GB/T 7320 - 2018 specifies the test method of thermal expansion of refractory materials. It is suitable for all kinds of refractory materials, and specifies the equipment required for the test, such as thermal expansion instrument, etc. Specify sample preparation, with strict requirements on size and shape. During the test, the sample is heated at a specific heating rate, and the length change at different temperatures is accurately measured, so as to obtain the thermal expansion coefficient. This standard provides a key basis for refractory manufacturers to control product mass, industrial kilns and other high temperature equipment designers to select materials, ensure that refractory materials are dimensionally stable in temperature changing environments, and ensure the normal operation and service life of high temperature facilities.