Quenching Lab

The "Quenching Lab" refers to a lab where we prepared 6 samples of steel to be cooled using different methods. Some will be either annealed, quenched, or air cooled. We will also be wrapping some with tight, thick aluminum foil to prevent oxidation. As you can see through this chart, sample 1 will be wrapped, and quenched, sample 2... etc.

Removing the samples from the heated kiln:

The furnace was heated to about 1700 degrees. The sample in the right picture is being air-cooled.

These are the samples after our heat treatment process:

The ones on the left were wrapped, notice the ones on the right have excessive scaling due to oxidation.

After the heat treatment process, we then used a hardness tester to see how the hardness of the samples were affected. Once we placed them in the hardness tester, we calibrated it, then read the values off the indicator.

Raw Data:

This is the raw data resulting from the testing. The unit for hardness used was the Brinell hardness number (HB or HBS), here abbreviated as "B".

Analysis:

Some samples were more brittle than others, some were soft, etc. And some had a significant amount of scaling and deformation, and some didn’t. Due to some scaling during the heat treatment some had less consistent hardness testing results, and some were more consistent. The ones that were protected from oxidation via being wrapped in aluminum foil were much more consistent in the hardness testing than the unwrapped ones. This pretty much lined up with what was predicted that the ones being more protected from oxidation would have less scaling and be more consistent.

Conclusion:

Based on the results of our testing, I believe it would be overall beneficial to always wrap the samples with some kind of heat resistant material such as aluminum foil or lower the overall oxygen levels in the heat treatment chamber, to result in better products, as the ones unprotected had excessive scale and deformed, and thus were unusable. As you can see in the pictures below, some of the parts had excessive scaling, and were deformed, in this case, somewhat in a curved shape which led to very inconsistent, inaccurate results.