Kim Tucker
CHE 3265 – Materials Lab
Section 2 (R 2:00-3:50)
Dr. Brenner
Due: 03.13.03
Experiment 4: Annealing Test
Purpose/Introduction:
Annealing is a form of heat treatment applied to a metal to soften it, relieve internal
stresses and instabilities, and make it easier to work or machine. It consists of heating the
metal to a specified temperature for a specified time, both of which depend on the metal
involved, and then allowing it to cool slowly. When annealing occurs, the modulus of
elasticity, yield strength, ultimate tensile and compression strength, and rupture stress are
greatly reduced.
In this lab, the effect of annealing brass is examined and analyzed.
Experimental Procedure:
To start the experiment a small cubic piece of brass is selected. The sample was placed
under a (1/8) inches stainless steel ball tip of the Rockwell Hardness Tester (the method
of using the Rockwell Hardness Tester is listed below). Once the hardness is determined
(from the Rockwell Hardness Tester), it is recorded in Table 1, and later analyzed.
Method of using the Rockwell Hardness Tester:
1.
Raise the anvil
2.
Adjust the dial until the long needle reaches the apex of the higher ∆
3.
Adjust the dial until the short needle reaches the apex of the lower ∆
Figure 1: Picture showing the Rockwell Hardness Tester. The picture includes the
direction that the dials should be in for test accuracy.
4. Crank lever – the dial should begin to move (this means that the load is being
applied).
5. When the crank stops moving, pull the dial forward. When the crank stops
moving again, take the hardness reading.
After the hardness readings are taken and recorded, the brass samples (from each student)
are annealed at over 1300ºF for 1 hour (this was done by Dr. Brenner).
The following week in lab each student repeated the Rockwell Hardness Test (above)
with the annealed pieces brass.
Discussion of Results
All data readings taken in this experiment is recorded in Table 1 (below).
Before Annealing(Rockwell h units)
After Annealing (Rockwell h units)
79.2
13.0
79.5
15.0
79.5
22.0
79.6
22.0
79.6
26.7
79.9
32.5
80.0
43.5
80.5
52.0
Table 1: Data collected from Rockwell Hardness Test