MICROSTRUCTURES PROPERTIES AND APPLICATIONS OF SEAMLESS TUNGSTEN TUBES BY P/M ROTARY PRESSING

Seamless tungsten tubes were made by the rotary pressing of P/M compacts.The hardness,density and structure during working process and the recrystallization temperation of tungsten tubes were tested.The applications of tungsten tubes were described.Structures of tungsten tubes with different deformation rates are as follows:Non-deforming structures exist at 11% deformation rate,long and fine pores can be seen at 66% and crystalline grains are broken and sintered pores disappear at 77%; Thin-wall seamless tungsten tubes with high accuracy used in furnace for standardizing tungsten-rhenium thermometer exhibit following parameters:φ40×0.25×540mm tube within a distance range of 100mm from the centre shows the axial temperature differences of ±l℃, ±6℃ and ±7℃ at 1200℃, 1400℃ and 1600℃ respectively, while φ30×0.25×286mm tube has an allowable error of 1377±12℃ within the isothermal region of 120mm.