November 2020 Volume 2

FORGING RESEARCH AND TECHNOLOGY

Figure 9: Forging schedule for Type 2 FDFD to produce forgings with round and square cross-section from ingots with rectangular cross-section.

Such combination of swaging with two and four dies allows one to forge various ingots with rectangular cross-sections in one FDFD and to obtain forgings with round and square cross-sections in a vast dimensional range without changing the dies. For example, from an ingot with a diameter of 1000 mm and using just one set of dies, it is possible to obtain forgings with square cross-sections and sizes of 600 x 600 mm or 250 x 250 mm and any other intermediate sizes. Herewith, this forging technological process does not use the “square-square“ technique, which needs high forging forces due to the big contact area between a workpiece and dies.The technological process developed by our company is based on the forging technique of implementing the swages with small contact areas between a workpiece and dies at each pass and, therefore, not so high of forces are required from a forging press. Type 3 FDFDs have much more complex designs in comparison with other types of forging devices, and, consequently, they are used mostly for the production of forgings with rectangular cross-sections. Such types of FDFDs are efficient for cases when a company produces a big quantity of forgings with rectangular cross sections, which are made from complex steels and alloys and have various sizes. The technological capabilities of Type 3 FDFDs are closely associated with its design features. In this device, two dies, which are located against each other, can change its location also with a help of electromotors, and owing to this a dimensional adjustment of the forgings with rectangular cross-section can be accomplished. It does not usually take more than one minute to change the settings from one dimension of a forging to another. All four dies in Type 4 FDFDs , as opposed to the FDFDs of Types 1-3, are moving uniformly in radial directions towards to each other. This does not give many advantages for Type 4 FDFDs over those devices of Types 1-3. Similar to forging in RFMs, a uniform radial swaging from four sides does not ensure an intensive deformational treatment of a metal as-cast structure. Therefore, Type 4 FDFDs are recommended to be used only for those workpieces that have already

undergone a preliminary deformational treatment (i.e., workpieces that do not already have an as-cast structure of the metal. However, Type 4 FDFDs have one significant advantage over Types 1-3 FDFDs. Depending on the technological task, Type 4 FDFDs can be manufactured with certain inclinations of sliding surfaces on sliders and top/bottom bodies of the device. Such forging devices with a certain inclination of sliding surfaces ensures a significant decrease of the technological force (up to 40%) during forging in comparison with the devices of Type 1-3. Owing to this such device provides a capability to forge workpieces from steels and alloys with a high deformation resistance—heat resistant steels and alloys, for example, , using the forging presses with low power. 5. Industrial Application The real advantages of FDFD application under industrial conditions can be assessed only through the case histories. For example, one of the companies in Western Europe introduced our technology to forge 9Cr1Mo ingots using 30MN forging press and Type 1 FDFD. Before FDFD was ordered and installed into this press, the forging of the ingots with diameters of 600 mm and lengths of 1500 mm was performed using two dies during 25 passes according to the following forging schedule (see the Forging Schedule No. 1 below): Forging Schedule No. 1: Ingot with Ø600 mm (1,0°) → 530 х 630 mm (2,90°) → 530 х 550 mm (3,90°) → 470 х 550 mm (4,90°) → 470 х 490 mm (5,90°) → 400 х 490 mm (6,90°) → 400 х 420 mm (7,90°) → 350 х 420 mm (8,90°) → 350 х 370mm(9,90°) → 300 х 370mm(10,90°) → 300 х 320 mm (11,90°) → 260 х 320 mm (12,90°) → 260 х 280 mm (13,90°) → 255 х 280 mm (14,90°) → 255 х 265 mm (15,90°) → 255 х 335 mm (16,45°) → 290 х 335 mm (17,90°) → 290 х 300 mm (18,90°) → 255 х 300 mm (19,90°) → 255 х 255 mm (20,90°) → 255 х 255 mm (21,45°) → 255 х 255 mm (22,90°) → Ø250 mm (23,45°) → Ø250 mm (24,40°) → Ø250 mm (25,35°) → final forging withØ250 mm.

FIA MAGAZINE | NOVEMBER 2020 115