Rockwell Hardness Testing Lab Report Sample

EXPERIMENTAL PROCEDURE

The specimen Al 2024 which was consist of 3.8-4.9% Cu, 1.2-1.8% Mg, 0.3-0.9% Mn, and Fe, Cr, Zn, Ti in a little amount had been inserted into a furnace set at 500oC approximately 50 minutes for a solution treatment before the lab. Its height was 7 mm and width was 25 mm.

At the beginning of the lab the specimen was removed from the furnace using tongs and quenched in water. Then, the specimen was put into the oil at 190oC for 6 min.

While waiting, another specimen Al 2024 at room temperature was used to measure Rockwell hardness. There was 1/16 inch steel ball. Instead of diamond, steel ball was used because Al is softer than steel. Minor load was 10 kg and major load was 100 kg. The test specimen is placed on the anvil.

It is a fast and inexpensive test. Automation is possible.The simplicity in the operation of a Rockwell hardness testing machine provides the added advantage that Rockwell hardness testing does not generally require a highly skilled operator to perform. Disadvantages include many arbitrary non-related scales and possible effects from the specimen support anvil. The indenter of the hardness test result is influenced when using a conical indenter. The test is useful for material selection, for process and quality control, and for acceptance testing of commercial products.

It is suitable for hardness tests on large unfinished parts such as forged parts, cast parts, hot rolled or pressed and heat treated parts.This is large advantage that the Brinell test has over the Rockwell test because it is easier to perform on steel or iron parts. These larger parts are heavier and inherently more expensive making it a crucial factor that they can still be used. It can be concluded that the Rockwell test is easier and more accurate for smaller samples of less coarse material. On the other hand, there is a limitation of range of application for a maximum Brinell hardness of 650 HBW and limitation for testing small and thin specimen and relatively large degree of damage to the specimen by the indentation.

The advantages of the Vickers hardness test are that extremely accurate readings can be taken, and just one type of indenter is used for all types of metals and surface treatments. Although thoroughly adaptable and very precise for testing the softest and hardest of materials, under varying loads, the Vickers machine is a floor standing unit that is rather more expensive than the Brinell or Rockwell machines.

For aluminium alloys Rockwell B scale is used because aluminium is softer than