What are the reasons for the damage of die-casting die?
- Date：2022-07-12
- Read：676
Is it true that in the production and manufacturing of aluminum die casting, mold shells often crack, so what is the reason? In fact, the common type of die castings is cracks, and the internal stress is the primary cause of die shell damage. Heat, mechanical equipment, organic chemistry and use impact are all the sources of internal stress, including internal stress and thermal stress of mechanical equipment.
1、 The whole process of mold shell making
1. Quality problems of rough edge calcined products
Some moulds only produce dozens of moulds, which will produce cracks. Although it is possible to only ensure the external specifications when calcining, the loose defects in steel, such as dendritic crystallization, cementite mixing, collapsing holes and bubbles, are widened along the processing method, resulting in streamline.
2. The drilling internal stress formed in the whole process of finishing machining such as CNC lathe, cutting and scraper can be removed according to the baking in the middle.
3. When grinding quenched steel, it causes cutting internal stress, friction heat, softened layer and carburized layer in the cutting process, which reduces the thermal fatigue limit and is very easy to cause thermal cracks and premature cracks. For H13 steel, heat it to 510-570 ° C after cutting, and maintain it for 1 hour every 25 mm thickness, so as to carry out internal stress removal and baking.
4. Internal stress of spark discharge machining. The surface of the mold shell causes a variety of white layers of electric grade elements and electric polarization elements, and the hard brittle layer has cracks and internal stress. In the whole process of spark discharge machining, high frequency must be selected to avoid white layer as much as possible, remove the grinding and polishing method, carry out quenching solution, and carry out at three-level quenching temperature.
2、 Mold shell solution
If the heat treatment process is not suitable, the crack of the mold shell will be quickly discarded. In particular, we only choose aging treatment, do not carry out heat treatment, and do a good job in the whole process of surface nitriding. Aluminum die-casting has more than a thousand times of energy, and surface cracks and cracks occur. The internal stress formed in the steel heat treatment process is the result of the accumulation of the internal stress in the refrigeration process and the internal stress in the mechanism during the change process. The internal stress in the heat treatment deforms and causes cracking. The internal stress must be removed in the solid state according to quenching.
3、 In the production process of aluminum die casting
1. Type temperature
The mold shell must be heated to a certain temperature before manufacturing. Strong refrigeration occurs in the mold shell filled with high-temperature metal materials, the temperature field inside and outside the mold shell increases, resulting in internal stress, and the mold shell has cracks on the surface, sometimes cracks. In the process of production, the mode temperature keeps rising. When the mode temperature exceeds the temperature, it is very easy to produce viscous molds, and the common faults of fitness components cause the destruction of the surface of abrasive tools. Install the refrigeration automatic control system to maintain the operating temperature of the mold shell within a certain area.
2. Battery charging type
When liquid metal materials are added with mold shells under high pressure and fast speed, it is inevitable to cause fierce impact and soft brush to the abrasive tools, which will cause internal stress and thermal stress of the equipment. In the whole process of impact, the liquid, residue and vapor of metal materials will also cause complex oxidation, which will accelerate the generation of corrosion and cracking together with the mold shell surface. When the saturated solution of metal material contains vapor, the low-voltage area first expands in the die. When the air pressure increases, internal gas cracking occurs, which leads to destruction and corrosion cracks according to the quality points of metal material pulled out of the surface of the die.
3. Templet
In the process of pulling out the core and opening the mold shell, if some components are deformed, the internal stress of mechanical equipment will be generated.
4. Production process
In each manufacturing process of aluminum die casting, the heat exchanger between the mold shell and the saturated solution of metal materials produces regular temperature changes on the surface of the mold shell, resulting in regular thermal deformation and collapse, resulting in regular internal stress. If the mold shell surface is subjected to internal stress under working pressure during heating during pouring, open the mold shell and release the casting, and the mold shell surface will bear the Lashin stress to reduce the temperature. When this kind of communication and exchange internal stress circulates continuously, the internal stress accumulated in the internal structure of the mold shell becomes larger and larger. When the stress exceeds the fatigue strength of the raw material, cracks will appear on the surface of the mold shell.
1、 The whole process of mold shell making
1. Quality problems of rough edge calcined products
Some moulds only produce dozens of moulds, which will produce cracks. Although it is possible to only ensure the external specifications when calcining, the loose defects in steel, such as dendritic crystallization, cementite mixing, collapsing holes and bubbles, are widened along the processing method, resulting in streamline.
2. The drilling internal stress formed in the whole process of finishing machining such as CNC lathe, cutting and scraper can be removed according to the baking in the middle.
3. When grinding quenched steel, it causes cutting internal stress, friction heat, softened layer and carburized layer in the cutting process, which reduces the thermal fatigue limit and is very easy to cause thermal cracks and premature cracks. For H13 steel, heat it to 510-570 ° C after cutting, and maintain it for 1 hour every 25 mm thickness, so as to carry out internal stress removal and baking.
4. Internal stress of spark discharge machining. The surface of the mold shell causes a variety of white layers of electric grade elements and electric polarization elements, and the hard brittle layer has cracks and internal stress. In the whole process of spark discharge machining, high frequency must be selected to avoid white layer as much as possible, remove the grinding and polishing method, carry out quenching solution, and carry out at three-level quenching temperature.
2、 Mold shell solution
If the heat treatment process is not suitable, the crack of the mold shell will be quickly discarded. In particular, we only choose aging treatment, do not carry out heat treatment, and do a good job in the whole process of surface nitriding. Aluminum die-casting has more than a thousand times of energy, and surface cracks and cracks occur. The internal stress formed in the steel heat treatment process is the result of the accumulation of the internal stress in the refrigeration process and the internal stress in the mechanism during the change process. The internal stress in the heat treatment deforms and causes cracking. The internal stress must be removed in the solid state according to quenching.
3、 In the production process of aluminum die casting
1. Type temperature
The mold shell must be heated to a certain temperature before manufacturing. Strong refrigeration occurs in the mold shell filled with high-temperature metal materials, the temperature field inside and outside the mold shell increases, resulting in internal stress, and the mold shell has cracks on the surface, sometimes cracks. In the process of production, the mode temperature keeps rising. When the mode temperature exceeds the temperature, it is very easy to produce viscous molds, and the common faults of fitness components cause the destruction of the surface of abrasive tools. Install the refrigeration automatic control system to maintain the operating temperature of the mold shell within a certain area.
2. Battery charging type
When liquid metal materials are added with mold shells under high pressure and fast speed, it is inevitable to cause fierce impact and soft brush to the abrasive tools, which will cause internal stress and thermal stress of the equipment. In the whole process of impact, the liquid, residue and vapor of metal materials will also cause complex oxidation, which will accelerate the generation of corrosion and cracking together with the mold shell surface. When the saturated solution of metal material contains vapor, the low-voltage area first expands in the die. When the air pressure increases, internal gas cracking occurs, which leads to destruction and corrosion cracks according to the quality points of metal material pulled out of the surface of the die.
3. Templet
In the process of pulling out the core and opening the mold shell, if some components are deformed, the internal stress of mechanical equipment will be generated.
4. Production process
In each manufacturing process of aluminum die casting, the heat exchanger between the mold shell and the saturated solution of metal materials produces regular temperature changes on the surface of the mold shell, resulting in regular thermal deformation and collapse, resulting in regular internal stress. If the mold shell surface is subjected to internal stress under working pressure during heating during pouring, open the mold shell and release the casting, and the mold shell surface will bear the Lashin stress to reduce the temperature. When this kind of communication and exchange internal stress circulates continuously, the internal stress accumulated in the internal structure of the mold shell becomes larger and larger. When the stress exceeds the fatigue strength of the raw material, cracks will appear on the surface of the mold shell.