ENGR 244 lab 1.docx - Objective The objective of this...

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Objective:The objective of this experiment is to find the resistance of different metals to indentation under a set of specific conditions, and ultimately find the Brinell Hardness of the metals being studied.Introduction:The Brinell Hardness Test is used to determine how hard different materials are, in order for engineers to make an informed decision on the materials that they would like to use in their work. For example, steel is preferred in buildings frames over aluminum because steel is a hardermaterial. The Brinell Hardness Test, first introduced by J.A., Brinell in 1900, uses a small steel ball to indent various metals. The steel ball is pressed against the flat surface of a metal and held there for 15 seconds. The resulting diameter of the indentation is measured and together with the load applied and the area of the curved surface, the Brinell Hardness of a metal can be found. The downfall for this particular test is that a hardness of over 627 HB will indent the steel ball, meaning that only certain metal with HB under 627 can be tested. In this experiment we will be testing steel and aluminum. Before starting this experiment we can assume that steel is a harder metal than aluminum. This assumption was reached by studying metals in previous classes and by touch. Steel feels heavier in hand, and we can draw the assumption that it is also denser than aluminum. Because of this we will be subjecting steel and aluminum to different loads, steel will be subjected to 10,000N and aluminum to 5,000N. Due to the limitations of the Brinell Hardness Test mentioned above, other hardness tests were created. For example, one can use the Rockwell,Vickers, Knoop, Shore, Mohs, or Barcol Hardness tests to measure how hard a metal is. Every one of these tests have their own upside and downside, but they all fall on a specific ASTM (American Society for Testing & Materials) standardized scale. The Brinell Harness Test falls in the ASTM E10 scale (where the E signifies cast iron, aluminum, magnesium alloys, and bearing metals).

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