Heat Induction Of Metals

The main objective in lab #1 was to test Aluminum, Low Carbon Steel, Brass, and Stainless Steel. There were four labs performed on all four of these metals, they were performed as follows in order; Thermal Conductivity, Magnetic Properties, Thermal Expansion, and Elongation. Heat was used to test thermal expansion, to see how far a piece of metal would expand when it was left in a 500 degree v-slot for five minutes. When Thermal Conductivity was tested the rods were put on a 500 degree plate and a wax ring was placed in the v slot. Magnetic Properties were tested by placing a magnet to a strip of steel and heating it up so that the atoms move around and the magnet falls off. The last experiment that was done was an Elongation experiment where the specimen that was under stress was placed in the tensile testing machine and stressed to multiple psi. My conclusion was that certain metals are better for certain applications than others because of their different molecular structure and tensile strengths.

Many different experiments can be run on metals to test their structure and or tensile strength because there are so many different points to hit while testing metals. The objective of the lab that was performed was to demonstrate some of the physical properties of four different metals that are common to the industry today.

There were specific procedures followed for the tests that were administered. The first test ran by this specific group was the Thermal Conductivity test. The procedure went as follows, First wax rings were made and placed onto each of the rods in the rod pack. The rod pack was a metal block with four different rods sticking out the end of the block. The rod pack was then set in the clamp of the heat source, and the voltage control was set at 500 degrees. The time was recorded for each wax ring to fall into the catch tray below. The rod pack was removed with thick insulated gloves and placed into a cooling tray.

Thermal conductivity testing and analysis

The second test ran in lab 1 was for magnetic properties. A Parker Magnetic inspection unit was used, as well as a test stand and a magnet. The magnet was placed on the test strip and power connectors were hooked on to the strip as well. The controller was put on setting six and the controller button was pressed.

Parker Magnetic Inspection Unit

Lab 1-C was tested for Thermal Expansion. The four different materials were placed in the hot plate with the V-slotted holding fixtures and set the dials to zero. Each rod was placed in a separate V-slot and watched for five minuets. After the five minuets were up the rods were taken out of the holding place slots and placed in a cooling bin. Then the amount of elongation was calculated and recorded on a table.

Heat plate for Thermal Expansion

The fourth and final test ran on the materials was Elongation. Only three of the rods were used the steel, aluminum, and brass. One of the specimens needs to be placed in the jaws of the Comten tensile strength test machine. Make sure that the psi reads zero, then begin to put pressure on the piece of metal. The force in psi went 400, 500, 600, 750, 800, 1000, 1200, 1250, and 1500. The different types of metal were stretched to only certain psi points on the chart, and the chart below will show what metal was stretched to what psi. Each time a metal has a different pressure on it the data should be recorded off of the dial that shows the amount the specific metal has stretched. The force in pounds is needed to find the strongest and either least or most flexible, so the cross sectional area needs to be known. The Stress in psi is found by plugging in the specimen diameter, which is .200 inches, and placing it in the equation 3.14 x .200^2 divided by 4 and the stress is found by plugging that answer, which is .032 rounded. That answer was placed under the force applied in an equation.

Tensile Testing Staion

The results of the experiments were not at all surprising to me, except that in the first experiment with the wax rings, the Aluminum conducted heat the quickest. I was under the impression that it would not conduct heat the quickest because of its ability to dissipate heat quickly. The Low Carbon Steel was second as the chart shows, and then the Brass followed, then last was the Stainless Steel

Specimen number Material Time to melt in (Sec)

1 Aluminum 45

2 Brass 100

3 Low Carbon Steel 63

4 Stainless Steel 280

On the second lab the strip of steel was placed between the two cables and was heated up so that the magnet fell off of the strip when it reached a certain temperature

In lab 1-C after five minutes, the materials had reached their maximum expansion. Aluminum, which had the best conductivity had the best Thermal Elongation. The Brass was next in line on expanding the farthest, the Low Carbon Steel was next, then the Stainless Steel was the piece of metal to expand the least after five minuets.

Specimen number Material Expansion(@ 5 min)

1 Aluminum .022 in

2 Low Carbon Steel .013 in

3 Brass .018 in

4 Stainless Steel .008 in

The results in the lab test 1-D, Elongation was comparable to lab 1-C. The results were longer, but that is to be expected because the specimens are being pulled mechanically instead of naturally expanding. The results are

...