Analysis of Tungsten Wire Cutting Resistance

The cutting resistance of tungsten wire is the result of the synergistic effect of multiple factors such as high hardness, high strength, fine grain structure, and surface protection, making it irreplaceable in the fields of industrial cutting wire, high temperature saw wire, and bulletproof fiber. The following is an analysis of the principle of tungsten wire’s cutting resistance, divided into core mechanisms and influencing factors:

1. Intrinsic properties of materials

Ultra-high hardness: The Vickers hardness of tungsten (300~500HV) is much higher than that of most metals (such as 200~300HV for steel). The high hardness directly resists the indentation and scratching of cutting tools, reducing its own vulnerability to cutting. Doping with tungsten carbide (WC) or surface coating (such as TiN) can increase the local hardness to more than 2000HV, forming a “hard shell” protective layer.

High melting point and high temperature stability: The melting point of 3422°C makes it difficult to soften or melt during high-temperature cutting (such as laser cutting, plasma cutting), maintaining structural integrity. The grains are not easy to coarsen at high temperatures (grain boundary migration is inhibited by rare earth oxides), avoiding strength loss.

Tensile strength and toughness: The tensile strength can reach more than 3500MPa, which is much higher than ordinary steel wire (~2000MPa), and can withstand dynamic impact loads during cutting without breaking easily. Rhenium (Re) doping can improve ductility, disperse local stress through plastic deformation, and prevent brittle fracture.

2. Microstructure strengthening mechanism

Grain boundary strengthening: The grain refinement process (grain size 1~5 μm) increases the density of grain boundaries, hinders dislocation movement, and delays crack initiation and expansion. Oxide doping (such as La₂O₃) at the grain boundary forms a pinning effect, inhibiting high-temperature grain boundary sliding.

Densification and defect control: Reduce porosity through isostatic pressing and high-temperature sintering, reduce internal stress concentration points, and avoid cracks originating from defects. At the same time, X-ray flaw detection and other detection methods are used to eliminate hidden dangers such as microcracks and inclusions.

Fibrous structure orientation: The multi-pass wire drawing process makes the grains highly oriented along the axial direction, forming a “fiber-like” toughened structure and improving the axial bearing capacity.

3. Surface and interface protection

Wear-resistant coating technology: Tungsten carbide (WC) or diamond-like carbon (DLC) coating is deposited on the surface, and the friction coefficient is reduced to 0.1~0.2, reducing the direct contact wear between the cutting tool and the tungsten wire surface. The coating can also isolate oxygen and corrosive media, delaying oxidation and chemical erosion.

Self-lubricating effect: Some coatings (such as WS₂) release sulfide particles during friction to form a lubricating film, reducing the risk of heat accumulation and adhesion during cutting.

4. Environmental adaptability

High temperature oxidation resistance: A dense tungsten oxide (WO₃) film is formed on the surface (the oxidation rate is slowed down by alloying), which can temporarily protect the substrate below 800°C. In an inert gas or vacuum environment, the oxidation reaction is suppressed and the performance is more stable.

Fatigue resistance and cyclic load: The strength retention rate is >90% under high cycle times (>10⁷ times), which is attributed to the suppression of crack propagation by fine grain structure and tensile strength.

5. Interaction with cutting tools

Hardness difference advantage: Tungsten wire hardness is significantly higher than conventional cutting tools (such as high-speed steel tool hardness ~800HV), forcing the tool itself to wear quickly instead of the tungsten wire being cut.

Energy dissipation mechanism: During cutting, external force disperses energy through plastic deformation (rhenium doped area) and elastic deformation (high elastic modulus), rather than concentrating and causing fracture.