High Performance Tungsten Plates Manufacture

Tungsten plate is mainly used to make temperature standard light source, tungsten evaporation boat, electron tube shed, heat shield, high temperature furnace components, X-ray tube tungsten target, etc. Satisfactory results have been obtained in these fields. With the continuous development of science and technology, the application of tungsten plate has been expanding, especially in nuclear energy, medical devices and other fields.

But in general, tungsten is a kind of material with high brittleness at low temperature. The strength and hardness of tungsten plate prepared by common method are insufficient (270MPa tensile strength at 1000 ~C) and 380 hardness (HV30). It has poor machinability, easy edge collapse and cracking, low yield, and difficult to meet the performance requirements of tungsten plate used under harsh conditions such as nuclear energy and medical equipment.

To this end, based on powder metallurgy, researchers have explored a method for manufacturing high-performance tungsten plates. The main processes include:

(1)The sintered tungsten sheet of powder metallurgy with the original thickness of 40 160mm was heated for 40 90 minutes in a hydrogen furnace at 1500 1600 C, then forged. The first processing rate was 30%60%. Then, at 1400 1550 C, tempered for 10 40 minutes and then forged, the processing rate was 20%38%. Then at 1300 1450 C, tempered for 10 30%. Clock, then forging, the processing rate is 15%

(2)The forged tungsten plate is subjected to heating and rolling, the first fire rolling heating temperature is 1200 °C -13 50 °C, the processing rate is 20% - 30%; then at 1100 °C - 1250 °C temperature, tempering 10 -30 minutes, and then rolling, the processing rate is 15% ‐ 25%; follow-up rolling is carried out according to each fire reduction of 50 °C -200 °C, the processing rate is 10% ‐ 25%, until the required size is reached.

(3) Stress relief annealing of the rolled tungsten plate is carried out in hydrogen furnace at 1000 1300 according to the final rolling temperature and the size of the rolled tungsten plate. The annealing time is 10 120 minutes.

By combining forging with rolling process and controlling cooling forging or rolling deformation sequentially, the large deformation of tungsten plate can be processed plastically, and the grain structure of the metal can be refined sufficiently. There are no defects such as voids and cracks among the grains. After stress relief annealing, tungsten plate has good mechanical properties, hardness HV30 (> 410) and B (> 350 MPa) at 1000 C. The cutting performance has been significantly improved, which can meet the stringent requirements in the fields of nuclear energy, medical devices and ion implantation.

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