Understanding the basics of green sand testing

• Published in: Modern casting Vol. 89; no. 3; pp. 38 - 40
• Main Author: GRANLUND, M. J
• Format: Journal Article
• Language: English
• Published: Des Plaines, IL American Foundrymen's Society 01.03.1999; American Foundry Society, Inc; American Foundry Society
• Subjects: Applied sciences; Casting; Die castings; Die-casting; Evaluation; Exact sciences and technology; Founding; Foundries; Foundry engineering; Metal castings industry; Metals. Metallurgy; Molding materials. Mold making. Core making; Nonferrous metals; Permeability; Process controls; Production management; Production techniques; Sand, Foundry; Testing; Compression; Temperature; Green sand molding; Quality; Humidity; Test method; Molding sand; Foundry; Compactibility; Hardness; Sand mold; Strength
• ISSN: 0026-7562; 2376-4430

The quality of a foundry's green sand has a definite impact on the quality of the castings. Maintenance and control of the system sand is not only an important job but also a demanding one, requiring a battery of tests aimed at improving consistency. Knowing why and how sand testing is performed, therefore, can offer important clues to improving quality in your foundry. Sand testing falls into two categories: checking consistency and evaluating physical and chemical properties of a sand mix. Tests such as moisture, permeability, green compression and compactibility are used to check consistency of the sand. Such tests, along with actual mold testing and physical tests like loss on ignition (LOI), AFS clay, 25 micron clay, methylene blue (MB) clay and screen analysis can explain casting quality. To obtain comparable results, each test must be run according to AFS standard methods. Testing equipment must be checked and calibrated. Samples, usually a quart or larger, should be taken nearest the point of use, and casting quality should be correlated to sand test results. It's important to follow statistical process control procedures, and graphing results makes them easier to track.