Outside the furnace, the aluminum alloy forging blank must be removed from oil and other wastes. The furnace cannot be mixed with the slab to prevent iron filings and air oxide filings from being mixed together, which is very easy to cause an explosion. The editor of Transit Aluminum specially reminds everyone that the blanks should not touch the heating components when installing the furnace to prevent short-circuit problems and damage to the heating components. The blanks in the furnace are placed 250-300mm away from the furnace mouth to ensure even heating. Put a thick steel plate between the blank and the heating wire to avoid over-burning of the blank during the heating process.
Aluminum alloy profiles have excellent heat transfer properties. All thin and thick blanks do not need to be heated, and can be heated immediately in a high-temperature electric furnace, and the regular blanks are heated to the limit of the aluminum alloy forging temperature. In order to better ensure the sufficient melting of the reinforcing phase, the heating time is generally still longer than the heating time of the slab, which can be measured at about 1.5 minutes per mm diameter (or thickness). Regarding whether the extruded billet or cold-rolled billet is heated to the forging temperature, is it necessary to have heat insulation, and the norm is that no cracks appear during aluminum alloy forging and free forging, and the casting must be insulated.
Deformation rate and degree of deformation
The deformation rate has no great harm to the plastic deformation of most aluminum alloy profiles. Only certain high-fine-grain reinforced aluminum alloy profiles can significantly reduce the plastic deformation when they are deformed at high speed. In addition, when connecting from a low deformation rate to a high deformation rate, the deformation resistance varies with the degree of fine-grain strengthening of the aluminum alloy, which is approximately 0.5-2.0 times larger. Therefore, aluminum alloy forging can be expanded at a low deformation rate as well as at a high deformation rate. However, in order to better expand the allowable degree of deformation and increase the consumption rate, reduce deformation resistance and improve the circulation of aluminum alloy filling molds, it is better to use presses and free forging to expand aluminum alloy forging than hammer forging. . For large and medium-sized aluminum alloy steel castings and die forgings, especially in this category.
When the aluminum alloy profile is forged on a high-speed hammer, the deformation rate is very large, the rolling friction force is very large, and the thermoelectric effect is also large, which makes the temperature rise (about 100°C) of the aluminum alloy during forging more significant. Therefore, the editor proposes that the initial forging temperature of aluminum alloy forging should be adjusted in many ways, and the heating temperature of the blank before forging should be the lower limit of the initial forging temperature originally requested.