Alloy elements in precision tubes significantly affect the low-temperature temper brittleness. Chromium and manganese promote the segregation of impurities like phosphorus at the Austenite grain boundaries, thereby enhancing low-temperature temper brittleness. Tungsten and vanadium have little effect, while molybdenum lowers the transition temperature of toughness to brittleness in low-temperature tempered precision tubes but is not sufficient to inhibit low-temperature temper brittleness. Silicon can delay the precipitation of cementite during tempering, raising its formation temperature, thus increasing the temperature at which low-temperature temper brittleness occurs in precision tubes.