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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