Magnesium alloy die-casting mold lubrication problem how to consider?
Magnesium alloy die casting aluminum alloy as easily as the sticky mold this is due to the very low solubility of magnesium in iron. But in some parts of the pressure due to hot metal at high speed impact pressure type surface sticking die or are likely to occur also need to use the appropriate pressure type lubricant as demoulding agent, thimble oil most cases using water-based pressure lubricant. Magnesium thermal content only the same volume of aluminum heat content of the 2/3, lubricant used less use time was also shorter generally can be reduced to the using time of 50% aluminum alloy. Recommend the use of magnesium for pressure type lubricant and special cleaning agent but aluminum pressure type lubricant generally can meet the requirements of the use of magnesium die casting. Die casting process should try to avoid what defect? Die casting production of pressure casting are relatively easy to produce the following some casting defects these defects how often and die-casting equipment, mold, and the specific operation of the process. In order to obtain high quality castings die-casting process should try to avoid these defects. ( 1) does not completely fill. The injection speed is not enough, die temperature is low, the liquid metal temperature is low, the gate design of inappropriate and insufficient pressure chamber exhaust will produce such defects. ( 2) cold shuts. Die temperature is too low resulted in partial metal ahead of crystallization when partial solidification of metal bump into each other and is easy to produce such defects. ( 3) porosity, shrinkage hole and hole. Die casting injection punch head first phase velocity caused by excessive volume of gas vent design unreasonable lubricant containing water in metal purity and low solidification pressure is insufficient casting system design is not reasonable and easy to generate such defects. ( 4) flow mark. This kind of defect is the result of the mold wall are pointed or lubricant overdose resulting in molten metal splash or turbulence. ( 5) the thermal crack. Due to the stress concentration sharp or casting off the top caused pressure bag and other reasons are likely to increase the hot crack tendency. ( 6) deformation, distortion and crack. In casting ejector when due to shrinkage stress may produce these defects |
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