An Analysis of Charpy Impact Testing as Applied to Cemented Carbide.

The impact energy or impact strength of WC-Co alloys is currently determined by loading an unnotched 14 inch x 14 inch x 2 inch sample in three point bending. This is done on a Charpy Impact tester of 24 ft. lbs. capacity Model CIM-24, Manlabs, Inc.. The results of these tests are generally considered to be an indication of the toughness of cemented carbide. However, much of the field experience where carbide is subjected to impact loading, such as in mining, does not correlate well with the charpy impact values of the various grades of cemented carbides. In an effort to better understand the nature and the limitations of impact testing, the above mentioned test was studied in detail via instrumentation of both the tester and the specimen.