Glass particle testing standards are published by ASTM and SAE. They include test methods for roundness of glass spheres and standard practice for measurement of liquid glass temperature by the gradient furnace method. In addition, SAE J 1173 goes over the size classification and characteristics of peening glass beads.
1.1 This test method 2 covers the determination of the percent of true spheres in glass spheres used for retroreflective marking purposes and industrial uses. 1.2 This test method includes two procedures as follows: 1.2.1 Procedure A, in which the selected specimen is split into two size ranges or groups prior to separation into true spheres and irregular particles, and 1.2.2 Procedure B, in which the selected specimen is split into five size ranges or groups prior to separation. 1.2.3 In determining compliance with specification requirements, either Procedure A or Procedure B may be used. Where tests indicate failure to meet the specified percent of true spheres and irregular particles, the referee test shall be made in accordance with Procedure B. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
1.1 These practices cover procedures for determining the liquidus temperature ( Note 1 ) of a glass ( Note 1 ) by establishing the boundary temperature for the first crystalline compound, when the glass specimen is held at a specified temperature gradient over its entire length for a period of time necessary to obtain thermal equilibrium between the crystalline and glassy phases. 1.2 Two methods are included, differing in the type of sample, apparatus, procedure for positioning the sample, and measurement of temperature gradient in the furnace. Both methods have comparable precision. Method B is preferred for very fluid glasses because it minimizes thermal and mechanical mixing effects. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
This specification covers the characteristics of glass beads used for peening, and provides for standard glass bead size numbers. The glass bead classification number is the approximate nominal diameter of the glass spheres in that classification, in hundredths of a millimeter, with the prefix GB added. Glass beads used for peening shall be made from high quality glass of the soda-lime type. They should be as resistant as possible to breakage from shock-impact, or by abrasion during shipment and handling. The particles should be substantially round, free-flowing, and free from chemical impurities or contaminants that might be detrimental to the workpiece.