CuCr50 Vacuum Interrupter Contact

CuCr50 is the high-chromium copper-chromium grade, 50% chromium in a copper matrix, for vacuum interrupters with severe interruption duty. The higher chromium content trades some conductivity for what severe duty actually needs: lower chopping current, better resistance to contact welding, and stable dielectric recovery under heavy interruption. CuCr50 is typically produced by infiltration (sintering a chromium skeleton, then infiltrating copper), which gives the dense, homogeneous structure that high-rated interruption demands.

We supply CuCr50 contacts to drawing for higher-rated vacuum circuit breakers, generator and capacitor switching, and high-cycle reclosers. For general-purpose distribution duty where conductivity matters more, see CuCr25 Vacuum Interrupter Contact. For geometry options, see CuCr Contact Disc.

Specifications

Property	Value
Material Grade	CuCr50 (Chromium 47–52 wt%, copper balance)
Production Process	Infiltrated / sintered
Form	Disc / AMF / RMF / custom geometry (per drawing)
Dimensions	Per drawing
Tolerance	Per drawing
Density	≥7.96 g/cm³ per GB/T 26867-2011
Electrical Conductivity	≥16 MS/m (≈28% IACS) per GB/T 26867-2011
Hardness	≥80 HB per GB/T 26867-2011
Oxygen Content	≤0.050 wt% per GB/T 26867-2011
Nitrogen Content	≤0.004 wt% per GB/T 26867-2011
Mounting Interface	Brazed to copper / copper-alloy stem per drawing

Exact certified properties for your lot are available with material documentation on request.

Applications

• Make-and-break contacts for higher-rated MV vacuum circuit breakers
• Generator circuit breakers (severe short-circuit interruption duty)
• Capacitor bank switching (capacitive current, dielectric recovery stress)
• High-cycle reclosers running fault-clear-reclose sequences
• Vacuum interrupters where anti-weld behavior governs reliability

Technical Notes

CuCr50's value is interruption behavior, not conductivity. At 50% chromium, the chromium phase is large enough to dominate the contact surface during arcing. This is what gives CuCr50 its lower chopping current and stronger resistance to welding under severe duty. A welded contact is a stuck breaker, so anti-weld behavior is a reliability property, not a performance nicety, in the duties CuCr50 is chosen for.

The trade-off is conductivity: ≥16 MS/m for CuCr50 versus ≥28 MS/m for CuCr25. For continuous-current-dominated distribution duty, that drop matters and CuCr25 is preferred. For interruption-dominated duty, generator breakers, capacitor switching, high short-circuit ratings, the interruption behavior wins and CuCr50 is the specification.

Infiltrated CuCr50 gives a dense, homogeneous chromium-copper structure with low porosity, which matters both for vacuum integrity and for consistent arc behavior. As with all VI contact material, low dissolved gas content is processed in to protect the vacuum over service life.

Sourcing & OEM

Custom CuCr50 contacts to your drawing are routine. Specify the geometry (disc, AMF, RMF), dimensions, stem interface, and your interruption duty; contact us for a project-specific quote.