RWMA Class 3 & 4 Beryllium Copper Alloys – C17510 and C17200

Beryllium Copper Applications

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Beryllium Copper Information

The amount of beryllium in beryllium copper alloys does not exceed 1/50th of the total alloy and is not less than 4/10ths of a percent. The percentage of beryllium in the copper makes these alloys’ strength comparable to high alloy steel. Beryllium copper alloys have features that include the fact that they are great conductors of temperature and are resistant to stress relaxation. Class 3 C17510 beryllium copper is a much better conductor than that of its Class 4 C17200 counterpart. On the other hand, Class 4 C17200 beryllium copper is much stronger than that of Class 3 C17510. Other titles for beryllium copper include spring copper and beryllium bronze.

Class 3 Beryllium Copper (C17510)

C17510 Specifications

  • ASTM B441
  • ASTM B534
  • MIL C-81021
  • SAE J461
  • SAE J463
  • UNS C17510
  • Class 3 Copper

Class 3 C17510 is specifically recommended for projection welding dies, flash and butt welding dies, current carrying shafts and bushings. As castings, C17510 (having higher strength than Class 2), is recommended for highly stressed welder structural current carrying members and heavy duty offset electrode holders.

Class 3 C17510 is generally recommended for spot welding and seam welding steels having high electrical resistance, such as stainless steels. The C17510 Alloy is heat treatable.

Its most common uses are in those applications that necessitate a lot of conductivity of temperature or electricity. Its ultimate tensile strength is 140 ksi while its hardness is RB 100. The conductivity of C17510 is about 45-60% of regular copper.

Class 4 Beryllium Copper (C17200)

C17200 Specifications

  • AMS 4651
  • AMS 4725
  • ASTM B194
  • ASTM B196
  • ASTM B197
  • ASTM B570
  • MIL C-21657
  • SAE J461
  • SAE J463
  • UNS C17200
  • Class 4 Copper

Class 4 C17200 has extremely high hardness and ultimate tensile strength although the electrical conductivity is lower than the Class 3 C17510.

Class 4 C17200 is available in heat treatable tempers. Alloys are used in a wide range of applications requiring high strength and stiffness with good conductivity.

Typical uses include electrical/electronic connectors, current-carrying springs, precision screw machined parts, welding electrodes, bearings, plastic molds and corrosion resistant components

RWMA Class/(Temper) Alloy Number Hardness Conductivity(%) Tensile Strength
Class 3 (HT) C17510 B95-102 48-60 110-140 ksi
Class 4 (HT) C17200 C38-44 22-28 180-220 ksi

C17510 Tempers

TB00 or A

This produces the softest form of the material. This is the condition or temper resulting from heating the material to a temperature sufficient to allow the beryllium to dissolve into a solid solution within the copper base metal, followed by rapid cooling.

Hardness: B20-45

TF00 or AT

This process is often referred to as Aging, Age Hardening or Heat Treating. This is the condition or temper resulting from the application of a specific time and temperature combination. This action produces an extreme strengthening effect within the material. The tensile properties change from copper-like to steel-like and the thermal and electrical properties also increase. The specific combination of time and temperature applied determines the final properties.

Hardness: B92-100

TD04 or H

In Beryllium Copper this means that the material is processed like the TB00/A temper material and then gets drawn through a die to make a shape. The extra drawing through the die makes the material harder.

Hardness: B78-88

TH04 or HT

In Beryllium Copper this means that the material is carefully annealed and then cold drawn to a specific size and then heat treated.

Hardness: B95-102

Health Hazard Information for Users of Beryllium Copper Alloys (MSDS)


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