Tungsten
- TUNGSTEN IN ELECTRICAL CONTACT METALS
- The refractory metals such as tungsten are superior as contact materials, not only as far as temperature resistance and resistance to mechanical wear concerned, but also in regard to the detrimental effects of arcing.
- In order to utilise the high contact qualities of tungsten in vaculoy contact materials it is necessary to combine these properties with the good electrical conductivities of the metals copper and silver - this is achieved using specialised powder metallurgy and vacuum furnacing techniques.
- These composite materials are a homogeneous mixture of the copper or silver with varying percentages of tungsten which are dependant on the type of contact application. The higher tungsten content improves arc resistance and mechanical wear but reduces electrial conductivity
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Tungsten Base Metals
Tungsten Base
TUNGSTEN BASE CONTACT METALS
COPPER TUNGSTEN
The copper tungsten grades for contact metals are Vaculoy CT60, CT70, CT75, CT78 and CT80. This range of compositions will cover most applications for arcing contacts in air blast, oil immersed and SF6 gas circuit breakers. The higher the conductivity grade Vaculoy CT60 is also for onload tapchanger contacts operating in oil.
VACULOY STANDARD GRADES
Copper Tables
| Material | Vaculoy grade | Application | Composition | Density g/cm | Hardness | Electrical Conductivity % IACS | Other Classification |
|---|---|---|---|---|---|---|---|
| Cop Tun | CT 60 | Arcing Contact | 60% Tungsten | 13.0 | 145 HV | 52 | 1w3 |
| Cop Tun | CT 70 | Arcing Contact Vacuum Switch | 70% Tungsten | 14.2 | 197 HV | 46 | |
| Cop Tun | CT 72 | Spark Erosion & Electro Chemical Machining | 72% Tungsten | 14.5 | 200 HV | 40 | 10w3 |
| Cop Tun | CT 75 | Arcing Contact | 75% Tungsten | 14.8 | 220 HV | 44 | 20w3 |
| Cop Tun | CT 75W | Projection Welding | 75%Tungsten | 15.2 | 240 HV | 40 | |
| Cop Tun | CT 78 | Arc Contact resistance welding | 78% Tungsten | 15.2 | 230 HV | 40 | |
| Cop Tun | CT 80 | Arcing Contact | 80% Tungsten | 15.5 | 235 HV | 40 | 40w3 |
| Cop Tun Carbide | CTC 67 | Electrical Upsetting | 67% Tungsten Carbide | 12.7 | 350 HV | 32 | 20k3 |
SILVER TUNGSTEN
The three grades of silver tungsten will cover most applications for arcing contacts in switchgear, control gear and circuit breakers operating in air or cells switches operating in chemical atmospheres. The higher conductivity grades ST50 and ST65 can also be used as main contacts and combined main/arcing contacts in medium duty switching operations or where an unacceptable temperature rise is experienced with higher tungsten grades.
SILVER TUNGSTEN CARBIDE
Vaculoy STC60 & STC72 are tungsten carbide silver composites with a higher hardness but lower electrical conductivity than the silver tungsten grades. They are suitable for air switching operations where a high arc and mechanical wear resistance are required. they are used in d.c switchgear, miniature circuit breakers an heavy duty relays.
VACULOY STANDARD GRADES
Silver Tables
| Material | Vaculoy grade | Application | Composition | Density g/cm | Hardness | Electrical Conductivity % IACS | Other Classification |
|---|---|---|---|---|---|---|---|
| Sil Tun | ST 50 | Arcing/Main Contact | 50% Tungsten | 13.4 | 110 HV | 58 | 50s |
| Sil Tun | ST65 | Arcing/Main Contact | 65% Tungsten | 14.8 | 150 HV | 50 | 35s |
| Sil Tun | ST75 | Arcing Contact | 75% Tungsten | 16.0 | 220 HV | 45 | 20s |
| Sil Tun Carbide | STC 60 | Arcing Contact vacuum switch | 60% Tungsten Carbide | 13.0 | 220 HV | 40 | |
| Sil Tun Carbide | STC 72 | Contact | 72% Tungsten Carbide | 13.8 | 400 HV | 22 | |
| Sil Cad Oxi | SC 85 | Main Contact | 85% Silver | 9.9 | 68 HB | 75 | |
| Sil Cad Oxi | SC 90 | Main Contact | 90% Silver | 9.95 | 64 HB | 78 | |
| Silver Nickel | SN70 | Atcing/Main Contact | 70% Silver | 9.8 | 65 HB | 60 |
Applications
OTHER APLICATIONS FOR TUNGSTEN BASED METALS
Spark erosion & Electro-Chemical Machining
Vaculoy CT72 provides a spark machining material with the properties required when conventional electrode materials erode too quickly. It is particularly suitable for fine finish and sharp definition work, especially when eroding hardened steels and tungsten carbide.
In electro chemical machining it resists damage by spark and electrolyte glow whilst having adequate electrical conductivity.
Resistance Welding
Vaculoy CT75W is a fine grain tungsten copper composite to BS4577-B11. It has a high hardness and resistance to deformation at elevated welding, flash butt and spot welding.
Electrical Upsetting
Vaculoy CTC67 is a tungsten carbide composite conforming to BS4577-B12. It has, because of the use of tungsten carbide, a higher hardness and heat strength than CT75W and is uses as dies and anvils in electrical upsetting.
Availability
ELECTRICAL CONTACT METALS
- All VACULOY contact metals can be supplied as follows:-
- as contact tips
- as manufactured contact assemblies
- as contact tips brazed to contact bodies supplied by customers
V I Products are also able to re-tip used contacts. This service is particularly useful when contacts are obsolete.
ECM & EDM Electrode Metals
Plates up to 1" thick, rods up to 2" dia and discs up to 3 1/2" diameter are normally available ex-stock.
Non Standard shapes and sizes are available to order.
Projection Welding & Electrical Upsetting Metals
Vaculoy CT75W & CTC67 is available as shaped tips, small plates and rods, or if required can be supplied brazed to copper alloy electrode bodies.
COPPER TUNGSTEN
The copper tungsten grades for contact metals are Vaculoy CT60, CT70, CT75, CT78 and CT80. This range of compositions will cover most applications for arcing contacts in air blast, oil immersed and SF6 gas circuit breakers. The higher the conductivity grade Vaculoy CT60 is also for onload tapchanger contacts operating in oil.
VACULOY STANDARD GRADES
Copper Tables
| Material | Vaculoy grade | Application | Composition | Density g/cm | Hardness | Electrical Conductivity % IACS | Other Classification |
|---|---|---|---|---|---|---|---|
| Cop Tun | CT 60 | Arcing Contact | 60% Tungsten | 13.0 | 145 HV | 52 | 1w3 |
| Cop Tun | CT 70 | Arcing Contact Vacuum Switch | 70% Tungsten | 14.2 | 197 HV | 46 | |
| Cop Tun | CT 72 | Spark Erosion & Electro Chemical Machining | 72% Tungsten | 14.5 | 200 HV | 40 | 10w3 |
| Cop Tun | CT 75 | Arcing Contact | 75% Tungsten | 14.8 | 220 HV | 44 | 20w3 |
| Cop Tun | CT 75W | Projection Welding | 75%Tungsten | 15.2 | 240 HV | 40 | |
| Cop Tun | CT 78 | Arc Contact resistance welding | 78% Tungsten | 15.2 | 230 HV | 40 | |
| Cop Tun | CT 80 | Arcing Contact | 80% Tungsten | 15.5 | 235 HV | 40 | 40w3 |
| Cop Tun Carbide | CTC 67 | Electrical Upsetting | 67% Tungsten Carbide | 12.7 | 350 HV | 32 | 20k3 |
SILVER TUNGSTEN
The three grades of silver tungsten will cover most applications for arcing contacts in switchgear, control gear and circuit breakers operating in air or cells switches operating in chemical atmospheres. The higher conductivity grades ST50 and ST65 can also be used as main contacts and combined main/arcing contacts in medium duty switching operations or where an unacceptable temperature rise is experienced with higher tungsten grades.
SILVER TUNGSTEN CARBIDE
Vaculoy STC60 & STC72 are tungsten carbide silver composites with a higher hardness but lower electrical conductivity than the silver tungsten grades. They are suitable for air switching operations where a high arc and mechanical wear resistance are required. they are used in d.c switchgear, miniature circuit breakers an heavy duty relays.
VACULOY STANDARD GRADES
Silver Tables
| Material | Vaculoy grade | Application | Composition | Density g/cm | Hardness | Electrical Conductivity % IACS | Other Classification |
|---|---|---|---|---|---|---|---|
| Sil Tun | ST 50 | Arcing/Main Contact | 50% Tungsten | 13.4 | 110 HV | 58 | 50s |
| Sil Tun | ST65 | Arcing/Main Contact | 65% Tungsten | 14.8 | 150 HV | 50 | 35s |
| Sil Tun | ST75 | Arcing Contact | 75% Tungsten | 16.0 | 220 HV | 45 | 20s |
| Sil Tun Carbide | STC 60 | Arcing Contact vacuum switch | 60% Tungsten Carbide | 13.0 | 220 HV | 40 | |
| Sil Tun Carbide | STC 72 | Contact | 72% Tungsten Carbide | 13.8 | 400 HV | 22 | |
| Sil Cad Oxi | SC 85 | Main Contact | 85% Silver | 9.9 | 68 HB | 75 | |
| Sil Cad Oxi | SC 90 | Main Contact | 90% Silver | 9.95 | 64 HB | 78 | |
| Silver Nickel | SN70 | Atcing/Main Contact | 70% Silver | 9.8 | 65 HB | 60 |
OTHER APLICATIONS FOR TUNGSTEN BASED METALS
Spark erosion & Electro-Chemical Machining
Vaculoy CT72 provides a spark machining material with the properties required when conventional electrode materials erode too quickly. It is particularly suitable for fine finish and sharp definition work, especially when eroding hardened steels and tungsten carbide.
In electro chemical machining it resists damage by spark and electrolyte glow whilst having adequate electrical conductivity.
Resistance Welding
Vaculoy CT75W is a fine grain tungsten copper composite to BS4577-B11. It has a high hardness and resistance to deformation at elevated welding, flash butt and spot welding.
Electrical Upsetting
Vaculoy CTC67 is a tungsten carbide composite conforming to BS4577-B12. It has, because of the use of tungsten carbide, a higher hardness and heat strength than CT75W and is uses as dies and anvils in electrical upsetting.
Availability
ELECTRICAL CONTACT METALS
- All VACULOY contact metals can be supplied as follows:-
- as contact tips
- as manufactured contact assemblies
- as contact tips brazed to contact bodies supplied by customers
V I Products are also able to re-tip used contacts. This service is particularly useful when contacts are obsolete.
ECM & EDM Electrode Metals
Plates up to 1" thick, rods up to 2" dia and discs up to 3 1/2" diameter are normally available ex-stock.
Non Standard shapes and sizes are available to order.
Projection Welding & Electrical Upsetting Metals
Vaculoy CT75W & CTC67 is available as shaped tips, small plates and rods, or if required can be supplied brazed to copper alloy electrode bodies.
