REFACTORY METALS

RWMA Class

Type of Material

CDA No.

Primary Use

10

Copper-Tungsten

C74450

Class 10 Copper Tungsten is used for flash and butt welding electrodes in applications in which high heat resistance, higher electrical and/or thermal conductivity, high malleability, and low thermal expansion are required. This metal is created by combining 45% copper and 55% tungsten, resulting in a dense, hard metal with superior wear resistance and strength.

11

Copper-Tungsten

C74400

Class 11 Copper Tungsten contains 25% copper and 75% tungsten. Like Class 10, it has superior wear resistance and strength and good thermal and electrical conductivity. However, it is harder than Class 10 and used in applications that require moderate pressure. Common uses include projection welding electrodes, flash and butt welding electrodes, light upsetting and seam welding bushings, and spot welding low conductivity steels. It is also widely used in chip carriers, substrates, flanges, and frames for power semiconductor devices.

12

Copper-Tungsten

C74350

Class 12 Copper Tungsten contains 20% copper and 80% tungsten. Stronger than Class 10 and 11 Copper Tungsten, it is commonly used in heavy duty projection welding electrodes, electro-forming and -forging electrode facings for upsetting studs and rivets, and cross wire welding. IT is also used in the liners of some specialty shaped explosive charges for the defense and oil and gas industries.

13

Tungsten

C74300

Tungsten has the second highest melting point of all elements. It is extremely dense and has low ductility. It is commonly used in cross wire welding copper and brass, resistance brazing, and welding of braided copper wire. It is also has many non-welding applications, such as filaments for incandescent light bulbs, x-ray filaments and targets, and penetrating projectiles.

14

Molybdenum

C42300

Molybdenum has the sixth highest melting point of all elements and is used in high temperature and high pressure applications. It has similar welding applications as Class 13 Tungsten; however, it is not as hard, but it has a more stable price and can be machined into special contours.

20

Dispersion Strengthened Copper

C15760

Dispersion Strength Copper contains copper and aluminum oxide, giving this metal electrical and thermal conductivity similar to copper but greater strength and resistance to softening at high temperatures. DSC electrodes are particularly useful when welding metallic coated metals, such as galvanized steel and terne plate. In its electrical applications, DSC is used in incandescent lamp lead wires.

RWMA Class/(Temper)

Alloy Number

Hardness

Conductivity(%)

Tensile Strength

Class 10
(1W3)

55W; 45CU

B77

53

110 ksi

Class 10
(5W3)

70W; 30CU

B95

48

140 ksi

Class 11
(10W3)

75W; 25CU

B98

45

150 ksi

Class 12
(30W3)

80W; 20CU

B103

41

170 ksi