The density requirement constitutes the primary foundational parameter for the shielding performance of tungsten alloy shielding containers, directly governing ray attenuation per unit thickness and overall volumetric efficiency. Industry practice generally demands that the actual density of tungsten alloy approach its theoretical value while maintaining highly uniform density distribution throughout the container to prevent localized low-density zones from becoming leakage paths.
To meet this objective, production employs high-purity tungsten powder with precisely proportioned binder phase, processed through wet milling and mixing, cold isostatic pressing or injection molding, dewaxing pre-sintering, and vacuum or hot isostatic pressing sintering to achieve full densification during the liquid phase stage. Post-sintering verification of overall and local density consistency is conducted via ultrasonic, radiographic, or CT density scanning. Any porosity, inclusions, or undissolved tungsten particles are considered unacceptable, requiring complete container rejection and rework.
Density uniformity requires no significant gradient from surface to core or from hole bottom to sidewall, with weld or heat-affected zones exhibiting density not lower than the main body. Practical production achieves this through optimized powder particle size distribution, controlled sintering temperature field uniformity, and hot isostatic pressing post-treatment. Finished container density values must be clearly stated in the delivery report and archived with the container for its lifetime.
Stable fulfillment of density requirements enables tungsten alloy shielding containers to provide reliable shielding with relatively thin walls in nuclear medicine hot cells, isotope production, and industrial irradiation facilities while maintaining reasonable weight and space occupation.
