NSRW Group A Material

Group A - Copper Base Alloys

RWMA	Condition	Principal Elements	RWMA Alloy Number	Hardness Rockwell	Electrical Conductivity %I.A.C.S.	Ultimate Tensile Strength, psi	Elongation %in 2	Permanent Softening Begins at °C °F
Class 1	Wrought*	Copper, Cadmium	1.16200	70 B	90	65,000	15	350	660
Class 1	Wrought**	Copper, Zirconium	1.15000	70 B	90	66,000	10	500	930
Class 2	Cast Wrought***	Copper, Chromium	2.182000	70 B 83 B	80 85	50,000 75,000	20 15	500 500	930 930
Class 2	Wrought***	Copper Chromium Zirconium	2.18150	83 B	85	75,000	15	500	930
Class 3	Cast	Copper Nickel Silicon, Chromium	3.18000	90 B	48	85,000	10	455	850
Class 3	Cast Wrought	Copper, Nickel Beryllium	3.17510	95 B 100 B	48 48	95,000 110,000	10	455 455	850 850
Class 4	Cast Wrought	Copper, Beryllium	4.17200	38 C 38 C	20 23	110,000 170,000	4	375 375	710 710
Class 5	Cast	Copper, Aluminum	5.95300	92 B	13	85,000	15	620	1150
	Cast Wrought	Pure Copper	.	30 B 40 B	95 100	25,000 40,000	50 35	200 200	390 390

Class 1 Alloy (Copper Zirconium)

Chromium Zirconium Copper has higher annealing temperature than standard Chrome Copper.

Class 2 Alloy (Copper Chromium)

Class 2 Alloy is a superior resistance welding electrode material specifically recommended for high level production spot and seem welding of clean mild steel, low alloy steels, low conductivity brasses and bronzes.

Suitable for projection welding dies, seam welder shafts and bearings, flash and butt welding dies and current carrying structural members.

Available as high strength and high electrical conductivity casting for such use as gun welder arms, welder platens and secondary structural members.

The Class 2 Alloy is heat treatable.

Class 3 Alloy (Copper Beryllium)

Class 3 Alloy is specifically recommended for projection welding dies, flash and butt welding dies, current carrying shafts and bushings. As castings, Class 3 Alloy (having higher strength than Class 2), is recommended for highly stressed welder structural current carrying members and heavy-duty offset electrode holders.

Class 3 Alloy is generally recommended for spot welding and seam welding steels having high electrical resistance, such as stainless steels.

The Class 3 Alloy is heat treatable.
See Material Safety Data Sheets,

Beryllium Free

Beryllium Free meets the mechanical requirements of Class 3 Copper.

Class 4 Alloy (Copper Beryllium)

Class 4 Alloy has extremely high hardness and ultimate tensile strength although the electrical conductivity is lower than the Class 3 Alloy.

It is generally recommended as electrode material for special flash, flash butt and projection welding applications where pressures are extremely high and wear is severe but where heating is not excessive. It is available as wrought material for highest quality dies and electrodes and may also be obtained as high strength castings. It is used frequently in the form of inserts and die facings, and may also be used for seam welder bushing.

Class 4 Alloy is available in the annealed condition in which state it can be more readily machined and may be subsequently heat treated to maximum hardness.
See Material Data Safety Sheets.

Class 5 Alloy (Copper Aluminum)

Class 5 Alloy is a copper bas alloy available principally in the form of castings having high mechanical strength and moderate electrical conductivity.

Class 5 Alloy is recommended principally as a high strength and low cost backing material for other resistance welding electrode materials, flash welding dies, and as high strength current carrying structural members of resistance welding equipment, such as secondary circuit welder arms, knees, platens, etc.

It may be used advantageously as natural or current carrying members in resistance welding fixtures where high strength, wear resistance and non-magnetic properties are required.