Selection of casting mold frame material, quenching and tempering hardness, and long-term thermal deformation control | Export mold frame standard
Improper material and quenching of the mold frame resulted in continuous creep deformation of the mold frame, causing 43% of the parting surfaces to not fit tightly, long-term aluminum running, and positioning deviation.
The mold frame is made of 45 # steel that has not been fully quenched and tempered, and has been exposed to an environment of 220-280 ℃ for a long time. The creep rate increases and the parting surface arches and deforms.
The quenched and tempered hardness is lower than HB220, indicating insufficient creep resistance; Above HB280, the toughness of the mold frame deteriorates and the bolt hole position is prone to cracking.
The thickness of the mold frame is insufficient, and the bending stress caused by thermal expansion of the mold cavity cannot be released. The middle part is arched and the two ends are in contact.
The distance between the installation hole of the mold frame guide column and the template is too small, resulting in thermal expansion and compression, deformation of the hole position, and deviation of the coaxiality of the guide.
The mold frame has not undergone stress relief aging, and after rough machining, it is directly quenched and tempered. The residual stress from machining is overlapped with thermal stress, and it slowly deforms in the later stage.
Low pressure die-casting molds (LPDC), reverse pressure casting molds (CPC), differential pressure casting molds for wheel hubs, low-pressure casting molds for wheel hubs, gravity casting molds, motorcycle wheel hub casting molds, structural component casting molds, aluminum alloy wheel hub molds, aluminum casting forming molds, low-pressure casting tooling molds. Many customers only focus on the H13 cavity and ignore the quality of the mold frame, resulting in frequent long-term mass production problems. Zhejiang Xinfeng Machinery Export Mold Standard Mold Frame: Priority is given to P20 or 42CrMo quenching and tempering, HB220–280， Rough machining followed by stress relief and aging before precision machining. For three consecutive high-temperature working conditions, ordinary 45 # steel formwork is not recommended and is suitable for short-term trial molding in small batches. Mold frame cooling air duct/auxiliary water cooling can reduce the temperature of the mold frame body and suppress creep. It is strongly recommended to increase mold frame cooling in high-temperature workshops in the Middle East. Once the mold frame undergoes creep and arching, it is difficult to repair, and most can only be replaced as a complete set of mold frames, which is costly. Overseas high-end customer drawings will clearly indicate the mold frame material, hardness, and aging requirements to avoid long-term deformation risks.
FAQ
1. Question: What are the recommended materials for export mold frames?
Answer: Priority is given to P20 and 42CrMo, and long-term mass production of 45 # is not recommended.
2. Question: What is the optimal range for the hardness of mold frame quenching and tempering?
Answer: HB220-280, balancing creep resistance and toughness.
3. Question: What are the typical manifestations of mold frame creep deformation?
Answer: The parting surface is arched, the mold is not tightly closed, and there is continuous running of aluminum.
4. Question: What is the sequence of mold frame processing steps?
Answer: Rough machining → stress relief aging → quenching and tempering → precision machining.
5. Question: Is there a plan to improve mold creep in high-temperature workshops?
Answer: Add mold frame auxiliary cooling to reduce the body temperature.
6. Question: Is it difficult to repair the deformed mold frame?
Answer: Creep belongs to permanent deformation, which is difficult to repair and often requires replacement.
