Where are Springs Used? - Spring Manufacturers Institute

Most experts agree that the rate of technology doubles
every 12 to 18 months in most fi elds, with some
industries far outpacing that rate. As technology consumers,
we can appreciate this fact every time we purchase a
new computer, wonder if our PDA will work with the latest
downloads or look at the advertisement for plasma screen
televisions. Bill Gates’ statement in 1981 that “640K ought
to be enough for anybody” helps prove
the point. Sometimes we forget the rapid
pace at which changes can and do take
place throughout industry, including
materials. Materials technology may not
progress at the rates experienced in the
electronics or medical fi elds, but it is
growing and affecting us in many ways –
at home, at play and at work.
Five years ago, I had the distinct
pleasure of being a keynote speaker at the
Close the Loop Technical Symposium,
hosted by the Spring Manufacturers Institute
(SMI). The topic of my presentation dealt with what we
might expect to see happen in materials in the future. It was
not aimed specifi cally at the spring industry but discussed
materials in general, and suggested ways that technological
advancements might eventually impact spring materials
and manufacturers in the future. This article provides a brief
update on the technologies that were discussed in 1999 and
takes another look ahead at what we might expect in the future.
Aerogels and Thin Film Coatings
At Close the Loop, I described the concepts of aerogels
and thin fi lm diamond coating techniques. Aerogels are
also known as “solid smoke” in some circles because that is
exactly how they appear: as if someone had frozen smoke in
place. Most aerogels are silica-based and weigh much less
than one-hundredth of the same material in solid form. In
1999, these materials were pure laboratory curiosities whose
uses were mere speculations. One anticipated application
was to replace the gas-fi lled space in thermal-paned windows,
since these materials were estimated to have R-values
in excess of 30. This speculation has become a reality.
However, the true use of these materials is turning
out to be culture-growth media for biological and medical
research, and for collecting specimens in outer space
exploration. Aerogels are thick enough to trap fl ying space
particles yet won’t damage them on impact like a hard
surface would.
Thin fi lm coatings, including diamond fi lms, are also
playing a part in many of our everyday lives. If you wear
glasses and have one of the newest scratch-resistant lenses,
you may already be using one of the latest thin fi lm technologies.
Scientists have developed the capability to apply very
thin diamond fi lms to vastly improve the scratch resistance
of the glass surface.
Other uses involve application of the thin diamond
fi lm on wear-sensitive surfaces or on surfaces requiring
resistance to various corrosive agents. Although still in its
infancy and relatively expensive, this technology does have
some very widespread appeal because it offers opportunities
to solve material problems that currently have limited
solutions.
What Then?
A look back at the future uses of materials technology.
Yesterday’s sci-fi becomes tomorrow’s standard.
By Terry Bartel Ph.D.
Elgiloy Specialty Metals
As a side issue, the introduction of these thin fi lm coatings
has also inspired and necessitated the development of a
whole new generation of testing methods and equipment. Tie
this in with the advancements being made in computers and
nanotechnology, and we are beginning to see a whole new
generation of portable testing and inspection equipment.
Carbon and Stainless Materials
Of course, all springs are produced from some material.
For purposes of this discussion, carbon steel, stainless steel
and some of the more exotic alloys will cover nearly 100
percent of everything used to produce a spring. Although
probably not appreciated or noted by many, there have
been several improvements in the materials used for spring
applications.
One major change that has affected virtually all carbon
and stainless steel springs is the development and constant
improvement of the continuous-casting process. The raw
material producers’ goal in developing this process was cost
savings. With the continuous casting process, they could
produce a billet that they could use for direct rolling to a
hot-rolled rod, which eliminated the pouring of huge ingots
of material and the subsequent reduction of this ingot to the
starting billet. The fi rst attempts were in the carbon steel
industry in the very early 1980s and seemed to be doomed
due to very poor product quality. Initial reaction of the
industry was that the product would be useful only for very
low-cost, low-quality springs or possibly welding wire.
However, through continued perseverance and development
work on such items as surface quality and internal soundness,
the process gained wide acceptance. The next logical
step was to apply the technique to stainless steels. Needless
to say, this was the case, and today all carbon and stainless
steel material used for spring production (with a few exceptions)
comes from continuous-cast material.
SPRINGS July 2004 21