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Destructive Tests - Coggle Diagram
Destructive Tests
Rockwell hardness
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A rounded cone (material diamond), used as indenter. - Presses on the test surface piece, with force 10 kilo pans, depth created is used as reference point. - F2=140kp increases, overall force is 150kp, F2 released the the force from current indentation is measured. - This is rockwell hardness HRC=(0.2-e)500
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Brinell Hardness Test
Brinell hardness test used to press hard spherical indenter with specific force on test piece. Choosing a suitable indenter, in the holding device, securing into place.
The piece of material should be place onto the support table with using the camera to identify the chosen indent point. Once the force of the indenter is done, it's diameter is measured using camera.
To calculate Brinell hardness equals to test force F divided by surface area of indentation.
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Monitor/control panel attached to upper part of machine, used to select/program different testing methods. Bellow this are microscope lens with digital camera and indenter, both are connected together, and can rotate. Support table can be adjusted in height.
Charpy Impact test
Strain aged plain carbon steel test:
With a machined test piece with a v notch, is placed on the lower end of the machine(centring device to adjust). The indicator is dragged down to prepare, pendulum released swings downwards/hits the middle narrow specimen, absorbing the pendulum's energy, being unable to reach as original height. The hammer end splits through notch to see how brittle the metal is and the low energy absorbed.
The next test was normalized steel, with same process when pendulum the energy is 182joules and the energy is absorbed so that the material is still intact
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Charpy impact test used to measure the toughness of materials under impact loading/in a stressed state.
Pendulum impacting machine has a heavyweight at the end, lifted in starting position known as the first step. Adjust machine accurately, by dragging indicator downwards releases without an object( should reach to zero).
Tensile test
Open up the head of upper/lower head of testing machine place material in, extensometer in position, set out correctly, correct testing parameters on computer.
- Extents amities sensor arms press on a test piece (gauge length shown at the bottom right of the screen, start 100mm)
- force increases, form a steep straight line, then elongates to 3mm, then gradually makes a round curve on the graph
- Feh(upper yield point), Fel (lower yield point), Fmax (maximum force), strength property of materials are calculated. To find the yield divide the force length over the cross sectional area to find Reh, Rel, Rmax(tensil)
- lossen the exometer to get out material, then after fracture shows the elongation and reduced the diameter of point reduced to 30%
Cylindrical shape with two threaded ends, gauge length 100mm, 10mm diameter
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Vickers Hardness test
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Vickers hardness test is used to press a pyramid diamond indent, with the exact defined force. After by evaluating the indentation. To start off with is by setting up the test by inserting the Vickers pyramid indent into the mounting device in machine. Place piece on the support table then switch to the camera to identify location for indentation. Meanwhile you can adjust until satisfied with the position. Allow the pyramid the touch the piece until force is pushed down to create indent. To find Vickers hardness value equals to test force over the surface area of indentation.
