Physical Properties Group A (Class 1, 2, 3, 4)

Group A Copper Base Alloys¹ Minimum Hardness Rockwell B or C as noted²      Minimum Electrical Conductivity
 
% IACS [Ms/m]
Size Range Class Class
IN MM 1 2 3 4 1 2 3 4
Diameter - Round Bar Stock
Up to 1" Up to 25 65 HRB 75 HRB 90 HRB 33 HRB 80% [46] 75% [43.5] 45% [26] 20% [11.6]
Over 1"-2" Over 25-51 60 HRB 70 HRB 90 HRB 33 HRC 80% [46] 75% [43.5] 45% [26] 20% [11.6]
Over 2"-3" Over 51-76 55 HRB 65 HRB 90 HRB 33 HRC 80% [46] 75% [43.5] 45% [26] 20% [11.6]
Over 3"-3 1/2" Over 76-89 50 HRB 65 HRB 90 HRB 33 HRC 80% [46] 75% [43.5] 45% [26] 20% [11.6]
Thickness - Square, Rectangular & Hexagonal Bar Stock
Up to 1" Up to 25 55 HRB 70 HRB 90 HRB 33 HRB 80% [46] 75% [43.5] 45% [26] 20% [11.6]
Over 1" Over 25 50 HRB 65 HRB 80% [46] 75% [43.5] 45% [26] 20% [11.6]
Thickness - Forgings and Plates
Up to 1" Up to 25 55 HRB 65 HRB 90 HRB 33 HRB 80% [46] 75% [43.5] 45% [26] 20% [11.6]
Over 1" to 2" Over 25 - 51 50 HRB 65 HRB 90 HRB 33 HRB 80% [46] 75% [43.5] 45% [26] 20% [11.6]
Over 2" Over 51 50 HRB 65 HRB 90 HRB 33 HRB 80% [46] 75% [43.5] 45% [26] 20% [11.6]

Notes:

1. All materials are in the fully heat treated and hardened condition. 

2. Rod and bar hardness are determined at mid-radius in accordance with ASTM test method E18.

Reference:

American Welding Society Publication J1.3