformation of the layer near the mandrel, thereby improving the uniformity of the overall deformation of the forging, so the theoretical flip angle ω should be η / 2; after rounding the number of flips n, it can be changed from 360° / n Obtain the actual flip angle ω t ; Considering that the deformation uniformity and compaction effect are poor during sequential turning, n turning should be divided into multiple groups for pressing, and each group is pressed symmetrically along the circumference. The flipping method of the invention can significantly improve the deformation uniformity in the circumferential and radial directions of the circular section of the forging, and improve the compaction effect of the forging.

Description

Technical field [0001] The invention belongs to the field of forging equipment and forging technology, and particularly relates to a method for extending and turning over a mandrel of an upper flat lower V anvil. Background technique [0002] With the continuous improvement of service life and safety, the quality and forging requirements of large forgings continue to increase. For example, the mechanical properties of a 700MW large hydraulic turbine hollow main shaft forging require a yield strength of ≥295MPa and a fracture strength of ≥480MPa. [0003] The hollow main shaft forgings of hydraulic turbines are typical large cylinder forgings. Compared with solid steel ingots to produce large cylinder forgings, the use of hollow steel ingots has the following advantages: significantly increase the utilization rate of steel ingots, eliminate the punching process, and simultaneously cool inside and outside to increase the solidification rate and reduce segregation, and improve the pro...

AI Technical Summary

Problems solved by technology

However, the tooling is relatively complicated, and it does not consider enhancing the compaction effect to eliminate shrinkage and porosity defects

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