Approximate Equivalent Hardness Numbers for Cartridge Brass (70% Cu, 30% Zn)
Rockwell Hardness Number
Brinell Hardness Number
B scale, 100 kgf
1/16 in. (1.588 mm) ball
HRBF scale, 60 kgf
1/16 in. (1.588 mm) ball
HRF500 kgf, 10 mm ball
HBS93.5 110.0 169 -- 109.5 167 93.0 -- 166 92.5 109.0 164 92.0 -- 162 91.5 108.5 161 91.0 -- 159 90.5 108.0 157 90.0 107.5 156 89.0 -- 154 88.5 107.0 152 88.0 -- 150 87.5 106.5 149 87.0 -- 147 86.0 106.0 146 85.5 -- 144 85.0 105.5 142 84.0 105.0 141 83.5 -- 139 83.0 104.5 138 82.0 104.0 136 81.5 103.5 135 80.5 103.0 133 80.0 -- 131 79.0 102.5 129 78.0 102.0 128 77.5 101.5 126 77.0 101.0 124 76.0 100.5 122 75.0 100.0 121 74.5 99.5 120 73.5 99.0 118 73.0 98.5 116 72.0 98.0 114 71.0 97.5 113 70.0 97.0 112 69.0 96.5 110 68.0 96.0 108 67.0 95.5 106 66.0 95.0 105 65.0 94.5 103 64.0 94.0 101 63.0 93.0 99 62.0 92.6 97 61.0 92.0 95 59.5 91.2 94 58.0 90.5 92 57.0 89.8 90 56.0 89.0 88 54.0 88.0 86 53.0 87.2 85 51.0 86.3 83 49.5 85.4 82 47.5 84.4 80 46.0 83.5 79 44.0 82.3 77 42.0 81.2 76 40.0 80.0 74 37.5 78.6 72 35.0 77.4 70 32.0 76.0 68 30.0 74.8 66 27.5 73.2 64 24.5 71.8 63 21.5 70.0 62 18.5 68.5 61 15.5 66.8 59 12.5 65.0 57 10.0 62.5 55 -- 61.0 53 -- 58.8 52 -- 56.5 50 -- 53.5 48 -- 50.5 47 -- 49.0 46 -- 47.0 45 -- 45.0 44 -- 43.0 43 -- 40.0 42 Source: ASTM E140