Die casting factory: Principle of selection of die casting alloy temperature


Date:

2022-11-29

Die casting mould factory said that in the process of die casting, the forming conditions of die casting mould parts are very bad, and they are subjected to the repeated action of mechanical wear, chemical erosion and thermal fatigue.

Die casting factory: Principle of selection of die casting alloy temperature

Die casting mould factory said that in the process of die casting, the forming conditions of die casting mould parts are very bad, and they are subjected to the repeated action of mechanical wear, chemical erosion and thermal fatigue.

1. Molten metal enters the cavity at high pressure and high speed, producing strong friction and impact on the surface of the cavity, resulting in erosion and wear on the surface of the cavity.

2. Molten metal will inevitably bring slag into the pouring process. The slag produces complex chemical action on the surface of the molded part, and the aluminum and iron compounds act like wedges, accelerating the formation and development of cracks in the die casting die.

3. Thermal stress is the main reason of surface crack of injection parts. In the production process of each die casting, the surface of the molded part is not only scoured by the molten metal at high speed and high pressure, but also absorbs the heat released by the metal in the solidification process, resulting in heat exchange. In addition, due to the heat conduction of the mold material, the surface temperature of the molding part rises sharply, resulting in a large temperature difference with the inside, resulting in internal stress. When the molten metal is filled with the cavity, the surface of the cavity first reaches high temperature expansion, and the internal mold temperature is low, the relative expansion amount is small, so that the surface surface produces compressive stress. After opening the mold, the surface of the mold cavity is in contact with the air, and is chilled by the compressed air and the coating, resulting in tensile stress. The alternating stress increases with continuous production. When the fatigue limit of the die material is exceeded, the surface surface of the die will undergo plastic deformation and crack will occur.

Die casting factory states that the pouring temperature of the metal should be correctly selected during the use of die casting molds in order to better fill all the cavities and depths of the die casting mold and to ensure that the metals melt with each other as they flow. Selection principle of die casting alloy temperature:

1. The lower the temperature of casting metal, the longer the service life of die casting mold;

2. Low temperature die casting can reduce the increase of exhaust groove depth and the risk of molten metal splash;

3. Low temperature die casting can reduce the chance of the pressure chamber being locked by the ejector rod;

4. Using low temperature die casting can reduce the shrinkage cavity and crack of the casting.

In short, under the condition of technological conditions, the temperature of die-casting alloy should be selected as low as possible.

Die casting mould factory said that as a release agent for lubricating die casting mould and die casting, it is convenient for discharging die casting mould; As the lubricant of the die casting mold and the moving parts of the press, it can reduce the friction and prolong the service life of the die casting mold. In addition, it can also be used as a coolant for die casting mold to reduce the thermal fatigue caused by long-term work of the mold, thus extending the life of the mold.

The selection of lubricants shall meet the following requirements:

(1) Die casting can not stick in the cavity;

(2) Can not corrode the steel on the surface of the mold;

(3) no toxic gas will be produced;

(4) heating will not produce ash;

(5) After lubrication, it should be uniformly attached to the cavity and working surface, and not washed away by high pressure metal.