Engineering Principles: Tensile Strength Test Assignment
TENSILE STRENGTH TEST
ENGINEERING PRINCIPLES
ASSESSMENT TWO
Alan Tait
PLAGERISM
I can confirm that all works contained in this report are my own. My sources are from information and data collected from experiments carried out in the class. I understand that if the work in this report is deemed not to be my own then it shall be rendered void.
Signed______________________________________
INTRODUCTION
As a class we were given a piece of mild steel with the following dimensions-a recorded area of 20mm squared, a length of 25mm and with a carbon content of 0.1%. The test was carried out in the mechanical engineering lab (T22) using a Hounsfield H20K-W tester calibrated to +/- 5%, a PC and a printer.
PROCEDURE
1. Set readout at zero.
2. Load material to holder.
3. Load holder to machine.
4. Set machine at a load of 15N to apply tension to the material.
5. Set the force to zero.
6. Set the distance to zero.
7. Press the test button to start test (the material is extended at a constant and even speed).
8. Record the force (2.9mm moved = 6.3KN of force).
9. Once material breaks stop test.
10. Print results (break point 8mm).
DISCUSSION
On looking at the graph (attached) it shows a typical curve for a ductile material clearly showing the yield point, the part from 0-A is linear as the material is being stretched in an elastic manner. Should the load be removed in this area the material would go back to its normal state, point A being the “limit of proportionality”. At this point many materials in this case mild steel will undergo a sudden extension which is called the yield point, this happens with no increase in load. Beyond point A the plot is no longer linear as the material has begun behaving in plastic manner, now if the force is removed in this “plastic range” the material will shrink back somewhat but will remain deformed as a result of the stretching. Past point B the material extends with a reduced load, however due to
ENGINEERING PRINCIPLES
ASSESSMENT TWO
Alan Tait
PLAGERISM
I can confirm that all works contained in this report are my own. My sources are from information and data collected from experiments carried out in the class. I understand that if the work in this report is deemed not to be my own then it shall be rendered void.
Signed______________________________________
INTRODUCTION
As a class we were given a piece of mild steel with the following dimensions-a recorded area of 20mm squared, a length of 25mm and with a carbon content of 0.1%. The test was carried out in the mechanical engineering lab (T22) using a Hounsfield H20K-W tester calibrated to +/- 5%, a PC and a printer.
PROCEDURE
1. Set readout at zero.
2. Load material to holder.
3. Load holder to machine.
4. Set machine at a load of 15N to apply tension to the material.
5. Set the force to zero.
6. Set the distance to zero.
7. Press the test button to start test (the material is extended at a constant and even speed).
8. Record the force (2.9mm moved = 6.3KN of force).
9. Once material breaks stop test.
10. Print results (break point 8mm).
DISCUSSION
On looking at the graph (attached) it shows a typical curve for a ductile material clearly showing the yield point, the part from 0-A is linear as the material is being stretched in an elastic manner. Should the load be removed in this area the material would go back to its normal state, point A being the “limit of proportionality”. At this point many materials in this case mild steel will undergo a sudden extension which is called the yield point, this happens with no increase in load. Beyond point A the plot is no longer linear as the material has begun behaving in plastic manner, now if the force is removed in this “plastic range” the material will shrink back somewhat but will remain deformed as a result of the stretching. Past point B the material extends with a reduced load, however due to