Group C Specialty Materials Alloy Number Rockwell Hardness

Electrical Conductivity

%IACS [Ms/m]

     Yield Strength

0.2% Offset

Ksi [Mpa]

       Ultimate Tensile Strength

Ksi [Mpa]

Elongation %
Minimum Minimum Typical Typical IN 2" or 4 X D
Class 20 C15760 75 HRB 75% [43.5] 60 [413] 74 [510] 25
Class 21 C15715 62 HRB 92% [51] 48 [331] 58 [400] 30
Class 22 C15725 87 HRB 87% [49] 54 [332] 65 [448] 27

Note: Acceptance is based on hardness and conductivity only.

Reference: American Welding Society Publication J1.3