Transcript
MEET THE CHALLENGE SM
A R e v o l u t i o n a r y S u r f a c e H a r d e n i n g P r o c e s s a n d S e r v i c e
swagelok.com
As a major developer and provider of fluid
system products, assemblies, and services,
Swagelok Company knows the importance
of materials research and chemistry; theyve
been important elements in the design and
manufacture of the companys high-quality
products for more than 60 years.
A commitment to materials science
research, equipment, and personnel has
helped set us apart and has led to an excit-
ing breakthrough: Swagelok SAT12 ser-
vices. Today, a wholly-owned subsidiary of
Swagelok Company, Swagelok Technology
Services Company (STSC) has been cre-
ated to bring the benefits of the Swagelok
SAT12 service to market.
The technology behind the service is a
patented method of heat treating austenitic
stainless steels. In effect, the Swagelok
SAT12 surface hardening process enables
ordinary stainless steel to adopt certain
performance characteristics of expensive
alloys, like Hastelloy or titanium.
Benefits:
Increased surface hardness, while retaining significant ductility
Improved wear resistance
Improved fatigue resistance
Improved corrosion resistance in certain media, such as saltwater
No distortion or change of shape
Challenging Convention: SAT12SM Services
The TechnologySo, you know you need the corrosion
resistance of stainless steel. But what if that
stainless steel could be twice as hard? And
have improved wear and fatigue resistance?
Sound Impossible?Its not. A paradigm-shifting technology,
the Swagelok SAT12 patented surface
hardening process diffuses an unexpected
~10% carbon atoms into the austenitic, or
face-centered cubic (FCC), crystal structure
of the stainless steel. The process actually
enables unit cells to draw in carbon atoms
to increase surface hardnesswithout
forming chromium-rich carbides that would
compromise the benefits of the SAT12
process.
But, How?First, the stainless steel is placed in an
atmosphere of carbon-assisted gaseous
HCl, which removes the passive oxide
layer. Next, the stainless steel is heated in a
mixture of gases containing carbon at a low
temperaturenever above 538C (1000F).
Carburization begins to occur at a tempera-
ture high enough to promote carbon atom
diffusion but low enough to prevent carbide
formation. At the end of the process, the
amount of carbon in the interstices of the
alloy crystals has been elevated; in fact, car-
bon levels may be as much as 80,000 times
higher than the concentration that thermo-
dynamics and kinetics suggest would be
possible.
A patented dual act ivat ion/carburizat ion strategy creates optimal condit ions to enable carbon diffusion
that results in a strong and robust case layer.
Low-Temperature Carburizat ionCO+H2+N2
Surface ActivationHCL + N
2
temp
cooling
Arguably, the SAT12 process is one of the most significant breakthroughs in materials science in
many decades, as well as one with many extraordinary
technological implications.
Arthur Heuer, Ph.D., University Professor and Kyocera Professor of Materials
Science and Engineering at Case Western University.
Custom-bui l t furnaces, as wel l as custom-made hardware and software, enable a t ight ly-control led process .
Surface Activat ionHCl+N2
Cool ing
Tem
pera
ture
Time
Substrate Material
Hardened Case Layer
Part Surface (with crevices and inclusions)
In terms of hardness, the carbon behaves
like a carbide, but it is not one. The carbon
atom locates in the interstitial space of the
unit cell, expanding the crystal lattice and
increasing its hardness.
This is not a flash heat treating process.
A slow diffusion rate enables repeatable
control of the process, as well as consistent
case depths over the surface of the part
from part to part and from batch to batch.
The ServiceIs SAT12 the right choice for you?
Weve treated hundreds of millions of
ferrules used in our flagship product, the
Swagelok tube fitting. Weve witnessed
the remarkable advantages this service
has provided in many other applications
as well: wear plates in pulp and paper
mills; fasteners with demanding corrosion
and wear requirements; medical devices
requiring autoclave and sterilization;
electronic equipment that is sensitive to
magnetics, yet necessitates increased
hardness; marine equipment that calls for
increased corrosion resistance; bearings
that require resistance to brinelling and
wear; automation equipment for lubricant-
free or lubricant-sensitive applications; and
better wear and scratch resistance for metal
injection molding applications. But we also
know that the treatment process is highly
application specific.
Swagelok has a long history of leadership in the research and treatment of metals, and the
SAT12 process presents a great opportunity for us to help customers who have concerns about
corrosion and wear.
Art Anton, President and Chief Executive Officer, Swagelok Company
During the SAT12 process, large batches of metal parts
numbering in the thousandsare treated at one t ime.
Thats why the SAT12 service is customized
to meet your individual needs.
A six-step approach helps ensure that
SAT12 is the right choice for you:
1. Initial consultation. Your inquiry is
assessed through an initial consultation
where well be happy to answer any
questions you have about the service.
Well also ask you to fill out a questionnaire
that helps us uncover your needs and
expectations.
2. Application review. A team of
technical experts reviews the opportunity
to determine whether your product can
benefit from the SAT12 service. If your
application matches our capabilities, the
team evaluates the specific performance
requirements.
3. Development of processes specific
to base materials. The team chooses
a treatment formula and may optimize or
adjust the process parameters, as needed,
to meet your requirements.
4. Treatment of net shaped parts.
Although surface preparation is the first
step in the treatment process, components
must be clean; dry; and free of surface
polishes, contaminants, and coatings. Parts
are handled in a batch treatment process
that is tightly controlled using custom-made
equipment and controls. Components are
post cleaned to remove residual carbon.
You can also choose from optional cleaning
services, such as washing with deionized
water, chemical treatments, electrochemical
polishing, and tumbling.
5. Testing and validation of treated
parts. Components are checked for
surface hardness; case depth is evaluated
by batch. Depending on your performance
requirements, optional test capabilities
are available: corrosion testing in various
environments; fatigue testing; and scanning
electron microscope surface analysis.
6. Documentation of results. Youll
receive a letter of compliance with your
finished products. Surface hardness and
case depth results are available if needed.
The Results
Increased wear resistance. The unique
combination of hardness and ductility
enhances wear resistance.
Increased surface hardness. When the
SAT12 process is applied to austenitic
stainless steels, youll find that the surface
hardness increases by at least two times,
relative to the core. Improvements occur
at the surface of the treated stainless steel
component, not all the way through to the
core, which is why the process is referred
to as case hardening.
Increased fatigue resistance. Higher
compressive stresses means that treated
components will have longer life in harsher
environments. Youll reap the benefits in
applications that involve high frequency
vibration and cyclical impulses.
This pump wear plate is used in a corrosive pulp
and paper appl icat ion. I t s a sacrif ic ial part
of the pump housing that is normally changed
as a result of wear, as often as every three weeks.
Field tests indicate that the wear plate treated by
the SAT12 process has lasted 25 months longer
and st i l l goingthan the untreated product.
ASTM G-99:Ball-on-Disk Unidirectional Sliding
wear rate (mm 3/N-m)
Ball Disk
Swagelok SAT12SM treated
2.9 x 10-6
9.2 x 10-6
8.3 x 10-6
1.6 x 10-5
3.0 x 10-6
1.9 x 10-6
Non-treated6.3 x 10-4
6.1 x 10-42.1 x 10-4
2.5 x 10-4
Test condition: 5 N load, 0.1 m/s sliding speed, 500 m sliding distance.
The results of this test
indicate that the 316
stainless steel plate and
bal l treated with the SAT12
process showed signif icantly
less material loss than the
untreated material in the
same test condit ions.
untreated treated
0 1010 20 30 40 50
0 10 20 30 40 50
1,200
800
400
0
12
8
4
0
0
-1
-2
Xc(at.%)
HV25
(GPa)
Depth from surface (m)
Depth from surface (m)
Left: A wel l-equipped metal lurgical lab is on-site and can provide needed test ing or val idat ion.
Maintained or improved corrosion resistance.
The corrosion resistance of your base
stainless steel is maintained throughout the
SAT12 process. And, in some media, youll
benefit from improved corrosion resistance.
For example, in a saltwater solution,
specimens treated with the SAT12 process
showed no damage after one week, whereas
untreated specimens showed damage within
hours.
These treated 316L stainless steel specimens showed crevice-corrosion
behavior comparable to highly corrosion-resistant exotic al loys.
Al loy 625
after 60 hours
Untreated 316L
after an hour
Treated 316L
after 160 hours
To schedule your initial consultation, send an
email to SAT12service@swagelok.com.
0 1010 20 30 40 50
0 10 20 30 40 50
1,200
800
400
0
12
8
4
0
0
-1
-2
Xc(at.%)
HV25
(GPa)
Depth from surface (m)
Depth from surface (m)
This graph shows that treated specimens have compressive
stresses above the yield stress of 316 stainless steel which
helps increase the fat igue resistance of the component.
In this graph, smaller circles show the increased hardness of
the 316 stainless steel, relat ive to the surface of the part. The
1200 HV (Vickers Scale) is equivalent to approximately Rockwell
C hardness of 60 to 65, similar to that of tool steel. The larger
circles demonstrate the concentrat ion of dif fused carbon
atomic % (at.%) relat ive to the surface of the part.
All service marks and trademarks shown are owned by Swagelok Company unless otherwise noted.Hastelloy is a registered trademark of Haynes International, Inc. 2008 Swagelok Company, Printed in U.S.A., GLI, August 2008, R0, CORP-0011
MEET THE CHALLENGE SM
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