1, the heat treatment quality of aluminum extrusion die directly affects the service life of the extrusion die, the die is quenched "+" multiple tempering to meet the hardness requirements. Quenching is to improve the hardness of the mold, multiple tempering is to improve the toughness of the mold, stable internal organization. The hardness value of mould heat treatment is stipulated: large aluminum extrusion mould (F> 500mm), HRC45-48; Medium die (F300~500mm), HRC47-50; Small extrusion die (F< 300mm), HRC48-51; Test three points on the same plane of a set of molds, and the hardness value of each point should be qualified within the specified range.
2. Special attention should be paid to the following points in the heat treatment process of extrusion die:
A. The heating speed of the high temperature section should be fast, and the holding time should not be too long, in order to prevent the extrusion mold from over-burning or overheating, overheating - coarse grain, over-burning - low melting point elements and inclusion dissolution;
B. Aluminum extrusion die should be tempered in time after quenching to prevent cracks;
C, extrusion mold after heat treatment found hardness is not enough or uneven hardness, should be annealed, according to the process of heat treatment (when the hardness value < At HRC35, no annealing, direct heat treatment);
D, for large aluminum extrusion die or finished die with complex cavity, a de-stress tempering procedure should be added (to eliminate the stress of electric machining and machining, that is, to eliminate the thermal stress and organizational stress);
E. Temperature of the quenching oil of the mold? 100°C to ensure quenching effect.
