Nowadays, hardness testers have been widely used in the measurement of the hardness of various metal materials in factories, and other industries. However, there are many types of hardness tests, and consumers often worry about the choice of test. The scope of use of every test is different but the most common method is Rockwell.
The Rockwell test uses three loads and three indenters, which have a total of 9 combinations, to make 9 scales: HRA, HRB, HRC, HRD, HRE, HRF, HRG, HRH, and HRK. The application of these 9 rulers covers almost all commonly used metal materials. In this article we will talk about Scale B only.
I. What is the Rockwell Hardness Test?
The Rockwell hardness test is defined in ISO 6508 & ASTM E-18 as the most widely used hardness test method in the world, applicable to almost all metals and to some extent plastics. The Rockwell hardness test measures the eternal depth created by a specific indenter and a specific test force. Rockwell hardness testing requires less pattern surface preparation, which makes testing quicker and easier, and is widely used in many industries around the world. The main advantage of Rockwell hardness testing is the speed of the test, which can be displayed immediately after the indentation.
II. What is the Rockwell B Scale?
Rockwell scale B is the hardness measuring scale with the symbol HRB. The range of the scale lies between 20-100HRB with an intender(1.5875mm ball). When the hardness of the sample is less than 20HRB, the deformation of the sample lasts for a long time, and the scale on the watch will move slowly, making it difficult to measure accurately. When HRB>100, because the ball is pressed into the depth too shallowly, the sensitivity and accuracy are reduced.
Related Article: Importance of Hardness Conversion: Rockwell Hardness C Scale
Related Article: How to Choose Rockwell Hardness Scale?
III. When will you Use the Rockwell B Scale?
Rockwell hardness scale is suitable for the determination of low hardness materials (hardness lies between 20 to 100), such as annealed medium carbon and low carbon steel, malleable cast iron, various brass and most bronzes, and various hard aluminum alloys after solution treatment and aging.
IV. Rockwell Hardness B Scale Conversion Chart
Rockwell | Superficial Rockwell | Brinell | Vickers | Knoop | |||||
B | A | E | 15T | 30T | 45T | HB | HB | HV | HK |
30kgf | 60kgf | 100kgf | 15kgf | 30kgf | 45kgf | 10 mm Steel Ball | 10 mm Steel Ball | 10kgf | Diamond |
1/16″ steel Ball | Daimond | 1/8” steel Ball | 1/16″ steel Ball | 1/16″ steel Ball | 1/16″ steel Ball | 3000kgf | 500kgf | Diamond | 500gf+ |
100 | 61.5 | – | 93.1 | 83.1 | 72.9 | 240 | 201 | 240 | 251 |
99 | 60.9 60.2 59.5 58.9 | – | 92.8 | 82.5 | 71.9 | 234 | 195 | 234 | 246 |
98 | 58.3 57.6 | – | 92.5 | 81.8 | 70.9 | 228 | 189 | 228 | 241 |
97 | 57 | – | 92.1 | 81.1 | 69.9 | 222 | 184 | 222 | 236 |
96 | 56.4 | – | 91.8 | 80.4 | 68.9 | 216 | 179 | 216 | 231 |
95 | 55.8 55.2 54.6 54.0 | – | 91.5 | 79.8 | 67.9 | 210 | 175 | 210 | 226 |
94 | 53.4 52.8 52.3 51.7 | – | 91.2 | 79.1 | 66.9 | 205 | 171 | 205 | 221 |
93 | 51.1 50.6 | – | 90.8 | 78.4 | 65.9 | 200 | 167 | 200 | 216 |
92 | 50.0 49.5 | – | 90.5 | 77.8 | 64.8 | 195 | 163 | 195 | 211 |
91 | 48.9 | – | 90.2 | 77.1 | 63.8 | 190 | 160 | 190 | 206 |
90 | 48.4 | – | 89.9 | 76.4 | 62.8 | 185 | 157 | 185 | 201 |
89 | 47.9 | – | 89.5 | 75.8 | 61.8 | 180 | 154 | 180 | 196 |
88 | 47.3 | – | 89.2 | 75.1 | 60.8 | 176 | 151 | 176 | 192 |
87 | 46.8 46.3 | – | 88.9 | 74.4 | 59.8 | 172 | 148 | 172 | 188 |
86 | 45.8 45.3 | – | 88.6 | 73.8 | 58.8 | 169 | 145 | 169 | 184 |
85 | 44.8 44.3 | – | 88.2 | 73.1 | 57.8 | 165 | 142 | 165 | 180 |
84 | 43.8 43.3 | – | 87.9 | 72.1 | 56.8 | 162 | 140 | 162 | 176 |
83 | 42.8 | – | 87.6 | 71.8 | 55.8 | 159 | 137 | 159 | 173 |
82 | 42.3 | – | 87.3 | 71.1 | 54.8 | 156 | 135 | 156 | 170 |
81 | 41.8 | – | 86.9 | 70.4 | 53.8 | 153 | 133 | 153 | 167 |
80 | 41.4 | – | 86.6 | 69.7 | 52.8 | 150 | 130 | 150 | 164 |
79 | 40.9 | – | 86.3 | 69.1 | 51.8 | 147 | 128 | 147 | 161 |
78 | 40.4 | – | 86 | 68.4 | 50.8 | 144 | 126 | 144 | 158 |
77 | 40 | – | 85.6 | 67.7 | 49.8 | 141 | 124 | 141 | 155 |
76 | 39.5 | – | 85.3 | 67.1 | 48.8 | 139 | 122 | 139 | 152 |
75 | 39.0 | – | 85 | 66.4 | 47.8 | 137 | 120 | 137 | 150 |
74 | 38.6 | – | 84.7 | 65.7 | 46.8 | 135 | 118 | 135 | 147 |
73 | 38.1 | – | 84.3 | 65.1 | 45.8 | 132 | 116 | 132 | 145 |
72 | 37.7 | – | 84 | 64.4 | 45.8 | 130 | 114 | 130 | 143 |
71 | 37.2 | 100 | 83.7 | 63.7 | 43.8 | 127 | 112 | 127 | 141 |
70 | 36.8 | 99.5 | 83.5 | 63.1 | 42.8 | 125 | 110 | 125 | 139 |
69 | 36.3 | 99 | 83 | 62.4 | 41.8 | 123 | 109 | 123 | 137 |
68 | 35.9 | 98 | 82.7 | 61.7 | 40.8 | 121 | 108 | 121 | 135 |
67 | 35.5 | 97.5 | 82.4 | 61 | 39.8 | 119 | 106 | 119 | 133 |
66 | 35 | 97 | 82.1 | 60.4 | 38.7 | 117 | 104 | 117 | 131 |
65 | 34.6 | 96 | 81.8 | 59.7 | 37.7 | 116 | 102 | 116 | 129 |
64 | 34.1 | 95.5 | 81.4 | 59 | 36.7 | 114 | 100 | 114 | 127 |
63 | 33.7 | 95.1 | 81.1 | 58.4 | 35.7 | 112 | 99 | 112 | 125 |
62 | 33.3 | 94.5 | 80.8 | 57.7 | 34.7 | 110 | 98 | 110 | 124 |
61 | 32.9 | 93.5 | 80.5 | 57 | 33.7 | 108 | 96 | 108 | 122 |
60 | 32.4 | 93 | 80.1 | 56.4 | 32.7 | 107 | 95 | 107 | 120 |
59 | 32 | 92.5 | 79.8 | 55.7 | 31.7 | 106 | 94 | 106 | 117 |
58 | 31.6 | 92 | 79.5 | 55 | 30.7 | 104 | 92 | 104 | 117 |
57 | 31.2 | 91 | 79.2 | 54.4 | 29.7 | 103 | 91 | 103 | 115 |
56 | 30.7 | 90.5 | 78.8 | 53.7 | 28.7 | 101 | 90 | 101 | 114 |
55 | 30.3 | 90 | 78.5 | 53 | 27.7 | 100 | 89 | 100 | 112 |
54 | 29.9 | 89.5 | 78.2 | 52.4 | 26.7 | – | 87 | – | 111 |
53 | 29.5 | 89 | 77.9 | 51.7 | 25.7 | – | 86 | – | 110 |
52 | 29.1 | 86 | 77.5 | 51 | 24.7 | – | 85 | – | 109 |
51 | 28.7 | 87.5 | 77.2 | 50.3 | 23.7 | – | 84 | – | 108 |
50 | 28.2 | 87 | 76.9 | 49.7 | 22.7 | – | 83 | – | 107 |
49 | 27.8 | 86.5 | 76.6 | 49 | 21.7 | – | 82 | – | 106 |
48 | 27.4 | 85.5 | 76.2 | 48.3 | 20.7 | – | 81 | – | 105 |
47 | 27 | 85 | 75.9 | 47.7 | 19.7 | – | 80 | – | 104 |
46 | 26.6 | 84.5 | 75.6 | 47.9 | 18.7 | – | 80 | – | 103 |
45 |
| 84 | 75.3 | 46.5 | 17.7 | – | 79 | – | 102 |
44 |
| 83.5 | 74.9 | 45.7 | 16.7 | – | 78 | – | 101 |
43 |
| 82.5 | 74.6 | 45 | 15.7 | – | 77 | – | 100 |
42 |
| 82 | 74.3 | 44.3 | 14.7 | – | 76 | – | 99 |
41 |
| 81.5 | 74 | 43.7 | 13.6 | – | 75 | – | 98 |
40 |
| 81 | 73.6 | 43 | 12.6 | – | 75 | – | 97 |
39 |
| 80 | 73.3 | 42.3 | 11.6 | – | 74 | – | 96 |
38 |
| 79.5 | 73 | 41.6 | 10.6 | – | 73 | – | 95 |
37 |
| 79 | 72.7 | 41 | 9.6 | – | 72 | – | 94 |
36 |
| 78.5 | 72.3 | 40.3 | 8.6 | – | 72 | – | 93 |
35 |
| 78 | 72 | 39.6 | 7.6 | – | 71 | – | 92 |
34 |
| 77 | 71.7 | 39 | 6.6 | – | 70 | – | 91 |
33 |
| 76.5 | 71.4 | 38.3 | 5.6 | – | 69 | – | 90 |
32 |
| 76 | 71 | 37.6 | 4.6 | – | 69 | – | 89 |
31 |
| 75.5 | 70.7 | 37 | 3.6 | – | 68 | – | 88 |
30 |
| 75 | 70.4 | 36.3 | 2.6 | – | 67 | – | 87 |
Conclusion
The Rockwell hardness B scale used for soft or mild metal materials, is the second most common hardness scale in the testing field. The information provided in this article is likely to be enough for you if you want to proceed with this test for hardness deduction purposes. Know more about scales of Rockwell Hardness test or other popular hardness testing methods by visiting our website.