Tungsten, molybdenum, tantalum thiab niobium yog qhov tseem ceeb cov ntaub ntawv rau lub chaw ua dav hlua thiab tiv thaiv industries vim lawv lub zog: cov high-kub stability, ceev thiab tensile lub zog, lawv zoo heev cov ntaub ntawv uas machinability, thiab tawg tiv thaiv.