Brinell hardness test
The Brinell hardness test presses a hard metal ball into the material and measures the size of the indentation. This method is good for soft or coarse-grained materials like cast iron.
Physical-Chemical Mechanism of Action
The Brinell hardness test uses a hard metal ball that is pressed into the material with a defined force (e.g., 1000 kgf). The ball deforms slightly and leaves an indentation on the material surface. The size of this indentation is measured and used to calculate the hardness.
Metallurgical Relevance & Risks in Welding
The Brinell hardness gives an indirect measure of the average hardness of a material. It is especially useful for soft or coarse-grained materials where other hardness methods like the Rockwell test are not as precise. Too high a pressure can deform the material and produce false results. Too low a pressure leads to a too large indentation and inaccurate values.
Workshop Practice & Action Instructions
Use a ball with a diameter of 10 mm and press it with a force of 1000 kgf into the material. The measurement of the indentation is done after the material has cooled. Make sure the pressure is exactly maintained and the ball is pressed perpendicular to the surface. For uneven or too large indentations, repeat the test.