By inserting a tube into the melted iron to form a greybody tube and to make the emissivity steady.The temperature of the melted iron can be obtained using a optical fiber thermometer.

其途径即个空芯导管插入铁水,形成个似灰体腔,使腔内铁水表面发射率基本不变,然后纤比色测温仪示出温度。