Solid material objects come in contact with each other, exerting and transferring forces. The outcome from this contact is subject to the relative hardness of each material and to the magnitude of the stresses induced relative to their yield or fracture strengths. In order to predict accurately what can happen because of this contact, the hardness of materials is tested and measured.
This paper investigates Hardness and Impact Test of Metals. In particular, it focuses on performing hardness tests on various metal specimens using the Rockwell Hardness Tester and the Brinell Hardness Tester (macroindentation measurements).Then it investigates the relation between the hardness numbers to tensile strength and it performs impact test on steel specimens.
[...] This paper focuses on performing hardness tests on various metal specimens using the Rockwell Hardness Test and the Brinell Hardness Test (macroindentation measurement). a. Rockwell Test Rockwell Test is a hardness test that measures the degree of penetration into a metal caused by a diamond or ball indenter that is applied under a fixed load (Davis, 1998). An indenter is pressed into the surface of the metal to be tested under specific load for definite time interval. After the load is released the depth of the indentation is measured. [...]
[...] Hardness is evaluated by converted read diameter into Brinell hardness number (BHN) by the formula: L BHN = where: L - Load - D d ) D Ball diameter d Diameter of the indentation c. Impact Test Toughness is the ability of material to withstand big loads without breaking. Toughness is related to strength. Resilience is the ability of a material to absorb impact without breaking or permanently deforms. The amount of energy absorbed up to the elastic limit is called modulus of resilience. [...]
[...] The hammer traveled less in steel-sample, than in the case of aluminum sample Discussion of results Rockwell Hardness Test SCALE: 100 kg, BALL) Two different materials were tested: bolted and welded. First readings were taken close to the fracture edges and are higher compared to the following ones. In the fracture area the material is harder, and indentations are smaller. 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. [...]
[...] Start close to the fracture and going towards the center of material Brinell Test 1. Load testing machine with material 2. Read width of the indent with light scope 3. Recorded width convert into Brinell Hardness Number 4. Summary of results Rockwell Hardness Test BOLTED sample - SCALE: 100 kg, BALL) READING ROCKWELL # TENSILE scale) (psi) Rockwell Hardness Test WELDED sample - SCALE: 100 kg, BALL) READING ROCKWELL # TENSILE scale) (psi) Brinell Hardness Test BOLTED sample - (SCALE: kgs on dia. [...]
[...] Steel 1045 sample absorbed more energy implying that material is tougher than aluminum Comparison of Rockwell Test and Brinell Test a. Rockwell Test Strengths Direct reading from the machine's scale (does not need light scope) Leaves prick mark only Read marks on slopes without errors Weaknesses Material has to be clean Head has to be changed b. Brinell Test Strengths Has to be changed load only, not swapping head A wide range of test forces and ball sizes to suit every application. [...]
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