What's the effect of mold heat treatment?
Mold heat treatment is to play the potential of mold materials, improve the performance of the mold. The mould performance must be satisfied: (including high strength, high temperature strength, thermal fatigue resistance) high hardness (wear resistance) and high toughness, and also has good machining, (including polishing good) weldability and corrosion resistance etc..
Mold heat treatment is an important process to ensure the performance of the mold. It has a direct impact on the manufacturing accuracy of the mold, the strength of the plastic mold, the service life of the die and the manufacturing cost of the mold.
Complex mold, the processing technology is correct or not, the deformation of the mold often have a greater impact, and some of the mold heating process contrast, it can be seen that the heating rate is faster, often produce larger deformation.
(1) the cause of deformation
Any metal heating will be expanded, because the steel when heated with a mold, each part of the uneven temperature (i.e. the non-uniform heating) will inevitably lead the mold expansion of the inconsistency, which causes uneven heating stress. In the following steel transition point temperature, uneven heating mainly produce thermal stress, phase transition temperature over uneven heating, will produce the transformation range, produces both stress. Therefore, the faster the heating rate, the greater the temperature difference between the die surface and the heart, and the greater the stress, the greater the deformation of the mold after heat treatment.
(2) preventive measures
When the complex mold is heated under the phase change point, it should be heated slowly. Generally speaking, the mold vacuum heat treatment deformation is much smaller than that of the salt bath furnace. By using a preheating, preheating for low alloy steels for high alloy mould, diamond mould should adopt two preheating.