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在工业生产和科学研究中测量1000℃以上温度时,经常使用铂铑——铂热电偶。由于铂铑和铂都是贵金属,所以电偶丝直径较细,一般约为0.5mm,这就要求使用时注意,否则极易损坏。根据在工作中的体会必须注意以下几点: (1)连续使用三个月后偶丝内部晶粒已粗大,其表现是偶丝比正常硬,通电时可看出温度比正常的低(电阻变化)。此时必须作退火处理,以改善内部组织使晶粒细化恢复原有的机械强度;方法是将偶丝去掉瓷
When measuring temperatures above 1000 ° C in industrial production and scientific research, platinum-rhodium-platinum thermocouples are often used. As platinum and rhodium and platinum are precious metals, so the electric wire diameter smaller, usually about 0.5mm, which requires attention when used, otherwise easily damaged. According to the experience in the work must pay attention to the following points: (1) After three months of continuous use of wire inside the grain has been coarse, its performance is even wire than normal hard, power can be seen when the temperature is lower than normal (resistance Variety). At this point must be annealed to improve the internal organization of grain refinement to restore the original mechanical strength; method is to remove even the wire porcelain