laboratory 2 steel copy

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Laboratory 2: Properties of an Unknown Type of Steel

ME 3034-001

2/17/13

Abstract


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Unknown Type of Steel was tested to determine its material properties. The

tensile test was conducted on eleven steel samples, which were unknown type of

steel. From the data the average values for Modulus of Elasticity, Ultimate Tensile

Strength (UTS) and Yield Stress for each sample were obtained. The average values

are Modulus of Elasticity = 24.72 *10^6 [psi], UTS = 45640 [psi] and Yield Strength =

25181 [psi]. The finding of this experiment allowed to make an educated guess on

the type of steel that was tested which is either Cast Iron Grey Class 60 or nodular

(ductile Iron).

Introduction

The objective of the experiment is to determine the type of steel by testing

the material properties of each sample. The tensile testing was conducted using

Instron Tensile Testing Machine on eleven samples to obtain material properties.

Material properties are Modulus of Elasticity, Ultimate Tensile Strength (UTS) and

Yield Strength. Samples of steel are of an unknown type and from the tensile testing

the conclusion on the type of the steel is made.

Modulus of elasticity is obtained from the graph of Stress vs. Strain, Modulus of

Elasticity, which is the slope of the elastic region of the Stress vs. Strain curve. The

UTS can be obtained from the maximum stress value on the graph, and the yield

strength can be obtained using 0.0022 % method offset on the graph.

Modulus of elasticity was then determined from the collected data.

Modulus of Elasticity or Youngs Modulus (E) is defined by Hookes Law:

Hooks Law:

E =

(1)

Where:

Stress [psi]

= Strain [in./in.]

=


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Stress:

(2)

Where:

Stress[psi]

F = Force (lb)

A = Cross Sectional Area (in.2)

Strain:

=l lo

lo (3)

Where:

Strain

l= Length after force is applied

lo= Gauge length

Experimental Methods

The experiment was conducted using Instron Tensile Testing Machine, Figure 1, and

Merlin tensile test program.

Figure 1. Instron Tensile Test Machine

=F

A

=

lb

in.2

(in.

in.)

(in.)

(in.)


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Wear safety goggles and making sure the machine is safely closed for operation. The

steps of this experiment: Clamp down the top part of the sample into the jaws of the

Instron Machine. Connect extensometer and set the gauge length to 1 inch. Clamp

down the bottom part of the sample into the Instron Tensile Test Machine; Balance

the load in the Merlin program, and input length and width of the sample. Then run

the Test. The output is then the elongation and the load applied of the samples.

Testing Method: Tensile Test

Equipment used: Calipers, Instron Tensile Test Machine, Merlin Tensile Test

program.

Materials used: Eleven samples of an unknown type of steel

Analysis/Results

Modulus of Elasticity, Ultimate Tensile Strength (UTS), and Yield Stress was

determined from this experiment by tensile testing eleven samples of an unknown

type of steel. The results are shown in Table 1 for each sample, and the average

values were computed.

Table 1. Material Properties of Steel Samples

Sample # Modulus [10^6 psi] Yield Strength UTS [psi]1 24.3 22500 41550

2 25.3 22000 44544

3 19.6 21500 41980

4 27.2 21500 42279

5 31.9 23500 45825

6 26.5 26500 52974

7 26.7 27500 53794

8 26.3 24500 46095

9 20.2 20500 43075

10 19.6 23000 43312

11 24.3 22000 42622

Average 24.72 25181 45640

The average values of the samples can be compared to standards (i.e. MatWeb.com).

Then determine the type of steel that was used, which either Cast Iron Grey Class 60

or nodular (ductile Iron). The comparison was done using the average values and a


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reference. Figure 2 shows stress vs. strain curve for all eleven samples of unknown

type of steel.

Figure 2. Stress vs. Strain curve

From Table 1 and Figure 2, the average values are Modulus of Elasticity = 24.72

*10^6 [psi], UTS = 45640 [psi] and Yield Strength = 25181 [psi]. From this and the

average modulus of elasticity of the samples that was compared to the standard. The

samples was determined to be Cast Iron Grey Class 60, or nodular (ductile Iron).

From this Experiment mechanical properties of the steel samples were determined.

All of the samples behaved in a similar way, however there were some fluctuations.

The average value was used to compare to the standards.

Discussion/Conclusion

y = 17.6E+06x

0

10,000

20,000

30,000

40,000

50,000

60,000

0.000 0.100 0.200 0.300 0.400 0.500 0.600

S

tress[lb/in.2

]

Strain [ in./in.]

Sample # 1 Sample 2

Sample 3 Sample 4

Sample 5 SAmple 6

Sample 7 Sample 8

Sample 9 Sample 10

Sample 11 Linear (E)


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The findings of this experiment confirm that the unknown type of steel is either Cast

Iron Grey Class 60 or nodular (ductile Iron). If a material has certain mechanical

properties than that material can be determined just by comparing the mechanical

properties of the standards or to known values for known type of material.

This test could have been done to almost any type of metal or material.

Some of the data points had to be discarded, either due to negative values or

slippage of the Instron Tensile Testing Machine. Negative values and slippage values

were discarded so that the accurate Modulus of Elasticity could be computed.

Some of the error sources are from not clamping down the jaws of the Instron

Machine tight enough, getting incorrect data, extensometer could be off, therefore

the measurement could have been a little off.


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Table of Contents

Page Number

Abstract 1

Introduction 1

Experimental Methods 2

Analysis/Results 3

Discussion/Conclusion 5

References 7


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References

Callister, William D. Material Science and Engineering An Introduction. New York:

John Wiley & Sons, Inc., 2010

http://www.alliance.seas.upenn.edu

http://www.engineersedge.com/manufacturing_spec/properties_of_metals_strengt

h.htm
https://alliance.seas.upenn.edu/~medesign/wiki/index.php/Courses/MEAM247-11C-P2P1https://alliance.seas.upenn.edu/~medesign/wiki/index.php/Courses/MEAM247-11C-P2P1https://alliance.seas.upenn.edu/~medesign/wiki/index.php/Courses/MEAM247-11C-P2P1

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