Steel and Metals Applications Index
Each item in the following list will eventually take you to another, in-depth
list of references articles, vendor applications information or a direct download
of a related technical paper. Those items in blue have been so linked, the rest
will follow as we acquire them.
of those references are hyperlinked to other web sites. Some of the others are
papers which have been collected and require an authenticated registration before
access to the hyperlink is provided. This is still free, however, and requires
only a valid email address for access when implemented.
anyone would like to add to this list, let
us know, please and we will do our best to comply.
of noncontact process temperature measurements in steel manufacturing" Includes
a paper presented at the 1999 SPIE Thermosense Meeting, courtesy of the copyright
holder, SPIE: The International Society For Optical Engineering .
temperatures in pelletizing operations
oven temperature measurements and transfer belts protection
in Blast Furnace environments
Domes and Bustle Pipe Temperatures
Measurement of Liquid Iron, Liquid Steel and other molten metals
Detection in Steel pouring streams and detection of Iron in Slag streams
- IR Radiation Thermometers
for oxidized steel objects in cooler surroundings (e.g. Continuous Casting, Hot
Rolling, Cold Rolling)
measurement of steel surface temperatures in Reheat Furnaces
Radiation Thermometers used in Continuous Anneal Furnaces
temperature measurement on Coating Lines, e.g. Tin, Zinc, plastic film
- Measuring steel sheet
surface temperatures in the Galvanneal process
IR Radiation Thermometers measurements on-line
for Reheat Furnaces
in Batch Anneal Furnaces
Reduction temperature measurements
in Continuous Anneal Furnaces
Steel Industry was one of the first to use temperature sensors for automatic process
control and QA measurements. The extent of temperature sensor use in steel mills
and process plants is quite large. Virtually all kinds are used, ranging from
liquid-in-glass thermometers in the testing and QA labs to networked infrared
line-measuring sensors called "line scanners" and computer-linked thermal
imaging versions of area-measuring infrared thermometers for detecting slag on
the stream of liquid steel poured from a melting vessel into a transfer ladle.
By and large, the majority of the temperatures
sensor applications that get the most attention are those involved in monitoring
or controlling a process. That's where the money is made. That's where productivity,
acceptable quality tons, or parts per unit time, are produced. A vital part of
productivity is the yield, that fraction of production that is within acceptable
examples on yield in USA steel plants and temperature sensor technology from first
hand observations by the author of this page:
It is most interesting to note that in USA hot rolling operations of sheet steel,
for instance, the vast majority of produced tons are monitored by a spot IR Radiation
thermometer measuring the centerline temperature of the product at the roughing,
finishing and cooling section exits. Yet, the line-measuring IR radiation thermometer
(line-scanner) was introduced to the steel industry in the 1980's by Japanese
steel makers Nippon Steel and N.K.K Steel.
These devices were shown to be capable of monitoring the temperature across the
entire strip width and several instrument companies
have produced commercial instruments. The fact that one could determine whether
an off-centerline portion of the strip did or did not not acheive desired temperatures
seems, even today, not to interest many US steel makers based on the number of
these temperatures are key process variables in a yield analysis program and remain
unquantified in most hot mills in 2002, nearly 20 years after the introduction
of the technology! It's a sorry state in those mills where line-scanner equipment
has been installed with all good intentions and effectively are not used by operations.
The lack of adoption of even old technology in US Steel plants exists in other
temperature measurement areas as well. It is often interesting to look around
the iron and steel making areas and ask what thermocouple calibration tables are
used,not the type of thermocouple. One gets a quick answer on the latter score.
No, the really interesting 'technical' question is: "What year is the calibration
of your thermocouple table based upon?" This, of course, refers to the year
of the International Temperatature Scale, ITS, or International Practical Temperature
Scale, IPTS, upon which the thermocouple table is based. The present standard
is ITS-90, the Scale introduced in 1990.
is not surprising to hear, or even see, the tables referred to as 1948 or 1960.
This, in and of itself, does not make a huge difference in the actual measurements
made, but can make it a bit difficult for one to claim that their ISO-9000 or
QS-9000 compliant quality system includes all measurement control devices, especially
thermocouples, that are "traceable to the appropriate fundamental or national
standard". The last time anyone looked, most national standard agencies,
like NIST in the USA, were not certifying thermocouple standards to IPTS-68,
or some earlier, out-of-date reference, but rather were certifying everything
to the ITS-90 scale.
it take to get all areas of steel mill plant temperature sensor measurement devices
up to snuff? Not much. Awareness is the first step. We all know that measurment
without traceable calibration is a very poor quality approach, but why is it tolerated
at the higest levels of steel company management? Could it be that no one is really
Most steel coil batch anneal (BA) furnace operations were originally controlled
by Type J, 8-gauge wire thermocouples. That was prior to the development of the
stainless steel swaged or mineral-insulated metal sheathed (MIMS) construction.
BA operations switched to the new thermocouple style but never updated their know-how
on these latter thermocouples. They are not without their faults and ASTM recommendations
for the maximum temperature use of MIMS Type J Thermocouples is well below the
temperatures they experience in BA typical operations (Ref:ASTM
E-608). The use of ASTM Standard E-1380 for testing
such thermocouples does not seem to be widely used either.
This is a blatent misuse of technology and most likely a significant contributor
to uncontrolled variability on the operation of a BA shop. It is also very difficult
to imagine a quality system auditor failing to find such inconsistancies, but
the rules are changing and it is no doubt they, too, will begin to check for such
facts are that both the Type K and Type N thermocouples in MIMS configuration
are priced nearly the same as the Type J and they have recommended use limits
well within the ASTM specs and, further, the Type N were demonstrated in a 1992
paper by another Japanese steel company, Sumitomo Metals, to be a superior thermocouple
for this application.
This writer knows of only one USA steel plant that has adopted the Type N MIMS
thermocouple in BA operations, the former LTV Steel Indiana Harbor plant-Kudos
to the plant electronics and instrument system engineers for acheiving improvements
using current measurement technology!
If anyone knows of other plant examples of measurement inprovements with modern
temperature sensor technology, we'd be happy to recognize them here, too.
of the classic, near-impossible measurements for radiation thermometers can be
found in Steel Mill uses, e.g., the hotter background problem (the surroundings
are hotter than the object of measurement) exists in hot strip and bar mill
reheat furnaces; the hotter background combined with uncertain emissivity
problem exists in continuous anneal furnaces. Fortunately, there are solutions
or work-arounds for both these problems, although they are not widely known and
even less well understood by those normally charged with specifiying and/or maintaining
the requisite measuring devices. Similar problems in the Aluminum and Brass Industries
plague many operations such as hot rolling, extruding and cold
Yes, infrared radiation thermometers,
those unstandardized, frustrating temperature sensors, are widely used in metal
processing operations simply because nothing else will work. If automation engineers
could accurately model all their processes, they would do away with those "pyrometers"
(as they are called), because they are also perceived to be a maintenance pain
in the neck. Yet, over the years of successful use, many such devices and their
supportive suppliers have earned, in some plants, a good reputation for accuracy
and reliability. Their maintenance requirements are not all that intensive and,
like many other measuring devices, they are much more reliable if checked and
adjusted on a regular and not too infrequent basis.
is not to say that radiation thermometers of the spot, line and area measuring
types are all excellently made devices. There is only one clear standard in the
USA for characterizing them and, to this writer's knowledge, no metal industry
company in the USA has yet adopted that standard (ASTM
E1256) as a qualification for their sensors. So, the industry
has learned, not by staying current with the technicnology, but by the notoriously
expensive techniques of trial and error to find reliable vendors with good products
and services. The situation is made worse by the economics of the industries.
For instance, in the USA, very few, if any, organizations even have incoming inspection
or calibration verification on new or repaired equipment. It's not that they don't
know how. Most don't have time or manpower to do it. Others have lost the skills
to do it in-house through force reduction measures focused on short term survival.
The recent dire economic straits of many
steel companies in the USA has not changed the fact that most still make steel
and still use lots of temperature sensors as critical components of the processes.
We hope these application repositories can help existing and future engineers
to save some time by not reinventing existing successes and providing guides to
sources of technical abilities.
are a series of topics that we expect to cover and fill our by the end of 2002,
if not sooner. Most of the information about each of these topics is available
in the open, published literature. We shall summarize each of them, in turn, and
provide hypertext links to those resources that exist on the Web rather than copy
existing information. Those papers that are not as easily obtained will hopefully
be available here by permission of the various copyright holders. Time and the
details will tell how successful this effort is.
additional feature, to help save time, will be a listing with each topic of the
suppliers of equipment for these applications that we have uncovered. These are
not de facto recommendations. Someone other than this organization must still
make a quality judgement on the equipment sold by each organization listed. We're
just shortening the list (or perhaps lengthening it-depending how extensive one's
view has been) by listing those who offer equipment in these specific areas.