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

2009 ◽  
Vol 131 (5) ◽  
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 ◽  
Austenitic Stainless Steels ◽  
Creep Rupture ◽  
Particulate Filter ◽  
Alloy Development ◽  
Wide Range

Oak Ridge National Laboratory and Caterpillar (CAT) 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-rupture strength is about 50–70% greater. 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 wrought Ni-based superalloys such as 617. CF8C-Plus steel was developed in about 1.5 years using an “engineered microstructure” alloy development approach, which produces creep resistance based on the formation of stable nanocarbides (NbC), and resistance to the formation of deleterious intermetallics (sigma, Laves) during aging or service. The first commercial trial heats (227.5 kg or 500 lb) of CF8C-Plus steel were produced in 2002, and to date, over 27,215 kg (300 tons) have been produced, including various commercial component trials, but mainly for the commercial production of the Caterpillar regeneration system (CRS). The CRS application is a burner housing for the on-highway heavy-duty diesel engines that begins the process to burn-off particulates trapped in the ceramic diesel particulate filter (DPF). The CRS/DPF technology was required to meet the new more stringent emissions regulations in January, 2007, and subjects the CRS to frequent and severe thermal cycling. To date, all CF8C-Plus steel CRS units have performed successfully. The status of testing for other commercial applications of CF8C-Plus steel is also summarized.

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.

ALLOY 0Cr25Ni6Mo3CuN

Alloy Digest ◽  
1998 ◽  
Vol 47 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Temperature Performance ◽  
Steel Research ◽  
Oil Refinement

Abstract ALLOY 0Cr25Ni6Mo3CuN is one of four grades of duplex stainless steel that were developed and have found wide applications in China since 1980. In oil refinement and the petrochemical processing industries, they have substituted for austenitic stainless steels in many types of equipment, valves, and pump parts. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming and joining. Filing Code: SS-706. Producer or source: Central Iron & Steel Research Institute.

Microanalysis for Design and Development of Improved High-Temperature Alloys

2001 ◽  
Vol 7 (S2) ◽  
pp. 544-545
Author(s):  
Philip J. Maziasz
Keyword(s):  
High Temperature ◽  
Creep Resistance ◽  
Power Plants ◽  
Austenitic Stainless Steels ◽  
High Temperature Creep ◽  
Alloy Development ◽  
Temperature Creep ◽  
Microstructural Design ◽  
Engineering Alloys ◽  
Processing Optimization

Alloy development can range from purely empirical, trial-and-error efforts to very theoretical, based on either fundamental first-principles calculations or computational-modeling using various kinds of data base inputs. However, “real-world” efforts to improve or optimize complex engineering alloys often cannot afford the time or cost of either extreme approach. in the past 10-15 years, an alloy development and processing optimization methodology has been developed that utilizes strategic microanalytical data (both detailed microstucture and microcompositional information) as the critical input that then enables efficient and effective design of various kinds of alloys for improved high-temperature performance [1-6]. in many cases, first time tests produce outstanding high-temperature creep or creep-rupture results, and enable improvements without trading off one property for another. This invited paper will highlight several examples of significantly improved creep resistance obtained using such microstructural design.This microstructural design methodology for high-temperature creep-resistance was initially developed for and demonstrated in austenitic stainless steels (Fe-14Cr-16Ni) designed for improved creep-strength and rupture resistance at 700°C and above for superheater and boiler tubing in advanced fossil power plants.

Selecting and Developing Advanced Alloys for Creep-Resistance for Microturbine Recuperator Applications

2001 ◽  
Author(s):  
Philip J. Maziasz ◽  
Robert W. Swindeman
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Creep Strength ◽  
Creep Resistance ◽  
Low Cost ◽  
Cost Effective ◽  
Creep Rupture ◽  
High Temperature Strength ◽  
Steel Alloys ◽  
Surface Plate

Recuperators are considered essential hardware to achieve the efficiencies desired for advanced microturbines. Compact recuperator technologies, including primary surface, plate and fin, and spiral, all require thin section materials that have high-temperature strength and corrosion resistance up to 750°C or above, and yet remain as low-cost as possible. The effects of processing and microstructure on creep-rupture resistance at 750°C and 100 MPa were determined for a range of austenitic stainless alloys made into 0.1 mm foils. Two groups of alloys were identified with regard to improved creep-resistance relative to type 347 stainless steel. Alloys with better creep-rupture resistance included alloys 120, 230, modified 803 and thermie-alloy, while alloy 214 and 625 exhibited much better creep strength. Alloys 120 and modified 803 appeared to have the most cost-effective improvements in creep-strength relative to type 347 stainless steel, and should be attractive for advanced microturbine recuperator applications.

ARCELORMITTAL K03

Alloy Digest ◽  
2009 ◽  
Vol 58 (8) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Stainless Steels ◽  
Lower Cost ◽  
Austenitic Stainless Steels ◽  
Heat Treating ◽  
Temperature Performance

Abstract ArcelorMittal K03 is a ferritic stainless steel, mostly used as a stable price, lower-cost substitute for nickel-containing austenitic stainless steels. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1042. Producer or source: Arcelor Stainless Processing LLC.

ALLOY 00Cr18Ni5Mo3Si2

Alloy Digest ◽  
1997 ◽  
Vol 46 (11) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
Temperature Performance ◽  
Steel Research ◽  
Oil Refinement

Abstract ALLOY 00Cr18Ni5Mo3Si2 is one of four grades of duplex stainless steel that were developed and have found wide applications in China since 1980. In oil refinement and the petrochemical processing industries, these duplex stainless steels have substituted for austenitic stainless steels in many types of equipment, valves, and pump parts. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming and joining. Filing Code: SS-702. Producer or source: Central Iron & Steel Research Institute.

Selecting and Developing Advanced Alloys for Creep-Resistance for Microturbine Recuperator Applications1

2002 ◽  
Vol 125 (1) ◽  
pp. 310-315 ◽  
Author(s):  
P. J. Maziasz ◽  
R. W. Swindeman
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Creep Strength ◽  
Creep Resistance ◽  
Low Cost ◽  
Cost Effective ◽  
Creep Rupture ◽  
High Temperature Strength ◽  
Steel Alloys ◽  
Surface Plate

Recuperators are considered essential hardware to achieve the efficiencies desired for advanced microturbines. Compact recuperator technologies, including primary surface, plate and fin, and spiral, all require thin section materials that have high-temperature strength and corrosion resistance up to 750°C or above, and yet remain as low cost as possible. The effects of processing and microstructure on creep-rupture resistance at 750°C and 100 MPa were determined for a range of austenitic stainless alloys made into 0.1-mm foils. Two groups of alloys were identified with regard to improved creep resistance relative to type 347 stainless steel. Alloys with better creep-rupture resistance included alloys 120, 230, modified 803 and alloy 740 (formerly thermie-alloy), while alloy 214 and 625 exhibited much better creep strength. Alloys 120 and modified 803 appeared to have the most cost-effective improvements in creep strength relative to type 347 stainless steel, and should be attractive for advanced microturbine recuperator applications.

AFM Characterization of Structural Evolution and Roughness of AISI 304 Austenitic Stainless Steel under Severe Deformation by Wavy Rolling

2013 ◽  
Vol 794 ◽  
pp. 230-237 ◽  
Author(s):  
K. Chandra Sekhar ◽  
Bhagwati Prasad Kashyap ◽  
Sandeep Sangal
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Shear Bands ◽  
Structural Evolution ◽  
Austenitic Stainless Steels ◽  
Structural Development ◽  
Deformation Bands ◽  
Aisi 304 ◽  
Wide Range

Stainless steels such as ferrritic, austenitic, martensitic and duplex stainless steels are well known for their corrosion resistance to varying extents. Among these, austenitic stainless steels exhibit superior corrosion resistance and better ductility for formability. Therefore, the ability to give simple to intricate shapes in this grade of steel brings their potential for a wide range of applications. However, the meta-stable austenite in AISI 304 is known to undergo a strain induced martensitic (SIM) transformation during conventional rolling at room temperature. This strain induced martensite causes reduction in ductility and limits formability of stainless steel. Therefore, wavy rolling technique was developed to strengthen the stainless steel through microstructural refinement. In the current study, wavy rolling with 1.5 mm amplitude was conducted on 1 mm thick stainless steel sheet to different cycles ranging from 1-4. These rolled samples were characterized by optical and Atomic Force Microscopy (AFM) with resolutions down to the nanolevel. This AFM tool is in a position to bring out the details of grain refinement and topographical roughness emerging from crystalline and microstructural defects like orientation, precipitation, stacking faults, deformation bands, slip lines and shear bands with progress in rolling as referred by the number of rolling cycles here. The structural development is semi-quantitatively related to the degree of deformation and its effect on tensile properties during wavy rolling cycle. Keywords: Structural properties; Roughness; Deformation; Wavy rolling.

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