MET assignment 2

Spring 2020

MET 180

Materials & Processes

TAP 2

Hardness Test

Date: Section:

Student Name	Student ID
Sara alqattan	89221

Feedback/Comments:

Grade: /100

1. Introduction

In this experiment, students will perform various Hardness Tests for different test specimens using hardness test machine. Brinell, Rockwell and Vickers hardness measurements will be conducted.

2. Objectives

· Demonstrate the typical phenomena of Brinell, Rockwell and Vickers hardness measurements and responses.

· To perform hardness test using the hardness test machine to measure the hardness of metals using the various indenters.

3. Equipment/Components/Software:

Software	-
Equipment	Hardness Test Machine
Components/ Specimen/	Test Specimens

4. Theory

Rockwell Test:

Depth of penetration, t:

t in mm

Vickers Test:

Length of the impression diagonal, L

L in mm

Brinell Test:

Diameter of the impression, d:

d in mm

5. Experimental Procedure

Hardness test machine will be used to measure the hardness properties of test specimens (Figure 1).

Figure 1. Hardness test machine.

The settings of the hardness test will be done through the main screen of the test machine (Figure 2).

Figure 2. Main screen

Performing a Rockwell Test

· Setup the tester for the required Rockwell scale using the Setup menu.

· Put a workpiece on the test table or anvil.

· Make sure the correct ball or cone indenter is installed.

· Turn the elevator spindle clockwise until the workpiece

· firmly touches the clamping attachment or

· is located no more than 0.8 mm to 1 mm from the indenter.

· Press OK to start the test.

· The testing procedure will proceed automatically.

· On the testers GUI (Graphical User Interface) the load progress bar moves slowly upwards until it reaches the pre-load position.

· On the yellow message bar the procedure and progress can be followed.

· After the main load has been applied the tester will pause according to the selected dwell time.

· When the dwell time has passed, the tester will unload the main force automatically and return to the pre-load position.

· The hardness value measured will be displayed on the GUI.

· Remove the workpiece from the clamping attachment, if applied, by turning elevator spindle counter clockwise and move the workpiece into a new position to perform another test.

Performing a Vickers Test

· Setup the tester for the required Vickers force from the Setup menu.

· Put a workpiece on the test table or anvil.

· Make sure the correct Vickers pyramid indentor is installed.

· Turn the elevator spindle clockwise until the workpiece

a) firmly touches the clamping attachment or

b) is located no more than 0.8mm to 1mm from the indentor.

· Press OK to start the test.

· The testing procedure will proceed automatically.

· On the testers GUI (Graphical User Interface) the load progress bar moves slowly upwards until it reaches the final force position.

· On the yellow message bar the procedure and progress can be followed.

· This following screen appears on the GUI when the workpiece has been removed from the indentor.

· Set the digital eyepiece to zero.

· Turn the micrometer knobs on the digital eyepiece

making sure the two filar lines in the microscope slightly touch each other (no light visible between the filar lines) and press OK on the GUI.

· Your digital eyepiece is now set to zero.

· The GUI now shows the input fields D1 and D2.

Positioning of workpiece:

· After making the indentation, move the sliding table (with the workpiece) from position A to position B.

· Look through the eyepiece and turn the elevator screw clockwise or counter clockwise to bring the surface of the workpiece into focus.

· Position the filar lines first in position D1 on the indent and press the conformation button on the eyepiece.

· Then position the eyepiece to measure D2 (turn the eyepiece 45° counter clockwise), position the filar lines in position D2 on the indent and press the confirmation button on the eyepiece.

· The GUI now shows the hardness value in Vickers.

· Repeat the procedure for multiple measurements.

Performing a Brinell Test

· Setup the tester for the required Brinell force from the Setup menu.

· Put a workpiece on the test table or anvil.

· Make sure the correct Brinell ball indentor is installed.

· Turn the elevator spindle clockwise until the workpiece

a) firmly touches the clamping attachment or

b) is located no more than 0.8mm to 1mm from the indentor.

· Press OK to start the test.

· The testing procedure will proceed automatically.

· On the testers GUI (Graphical User Interface) the load progress bar moves slowly upwards until it reaches the final force position.

· On the yellow message bar the procedure and progress can be followed.

· This following screen appears on the GUI when the workpiece has been removed from the indentor.

· Set the digital eyepiece to zero.

· Turn the micrometer knobs on the digital eyepiece

making sure the two filar lines in the microscope slightly touch each other (no light visible between the filar lines) and press OK on the GUI.

· Your digital eyepiece is now set to zero.

· The GUI now shows the input fields D1 and D2.

Positioning of workpiece:

· After making the indentation, move the sliding table (with the workpiece) from position A to position B.

· Look through the eyepiece and turn the elevator screw clockwise or counter clockwise to bring the surface of the workpiece into focus.

· Position the filar lines first in position D1 on the indent and press the conformation button on the eyepiece.

· Then position the eyepiece to measure D2 (turn the eyepiece 45° counter clockwise), position

· the filar lines in position D2 on the indent and press the confirmation button on the eyepiece.

· The GUI now shows the hardness value in Brinell.

· Repeat the procedure for multiple measurements.

Figure 3. General characteristics of hardness-testing methods and formulas for calculating hardness.

6. Experimental Work

Watch the video links below to observe how hardness tests are being performed.

Answer the experimental questions accordingly. (49 Points: 7 pts each)

Rockwell Harness Test

https://www.youtube.com/watch?v=G2JGNlIvNC4

Vickers Harness Test

https://www.youtube.com/watch?v=7Z90OZ7C2jI

Brinell Harness Test

https://www.youtube.com/watch?v=RJXJpeH78iU

(Use blue color in your answers)

Question 1:

What type of indenter is used for the Rockwell hardness test?

Made of diamond

Question 2:

What is being measured for the Rockwell hardness test method?

Measured the permanent depth of indentation of ahard indenter under a test force

Question 3:

What type of indenter is used for the Vickers hardness test?

Diamond pyramid

Question 4:

What are being measured for the Vickers hardness test method?

Compressive weal for the tarbert charger

Question 5:

What type of indenter is used for the Brinell hardness test?

Steel ball

Question 6:

What is being measured for the Brinell hardness test method?

It measured by the diameter of the indentation with microscope

Question 7:

How is the height of the test specimen on the support table (anvil) being adjusted?

The help table was changed in accordance with tallness so the example can be situated at the right separation to the magnifying lens focal point and the indenter

7. Report

Hardness Test results for the Rockwell, Vickers and Brinell tests are provided in Table 1.

Table 1: Hardness test results

Harness Test	Specimen Material	Indenter Type	Load Applied (kg)	Selected Hardness Scale	Test Result
Rockwell	Aluminum	1/16 in diameter steel ball	100	HRB	52
Vickers	Aluminum	Diamond pyramid	10	HV10	385
Brinell	Aluminum	5mm carbide ball	1000	HB100	469

Answer the questions in tasks 1, 2 and 3 according to the Table 1:

(Use blue color in your answers)

Task 1: (17 points)

For the Rockwell Hardness Test, calculate the depth of penetration, t in mm by using the formula below.

52=130-500t

52-130=-500t

-78=-500

-78/-500=-500t/-500

t=0.156mm

Task 2: (17 points)

For the Vickers Hardness Test, calculate the length of the impression diagonal, L in mm by using the formula in Figure 3.

P = 10 kg

385=1.854(10kg)/L2

L^2=0.0441

=

L=0.21mm

Task 3: (17 points)

For the Brinell Hardness Test, calculate the diameter of the impression, d in mm by using the formula below.

P = 1000kg

=1.62mm

Task 4: (Bonus: 10 points: 5 pts each)

Answer the following questions about the hardness test:

a) Define the mechanical property hardness.

Hardness is defined as the resistance of a material to permanent deformation during application of load.

b) What does the hardness of material indicate?

Hardness is measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion

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