Manufacturing Techniques of Tungsten Crucible: Isostatic - Sintering, Forging, Spinning

With the rapid development of tungsten industry, the market demand for tungsten crucible is gradually increased, and the requirements of quality for product are more strictly. Therefore, the manufacturing techniques and properties of tungsten crucible play a significance role in the development and utilization of tungsten materials. There will be a brief analysis of these threemanufacturing techniques.

Isostatic - sintering process: Nowadays, it is one of the most important manufacturing techniques for the industrial tungsten crucible production. This technique consists of preparing raw materials, loading powder, isostatic pressing, sintering at a high temperature, lathe processing, product testing, etc. First of all, mold should be assembled according to the required size of products. And then tungsten powder material that has reached the national standard should be put into a mold and the mold must be sealed immediately. Next is to put it in an isostatic press with a pressure of 180-250MP. After that, the pressed compact should be sintered in a high temperature induction sintering furnace under super-heating rate sintering between 80 degrees centigrade and 150 degrees centigrade one hour. The holding time should last for 4 or8 hours. Finally, process the product in accordance with its requirement. After processing, it is time to test the appearance size, density of finished product.

Forging process: Forging process is a manufacturing process involving the shaping of metal using localized compressive forces. Adopting this process to make tungsten crucible mainly consist of three steps: billet preparation, forging and machining. In general, the relative density of the billet is between 90% and 95%. In the preparation of the billet, the size and quality of the tungsten rod are needed to calculate in accordance with the requirements of the finished product. Then put the tungsten rod in a hydrogen furnace to heat under a temperature of 1400-1600 ℃. After keeping warm for a while, forging the billet, and then repeated heating and forging billets for some times until the size of billet meet the requirements. After the forging, the billet can be annealed, and then processed in accordance with the size and the outlook of the finished product.

Spinning process: When use this method for making tungsten crucible, users should prepare tungsten billet before. And then make it into a sheet which conforms to the design by hot-rolling process to hot-rolled, and process it into a few pieces of wafers, and put it on a hot spinning machine. After that, heating mixed flame which consists of hydrogen and air mixing. And after spinning for several times, the shape tungsten plate becomes the shape of the tungsten crucible, and finally cools it into finished tungsten crucible.

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