Key points of heat treatment for aluminum profile extrusion molds
1. The quality of heat treatment for aluminum profile extrusion molds directly affects their service life. The molds are quenched and tempered multiple times to meet the hardness requirements. Quenching is to improve the hardness of the mold, and multiple tempering is to improve the toughness of the mold and stabilize the internal structure. Hardness value regulations for mold heat treatment:
Large aluminum extrusion mold (F>500mm), HRC45-48; Medium mold (F300~500mm), HRC47-50; Small extrusion mold (F<300mm), HRC48-51; Three points are tested on the same plane of a set of molds, and the hardness value of each point should be within the specified range to be considered qualified.
2. Special attention should be paid to the following points during the heat treatment process of extrusion molds:
a. The heating speed in the high-temperature section should be fast, and the insulation time should not be too long to prevent the extrusion mold from overheating or overheating. Overheating - coarse grains, overheating - low melting point elements and inclusions will dissolve;
b. After quenching, aluminum extrusion molds should be tempered in a timely manner to prevent cracking;
c. If the hardness of the extrusion mold is found to be insufficient or uneven after heat treatment, annealing should be carried out and the heat treatment should be carried out again according to the process (when the hardness value is less than HRC35, annealing can be omitted and heat treatment can be carried out directly);
d. For large aluminum extrusion molds or finished molds with complex cavities, a stress relieving and tempering process should be added (to eliminate electrical and mechanical processing stresses, that is, to eliminate thermal and structural stresses);
e. What is the temperature of the quenching oil for the mold? 100 ° C to ensure quenching effect.