Gray Structure Defects in Casting Process and Solutions
Gray structure defects are common in casting process and are one of the most serious casting defects. Gray structure defects will result in weak internal mechanical properties and seriously reduce the service life of parts, thus affecting the quality and performance of parts. Gray structure defects will weaken the mechanical properties of parts, which are detrimental to parts and cannot be used. Therefore, the elimination of gray structure defects is the key to the quality and service life of parts. The following is an analysis of the causes and solutions of the gray structure in the casting process.
Firstly, the main causes of gray structure defects are-machinery vibration and sand sticking. When the vibration of the machine is too large, it will cause the wet sand core being destroyed and unable to form the required structure, which will cause the formation of gray structure. As well, when the wet sand in the core sticking on the surface of the core box, the core formed by vibration tends to be incomplete, while grey structure defects form. In addition, the casting material may also be affected. Since the casting material has a large specific gravity, the core is in a dense state, which may block the release of sand, resulting in the formation of grey structure.
Secondly, the grey structure defects can be solved by treating or replacing the core box, adjusting the vibration intensity, and adjusting the casting material. Firstly, the core box can be treated in advance to make it more smooth, so that it will not cause the sand sticking effect and form the grey structure. For too strong machine vibration, it would be better to adjust the vibration and intensity, and reduce the vibration at the working frequency range to avoid the gray structure caused by machine vibration. Finally, the sand sticking effect requires the adjustment of the casting material. The casting material should be selected for the appropriate viscosity, which can effectively relieve the sand sticking effect and reduce the occurrence of gray structures.
In summary, the grey structure defect is a common casting defect。 It will greatly reduce the mechanical properties of the parts and cause short service life, thus affecting the application performance of the parts. Therefore, it is necessary to take effective measures to solve the grey structure defects in the casting process. To solve the gray structure, the main method is to treat the core box, adjust the vibration intensity and adjust the casting material. It is suggested to test the core box and select the appropriate casting material in the casting process to reduce the formation of gray structure defects.
