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A D V A N C E D
M A T E R I A L S
&
P R O C E S S E S | J A N U A R Y
2 0 1 6
3 7
PHASE TRANSFORMATIONS
Bain joined the newly formed Re-
search Laboratory of U.S. Steel in 1928.
His first assignment was to design and
equip a laboratory in a vacant building
in Kearney, N.J. Here he undertook re-
search on the transformation of austen-
ite to pearlite in 0.80% carbon steel. This
steel had the carbon content that formed
only pearlite, called the eutectoid com-
position. He hired a young metallurgist,
E.S. Davenport, to help with his research.
The experiment was unique in that
they studied the formation of pearlite
over time at a constant temperature.
This was the first time anyone had
studied a metal reaction as a function
of time. It had been assumed that only
temperature was important in transfor-
mation. They heated very thin samples
to the austenitic phase, and quenched
them in a bath heated to the transfor-
mation temperature. At various time
intervals, a sample was removed and
quenched in a room temperature water
bath to form martensite in the untrans-
formed austenite. The microstructure
was then examined to measure the
amount of pearlite that had formed at
the constant higher temperature.
Plotting the percent transforma-
tion against time on a logarithmic scale
for transformation to start, to progress,
and to end provided the rate of trans-
formation. The resulting curves started
slowly, progressed rapidly, and ended
slowly. Plotting the beginning and end-
ing times for many different tempera-
tures resulted in a curve with a c-shape.
At the highest temperatures, the start
and end of transformation was delayed
in time. As temperature decreased, the
reaction was faster until about 1100°F.
At even lower temperatures, the reac-
tion rate decreased again and a newmi-
crostructure formed that was not pearl-
ite. This new phase was named bainite
in his honor.
The paper published by Davenport
and Bain in 1929 received worldwide at-
tention, and with his previous research
on tool steels, alloy steels, and his pio-
neering work in x-ray diffraction, he was
recognized as America’s leading metals
scientist. During his active research ca-
reer at U.S. Steel, Bain and his coauthors
published 20 technical papers between
1929 and 1939. He also coauthored a
book on tool steels with Marcus Gross-
mann in 1931 and published his book
Functions of the Alloying Elements in
Steel in 1939. He was promoted to vice
president of research and technology of
the Carnegie-Illinois Steel Corp. in 1943
and moved to Pittsburgh where he later
became vice president of research and
technology for the entire U.S. Steel Corp.
The corporation built a research campus
in 1956 in Monroeville, Pa., which includ-
ed the Edgar C. Bain Laboratory for Fun-
damental Research.
AWARDS AND HONORS
Bain was active in many technical
societies, served as president of ASM
in 1937, was elected into the Nation-
al Academy of Sciences in 1954, and
received many other honors. He also
earned several awards for his career in
metals research. These include the Rob-
ert W. Hunt Medal in 1929, Henry Mari-
on Howe Medal in 1931, Albert Sauveur
Achievement Award in 1946, ASM Gold
Medal in 1949, and the Franklin Insti-
tute’s John PriceWetherill Medal in 1949.
Edgar Bain suffered a stroke in 1959 that
left him partially paralyzed. He contin-
ued to consult from his home and wrote
his autobiography, Pioneering in Steel
Research: A Personal Record, published
by ASM in 1975 after his death in 1971.
For more information: Charles R.
Simcoe can be reached at
.
Isothermal transformation diagram for an iron-
carbon alloy of eutectoid composition (0.80%C),
including austenite to pearlite and austenite
to bainite transformations. Courtesy of ASM.
Aerial view of U.S. Steel’s Research Center showing the Edgar C. Bain Laboratory
for Fundamental Research on the left. Courtesy of Historic Pittsburgh,
Granular bainite. Courtesy of EWI.