JJF1376-2012 {Calibration Specification for Box type Resistance Furnace} is applicable to the calibration of box type resistance furnaces (hereinafter referred to as "box type furnaces") with working temperatures not exceeding 1300 (2). The given measurement characteristic indicators include furnace temperature uniformity, furnace temperature stability, furnace temperature deviation, and furnace temperature difference. The calibration of metrological characteristics is usually carried out under no-load conditions. Temperature measurement points are arranged according to JJF1376-2012 regulations. When the furnace temperature reaches the calibration temperature and is in a thermally stable state, begin reading. Within 60 minutes, record the temperature of each temperature measurement point every 3 minutes. Measure at least 20 times. Each temperature measurement point should be recorded within 1 minute.