Brinell Hardness Number

The principle of the Brinell hardness test is that the spherical surface area of a recovered indentation made with a standard hardened steel ball under specific load is direcdy related to the property called hardness. In the following, HBN = Brinell hardness number, P = load in kgf,... 

In practice it is stiU necessary to read the diameter of the Brinell impressions with a caUbrated microscope however, the computations to derive the Brinell hardness number are uimecessary for standard loads and indentors. Table 1 of ASTM ElO (2) contains the tabulated relation between indentation diameter and hardness number. 

For erosive wear. Rockwell or Brinell hardness is likely to show an inverse relation with carbon and low alloy steels. If they contain over about 0.55 percent carbon, they can be hardened to a high level. However, at the same or even at lower hardness, certain martensitic cast irons (HC 250 and Ni-Hard) can out perform carbon and low alloy steel considerably. For simplification, each of these alloys can be considered a mixture of hard carbide and hardened steel. The usual hardness tests tend to reflect chiefly the steel portion, indicating perhaps from 500 to 650 BHN. Even the Rockwell diamond cone indenter is too large to measure the hardness of the carbides a sharp diamond point with a light load must be used. The Vickers diamond pyramid indenter provides this, giving values around 1,100 for the iron carbide in Ni-Hard and 1,700 for the chromium carbide in HC 250. (These numbers have the same mathematical basis as the more common Brinell hardness numbers.) The microscopically revealed differences in carbide hardness accounts for the superior erosion resistance of these cast irons versus the hardened steels. 

Brinell hardness number Vickers hardness number hour... 

Bhn Brinell hardness number CPRR Center for Plastics Recycling... 

The Brinell test uses an indentor of 10 mm diameter hardened steel ball, and applies a load which is usually 3000 kg. The Brinell hardness number (BHN) is defined as the load, F (kilogrammes), divided by the surface area of the indentation. The expression given below describes the definition. 

Figure 6.2 shows yield stress versus shear modulus data for face-centered cubic metals at about 78 K. The yield stresses were derived from Brinell Hardness Numbers (Gilman, 1960). The slope of the correlation line is tb = G/333, in good agreement with the theoretical estimate of the previous paragraph. 

Figure 6.2 Yield stresses derived from Brinell Hardness Numbers for pure f.c.c. metals versus their shear moduli. The measurements were made at the temperature of liquid nitrogen (after Gilman, 1960).

Figure 7.2 Brinell Hardness Numbers (BHN) of the fee transition metals as a function of their average shear moduli (taken from Ledbetter, 2001).The hardness numbers are low temperature values measured at -200 °F. Note that this figure is similar to Figure 6.2 without A1 and Pb. Chin-Gilman parameter = H/G = 0.0044.

Mating wear surfaces of hardenable materials shall have a difference in Brinell hardness number of at least 50 unless both the stationary and the rotating wear surfaces have Brinell hardness numbers of at least 400. 

The hardness number is usually combined with the name of the method used, to indicate how the value was obtained. The commonly used tests are the Brinell, Rockwell, and Vickers hardness tests. The results of these tests are presented as the HB or Brinell hardness number, or the HV, and so on. 

Electrical conductivity Brinell hardness number Surface tension Viscosity... 

Fig. 17. Isothermal transformation (II) diagram for a plain carbon eutectoid steel (1). Ae is A temperature at eqiiflibrium BHN, Brinell hardness number ...

The Brinell hardness number is based on the indentation of the surface under test by a ball of specific diameter, usually 10 mm, when pressed into the test surface. It is usually expressed in kilograms/square millimeter, thus small numbers represent low hardness. 

There are two types of hardness test static tests that involve the formation of a permanent indentation on the surface of the test material and dynamic tests in which a pendulum is allowed to strike the test material from a known distance. Vickers and Brinell tests, two examples of static methods, are the most commonly used methods for determining the hardness of pharmaceutical materials. In the Brinell test, a steel ball of diameter D is pressed on to the surface of the material, and a load F is applied for 30 sec and then removed. The diameter dj of the indentation produced is measured, and the Brinell Hardness Number (BHN) calculated by... 

Biot number based on square root of area Brinell hardness number capacitance coulomb/volt capacity m... 

There are four major indentation hardness tests, which differ from each other in the shape of the indenter (Figure 10.23). The first of these, described in 1900, was the Brinell test, using a 10 mm steel ball indenter (Figure 10.23a), giving the Brinell hardness number, BHN. This was suitable only for metals softer than steel. In 1920 Rockwell developed a number of tests, including the B, E, F and G scales, in which the indenter is steel, and the A, C and D scales, using a conical diamond indenter with a spherical tip (Figures 10.23b and 10.23c). In the Rockwell test the difference in size between the... 

Another convenient conversion is that of Brinell hardness to ultimate tensile strength. For quenched and tempered steel, the tensile strength (psi) is about 500 times the Brinell hardness number (provided the strength is not over 200,000 psi). 

A hardened steel ball 10 mm in diameter is pressed into the flat surface of the test specimen under load of 500 kg for 30 sec. The load is then removed, and the diameter of the indent produced is measured (Figure 3.42). The Brinell hardness number (BHN) is then defined as... 

ATMI American Textile Manufacturers Insti- Bhn Brinell hardness number... 

Brunauer-Emmett-Teller (method) billion electronvolt Brinell hardness number biot... 

One common hardness test is the Brinell test, in which a hardened steel ball is used as the indenter. The Brinell Hardness Number (BHN) is the applied force F divided by the surface area of the indentation, i.e.. 

Brinell Hardened steel ball Brinell hardness number (BHN) Is applied force divided by surface area of Indentation Meyer hardness number (MHN) uses projected area BHN = FtnDt MHN = 4F/tccF Spherical Indenters not used for ceramics... 

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