Table 12 Approximate equivalent hardness numbers for wrought coppers (>99% Cu, alloys C10200 through C14200) Vickers hardness No 100 kgf, gf, HV HV kgf, HK 500 gf, HK 130 128 126 124 122 120 118 116 114 112 110 108 106 104 102 100 98 96 94 92 90 88 86 84 138.7 136.8 134.9 133.0 131.0 129.0 127.1 125.1 123.2 121.4 119.5 117.5 115.6 113.5 111.5 109.4 107.3 105.3 103.2 101.0 98.9 96.9 95.5 92.3 133.8 132.1 130.4 128.7 127.0 125.2 123.5 121.7 119.9 118.1 116.3 114.5 112.6 110.1 108.0 106.0 104.0 102.1 100.0 98.0 96.0 94.0 92.0 90.0 127.0 125.2 123.6 121.9 121.1 118.5 116.8 115.0 113.5 111.8 109.9 108.3 106.6 104.9 103.2 101.5 99.8 98.0 96.4 94.7 93.0 91.2 89.7 87.9 Knoop Rockwell superficial hardness No hardness No Rockwell hardness Rockwell superficial hardness No No 15T scale, 15T scale, 30T scale, B scale, F scale, 15T scale, 15 15 30 100 60 kgf, 15 kgf, in kgf, in in kgf, in kgf, in kgf, (1.588 (1.588 (1.588 in (1.588 (1.588 mm) mm) mm) (1.588 mm) mm) ball, ball, ball, mm) ball, ball, HR15T(a) HR15T(b) HR30T(b) ball, HRF(c) HR15T(c) HRB(c) … 85.0 … 67.0 99.0 … 83.0 84.5 … 66.0 98.0 87.0 … 84.0 … 65.0 97.0 … 82.5 83.5 … 64.0 96.0 86.0 … 83.0 … 62.5 95.5 85.5 82.0 82.5 … 61.0 95.0 … 81.5 … … 59.5 94.0 85.0 … 82.0 … 58.5 93.0 … 81.0 81.5 … 57.0 92.5 84.5 80.5 81.0 … 55.0 91.5 … 80.0 … … 53.5 91.0 84.0 … 80.5 … 52.0 90.5 83.5 79.5 80.0 … 50.0 89.5 … 79.0 79.5 … 48.0 88.5 83.0 78.5 79.0 … 46.5 87.5 82.5 78.0 78.0 … 44.5 87.0 82.0 77.5 77.5 … 42.0 85.5 81.0 77.0 77.0 … 40.0 84.5 80.5 76.5 76.5 … 38.0 83.0 80.0 76.0 75.5 … 35.5 82.0 79.0 75.5 75.0 … 33.0 81.0 78.0 75.0 74.5 … 30.5 79.5 77.0 74.5 73.5 … 28.0 78.0 76.0 74.0 73.0 … 25.5 76.5 75.0 30T scale, 45T scale, 30 kgf, in (1.588 mm) ball, HR30T(c) 45 kgf, in (1.588 mm) ball, HR45T(c) 69.5 68.5 67.5 66.5 66.0 65.0 64.0 63.0 62.0 61.0 60.0 59.0 58.0 57.0 56.0 55.0 53.5 52.0 51.0 49.0 47.5 46.0 44.0 43.0 49.0 48.0 46.5 45.0 44.0 42.5 41.0 40.0 38.5 37.0 36.0 34.5 33.0 32.0 30.0 28.5 26.5 25.5 23.0 21.0 19.0 16.5 14.0 12.0 Brinell No hardness 500 kgf, 10 mm diam ball, HBS(d) 20 kgf, mm diam ball, HBS(e) … … 120.0 117.5 115.0 112.0 110.0 107.0 105.0 102.0 99.5 97.0 94.5 92.0 89.5 87.0 84.5 82.0 79.5 77.0 74.5 … … … 119.0 117.5 115.0 113.0 111.0 109.0 107.5 105.5 103.5 102.0 100.0 98.0 96.0 94.0 92.0 90.0 88.0 86.5 85.0 83.0 81.0 79.0 77.0 75.0 82 86.1 90.1 87.9 73.5 72.0 80 84.5 87.9 86.0 72.5 71.0 78 82.8 85.7 84.0 72.0 70.0 76 81.0 83.5 81.9 71.5 69.5 74 79.2 81.1 79.9 71.0 68.5 72 77.6 78.9 78.7 70.0 67.5 70 75.8 76.8 76.6 69.5 66.5 68 74.3 74.1 74.4 69.0 65.5 66 72.6 71.9 71.9 68.0 64.5 64 70.9 69.5 70.0 67.5 63.5 62 69.1 67.0 67.9 66.5 62.0 60 67.5 64.6 65.9 66.0 61.0 58 65.8 62.0 63.8 65.0 60.0 56 64.0 59.8 61.8 64.5 58.5 54 62.3 57.4 59.5 63.5 57.5 52 60.7 55.0 57.2 63.0 56.0 50 58.9 52.8 55.0 62.0 55.0 48 57.3 50.3 52.7 61.0 53.5 46 55.8 48.0 50.2 60.5 52.0 44 53.9 45.9 47.8 59.5 51.0 42 52.2 43.7 45.2 58.5 49.5 40 51.3 40.2 42.8 57.5 48.0 (a) For 0.010 in (0.25 mm) strip (b) For 0.020 in (0.51 mm) strip (c) For 0.040 in (1.02 mm) strip and greater (d) For 0.080 in (2.03 mm) strip (e) For 0.040 in (1.02 mm) strip Source: ASTM E 140 (Ref 6) … … … … … … … … … … … … … … … … … … … … … … 23.0 20.0 17.0 14.5 11.5 8.5 5.0 2.0 … … … … … … … … … … … … … … 74.5 73.0 71.0 69.0 67.5 66.0 64.0 62.0 60.0 58.0 56.0 54.0 51.5 49.0 47.0 44.0 41.5 39.0 36.0 33.5 30.5 28.0 74.5 73.5 72.5 71.5 70.0 69.0 67.5 66.0 64.5 63.5 61.0 59.0 57.0 55.0 53.0 51.5 49.5 47.5 45.0 43.0 41.0 38.5 41.0 39.5 37.5 36.0 34.0 32.0 30.0 28.0 25.5 23.5 21.0 18.0 15.5 13.0 10.0 7.5 4.5 1.5 … … … … 9.5 7.0 5.0 2.0 … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … 73.0 71.5 69.5 67.5 66.0 64.0 62.0 60.5 58.5 57.0 55.0 53.0 51.5 49.5 48.0 46.5 44.5 42.0 41.0 … … … Table 13 Approximate equivalent hardness numbers for cartridge brass (70% Cu, 30% Zn) Vickers hardness No., HV 196 194 192 190 188 186 184 182 180 178 176 174 172 170 168 166 164 162 160 158 156 154 152 150 148 146 144 142 140 138 136 134 132 130 128 126 124 122 120 118 116 114 Rockwell hardness No B scale, 100 F scale, 60 kgf, in (1.588 mm) ball, HRF kgf, in (1.588 mm) ball, HRF 93.5 … 93.0 92.5 92.0 91.5 91.0 90.5 90.0 89.0 88.5 88.0 87.5 87.0 86.0 85.5 85.0 84.0 83.5 83.0 82.0 81.5 80.5 80.0 79.0 78.0 77.5 77.0 76.0 75.0 74.5 73.5 73.0 72.0 71.0 70.0 69.0 68.0 67.0 66.0 65.0 64.0 110.0 109.5 … 109.0 … 108.5 … 108.0 107.5 … 107.0 … 106.5 … 106.0 … 105.5 105.0 … 104.5 104.0 103.5 103.0 … 102.5 102.0 101.5 101.0 100.5 100.0 99.5 99.0 98.5 98.0 97.5 97.0 96.5 96.0 95.5 95.0 94.5 94.0 Rockwell superficial hardness No 15T scale, 30T scale, 45T scale, 15 kgf, 30 kgf, 45 kgf, in (1.588 mm) ball, HR15T 90.0 … … … 89.5 … … 89.0 … … … 88.5 … … 88.0 … … 87.5 … … 87.0 … … 86.5 … … 86.0 … 85.5 … 85.0 … 84.5 84.0 … 83.5 … 83.0 … 82.5 82.0 81.5 in (1.588 mm) ball, HR30T 77.5 … 77.0 76.5 … 76.0 75.5 … 75.0 74.5 … 74.0 73.5 … 73.0 72.5 72.0 … 71.5 71.0 70.5 70.0 … 69.5 69.0 68.5 68.0 67.5 67.0 66.5 66.0 65.5 65.0 64.5 63.5 63.0 62.5 62.0 61.0 60.5 60.0 59.5 in (1.588 mm) ball, HR45T 66.0 65.5 65.0 64.5 64.0 63.5 63.0 62.5 62.0 61.5 61.0 60.5 60.0 59.5 59.0 58.5 58.0 57.5 56.5 56.0 55.5 54.5 54.0 53.5 53.0 52.5 51.5 51.0 50.0 49.0 48.0 47.5 46.5 45.5 45.0 44.0 43.0 42.0 41.0 40.0 39.0 38.0 Brinell hardness No 500 kgf, 10 mm ball, HBS 169 167 166 164 162 161 159 157 156 154 152 150 149 147 146 144 142 141 139 138 136 135 133 131 129 128 126 124 122 121 120 118 116 114 113 112 110 108 106 105 103 101 112 63.0 93.0 81.0 58.5 37.0 99 110 62.0 92.6 80.5 58.0 35.5 97 108 61.0 92.0 … 57.0 34.5 95 106 59.5 91.2 80.0 56.0 33.0 94 104 58.0 90.5 79.5 55.0 32.0 92 102 57.0 89.8 79.0 54.5 30.5 90 100 56.0 89.0 78.5 53.5 29.5 88 98 54.0 88.0 78.0 52.5 28.0 86 96 53.0 87.2 77.5 51.5 26.5 85 94 51.0 86.3 77.0 50.5 24.5 83 92 49.5 85.4 76.5 49.0 23.0 82 90 47.5 84.4 75.5 48.0 21.0 80 88 46.0 83.5 75.0 47.0 19.0 79 86 44.0 82.3 74.5 45.5 17.0 77 84 42.0 81.2 73.5 44.0 14.5 76 82 40.0 80.0 73.0 43.0 12.5 74 80 37.5 78.6 72.0 41.0 10.0 72 78 35.0 77.4 71.5 39.5 7.5 70 76 32.5 76.0 70.5 38.0 4.5 68 74 30.0 74.8 70.0 36.0 1.0 66 72 27.5 73.2 69.0 34.0 … 64 70 24.5 71.8 68.0 32.0 … 63 68 21.5 70.0 67.0 30.0 … 62 66 18.5 68.5 66.0 28.0 … 61 64 15.5 66.8 65.0 25.5 … 59 62 12.5 65.0 63.5 23.0 … 57 60 10.0 62.5 62.5 … … 55 58 … 61.0 61.0 18.0 … 53 56 … 58.8 60.0 15.0 … 52 54 … 56.5 58.5 12.0 … 50 52 … 53.5 57.0 … … 48 50 … 50.5 55.5 … … 47 49 … 49.0 54.5 … … 46 48 … 47.0 53.5 … … 45 47 … 45.0 … … … 44 46 … 43.0 … … … 43 45 … 40.0 … … … 42 Source: ASTM E 140 (Ref 6) Magnesium and magnesium alloys are tested by applying the Rockwell B scale, but when the alloys are softer (annealed), the indenter size is increased to 3.175 mm (⅛ in.) using the Rockwell E scale As with other metals and alloys, thin sections of magnesium alloys must be tested with the 15T or 30T scale to avoid the anvil effect Titanium The Rockwell A scale is best suited for testing titanium The 60 kgf load tends to increase the life of the diamond penetrator because there is an affinity between diamond and titanium, which usually shortens diamond life Titanium tends to adhere to the tip of the diamond penetrator and can readily be removed with 3/0 grade emery paper when the penetrator is rotated in a lathe Maintaining a clean diamond will give more reliable results Zinc and lead alloys are typically tested using the Rockwell method They exhibit extensive time-dependent plasticity characteristics and therefore require longer dwell time of load application to obtain accurate and repeatable results For materials that show some time-dependent plasticity, the dwell time of indent load should be to s using a diamond indenter For materials that show considerable time-dependent plasticity, dwell time should be 20 to 25 s using any indenter One method for determining the magnitude of time-dependent plasticity is to a series of tests at progressively longer dwell times As the dwell increases the hardness values will decrease significantly When the rate of change decreases significantly the proper dwell time has been reached Zinc The Rockwell E scale is used for zinc sheets down to 3.2 mm (0.125 in.) and the Rockwell H scale for sheets down to 1.25 mm (0.050 in.) gage These values are for zinc in the soft condition, thinner sheets may be tested if the zinc is relatively hard For thinner sheet, the 15T or 30T scale of the Rockwell superficial tester should be used Lead Most testing on lead is done on thicker specimens with the Rockwell E and H scales Tin plate is tested on the Rockwell superficial HR15T, HR30T, and HR45T scales along with a diamond spot anvil in accordance with the following criteria: Thickness Scale mm in