Tungsten Manufacturers & Suppliers

Tungsten carbide is a sintered composite of WC hard phase and cobalt metal binder — the cobalt content and WC grain size determine the property balance. Cutting tool grades typically use 6-12% cobalt binder with sub-micron to 1-micron WC grain size, optimizing hardness (1500-1800 HV) and wear resistance for high-speed metal cutting. Wear part grades for wire drawing dies, stamping dies, and crusher wear liners often use 15-25% cobalt binder with 2-5 micron grain size, trading some hardness for the transverse rupture strength needed to survive impact loading without fracturing. Titanium carbide (TiC) and tantalum carbide (TaC) additions in coated insert grades improve crater wear resistance by reducing chemical affinity between the carbide and steel workpieces at elevated cutting temperatures.

Tungsten carbide in the sintered state (1300-1800 HV) cannot be machined by conventional carbide tooling — it requires either diamond grinding or electrical discharge machining. Surface and cylindrical grinding with diamond wheels (typically resin-bonded or metal-bonded diamond, 100-400 grit) is the standard finishing process for WC blanks and wear inserts. Wire EDM is extensively used for profile cutting of WC die sections and punch shapes because it imposes no mechanical force on the brittle material and can produce sharp internal corners and complex contours. Tolerances of ±0.0002" are achievable in ground WC, and surface finishes of 4-8 µin Ra are standard on lapped WC faces. The recast layer from EDM (typically 0.0002" thick) is removed by subsequent polishing or grinding before use in fatigue-critical applications.

Tungsten heavy alloys (WHA) are liquid-phase sintered composites of 85-97% tungsten powder in a nickel-iron or nickel-copper binder matrix, achieving densities of 17-18.5 g/cm³ — significantly denser than lead (11.3 g/cm³) but non-toxic and mechanically superior. For radiation shielding, density is the primary figure of merit: a given thickness of WHA attenuates gamma radiation at roughly 1.7 times the efficiency of lead. This allows shield packages to be made 40% smaller for the same dose reduction, critical in medical linear accelerator collimators, isotope shipping containers, and industrial radiography cameras where compact shield geometry is required. Unlike lead, WHA can be machined to close tolerances (±0.001") and threaded, making it practical for precision collimators and syringe shields in nuclear medicine.