First, the choice of forging parting surface
The principle of the parting surface selection is not only determined by the open die forging, but also the mold, process and other aspects should be considered according to the forming characteristics of the multi-directional die forging.
1. Partitioning of the parting surface
The requirements for the symmetry of the forgings relative to the parting surface should be met as much as possible, especially for the forgings with shoulders, shoulders and branches with buds. The shape of the parting surface is selected as much as possible to avoid the surface.
2. The position of the center of the forging hole
Multi-directional die forgings are mostly forged forgings, and the design of the forgings should be determined in the horizontal direction as much as possible, and the deformation in the holes is in a collapsed state.
3. Combination of molds
Since the die forging uses a plurality of split molds, the mold is divided into a plurality of combined shapes. The single-die mold is simple to manufacture, but to form a closed mold with a plurality of modules and a good matching precision, it is necessary to consider the easy combination of the modules when selecting the parting surface, and the work is stable and reliable.
4. Calculation of clamping force
In the multi-directional die forging, the clamping force of the die to the material is generally 1 to 4 times the extrusion force of the punch to the bad material, and therefore, the clamping force is greater than the forming force. Therefore, the maximum projection surface of the forging should be placed under the main hydraulic cylinder of the equipment, that is, the direction of the clamping force is designed in the direction in which the device can generate the maximum pressing force.
Second, forging machining allowance and tolerance
Multi-directional die forgings, especially some medium and small forgings, are often formed by closed precision die forging. Therefore, when designing the forgings, the forgings should be as close as possible to the contour shape of the product parts, greatly reducing the machining allowance and tolerances. . The machining allowance and tolerance for multi-directional die forging are generally selected to be 20% to 50% of the normal open die forgings of hot die forging presses.
Third, the fillet radius and deep hole slope
The size of the fillet radius of the multi-directional die forging is determined to be the same as that of the closed die forging part. The value is generally 1/4~2/1 of the ordinary die forging.
Since the multi-directional die forging die is generally a separable die and the forging is easy to die, the die forging slope may not be designed, or a less than or equal to 30' small slope may be taken. In addition, the die forging of deep-hole forgings should be determined according to the forming method of the forgings, and only the back-squeezing deformation is required for the open-type reverse extrusion forming, and the die-forging inclination can be omitted at this time. In the case of closed-end reverse extrusion forming, in addition to the reverse extrusion deformation, the round table and the shoulder at both ends are formed by upsetting, and the die forging inclination can be selected from 30° to 1°.