Simple Solutions That Work! Issue 13

DEFECT PREVENTION Continued on next page 31 STANLEY FOREHAND Field Technical Service Manager HA INTERNATIONAL ARTICLE TAKEAWAYS: • Refractory Coatings are one of the products utilized to produce quality castings • Controlled processes lead to better understanding of what is changing in foundries • Learn the 5 keys to reducing casting defects through refractory coating 5 KEYS TO REDUCING CASTING DEFECTS THROUGH REFRACTORY COATINGS I n an industry that has been around for many centuries with a wealth of knowledge and experience, we still today find ourselves when analyzing casting defects asking, “what changed?” This is because we understand that our industry is process dependent and controlling those processes is key to success. Refractory coatings are one of the products that we utilize to produce quality castings. Although usage is small in comparison, these products are applied at the mold/metal interface which is critical when it comes to defects. Crushes, inclusions, scabs, expansion, gas, metal penetration, misruns and rough surface defects can all be affected by refractory coating practices. Therefore, how do we control this aspect of our foundry operations? 5 KEYS TO REDUCING CASTING DEFECTS THROUGH REFRACTORY COATINGS • Selection of Coating • Coating Preparation • Quality Control • Proper Application Techniques • Proper Drying of Coating Deposit KEY #1: SELECTION OF COATING Choose the right refractory blend for your application. A refractory coating is a protective material, applied to a core or mold surface, to enhance the surface finish of the casting and reduce defects that occur at the sand-metal interface. They accomplish this by filling voids, increasing the refractoriness of the mold or core, improving sand peel, and controlling what is happening in the mold. The refractory component is the workhorse of the coating. Coating suppliers utilize a wide range of refractories and can customize a coating to your foundries needs. Open conversation with Source: Foundry Management and Technology; October 21 Typical Refractories Utilized Microscopic View of Applied Refractory Coating