Low Carbon Tensile Test PDF

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Tensile test on low carbon steel...

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Tensile test report, Low Carbon steel Engineering, West Lothian College Bruce Duffy

Abstract The purpose of this report is to calculate the tensile strength of a range of materials. In this example a 10mm diameter sample of standard low carbon steel and Med carbon steel was used. These were set it up in a U.T.M which allowed us to record and make a graph of the amount of force it took to stretch these materials.

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Table of Contents

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1

Engineering Principles

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Computing & Engineering, West Lothian College

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Abstract

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Table of Figures

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1.0 Introduction

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2 Methodology

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2.1 Theory

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2.2 Equipment used

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2.3 Experiment

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3 Results

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3.1

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Table of Results

3.2 Graph of Results

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4 Discussion

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4.1 Possible Sources of Error

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4.2 Further Work

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5 Conclusion

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6 Bibliography

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7 Appendix

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Table of Figures

Figure 1 - Example of a good figure for describing equipment

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Figure 2 - Example of graphs in a report.

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1.0 Introduction

The purpose of the report is to find out both the limit of elasticity and the ultimate tensile strength of materials and also how tensile loads distorts these materials. Used a UTM machine to help us get these results and also .What is learnt from this is how tensile loading affects a sample which is one of the main objectives in this report. This gives a good understanding of the metal and how it would work in real life situations, for example if that particular metal should be used for construction work or other types of uses like cans, foils, kitchen utensils.

2 Methodology

The way that this experiment was achieved was using a piece of low carbon steel cylinder diameter of 10mm that was placed into a machine that would stretch the material when we manually pull down a leaver using a hydraulic system. The lever was moved small amounts at a time which overall increased the amount of newtons that was acting on the Metal. This was done while writing down the records of how much it has been stretched to how much force is used at that time, Proceeded this until it snapped. In this test it was found that at the first couple of pulls the machine does permanently distorts the metal. It was found that it keeps taking more and more force to pull the metal apart until it reaches its peak then it requires less force to pull apart. The rest of the changes are minuscule but gradually increase until it reaches its peak and requires less strength to pull it apart. This then makes the sample eventually break.

2.1 Theory

This experiment tested theories of what would happen to a sample of material when it was stressed. As the sample was progressively loaded it would eventually get to a breaking point where it just can’t take anymore force. which causes it to snap. The metal would stretch to its maximum point of stress it can take. The equations used in this experiment: Firstly the area of the metal would of had to be found to then include it into the equation of stress. So by using - π ⋅ r ^2=A Then using this value, plug it into - stress= Force/Area Bruce Duffy Engineering 2018

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Exemplar Engineering Report Engineering Materials This will provide the stress value at the metals limit of Elasticity which is the value we would want to use. The limit of Elasticity is the point just before the metal starts becoming very weak and basically not usable anymore. When considering real world scenarios, using any value for the stress equation that is above the Limit of Elasticity, it could risk potential breakage, which could then cause a mass amount of damage. Young's modulus- this is the ability of a material to withstand changed or deformity. This is found after, the stress of the material is calculated. Young's modulus is found by the stress divided by the change of length over the total length (Or strain).

2.2 Equipment used

The UTM ( Universal tensile test machine). This machine has many different uses when it comes to testing materials but in this case it was used to stretch the material apart. Also used a small monitor which read the results of each pull, of the newtons used. Also had a digital rule on the metal to calculate the length it stretched at.

Figure 1. Example of a good figure for describing equipment. (Brown, 2018)

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2.3 Experiment 1. Firstly got a piece of Low Carbon steel with a diameter of 10mm and

made sure it was in good condition 2. then set up the machine for use. Make sure it's working. 3. set up the metal in the machine by moving the locks apart to then easily place in the material, bring the material to a solid starting point without stretching it and zero it 4. pull down the leaver and took notes every 0.2mm at the start and then increased it to every 1mm 5. then drew a graph

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3 Results

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3.2 Graph of Results

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4 Discussion Thoughts going into the experiment it would work like any other tensile strength experiment, which it did. The graph it made and the results it gave were what were expected. That it would reach certain limit, then would eventually snap after being pulled too much. Comparing this to the Low carbon piece of steel, it was known that the way it was made it would make it stronger and more ductile when compared to the Medium piece of steel. Comparing the graphs together and also the results together then it can be see that the medium piece snapped a long time before the low carbon piece did, this is because the low carbon steel is a lot more ductile. So when the graphs were compared the Low carbon one was a lot longer than the Medium one and the Stress and young's modulus was a lot greater than the medium too.

4.1 Possible Sources of Error When doing the experiment since it was manually done, pulling the lever was not always accurate as sometimes it went 0.02 over for example, and at one point it went over by 0.12, ways to fix this would be using a computer instead of a manual system. Also the way all the results were recorded was by 1 person shouting out the reading on the monitor, this could have made people not hear certain readings and also write them down wrong, this could’ve been fixed by a larger monitor or give everyone a chance to come over and look at the results.

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5 Conclusion

The purpose of the report is to find out the ultimate tensile strength of a metal and also how tensile strength works on a metal. In this test the results found that at the first couple of pulls the machine does permanently distorts the metal, the rest of the changes are minuscule but gradually increase until it reaches its peak and requires less strength to pull it apart. This then makes the metal eventually brake. this is how tensile strength affects a metal which is one of the main objectives in this report. found that it keeps taking more and more force to pull the metal apart until it reaches its peak then it requires less force to pull apart. This gives a good understanding of the metal and how it would work in real life situations, for example if that particular metal should be used for construction work or other types of uses like cans, foils, kitchen utensils. In conclusion, what expected to happen, happened. it was known that at one point we would find the limit of elasticity and then it would be a gradual curve until it snapped. Errors with this could just be the readings of the monitor and accurate way of stretching the material. In future try to upgrade the system to make it accurate and better to work with. When comparing the graphs together of the different materials it was proven that the low carbon steel was more ductile than the medium.

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6 Bibliography Image of UTM machine- https://www.youtube.com/watch?v=67fSwIjYJ-E

7 Appendix

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