lab report

ME 241
MATERIALS LABORATORY
(Course Instructor: Hamid Nourollahi)
Spring 2015
LAB 1 – HARDNESS TESTING

The LAB:
• Vickers hardness testing of various materials

Samples (in inches)
• 6061-T6 Aluminum (½ x ½ x 1½)
• 1018 Cold Rolled Steel (½ x ½ x 1½)
• Half Hard Brass Alloy 360 (½ x ½ x 1½)
• 110 Copper (1 x 0.2 x 5.8)
• Zirconia (ZrO2 ) ceramic

Equipment
• Vickers Hardness Tester

Procedure

Setup:
• Make sure machine is plugged in
• Make sure 30kgs are loaded at the back of the machine
• Make sure lever (arrow F) is pushed totally to the right

Operating Procedure:
• Wear safety glasses & do not get fingers, hair or cloths near machine during operation.
• Place specimen onto the platform of the machine, beneath indenter.
• Adjust the height of the platform, using the wheel located on the right side of the machine (see arrow A in figure below), to ensure that the indenter is as close as possible to the surface of the specimen without touching.
• Step on the pedal located on the lower right hand side of the machine.
• Push down the lever located on the upper right hand side of the machine (see arrow B in Figure 1) and then wait for the lever to release (you should hear a clicking sound).
• Move the specimen under the microscope by moving the platform to the side using the lever located in the front of the machine (arrow F).
• Turn on the microscope light, located on the left side of the machine, and look into the microscope
1. Focus the microscope using the knob shown by arrow C in Figure
2. Measure the indent using the knobs next to the eyepiece.
i. Left knob (arrow D in figure below) adjusts entire piece
ii. Right knob (arrow E in figure below) fine tunes
3. Turn eye piece 90° and measure again.
• Repeat process 3 times for each material (make sure you leave at least 3 to 5 times the indent diameter between each indentation).

THE REPORT:

You work for a company that produces gears for automobiles and your boss asks you to evaluate which of these materials would be best suited for production. It has been determined that a hardness of 500 HV30 is needed to a good property to measure that would aid in the first stage of the materials selection process.

Your task is to determine which (if any) of these materials are suitable for this application. Your report (no more than five pages) should include (but not limited to) the following:

• A well-labeled photograph of the experimental setup and a description of the Vickers
macroindentation hardness test.
• The equation used in determining your hardness values.
• A table of your results in a table format showing all three values and the average. For
all specimens
• A plot of the data as Vickers Hardness (HV) (y-axis) vs. Material type (on the x-axis).
• Discuss your results, by also explaining the inherent reasons behind the difference (if
any) between the hardness of the specimens tested, and those reported in literature.
• Determine which material (if any) satisfies the company requirement of 500 HV30.
• Give your recommendation based on your findings and other considerations if
applicable.

Your report should fully conform to the format and organization as given in the
REPORTS & TECHNICAL WRITING DOCUMENT provided on blackboard.

APPENDIX:
Note: All values should be written as “Vickers hardness number HVF”, where F is the force applied. (Example: 800 HV20 represents a Vickers hardness of 800 made with a force of 20kgf which was applied for 10-15 seconds).

Note that the values read from the eyepiece are in micrometers.

Equations used:
(1)
Where,

F = load in kgf.
d = average length in millimeters.

Fig. 2.Indentation impression that should be measured.

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