Lost foam casting is a kind of casting technology. There will be various casting defects in the casting process, which will lead to the defects of castings. Lost foam casting is no exception. Blowback is a common phenomenon in lost foam casting. If it is serious, it may endanger the personal safety of pouring workers, which must be paid attention to. In order to reduce the blowback, the following measures can be taken:
First, the density of the foam model should be small. Under the premise of ensuring the surface quality of the foam and ensuring the strength of the model, the foam should be made lighter and better, so as to reduce the volume of gas generated during pouring.
Second, the foam model must be dried before coating. Each batch of foam model should check the weight change of the drying process and make a curve chart of baking weight change.
Third, the gating system, especially the sprue and runner, should not be coated, so that the gas generated during pouring can be quickly and fully pumped away without coating, which saves the consumption of coating. Finally, cover a baffle on the gate cup to block the molten steel sprayed back, so that it can not splash out and endanger the on-site operators.
Using the above methods can effectively prevent the back spray phenomenon in the process of Lost foam casting, better prevent the defects of castings, improve the quality of castings, and improve the safety of production.