Research Papers by MeltLab Systems
Ductile Nodularity by thermal analysis
David A. Sparkman, Nov 2008
Abstract: This initial paper shows how MeltLab measures the smoothness of the curve to determine
the degree of nodularity of a final ductile iron sample. Taking the casual observance of
Dr. Lampic, we have turned up a surprisingly reliable way to measure the growth shape of
graphite by bursts of energy produced by the growth of vermicular graphite. This method is
ideally suited to MeltLabs’s strong points of precision, noise suppression, and derivative
calculation.
Foundries wishing to participate in further proving out this method should contact us for a trial.
Ductile Microstructure by thermal analysis
David A. Sparkman, 2008
Abstract: A thought paper showing how different aspects of the thermal analysis curve indicate
different aspects of microstructure including pearlite, hypereutectic(solid riser prone),
hypoeutectic (more shrinkage prone), and eutectic (ideal). Shrink and carbides can be seen. The
potential is there to give a very quick micro analysis from molten iron in just 3 to 4 minutes.
Offsetting Shrinkage In Ductile Iron, Version 2
David A. Sparkman, 2006
The natural shrinkage that occurs during the solidification of Ductile Iron can be offset
by the expansion caused by the formation of graphite. Though this has been known for some
time, thermal analysis has some interesting contributions to understanding exactly what is
going on, and offers some opportunities for better control of late graphite expansion in
moderate section sizes. Different modes of solidification are examined and measured, and
the early and late graphite content are calculated using thermal analysis. Carbon flotation
is seen as a fourth form of solidification that is both hypereutectic and hypoeutectic.
Shrinkage is seen as a lack of late graphite growth needed to offset the natural contraction
of the Ferrite. Grain boundary shrinkage can be seen as an escape mechanism for minor
unfulfilled contraction. Stress relief heat treat increases the graphite volume thereby
collapsing any remaining of the grain boundary shrinkage and improving fatigue life and
other physical properties.
Improving the Accuracy of Thermal Analysis
David A. Sparkman, 2006
Thermal analysis is a fast and inexpensive way to see if a furnace of metal meets the basic
criteria for pouring. Often melting is the bottleneck of a foundry and having a furnace of
iron or aluminum or copper alloy on hold for the laboratory results can be costly. Some
foundries have great success with thermal analysis results while others have problems with
inaccuracy. This paper tries to cover all the sources of inconsistency and how to correct
them so that foundries can get the most good out of these instruments.
Note: this is only a working paper and references have been left out.