Tecquipment tensile tester

Engineering Science Guidance Notes

TENSILE TESTER KIT ES6

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TecQuipment allows you to print and photocopy this document only for use with the Engineering Science Kits.

TecQuipment has taken care to make the contents of this manual accurate and up to date. However, if you find any errors, please let us know so we can rectify the problem.

TecQuipment supply a Packing Contents List (PCL) with the equipment. Carefully check the contents of the package(s) against the list. If any items are missing or damaged, contact TecQuipment or the local agent.

DB/1012

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ES6 Guidance

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Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
The ES6 Kit - What is it and what can it do? . . . . . . . . . . . . . . . . . . . . 6

List of Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

General Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

The Work Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Using the Tensile Tester . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Specimens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Accurate Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Other Things You May Need . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Stress (σ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Strain (ε) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 Elastic Deformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 Actual and Nominal Strain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 Plastic Deformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 Elongation and Percentage Elongation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

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ES6 GuidanceIntroduction

Introduction These Guidance Notes introduce you to the theory for a set of experiments in an engineering science topic. You fit different parts of your kit to a Work Panel to do an experiment. Figure 1 shows a typical experiment.

Figure 1 A Typical Experiment

Each kit can do one or more experiments and each experiment has Worksheets that tell you how to do the experiment. You must use the Worksheets with the Guidance Notes as they:

• Introduce the parts in the kit, and list the experiments that it can do.

• Give you important information you need to do the experiments or complete your Worksheet.

Work Panel

Part of your Kit

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ES6 GuidanceThe ES6 Kit - What is it and what can it do?

The ES6 Kit - What is it and what can it do? Understanding the strength of materials and how they react to applied loads is very important to scientists and engineers. This kit includes a tensile testing machine that allows you to do tests on several common materials.

The tensile test is a destructive test that adds an increasing axial (tensile) load or force to a material specimen, while measuring its elongation. The tests help you to find the yield strength, tensile strength and elongation (an indication of ductility).

The kit comes in a plastic box with a lid and contains all the parts you need to do the experiments shown in Table 1. Refer to the Parts List in your kit to see what parts are included.

Your tutor may decide to ask you to do all the experiments or just a few. You must be sure what you need to do.

List of Experiments

Table 1 List of Experiments

Experiment

Does my teacher need me to do this experiment?

Have I got the Worksheet?

Tensile Test - Steel Specimen

Tensile Test - Aluminium Specimen

Tensile Test - Duralumin Specimen

Tensile Test - PVC Specimen

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ES6 GuidanceGeneral Notes

General Notes

The Work Panel

Figure 2 The Work Panel Mounted in Two Typical ways (Portrait and Landscape)

The Work Panel mounts on its Supports in different ways as needed by each experiment. The Worksheets show you which way TecQuipment recommends you to fit the Supports but you may find an alternative that fits better on your desk. To change how the Supports hold the Work Panel, ask your Teacher or a classmate to help you hold the Work Panel while you change the Supports around. However you mount the Work Panel, you must always use two Thumbscrews and Thumbnuts to hold each Support to the Work Panel.

Supports

Thumbscrews

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ES6 GuidanceGeneral Notes

Using the Tensile Tester

Figure 3 Front View of the Tensile Tester

The Tensile Tester is simple to use. Two chucks hold a specimen (see “Specimens” on page 11). The Load Nut at the top of the tester pulls the top chuck upwards, pulling the specimen up by 1 mm per complete turn. The Load Nut has a small notch and a scale divided into ten increments that helps you to see how far you have turned the control on each turn (each increment shows an upward pull of 0.1 mm).

The bottom chuck connects to the two large springs. A Dial Indicator measures the deflection of the springs as you apply force. The springs obey Hooke’s Law, so the measurement from the Dial Indicator helps to show force.

The Top Plate works with a vertical scale to help you to remember how many turns you have done with the Force Control (one turn = 1 mm).

Load Nut

Dial Indicator

Springs

Load Nut Scale

Top Chuck

Bottom Chuck

Vertical Scale

Top Plate

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ES6 GuidanceGeneral Notes

Fitting or Removing a Specimen

Figure 4 Remove the Safety Guard and Use the Hexagon Tool (supplied)

To fit a new specimen or remove a broken specimen, remove the Safety Guard and use the Hexagon Tool to undo the specimen fixings and refit them on the new specimen.

When fitting a new specimen, you may need to turn the Load Nut a few turns for the specimen to fit correctly.

Refit the Safety Guard.

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ES6 GuidanceGeneral Notes

Setting the Dial Indicator to Zero

Figure 5 Turn the Outer Bezel