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Project description
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The process of cold working a metal is performed for many different reasons in
both labs and in the real world. Cold working is an effective way of shaping
metallic materials while simultaneously increasing their strength [1]. This
process is important not only because it strengthens materials used in everyday
life such as soda cans and car metals but it also helps by proving which ones
can handle more of the natural stresses they will face. Aluminum cans are an
example of a real world product that derive 70% of their strength as a result of
strain hardening that occurs during its fabrication process [1]. One down side
that is faced in this process is the loss of ductility that occurs as a result of the
repeated bending and stress that the material goes through during working.
The objective of this experiment was to determine the change in mechanical
properties, specifically strength, by testing the hardness of annealed Copper
Alloy 110 and annealed 1018 Steel when subjected to cold working. By doing
this multiple times, the group will be able to receive a unique set of data that
will show the metal’s comparative hardness as well as a change in the shape
and size of the materials. After discussing and researching past experiments,
the group decided that after each roll through the Cold Roller machine, the
Copper Alloy 110 and 1018 Steel would both increase in strength and in
hardness and deform in shape.

METHODS
The cold working testing for this experiment was conducted using ASTM
Standards E18-11. Before the test procedures began the group gathered the
required materials, which are copper alloy 110 annealed and steel 1081
annealed and labeled them on each side front and back. Then measured the
baseline dimensions of the width and thickness in three different places along
the length to get the average to calculate the initial cross-sectional area. Then
they started the hardness test using the Wilson/Rockwell hardness tester series
500 with two different penetrators for each material and each trial consists of
the average of three tests that were done in three different places on the
material’s surface. For the steel 1081 annealed the B scale was used and for the
copper alloy 110 annealed the H scale was used. Then the samples were
subjected to cold working (CW) using the Cold Roller (motor/ manufacturer:
Brook Crompton Parkinson motors, S/N: 419427R, Frame #: ED90SD), (cold
rollers/ manufacturer: Durston, #: SK261A). After cold rolling, the sample was
remeasured to calculate the average cross-sectional area and the average

hardness. Before using the cold roller flip the samples to the other side. The
process of cold rolling, measuring the cross-sectional area and determining the
average hardness was repeated nine times while recording the collected data
and the visual deformations.
After all the trials were complete, the percent cold work was calculated using
the equation below:
%CW=|(Af-Ai)/Ai|*100 (1)
where Af is the final cross-sectional area and Ai is the baseline cross-sectional
area. Finally, a graph was generated which plotted percent cold work against
hardness.

RESULTS
During the lab, data was recorded for the three hardness tests and width and
thickness, which was used to calculate the cross-sectional area. After the
average hardness and area had been calculated, the test was repeated. Once the
test was repeated at least ten times, data was compiled with the other group for
a greater sample size. The data from the hardness and area was then used to
calculate the percent cold work, the standard deviation of hardness, and the
coefficient of variation of Below are graphs which summarize the results.
DISCUSSION
In this lab, the objective was to determine the effects of cold working on copper
alloy 110 annealed and steel 1081 annealed. And after each trial the collect data
and observations on the two materials that were used. The two materials
showed deformation and change in area after two or more trials in the cold
working process. In the third trial the copper alloy 110 annealed showed a
deformation while the steel 1081 annealed deformed after the sixth trial. Also,
the hardness test showed how the hardness of the two materials increased after
each trial and the cross-sectional area decreased. The experiment explains how
the cold work effects materials in hardness and tensile strength by increasing
the dislocation density and defects in the crystal structure of the material.
Additionally, the line defects would also help to block the slip to occur which
helps to increase the strength of the material.and the ductility of the material
decrease.(8.2 Strain-Hardening Mechanisms “frank-Read source”).

CONCLUSIONS
It was discovered that the hypothesis was confirmed in that when the Copper
Alloy 110 and 1018 Steel were subjected to the cold roller, they then increased
in hardness and strength while decreasing in surface area caused by
deformation.