GB/T 22459.4-2022 specifies the test method for the normal temperature flexural bonding strength of refractory mortars, applicable for determining the flexural bonding strength of the bonded surface after refractory mortar bonds refractory bricks and is dried or fired. The standard defines requirements for specimen preparation, environmental conditioning, test procedures, and result calculation. It primarily utilizes instruments such as a flexural testing machine, drying oven, and heating furnace, along with measurement tools like balances and calipers. The method involves bonding refractory brick test pieces with mortar to form specimens, subjecting them to specified temperature and humidity treatments, applying bending stress at a constant rate until the bonded surface fractures, recording the maximum fracture load, and calculating the strength value. This provides a unified basis for quality control of refractory mortars and assessment of masonry service life.