When machining the precision investment casting components, the blow holes are easily found in the custom casting parts.
So the casting parts with blow holes have to be scrapped. This will increase the casting prices and machining cost.
With the assistance of more than 15 years of casting experience, our workers found the reasons to cause the blow holes as follows:
1.In most cases, the blow holes are mainly caused by the lack of sufficient roasting of the precision casting shell. When the molten steel is poured, a large amount of gas cannot be discharged smoothly, and then invades the molten metal to form bubbles.
2.Due to the shelling process or the shell material, the gas permeability of the shell is too poor, the gas in the cavity is difficult to discharge, and the blow holes are formed in the molten metal.
3.During pouring, the air in the molten steel can not discharged to form casting blow holes.
How to avoid the investment casting blow holes?
1.When lost-wax investment casting process, it is better to design the highest point of the complex casting parts to arrange the air to discharge.
2.When designing the gating system, it is necassary to think more about the shell exhaust requirements.
3.The calcination temperature and time of the shell should be reasonable, and the holding time should be sufficient.
4.The wax should be thoroughly removed when dewaxing.
5.Properly reduce the spacing between the pouring spout and the sprue cup, and the pouring speed should be averaged to ensure that the steel level is filled with the cavity and the air is soaked into the molten steel as little as possible, so that the gas in the cavity and the molten steel can be smoothly discharged.
So if you need high quality investment casting components, steel casting parts, water glass casting process, silca sol casting method, sand casting, please feel free to contact firstname.lastname@example.org or email@example.com or call us 86-18132789710.