Check here various Brinell To Rockwell Hardness Conversion
Different Conversion of Brinell To Rockwell C Conversion, Brinell To Rockwell B Conversion and Brinell To Rockwell Chart
Difference Between Brinell and Rockwell Hardness
- Indenters of Brinell and Rockwell Hardness
- In case of Brignell’s method, the penetrator is a calcareous ball (for hardness up to 450HB) or hard metal (for hardness up to 650HB) of diameter D, which is emitted by force F in the surface layers of the material. The standard diameters of balls are 10, 5, 2.5, 2 and 1 mm.
- In Rockwell’s method several types of penetrators are used: for soft materials, a small steel ball (HRB method) is used, for hard materials a diamond cone (HRC method). The diamond cone has a peak angle of 1200 and a radius of 0.2 mm round, while the diameter of the steel balls is 1/16″, 1/8″, 1/4″ and 1/2″.
- Duration of Brinell and Rockwell Hardness
- The Brinell test is very slow (30 – 60sec).
- Rockwell’s test is shorter (10 – 15sec).
- Calculation of Brinell and Rockwell Hardness
- Brinell’s Hardness (HB) is the ratio of the applied force F (N) and the surface of the fingerprint S (mm2): HBW = (F*0.102/ S); S = π* D* h.
- In Rockwell’s method HRB = 130 – (e/0.002); HRC = 100 – (e/0.002)
- Application of Brinell and Rockwell Hardness
- The Brinell method is used for soft and medium hard materials.
- Rockwell’s test is used for soft and medium hard materials (aluminum, soft steel, Cu alloys etc.)
- Advantages of Brinell and Rockwell Hardness
- Advantages of Brinell’s method is the simple surface preparation and the easy measurement of the print diameter.
- Rockwell method is faster, there is higher speed immediate reading of hardness on the device and the test leaves shallow imprint.
- Disadvantages of Brinell and Rockwell Hardness
- Disadvantages of Brinell’s method are that hardness of ≥ 650 HB cannot be measured; the hardness is dependent on the load and according to X (degree of load) so it is necessary to choose the appropriate force F; after the measurement, the impression is large and leaves a visible trace.
- For Rockwell’s test there is the possibility of a cone breakage and the imprecision ± 2 HRB / HRC.
- Rockwell Hardness Test
- Quick and cost-effective process
- The Rockwell hardness is based on difference of indentation depth of indenter from two different load applications.
- Not always the most accurate hardness testing method
- No specimen preparation required
- Ball Indenter 1/16 , 1/8 , 1/4 and 1/2 inches diameter.
- Testing Load - Two loads Minor 10Kgf, Major 60 -100-150 Kgf
- Hardness value is directly readable , no optical evaluation required
- Non-destructive testing
- First minor load is applied to achieve zero level then major load is applied for specific period.
- Indenter Size - Conical diamond indenter with 120° Included angle.
- Brinnel Hardness Test
- In Brinell hardness test hard ball indenter is pressed under load on surface of material.
- Indenter- Ball indenter e.g. 1mm, 2.5mm, 5mm and 10mm ball diameter
- High risk of deforming the materials to be tested when testing in micro range with very high test loads.
- Teating Load - Single load from 1kgf to 3000 Kgf
- Process is very slow ( the test cycle takes somewhere between 30 and 60 seconds )
- It can be applied on thin specimens of very hard materials.
- Can be used to test non-homogenous materials ( castings ).
- Surface quality of the metal must be very good because the indent is measured optically.
- Brinell hardness number is expressed as ratio of load and area of indentation.
Hardness ranges for heat treated steel
HARDNESS CONVERSION TABLE
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