GB/T 5988 - 2022 Specifies refractory heating permanent line change test. The standard details the test equipment, such as high temperature furnace, measurement ruler, etc. Clarify the sample prepative requirements, covering shape, size, etc. Operationally, specify the heating procedure, such as heating rate and holding time. Accurately calculate the permanent line change rate by measuring the size before and after heating. This provides a key basis for the mass control of refractory materials, helps enterprises understand the size Stability of materials at high temperatures, and facilitates the rational selection of materials in the construction and maintenance of high temperature equipment such as industrial kilns to ensure the reliable operation of equipment.