This versatile nondestructive testing method can be used on almost any metallic material.

Introduction

Brinell Hardness Testing is a nondestructive testing method that determines the hardness of a metal by measuring the size of an indentation left by an indenter. At a defined ball diameter and test force, larger indents left in the surface by the Brinell Hardness Testing Machine indicate a softer material. The indenter on a Brinell Hardness Testing machine is spherical and leaves a rounded indent on the tested material. The indenter is usually made of tungsten carbide.

Equipment Required



Brinell microscope

Brinell Hardness Testing Machine

Indenter Sphere

Description of the Brinell Hardness Testing Machine

The Brinell Hardness Testing Machine has a loading system that includes leavers, weights, hydraulic dashpot, and plunger enclosed in the iron body of the machine. The material to be tested sits on an anvil that can be elevated with a screw. The ball indenter descends on the material with a specified force in order to determine loads on the specimen.

How the Test Works



The test consists of forcing a steel ball of diameter ‘D’ under a load ‘P’ into the specimen for a specified amount of time and measuring the mean diameter ‘d‘ of the impression left on the surface after removal of the load. The Brinell Hardness Number (BHN) is then calculated as load divided by the surface area of indention.

Depth of Indentation (h) is determined with this equation:

Depth of Indentation (h) is determined with this equation:

Then, the Brinell Hardness Number is determined with this equation:

D = Diameter of Ball in mm

P = Applied load in kg-f, and

d = Diameter of indentation in mm.



Testing Requirements



1. The surface of the test material must be thoroughly cleaned before the test.

2. Select the proper indenter for the test.

3. Crank the test table to the set elevated position.

4. Maintain the load on the specimen for the exact specified time and then release it.

5. Take out the specimen and measure the diameter of the indentation formed on it by using the Brinell Microscope.



Testing Standards

ASTM E10

JIS Z 2243

ISO 6506

Applications

The wide test force range of the Brinell Hardness Testing Machine means it can be used on almost any metallic material. The part size is only limited by the testing instrument's capacity. Since this is a nondestructive testing method, the tested sample can usually be returned to operation.

Citations

Brinell Hardness Test for Metals. (2019, May 25). Retrieved from https://theconstructor.org/practical-guide/brinell-hardness-test/2447/.

Brinell test procedure. (2018, August 1). Retrieved from https://www.emcotest.com/en/the-world-of-hardness-testing/hardness-know-how/theory-of-hardness-testing/brinell/brinell-test-procedure/.