(1)Manganese sulfide porosity.
Cause of defect:this kind of air hole is located below the gray cast iron casting.The cast iron processing plant is mostly on the casting surface,which is often exposed after processing,with a diameter of about 2~6mm.Sometimes there is a small amount of slag in the tunnel.Metallographic study shows that this defect is caused by MNS segregation and slag mixing,which is caused by low pouring temperature and high content of manganese and sulfur in molten iron.
(2)Porosity caused by sand core gas.
Defect cause:pores and porous pores are often caused by poor exhaust of sand core.Because the sand core is hardened in the core box when the iron casting factory makes the core,the exhaust hole on the sand core is often insufficient.
(3)Liquid slag inclusion.
Defect cause:it is worth mentioning that changing the gating system design failed to eliminate this defect.Therefore,this defect can be considered as the result of low pouring temperature and molten iron pouring in micro reducing atmosphere.After processing,there will be individual small holes under the skin of gray cast iron castings,and the diameter of the holes is generally 1~3mm.In some cases,there are only 1~2 small holes.Metallographic study shows that these pores appear together with a small amount of liquid slag,but no s segregation is found here.
Conclusion:the common reason for the low pouring temperature is that the molten iron is transported and stays in the open ladle for a long time to dissipate heat before pouring.The use of ladle covers with thermal insulation can significantly reduce heat loss.
ABOUT KEVA
Keva Casting is a professional casting company that focuses on Construction, Machinery, Automobile, Hardware, Pipeline and many other industries.
We provide top quality products with the best service based on our complete production chain including our own mold design, advanced production techniques, and full management of the supply chain. Keva Casting has two factories located in Zhucheng, China's Shandong province.
We use "shell molding", which is a new technique that has been developed in recent years.This new technique has simplified production procedures and reduced air pollution compared with traditional sand casting and investment casting. Shell making and core making are faster to ensure production in enormous quantities. The dimensions and surface finishing are satisfactory for all kinds of industrial requirements. Besides supplying our own formwork & scaffolding systems, our casting products also supply OEM services in various industries.