Copper Tungsten Class

Resistance welding machine Manufacturers Association (RWMA) was founded in 1931, under the technical committee, is responsible for the standard work, including: Resistance welding device and Resistance welding technology standard terms and definitions; All kinds of resistance welding machine specifications; Bonding, spot welding, line welding, butt welding, sparks butt weld ends, etc.; Resistance welding electrode classification standard and its physical and alloy electrical quality minimum requirements; Spot welding rod clamps standards; Spot welding and welding electrode line standard; Name of commodity and its Numbers of signs and classification.

There are some RWMA classes for the copper tungsten alloy, just as followed:
RWMA CLASS 10 = 70% Tungsten – 32% Copper
•     Electrical Conductivity 47-52
•     Hardness Rockwell B 88-95
•     Density 13.93 grams/cc
Class 10 material is recommended as facings or inserts for projection welding electrodes and flash and butt welding dies where high electrical conductivity is desirable and a degree of malleability is necessary.

RWMA CLASS 11 = 75% Tungsten – 25% Copper
•     Electrical Conductivity 42-50
•     Hardness Rockwell B 88-95
•     14.80 Density grams/cc
Class 11 (a harder material than Class 10) is recommended as facing inserts for flash and butt welding dies and general purpose projection welding electrodes.  It may also be used as seam welder bearing inserts and facing for electro-forming or electro-forging, such as stainless steel.

RWMA CLASS 12 = 80% Tungsten – 20% Copper
•     Electrical Conductivity 41-49
•     Hardness Rockwell B 99-104
•     15.60 Density grams/cc
Class 12 material is specifically recommended for heavy duty projection welding electrodes and for die facings in electro-forming and electro-forging applications.  It is suitable as die material for electrical upsetting of rivets and studs.