我厂用RJJ-36-6回火炉进行齿轮件低温回火,由于热电偶有内外两层保护管,所以,在低温时热传导慢、热电偶对炉温反映“迟钝”,仪表指示温度滞后于炉内实际温度,炉温上下波动达±200℃。在生产中,经常出现回火不足和硬度低的问题,甚至出现废品。经分析,我们将热电偶头部的内陶瓷管去掉20毫米长一段,外铁管轴向两侧磨去4毫米(如图所示),使热偶丝直接测到了炉内的 I plant with RJJ-36-6 tempering furnace gear tempering, the thermocouple inside and outside the two layers of protective tube, so at low temperatures, heat conduction slow, thermocouple reflects the furnace temperature “slow”, the meter indicates the temperature lags behind The actual furnace temperature, temperature fluctuations up and down ± 200 ℃. In production, often lack of tempering and low hardness problems, and even scrap. After analysis, we remove the inner ceramic tube of the thermocouple head 20 mm long, the outer iron tube to both sides of the mill to 4 millimeters (as shown), so that the thermocouple wire directly measured in the furnace