Key points of heat treatment of aluminum extrusion die
1. The quality of heat treatment of aluminum extrusion die directly affects the service life of the extrusion die. The die is quenched by “+” multiple times to achieve the hardness requirement. Quenching is to improve the hardness of the mold. Multiple tempering is to improve the toughness of the mold and stabilize the internal structure. The hardness value of the heat treatment of the mold specifies:
Large aluminum extrusion die (F>500mm), HRC45-48; medium mold (F300~500mm), HRC47-50; small extrusion die (F<300mm), HRC48-51; test on the same plane of a set of molds At three points, the hardness value of each point should be within the specified range.
2. Pay special attention to the points during the heat treatment of the extrusion die:
a, the high temperature section heating rate should be fast, the holding time should not be too long, in order to prevent over-burning or overheating of the extrusion die, overheating - coarse grain, over-burning - low melting point elements and inclusions to dissolve;
b. After the aluminum extrusion die is quenched, it should be tempered in time to prevent cracks;
c. After the heat treatment of the extrusion die, if the hardness is not enough or the hardness is not uniform, the annealing should be performed, and the heat treatment should be repeated according to the process (when the hardness value is <HRC35, the heat treatment can be performed without annealing);
d. For large aluminum extrusion dies or complex molds with complex cavities, a stress-free tempering process should be added (eliminating electrical machining and machining stress, ie eliminating thermal stress and structural stress);
e, mold quenching oil temperature should be 100 ° C to ensure quenching effect.