Classification of tungsten rhenium thermocouples. There are three types of tungsten rhenium thermocouples included in China's national standards:
1. Tungsten rhenium 5-tungsten rhenium 26 has a nominal positive electrode composition of 95% tungsten and 5% rhenium, and a nominal negative electrode composition of 74% tungsten and 26% rhenium. The graduation number is WRe5 WRe26, abbreviated as W-Re5/26.
2. Tungsten rhenium 3-tungsten rhenium 25, its positive electrode has a nominal composition of 97% tungsten and 3% rhenium, and the negative electrode has a nominal composition of 75% tungsten and 25% rhenium. The graduation number is WRe3-WRe25, abbreviated as W-Re3/25.
3. Tungsten rhenium 5-tungsten rhenium 20 has a nominal positive electrode composition of 95% tungsten and 5% rhenium, and a nominal negative electrode composition of 80% tungsten and 20% rhenium. The graduation number is WRe5 WRe20 (A), abbreviated as W-Re5/20. Temperature measurement range: 0-2500 ℃