Industry news
Analysis and countermeasures of mould casting defects related to mould shell-2
In the process of investment casting, there are 35 kinds of casting defects frequently occurring, among which there are 18 kinds of defects caused by the mould shell problem.
Steel Leakage
Characteristics: The surface of the casting has an excess part, its shape is irregular, the surface is rough, mostly seen in narrow grooves and small diameter holes. The direct cause is the pouring of the metal liquid through the shell surface layer, drilling into the sand between the pores caused by.
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Causes |
countermeasures |
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High floating sand in holes, grooves or corners |
Shake and shake off the floating sand carefully after spreading the sand, and blow with an air nozzle if necessary. |
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Coarse abrasive particle size Paint lumps and other agglomerates in the abrasive. |
Use a finer grit Carefully sift out lumps and clumps in the spreading material. |
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Surfacing and transition layers of sprinkled sand are polygonal in shape and have poor flowability. |
Surfaces and transitions are made of spherical sand spreaders. |
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Insufficient partial drying/hardening of the top coat, low strength of the coating layer |
Extend drying/hardening time Change to a better quality binder if necessary |
| High viscosity of overcoat or backcoat slurry |
Reduce the viscosity of the overcoat or backcoat slurry as appropriate. |
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Improper slurry sticking operation method, so that the paint slurry can not enter the holes, grooves and corners, etc. |
Take care to wet the entire module completely and thoroughly, using tools such as air nozzles or brushes to assist if necessary. |
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Due to the small holes and slots, after making 1~2 layers of shells, coating and sanding can no longer be carried out. |
After making 1~2 layers of shells, fill the holes and grooves with fine dry sand, then seal them with slurry or fill them with self-hardening ceramic slurry, and use ceramic cores to form the holes and grooves if necessary. |