W3Re-W25Re thermocouple material and preparation method of thermocouple

Abstract

The invention discloses a W3Re-W25Re thermocouple material and a preparation method of a thermocouple. A negative pole W25Re alloy material comprises the following components in percentage by weight: 74.2%-75.5% of W and 24.5-25.8% of Re, a positive pole material W3Re alloy material comprises the following components in percentage by weight: 96.0%-97.5% of W, 2.5%-3.5% of Re, 0-0.5% of Co, 0-0.5% of Al and 0-0.5% of rare earth. The preparation method of the thermocouple comprises the following steps of: (a) respectively weighing all the components of the negative pole W25Re alloy material and the positive pole material W3Re alloy material according to the percentage by weight; (b) preparing pre-alloy powder; (c) forming; (d) pre-sintering; (e) performing vertical melting; (f) swaging; (g) drawing; (h) cleaning; (i) annealing; and (k) performing performance test and indexing calibration. The W3Re-W25Re thermocouple material disclosed by the invention can achieve the level of a precious metal thermocouple wire and improve temperature measurement response speed, temperature measurement precision and stability.

Description

technical field [0001] The invention relates to a thermocouple material, in particular to a W3Re-W 25Re thermocouple material and a method for preparing the thermocouple. Background technique [0002] With the development of modern technologies such as aerospace and deep-sea exploration, more stringent requirements have been placed on the physical and chemical properties of materials. Therefore, higher requirements have been placed on the control of the preparation process of materials, especially the precise control of temperature. At present, the contact thermocouples used for measurement in the high-temperature field are mainly precious metal series and tungsten-rhenium series. Compared with expensive and scarce precious metals, my country's tungsten-rhenium resources are abundant and cheap, and tungsten-rhenium thermocouples have higher melting points, Strength, thermal electromotive force and recrystallization temperature are widely used in petrochemical, metallurgical s...

AI Technical Summary

Problems solved by technology

[0003] At present, there are three types of tungsten-rhenium thermocouples widely used in the market: W3Re-W25Re, W5Re-W26Re and W5Re-W20Re. The W3Re produced by domestic and foreign manufacturers is doped with silicon, aluminum, potassium or other elements are added on this basis. , in order to improve the recrystallization temperature and mechanical properties of the alloy, but as the tungsten-rhenium alloy wire diameter becomes thinner, the splitting and brittle fracture of the W3Re alloy wire become more serious, and as a thermocouple material, the tungsten-rhenium alloy except In addition to good mechanical properties, it is more important to have stable thermoelectric properties. However, the thermoelectric potential of W3Re alloy wire doped with silicon, aluminum, and potassium elements is relatively dispersed, and the potential inhomogeneity of a single batch is usually 5 ~8°C, seriously reducing the temperature measurement accuracy of tungsten-rhenium thermocouples, affecting its popularization and application

As an alternative material for platinum-rhodium noble metal thermocouples, the temperature tolerance of the fast W3Re-W25Re thermocouple wire for molten steel temperature measurement is ±0.25%t (1500-1800°C), and the wire diameter is Φ0.08-0.1mm. There is a large difference from the temperature measurement tolerance (±0.125%t) of platinum-rhodium thermocouple wire, and there is still a big gap to replace platinum-rhodium thermocouple wire

In foreign countries, there is no report on the application of fine W3Re-W25Re to the temperature measurement of molten steel.

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