GB/T 2 2459.4 - 2022 is the fourth part of the refractory slurry standard, which specifies the test method of flexural bonding strength at room temperature. The standard specifies the equipment required for the test, such as flexural testing machines, etc., and elaborates the sample preparation process in detail, including specimen forming, maintenance conditions, etc. At the same time, it strictly specifies the test operation steps, such as loading rate and other key parameters. Through this standard, the flexural bonding strength of refractory slurry at room temperature can be accurately determined, which provides a scientific basis for evaluating its bonding performance in actual use. It is essential to ensure the mass and Stability of refractory masonry.