The production process of blade molybdenum foil belt
Molybdenum foil has pure molybdenum foil and rare earth molybdenum foil. The addition of rare earth oxides to molybdenum can significantly improve the microstructure, recrystallization temperature and high temperature properties of the materials. Due to the different physical and chemical properties of different rare earth oxides, the properties of alloy materials are different. Therefore, the doping elements should be selected according to the special needs of material properties and economic benefits. The main production processes of molybdenum foil strip are as follows: preparation of thick molybdenum and rare earth molybdenum alloy wire; rolling of key foil; electrolytic corrosion.
1.1 Preparation of crude molybdenum wire
Taking ammonium molybdate as raw material, adding hexahydrate rare earth nitrate solution and mixing evenly, adjusting the pH value of the suspension, and then reducing the dry impurities in the continuous hydrogen furnace for two times, the rare earth molybdenum alloy powder is prepared, which is screened and pressed, and then sintered into billets at high temperature. Then, it is processed into thick molybdenum wire by multi pass high temperature rotary forging, chain drawing or large turntable drawing, small rotating plate drawing, annealing and processing.
1.2 Rolling process
Molybdenum is a kind of hard to deform metal and it is difficult to process. Therefore, the key to produce molybdenum foil is to work out reasonable processing technology. At present, the production process of domestic molybdenum foil strip is as follows: preparation of molybdenum and molybdenum alloy wire - + pretreatment - → hot rolling and blooming first → warm rolling - → cleaning - → annealing - → cold rolling - → continuous annealing - → finishing rolling → molybdenum and rare earth molybdenum foil strip. The characteristics of molybdenum foil strip produced by rolling with coarse key wire are as follows: 1) the processing technology is simple; 2) continuous rolling is adopted, generally, warm blooming is adopted for 2-high or 4-high rolling mill, cold rolling and finishing rolling are carried out by 4-high, 6-high or 12-high rolling mills with tension before and after rolling, and 20-high rolling mill is also used for finishing rolling in some units; 3) it is appropriate to select less than or equal to the yield stress of molybdenum; ④ Small thickness tolerance and high yield; 5) continuous annealing with hydrogen protection is adopted for molybdenum narrow strip, and stress relief annealing is generally adopted with annealing temperature between 800 and 11009; during cold rolling, the total processing rate between two annealing should be controlled at about 60%, while the cumulative total processing rate of warm rolling is generally controlled at about 70%; 7) the width of molybdenum foil strip is very small, which is not limited by equipment capacity, so large processing rate can be selected in the initial stage of rolling, With the rolling process, the work hardening degree increases, and the pass processing rate should gradually decrease.
1.3 Electrolytic corrosion
In order to form edge shape on both sides of rolled molybdenum foil strip and improve the yield and consistency of edge section foil used for sealing, edge shaped molybdenum foil strip was obtained by continuous electrolytic corrosion. The specific process route is: electrolytic corrosion + water cleaning → weak acid neutralization → cleaning + alcohol dehumidification → drying → edge shaped molybdenum foil on both sides. The electrolytic corrosion medium is alkali solution. The edge angle of strip is controlled by adjusting the concentration of alkali solution, current density, forward speed of molybdenum strip and distance between two poles.
