Selection, Development and Testing of Stainless Steels and Alloys for High-Temperature Recuperator Applications

2003 ◽  
Author(s):  
Philip J. Maziasz ◽  
Bruce A. Pint ◽  
Robert W. Swindeman ◽  
Karren L. More ◽  
Edgar Lara-Curzio
Keyword(s):  
High Temperature ◽  
Stainless Steels ◽  
Gas Turbines ◽  
National Laboratory ◽  
Cost Effective ◽  
Department Of Energy ◽  
Oak Ridge ◽  
Industrial Gas Turbines ◽  
Improved Performance ◽  
Alternate Fuels

Compact recuperators/heat-exchangers are essential hardware that increases the efficiency of microturbines and smaller industrial gas turbines. There are several different kinds of recuperator technology (primary surface, plate and fin, spiral, and others), but they all have several common materials needs. Most commercial recuperators today are made from 347 stainless steel sheet or foil. Increased engine size, higher exhaust temperatures and alternate fuels all require greater performance (strength, corrosion resistance) and reliability than 347 steel, especially as temperatures approach or exceed 750°C. To meet these needs, the Department of Energy (DOE) has sponsored programs at the Oak Ridge National Laboratory (ORNL) to measure properties of commercial sheet and foil materials, to analyze recuperator components, and to identify or develop materials with improved performance and reliability, but which also are cost-effective. This paper summarizes high-temperature creep and corrosion testing of commercial 347 used for current recuperators, testing of HR 120 and modified 803 alloys, and development of modified 347 stainless steels.

Austenitic Stainless Steels and Alloys With Improved High-Temperature Performance for Advanced Microturbine Recuperators

2004 ◽  
Author(s):  
Philip J. Maziasz ◽  
Bruce A. Pint ◽  
John P. Shingledecker ◽  
Karren L. More ◽  
Neal D. Evans ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Stainless Steels ◽  
Gas Turbines ◽  
National Laboratory ◽  
Austenitic Stainless Steels ◽  
Cost Effective ◽  
Department Of Energy ◽  
Similar Data ◽  
Oak Ridge

Compact recuperators/heat-exchangers increase the efficiency of both microturbines and smaller industrial gas turbines. Most recuperators today are made from 347 stainless steel and operate well below 700°C. Larger engine sizes, higher exhaust temperatures and alternate fuels all demand recuperator materials with greater performance (creep strength, corrosion resistance) and reliability than 347 steel, especially for temperatures of 700–750°C. The Department of Energy (DOE) sponsors programs at the Oak Ridge National Laboratory (ORNL) to produce and evaluate cost-effective high-temperature recuperator alloys. This paper summarizes the latest high-temperature creep and corrosion data for a commercial 347 steel with modified processing for better creep resistanc, and for advanced commercial alloys with significantly better creep and corrosion resistance, including alloys NF709, HR120. Similar data are also provided on small lab heats of several new ORNL modified stainless steels.

Overview of Creep Strength and Oxidation of Heat-Resistant Alloy Sheets and Foils for Compact Heat-Exchangers

2005 ◽  
Author(s):  
Philip J. Maziasz ◽  
John P. Shingledecker ◽  
Bruce A. Pint ◽  
Neal D. Evans ◽  
Yukinori Yamamoto ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Heat Exchangers ◽  
Gas Turbines ◽  
High Efficiency ◽  
National Laboratory ◽  
Department Of Energy ◽  
Oak Ridge ◽  
Heat Resistant Alloy ◽  
Heat Resistant ◽  
Industrial Gas Turbines

The Oak Ridge National Laboratory (ORNL) has been involved in research and development related to improved performance of recuperators for industrial gas turbines since about 1996, and in improving recuperators for advanced microturbines since 2000. Recuperators are compact, high efficiency heat-exchangers that improve the efficiency of smaller gas turbines and microturbines. Recuperators were traditionally made from 347 stainless steel and operated below or close to 650°C, but today are being designed for reliable operation above 700°C. The Department of Energy (DOE) sponsored programs at ORNL have helped defined the failure mechanisms in stainless steel foils, including creep due to fine grain size, accelerated oxidation due to moisture in the hot exhaust gas, and loss of ductility due to aging. ORNL has also been involved in selecting and characterizing commercial heat-resistant stainless alloys, like HR120 or the new AL20-25+Nb, that should offer dramatically improved recuperator capability and performance at a reasonable cost. This paper summarizes research on sheets and foils of such alloys over the last few years, and suggests the next likely stages for manufacturing recuperators with upgraded performance for the next generation of larger 200–250 kW advanced microturbines.

Overview of Creep Strength and Oxidation of Heat-Resistant Alloy Sheets and Foils for Compact Heat Exchangers

2005 ◽  
Vol 128 (4) ◽  
pp. 814-819 ◽  
Author(s):  
Philip J. Maziasz ◽  
John P. Shingledecker ◽  
Bruce A. Pint ◽  
Neal D. Evans ◽  
Yukinori Yamamoto ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Heat Exchangers ◽  
Gas Turbines ◽  
High Efficiency ◽  
National Laboratory ◽  
Department Of Energy ◽  
Oak Ridge ◽  
Heat Resistant Alloy ◽  
Heat Resistant ◽  
Industrial Gas Turbines

The Oak Ridge National Laboratory (ORNL) has been involved in research and development related to improved performance of recuperators for industrial gas turbines since about 1996, and in improving recuperators for advanced microturbines since 2000. Recuperators are compact, high efficiency heat-exchangers that improve the efficiency of smaller gas turbines and microturbines. Recuperators were traditionally made from 347 stainless steel and operated below or close to 650°C, but today are being designed for reliable operation above 700°C. The Department of Energy (DOE) sponsored programs at ORNL have helped defined the failure mechanisms in stainless steel foils, including creep due to fine grain size, accelerated oxidation due to moisture in the hot exhaust gas, and loss of ductility due to aging. ORNL has also been involved in selecting and characterizing commercial heat-resistant stainless alloys, like HR120 or the new AL20-25+Nb, that should offer dramatically improved recuperator capability and performance at a reasonable cost. This paper summarizes research on sheets and foils of such alloys over the last few years, and suggests the next likely stages for manufacturing recuperators with upgraded performance for the next generation of larger 200-250kW advanced microturbines.

High Temperature Performance of Cast CF8C-Plus Austenitic Stainless Steel

2010 ◽  
Author(s):  
Philip J. Maziasz ◽  
Bruce A. Pint
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
High Temperature ◽  
Austenitic Stainless Steel ◽  
Gas Turbines ◽  
National Laboratory ◽  
Austenitic Stainless Steels ◽  
Medium Size ◽  
Temperature Oxidation ◽  
Oak Ridge

Covers and casings of small to medium size gas turbines, can be made from cast austenitic stainless steels, including grades such as CF8C, CF3M, or CF10M. Oak Ridge National Laboratory (ORNL) and Caterpillar have developed a new cast austenitic stainless steel, CF8C-Plus, that is a fully-austenitic stainless steel, based on additions of Mn and N to the standard Nb-stabilized CF8C steel grade. The Mn addition improves castability, as well as increasing the alloy solubility for N, and both Mn and N act synergistically to boost mechanical properties. CF8C-Plus steel has outstanding creep-resistance at 600°–900°C, which compares well with Ni-based superalloys like alloys X, 625, 617 and 230. CF8C-Plus also has very good fatigue and thermal fatigue resistance. It is used in the as-cast condition, with no additional heat-treatments. While commercial success for CF8C-Plus has been mainly for diesel exhaust components, this steel can also be considered for gas-turbine and microturbine casings. The purpose of this paper is to demonstrate some of the mechanical properties and update the long-term creep-rupture data, and to present new data on the high-temperature oxidation behavior of these materials, particularly in the presence of water vapor.

Developing New Cast Austenitic Stainless Steels With Improved High-Temperature Creep Resistance

2007 ◽  
Author(s):  
Philip J. Maziasz ◽  
John P. Shingledecker ◽  
Neal D. Evans ◽  
Michael J. Pollard
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Creep Strength ◽  
Stainless Steels ◽  
Creep Resistance ◽  
National Laboratory ◽  
Austenitic Stainless Steels ◽  
Alloy Development ◽  
Oak Ridge ◽  
Wide Range

Oak Ridge National Laboratory (ORNL) and Caterpillar have recently developed a new cast austenitic stainless steel, CF8C-Plus, for a wide range of high-temperature applications, including diesel exhaust components and turbine casings. The creep-rupture life of the new CF8C-Plus is over ten times greater than that of the standard cast CF8C stainless steel, and the creep-strength is about double. Another variant, CF8C-Plus Cu/W has been developed with even more creep strength at 750–850°C. The creep-strength of these new cast austenitic stainless steels is close to that of Ni-based superalloys like 617. CF8C-Plus steel was developed in about 1.5 years using an “engineered microstructure” alloy development approach, which produces creep resistance based on formation of stable nano-carbides (NbC) and prevention of deleterious intermetallics (sigma, Laves). CF8C-Plus steel won a 2003 R&D 100 Award, and to date, over 32,000 lb have been produced in various commercial component trials. The current commercialization status of the alloy is summarized.

Ceramic Gas Turbine Materials Impact Evaluation

2002 ◽  
Author(s):  
Mark van Roode ◽  
Oscar Jimenez ◽  
John McClain ◽  
Jeff Price ◽  
Vijay Parthasarathy ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Impact Damage ◽  
National Laboratory ◽  
Impact Resistance ◽  
Department Of Energy ◽  
Threshold Velocity ◽  
Oak Ridge ◽  
Engine Testing ◽  
The Impact

Impact of foreign or domestic material on components in the hot section of gas turbines with ceramic components is a common cause of catastrophic failure. Several such occurrences were observed during engine testing under the Ceramic Stationary Gas Turbine program sponsored by the U.S. Department of Energy. A limited analysis was carried out at Solar Turbines Incorporated (Solar), which involved modeling of the impact in the hot section. Based on the results of this study an experimental investigation was carried out at the University of Dayton Research Institute Impact Physics Laboratory to establish the conditions leading to significant impact damage in silicon-based ceramics. The experimental set up involved impacting ceramic flexure bars with spherical metal particulates under conditions of elevated temperature and controlled velocity. The results of the study showed a better correlation of impact damage with momentum than with kinetic energy. Increased test specimen mass and fracture toughness were found to improve impact resistance. Continuous fiber-reinforced ceramic composite (CFCC) materials have better impact resistance than monolithics. A threshold velocity was established for impacting particles of a defined mass. Post-impact metallography was carried out at Oak Ridge National Laboratory to further establish the impact mechanism.

scholarly journals High-Temperature Oxidation Resistance of Alumina-Forming Austenitic Stainless Steels Optimized by Refractory Metal Alloying

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 213
Author(s):  
Shuqi Zhang ◽  
Dandan Dong ◽  
Qing Wang ◽  
Chuang Dong ◽  
Rui Yang
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Stainless Steels ◽  
High Temperature Oxidation ◽  
National Laboratory ◽  
Austenitic Stainless Steels ◽  
Alloying Elements ◽  
Temperature Oxidation ◽  
Oak Ridge ◽  
Al2o3 Particles

Alumina-forming austenitic stainless steels are known for their superior high-temperature oxidation resistance. Following our previous work that solved the matching of major alloying elements in their specific 16-atom cluster formula, we here focus on the 800 °C air-oxidation resistance of 0.08 wt. % C alloy series satisfying cluster formula [(Al0.89Si0.05NbxTa0.06−x)-(Fe11.7−yNiyMn0.3)]Cr3.0−z(Mo,W)z, x = 0.03 or 0.06, y = 3.0 or 3.2, z = 0.07 or 0.2, to explore the effect of minor alloying elements Mo, Nb, Ta and W. This cluster formula is established particularly based on alloys which were originally developed by Oak Ridge National Laboratory. All samples are graded as complete oxidation resistance level according to Chinese standard HB 5258-2000, as their oxidation rate and oxidation-peeling mass are generally below 0.1 g/m2 × h and 1.0 g/m2, respectively. In alloys without Ta and W, a Cr2O3-type oxide layer is formed on the surface and Al2O3 particles of sizes up to 4 μm are distributed beneath it. In contrast, in Ta/W-containing alloys, a continuous protective Al2O3 layer is formed beneath the outer Cr2O3 layer, which prevents internal oxidation and provides the lowest weight gain. Instead of internal Al2O3 particles, AlN is formed in Ta/W-containing alloys. The W-containing alloy possesses the thinnest internal nitride zone, indicating the good inhibition effect of W on nitrogen diffusion.

scholarly journals Process Optimization of Hexoloy SX-SiC Towards Improved Mechanical Properties

1993 ◽  
Author(s):  
G. V. Srinivasan ◽  
S. K. Lau ◽  
R. S. Storm ◽  
M. K. Ferber ◽  
M. G. Jenkins
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Process Optimization ◽  
National Laboratory ◽  
Complete Characterization ◽  
Department Of Energy ◽  
High Temperature Application ◽  
Oak Ridge ◽  
Carbon Doped ◽  
Temperature Application

Hexoloy SX SiC materials, sintered with the addition of yttrium and aluminum containing compounds, have been demonstrated to possess higher toughness and strength than the boron and carbon doped Hexoloy SA [1]. Under a Department of Energy/Oak Ridge National Laboratory (DOE/ORNL) contract, a complete characterization was conducted on an SX composition selected for high temperature application. The particular composition selected for that study was Generation 1 SX-SiC (SX-G1), which contained about 2 wt% total additives.

High-Temperature Performance of Cast CF8C-Plus Austenitic Stainless Steel

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Philip J. Maziasz ◽  
Bruce A. Pint
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
High Temperature ◽  
Austenitic Stainless Steel ◽  
Gas Turbines ◽  
National Laboratory ◽  
Austenitic Stainless Steels ◽  
Medium Size ◽  
Temperature Oxidation ◽  
Oak Ridge

Covers and casings of small to medium size gas turbines can be made from cast austenitic stainless steels, including grades such as CF8C, CF3M, or CF10M. Oak Ridge National Laboratory and Caterpillar have developed a new cast austenitic stainless steel, CF8C-Plus, which is a fully austenitic stainless steel, based on additions of Mn and N to the standard Nb-stabilized CF8C steel grade. The Mn addition improves castability, as well as increases the alloy solubility for N, and both Mn and N synergistically act to boost mechanical properties. CF8C-Plus steel has outstanding creep-resistance at 600–900°C, which compares well with Ni-based superalloys such as alloys X, 625, 617, and 230. CF8C-Plus also has very good fatigue and thermal fatigue resistance. It is used in the as-cast condition, with no additional heat-treatments. While commercial success for CF8C-Plus has been mainly for diesel exhaust components, this steel can also be considered for gas turbine and microturbine casings. The purposes of this paper are to demonstrate some of the mechanical properties, to update the long-term creep-rupture data, and to present new data on the high-temperature oxidation behavior of these materials, particularly in the presence of water vapor.

Advanced Research and Technology Development Fossil Energy Materials Program

1988 ◽  
Vol 110 (4) ◽  
pp. 670-676
Author(s):  
R. R. Judkins ◽  
R. A. Bradley
Keyword(s):  
Technology Development ◽  
National Laboratory ◽  
Development Program ◽  
Ceramic Composites ◽  
Department Of Energy ◽  
Energy Materials ◽  
Alloy Development ◽  
Fossil Energy ◽  
Oak Ridge ◽  
Research Activities

The Advanced Research and Technology Development (AR&TD) Fossil Energy Materials Program is a multifaceted materials research and development program sponsored by the Office of Fossil Energy of the U.S. Department of Energy. The program is administered by the Office of Technical Coordination. In 1979, the Office of Fossil Energy assigned responsibilities for this program to the DOE Oak Ridge Operations Office (ORO) as the lead field office and Oak Ridge National Laboratory (ORNL) as the lead national laboratory. Technical activities on the program are divided into three research thrust areas: structural ceramic composites, alloy development and mechanical properties, and corrosion and erosion of alloys. In addition, assessments and technology transfer are included in a fourth thrust area. This paper provides information on the structure of the program and summarizes some of the major research activities.

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