Hardness has been defined in several ways over time, mostly by physicists, metallurgists and engineers. Different definitions range from hardness being defined as a collection of properties of a material more or less related to each other to resistance to permanent indentation. The difficulty to define hardness fundamentally indicates that hardness is not a basic property of a material, but instead, it is a composite of yield strength, work hardening, true tensile strength, modulus, and others factors.This paper investigates Hardness Test of Metals. In particular, it focuses on performing hardness tests on various metal specimens using the Brinell Test and the Rockwell Test. In Brinell Test the experiment concludes that the smallest indentation is close to the welded fracture indicating that the material is the harder in welded area compared with the middle of the sample. In Rockwell Test the experiment concludes that hardening of metal materials occurs during its straining because the molecules that float around within the material bound together causing friction and produce heat. This molecular regrouping gave additional strength to the material.
Keywords: Brinell Test, Rockwell Test
[...] Material is tougher closer to the fracture, and the ball is not able to penetrate more than in the area towards the middle of the material. In conclusion, hardening of metal materials occurred within material during its straining because molecules that floated around within the material bound together causing friction and produce heat. This molecular regrouping gave additional strength to the material. References Agricola, G (1556). De re Metallica. Dover Publications Inc. (Dec 1912) ISBN-13: 978-0486600062 Ainbinder S. B., Loginova, A. Ya. (1971). Investigation of the relation between the depth of penetration and indentation diameter in polymer hardness [...]
[...] The Experiment The objective of the experiment tested in this paper is to perform hardness tests on various metal specimens using the Brinell Test and the Rockwell Test. A list of abbreviations used in the experiment is presented below: PSI Pounds per Square Inch (U.S. Customary System) kg Kilogram in. Inches mm Millimeter D Diameter BHN Brinell Hardness Number s/n Serial Number Experiment Procedure Brinell Test The apparatus used for performing the Brinell Test is a Brinell Testing Machine, MODEL 4316, calibrated by: MICRO-CAL, INC. [...]
[...] Rockwell Test Rockwell hardness test was introduced in 1919 by Stanley Rockwell, a metallurgist in a ball bearing company and it helped overcoming the difficulties of Brinell Test. The method was introduced to measure the degree of penetration into a metal caused by a diamond or ball indenter that is applied under a fixed load (Davis, 1998). Typical Procedure An indenter as diamond ground to a 120 degrees cone with a spherical apex that has 0.2 mm radius is pressed into the surface with a specific load of 10 kg followed by 100 kg applied for five seconds (Figure 2). [...]
[...] The objective of the test method should be to minimize human intervention by using robustness concepts to eliminate the need for delicate balancing. To that end, mistake-proofing mechanisms that act only upon known human errors, without providing knowledge-based human intervention are required (Bajaria,1996). From Hardness Testing there are several material's properties that which can be derived such as composition of metals and ceramics, cutting ability of materials, depth and structure, engineering strength of metals, abrasive strength of materials, fracture strength, wear of materials, surface coating quality, glass transition temperature and others. [...]
[...] Summary of results The results of Brinell Test and Rockwell Test are summarized below in order to be discussed in the conclusions in section 4. Brinell Test bolted sample - (SCALE: kgs on dia. ram kg load) READING INDENT.(mm) BRINELL # TENSILE (psi) Brinell Test welded sample - (SCALE: kgs on dia. ram kg load) READING INDENT.(mm) BRINELL # TENSILE (psi) Rockwell Test bolted sample - SCALE: 100 kg, BALL) READING ROCKWELL # TENSILE scale) (psi) Rockwell Test welded sample - SCALE: 100 kg, BALL) READING ROCKWELL # TENSILE scale) (psi) Conclusions Brinell Test (SCALE: kgs on dia. [...]
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