The objective of this experiment was to determine the average Brinell Hardness of steel and
aluminum.
Introduction
According to Brinell, the definition of hardness is “the resistance to permanent indentation under
static or dynamic loads-indentation hardness.” The experiment consisted of using an apparatus
containing a hydraulic ram and cylinder. Small indentations with a 10 mm diameter steel ball
were formed on steel and aluminum flat disks. Each sample to form the indentations lasted
roughly 15 seconds and loads of approximately 10 kN and 5 kN were used on steel and
aluminum respectively. The thickness of the indentation was found using the equation
, where D is the diameter of the steel ball and d is the diameter of the indentation. The area was
found using the equation , which then allowed us to find the Brinell Hardness using, . The goal
of this experiment is to determine the strength of different materials under a given load. The
experiment should not be used on extremely hard materials as the ball itself will deform. To
obtain the best results, the center of the indentation should always be at least 2.5 times the
diameter of the indentation away from the edge of the disc or another indentation. The test load
should also be large enough that the diameter of the impression is 2.50 to 6.00 mm.
Procedure
1. Place the sample on the lower adapter of the apparatus. Confirm a zero reading and
properly assess that the valve is shut.
2. Using the steel ball apply a load of 10 x 103 N on the steel disk for approximately 15
seconds. Repeat for another 2 trials.
3. On the aluminum disk apply a load of 5 x 103 for approximately 15 seconds. Repeat for
another 2 trials.
4. Use a microscope and ruler to measure the diameters of the indentations.
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