The SAT12SM Surface-Hardening Service
Also known as low-temperature colossal super-saturation (LTCSS), the SAT12 service provides heat treating for austenitic stainless steel components. In the process, carbon is diffused interstitially into the lattice structure of the stainless steel. The result is stainless steel exhibiting:
 - Tool steel-like hardness
- Nickel alloy-like corrosion resistance
- High-levels of wear resistance
- Austenitic ductility
- No distortion or dimensional change
- No carbide formation
- Resistance to galling
The SAT12 service is made up of the following steps: - Consultation
- Pre-cleaning
- Furnace Treatment
- Post-Cleaning
- Testing
Process Development
Swagelok is the only manufacturer of tube fittings to offer the SAT12 service. We have independently developed and have international patents for commercial-scale processes to achieve low-temperature colossal super-saturation (LTCSS).
After Swagelok developed this process, it enlisted Case Western Reserve University of Cleveland, Ohio U.S.A. to help analyze the accomplishment. In addition, it is the only low-temperature case carburization process to tube fittings that is fully disclosed and published.
As a result, Swagelok and Case Western Reserve University were awarded a three-year $5.5 million grant from Ohio's Third Frontier Project. The grant enables Swagelok, in partnership with Case, to further research, evaluate and commercialize the paradigm-shifting technology.
Recent News
Mechanical Engineering Magazine explores the SAT12 patented surface-hardening process and the implications for hardness, wear and fatigue.
Documentation
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Colossal carbon supersaturation in austenitic stainless steels carburized at low temperature
Y. Cao, F. Ernst, G.M. Michal
Department of Materials Science and Engineering,
Case Western Reserve University
10900 Euclid Avenue, Cleveland, OH 44106-7204, USA
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Abstract
A novel, low-temperature (470°C) gas-phase carburization treatment, developed by the Swagelok Company, increases the surface hardness of 316 austenitic stainless steels from 200 to 1000 HV25 and improves the corrosion resistance. While normally the precipitation of carbides restricts the carbon concentration in the austenite of 316 steels to 0.015 at %, the Swagelok treatment generates a colossal supersaturation of up to 12 at % carbon in solid solution. Only upon extended treatment, does carbide precipitation eventually occur, but the colossal carbon supersaturation of the austenite is maintained. Unusual for austenitic stainless steels, the precipitates are Hagg carbide (M5C2).
© 2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.
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Low Temperature Collosal Super-Saturation
Engineering Materials Achievement Award
Sunniva Collins
Swagelok Company
Swagelok won the 2006 Engineering Materials Achievement Award for its surface treatment that both hardens the surface of stainless steel and improves corrosion resistance. |
Introduction
Low-temperature colossal super-saturation (LTCSS) is a novel surface hardening method for carburization of austenitic stainless steels without the precipitation of carbides. The formation of carbides is kinetically suppressed, enabling extremely high or colossal carbon supersaturation.
As a result, surface carbon concentrations in excess of 12 at.% are routinely achieved. This treatment increases the surface hardness by a factor of four to five, improving resistance to wear, corrosion, and fatigue, with significant retained ductility.
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Carbon Paraequilibrium in Austenitic Stainless Steel
G.M. MICHAL, F. ERNST, and A.H. HEUER
Department of Materials Science and Engineering, Case Western Reserve
University, Cleveland, OH 44106.
Contact e-mail: gmm3@case.edu
This article is based on a presentation made in the ‘‘Hillert Symposium on Thermodynamics & Kinetics of Migrating Interfaces in Steels and Other Complex Alloys,’’ December 2–3, 2004, organized by The Royal Institute of Technology in Stockholm, Sweden. |
Abstract
Carburization of austenitic stainless steels under paraequilibrium conditions—i.e., at (low) temperatures where there is essentially no substitutional diffusion—leads to a family of steels with remarkable properties: enhanced hardness, resulting in improved wear behavior, enhanced fatigue, and corrosion resistance, and with essentially no loss in ductility. These enhanced properties arise from an enormous carbon solubility, which, absent carbide formation, is orders of magnitude greater than the equilibrium solubility.
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United States Patent
Low-Temperature Case-Hardening Processes
Inventors
Peter C Williams, Cleveland Heights, OH
Steven V. Marx, University Heights, OH
Assignee
Swagelok Company, Solon, OH U.S.A
Patent Number: 6,093,303 B1
Date of Patent July 25, 2000 |
Abstract
A method of case hardening a chromium bearing nickel or ferrous based alloy, for example stainless steel, article, the method including the steps of activating the surface of the article; and carburizing the activate surface at a temperature below that temperature which would promote the formation of carbides. In one embodiment the surface is activated by disposing a layer of iron over the surface of the article.
Download patent number 6,093,303 B1
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United States Patent
Selective Case Hardening Processes at Low Temperature
Inventors
Peter C Williams, Cleveland Heights, OH
Steven V. Marx, University Heights, OH
Assignee
Swagelok Company, Solon, OH U.S.A
Patent Number: 6,165,597 B1
Date of Patent: December 26, 2000 |
Abstract
A selectively case hardened steel article by low temperature carburization includes a body made of chromomium-bearing nickel or ferrous-based all0y (for example stainless steel), a first portion of the body having a first hardness characteristics, and a second portion of the body having a second hardness characteristic; the second portion being less than the entire body and substantially free of carbides. One method for selective case harding by low-temperature carburization includes the steps of applying a carbon blocking mask over surface areas of the article that are not going to be carburized; activating those surface areas that are to be carburized; diffusing carbon into the activated surface areas at temperature below which carbides readily form; and remove the carbon blocking mask.
Download patent number 6,165,597 B1
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United States Patent
Selective Case Hardening Processes at Low Temperature
Inventors
Peter C Williams, Cleveland Heights, OH
Steven V. Marx, University Heights, OH
Assignee
Swagelok Company, Solon, OH
Patent Number: 6,461,448 B1
Date of Patent October, 8, 2002 |
Abstract
A method for case hardening a chromium bearing nickel or ferrous based alloy, for example stainless steel, article, the method including the steps of activating the surface of the article; and carburizing the activated surface of the article at a temperature below that temperature which would promote the formation of carbides. In one embodiment the surface is activated by disposing of a layer of iron over the surface of the article.
Download patent number 6,461, 448 B1
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United States Patent
Modified Low-Temperature Case-Hardening Process
Inventors
Peter C Williams, Cleveland Heights, OH
Steven V. Marx, University Heights, OH
Assignee
Swagelok Company, Solon, OH U.S.A
Patent Number: 6,547,888 B1
Date of Patent April, 15, 2003 |
Abstract
An iron-containing workpiece is cased hardened by low-temperature carburization during which one or more process steps - including adjusting the carburization temperature, adjusting the concentration of the carburization specie in the carburization gas and reactivating the surfaces to be carburized - is carried out to enhance the overall rate and uniformity of the carburization with minimized soot generation whereby carburization can be completed faster than possible in the past.
Download patent number 6,547,888 B1
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