EXPERIMENT 3 HARDNESS TEST DOCX

Title	EXPERIMENT 3 HARDNESS TEST
Author	Min YIh
Pages	8
File Size	59.6 KB
File Type	DOCX
Total Downloads	322
Total Views	441

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EXPERIMENT 3: HARDNESS TEST OBJECTIVE The objective of this experiment is to determine the hardness of a material by using a hardness tester. INTRODUCTION One of the mechanical properties that may be important to consider is hardness, which is a measure of a material's resistance to localized plastic deformation (e.g., a small dent or a scratch) or in other words, it is a measure of the resistance of a metal to permanent (plastic) deformation. Early hardness tests were based on natural minerals with a scale constructed solely on the ability of one material to scratch another that was softer. A qualitative and somewhat arbitrary hardness indexing scheme was devised, termed the Mohs scale, which ranged from 1 on the soft end for talc to 10 for diamond. Quantitative hardness techniques have been developed over the years in which a small indenter is forced into the surface of a material to be tested, under controlled conditions of load and rate of application. The depth or size of the resulting indentation is measured, which in turn is related to a hardness number; the softer the material, the larger and deeper the indentation, and the lower the hardness index number. The indenter, which is usually a ball, pyramid, or cone, is usually made of hardened steel, tungsten carbide, or diamond, a much harder material than the material being tested. 1...