1、14FTM19 AGMA Technical Paper Application of ICME to Optimize Metallurgy and Improve Performance of Carburizable Steels By J. Grabowski, J. Sebastian, A. Asphahani, C. Houser, K. Taskin and D. Snyder, QuesTek Innovations LLC2 14FTM19 Application of ICME to Optimize Metallurgy and Improve Performance
2、of Carburizable Steels Jeff Grabowski, Jason Sebastian, Aziz Asphahani, Clay Houser, Kerem Taskin and Dave Snyder, QuesTek Innovations LLC The statements and opinions contained herein are those of the author and should not be construed as an official action or opinion of the American Gear Manufactur
3、ers Association. Abstract QuesTek Innovations LLC has applied its Materials by Design computational design technology and its Integrated Computational Materials Engineering (ICME)-based methods to successfully design, develop and implement two new high-performance gear steels (Ferrium C61 and Ferriu
4、m C64 steels) that are being used in demanding gear and bearing applications in ground and aerospace military, commercial aerospace, high-performance racing, oil and gas and other industries. Additionally, QuesTek has successfully designed and developed two new high-performance steels (Ferrium S53 a
5、nd Ferrium M54 steels that can be used in gearing applications). All four Ferrium alloys are commercially available from Carpenter Technology and have been awarded SAE AMS numbers for procurement. QuesTek has also designed several other high performance alloys using ICME technologies, including a st
6、ainless nitridable bearing and gear steel and alloys for additive manufacturing applications. Copyright 2014 American Gear Manufacturers Association 1001 N. Fairfax Street, Suite 500 Alexandria, Virginia 22314 October 2014 ISBN: 978-1-61481-111-4 3 14FTM19 Application of ICME to Optimize Metallurgy
7、and Improve Performance of Carburizable Steels Jeff Grabowski, Jason Sebastian, Aziz Asphahani, Clay Houser, Kerem Taskin and Dave Snyder, QuesTek Innovations LLC Introduction QuesTek Innovations LLC (“QuesTek”) of Evanston, IL uses its proprietary Materials by Design expertise and technology in con
8、junction with its ICME-based methodologies to rapidly design, develop and qualify advanced alloys into demanding applications. Accelerating the historically slow and expensive materials design and development process, QuesTeks approach integrates extensive thermodynamic and kinetic databases with ad
9、vanced computational modeling tools to develop and optimize precise chemical compositions and processing parameters ensure specified property targets and meet desired performance goals. Optimization of design demands consideration of tradeoff in materials properties, necessitated by competing requir
10、ements. QuesTek has computationally designed and developed many new ultra high performance alloys, coatings, and materials including iron-, copper-, aluminum-, nickel-, molybdenum-, and titanium-based materials and numerous others. As a global leader in the field of ICME, QuesTek has proven that the
11、se materials can be developed much faster and at lower cost, while also providing unique, optimized properties that directly meet user-defined material performance goals for demanding applications in aerospace, oil and gas, high performance racing and other industries. Ferrium C61 and Ferrium C64 Ba
12、ckground Ferrium C61 (AMS 6517) and C64 (AMS 6509) steels are commercially available secondary-hardening gear steels that provide significantly improved tensile strength, case hardness, fracture toughness, fatigue strength, corrosion resistance, and temperature resistance, resulting in performance b
13、enefits over conventional gear steels such as AISI 9310 or Pyrowear Alloy 53. Table 1 provides a comparison of typical alloy properties. Ferrium C61 and C64 carburizable gear steels have been approved for use in a variety of demanding applications in next generation helicopters as upgrades from incu
14、mbent aerospace gearing and shaft steels that have been used for decades, being applied to demanding flight critical applications including transmission gear boxes and rotor shafts. Further, these steels are being applied to gearing components in high-performance racing, wind energy and oil and gas
15、sectors. Both C61 and C64 steels utilize an efficient nanoscale M2C carbide strengthening dispersion within a nickel-cobalt lath martensitic matrix. These Ferrium steels were designed considering the complex interplay of critical design factors including: martensitic matrix stability (Mstemperature)
16、; M2C carbide thermodynamic stability and formation kinetics; matrix cleavage resistance; and embrittling phase thermodynamic stability. Table 1. Tabular comparison of gear steel properties (typical) Typical alloy properties YS, ksi UTS, ksi Core hardness, HRC EI, % RA, % Fracture toughness, ksiin A
17、chievable surface hardness, HRC Tempering temperature, F AISI 9310 155 175 34-42 16 53 85 58-62 300 Pyrowear Alloy 53 140 170 36-44 16 67 115 59-63 400 Ferrium C61 (AMS 6517) 225 240 48-50 16 70 130 60-62 900 Ferrium C64 (AMS 6509) 199 229 48-50 18 75 85 62-64 925 4 14FTM19 Ferrium C64 was developed
18、 under a U.S. Navy STTR program aimed at reducing weight, improving fatigue performance, and improving high temperature operating capability of rotorcraft gear transmission relative to the incumbent alloy Pyrowear 53. Both C61 and C64 steels are being applied to power transmission applications where
19、 their very high core strengths, toughness and other mechanical advantages provide benefits including significantly reduced rotorcraft drivetrain weight or increased power density. Processing Ferrium C61 and C64 steels processing pathway permits significant reductions in manufacturing costs and sche
20、dules. Specifically designed to achieve high hardenability and resist grain growth at high temperatures, these steels take advantage of mild-gas quenching and high-temperature vacuum carburization processes. This combination results in considerable advantages (see Figure 1), including: 1. shorter th
21、ermal processing times at higher carburizing temperatures; 2. reduction of quench distortion, resulting in decreased grinding stock removal; 3. reduction of final machining and finishing costs by eliminating intergranular oxide formation and reducing quench distortion; 4. elimination of separate har
22、dening and oil quenching process steps after carburization, thus dismissing associated copper plating and stripping processes, and 5. preservation of good properties in large, thick-sectioned components. Further, numerous heat-treaters have developed heat treatment cycles that can achieve a wide ran
23、ge of case depth profiles. This ability to “dial in” the depth and profile of case carburization leads to improved manufacturing flexibility and control. Ferrium C61 and C64 steels processing is covered under SAE AMS 2759/7, and QuesTek is currently developing shot peening parameters and optimizing
24、superfinishing processes for both steels. Performance benefits Benefits of using the Ferrium gear steels vs. incumbent gear alloys such as Pyrowear 53, 9310 or EN36 -for power transmission applications can include: Smaller, lighter-weight gears for greater throughput or durability Gears and gearboxe
25、s using C-series Ferrium steels can handle higher impact loads and internal stress than comparable designs using traditional materials. In some cases, the gears and gearboxes can be reduced in size and weight due in part to (1) C61 steels very high fracture toughness and bending fatigue resistance,
26、and (2) C64 steels excellent surface contact fatigue resistance and bending fatigue resistance. Figure 1. Gear steel heat treat comparison (typical) 5 14FTM19 Smaller, lighter-weight driveshafts for greater throughput or durability Integral driveshafts (e.g., with integral gears) using C61 and C64 c
27、an handle approximately 20-25% higher loads than comparable driveshafts using traditional materials, or be reduced in size and weight by comparable amounts. C61s core UTS of 240 ksi is a 39% increase versus 9310, for example. C64s surface hardness of 62-64 HRC cannot be achieved in conventional gear
28、 steels such as 9310 without sacrificing their fatigue-resistant microstructures. Superior high temperature operability and survivability such as in oil-out emergency conditions or high-temperature environments The 900-925F tempering temperatures of C61 and C64 steels are 400-600F higher than most i
29、ncumbent alloys, yielding superior thermal stability. The combination of high fatigue strength, thermal stability, and high temperature strength translates to excellent potential scuffing and/or scoring fatigue resistance for both steels. These attributes are expected to benefit gear steel oil-out p
30、erformance, leading to an increase in time to reach acceptable landing sites in emergency situations, for example. Greater gear durability Gears and gearboxes using C61 and C64 steels can handle higher impact loads and internal stresses than comparable designs using traditional materials. In some ca
31、ses, gears and gearboxes can be reduced in size and weight due in part to C61 and C64 steels very high fracture toughness and bending fatigue resistances. The combination of excellent gear fatigue properties and high surface hardness in C64 makes it an option for improving durability (and reducing w
32、eight) in rotorcraft component designs that incorporate toothed-gears with integral bearing races (e.g., planetary gears in epicyclical rotorcraft transmission designs). New axial and single tooth bending fatigue data In an Army-funded Phase II SBIR program, QuesTek is further enhancing the fatigue
33、resistance of Ferrium C64 steel. Recently completed testing under the program consisted of single tooth bending fatigue (STBF) testing on C64 and Pyrowear 53 gears (see Figure 2). Testing concluded approximately 20% higher performance of C64 over Pyrowear 53 at ambient temperature, with a 50% failur
34、e stress of 219 ksi for C64 steel and 182 ksi for Pyrowear 53. For C61 core fatigue properties, refer to Figure 3. Figure 2. Initial STBF results for C64 steel and Pyrowear 53 (gears were manufactured and processed typical of aerospace gears) 6 14FTM19 Figure 3. Axial fatigue comparison (Ferrium C61
35、, 155 ksi, vs. 9310, 110 ksi) Applications There is currently a need for improved materials in rotorcraft platforms to allow for increased power transmission or weight reduction. Upgrades to engines on platforms such as the AH-64 Block III have been implemented in recent years, and in order to utili
36、ze the full power available by the engine upgrade, transmission and gearing components must also be upgraded. In some instances, full power may not be achieved due to limitations of current shafting materials and the allowable design envelope, which is of particular concern when considering rotor sh
37、afts. Incumbent materials such as 4340, AISI 9310 and Pyrowear Alloy 53 steels have not been able to keep pace with the need for increased pay loads. QuesTek is evaluating Ferrium C61 steel under a U.S. Army-funded SBIR program as a potential replacement for 9310 in the CH-47 Chinook helicopter forw
38、ard rotor shaft. C61 steel typically provides a 35% increase in ultimate tensile strength and a 50% increase in fracture toughness over 9310 steel, and is initially expected to provide a 20% increase in CH-47 payload capacity, excluding any redesign or light-weighting efforts. See Figure 4 for image
39、s from C61 prototype CH-47 shaft production. Three prototype rotor shafts were completed in 2013, with full-scale rig testing and component-level qualification to take place in 2014-2015. Figure 4. Ferrium C61 prototype CH-47 Chinook helicopter forward rotor shaft manufacturing pathway, illustrating
40、 forging (left and center) and rough machining (right). 7 14FTM19 In 2011, QuesTek announced a subcontract award from Bell Helicopter, a Textron Company, to jointly evaluate the application of Ferrium C64 steel for helicopter gears, as part of the $30 million Technology Investment Agreement awarded
41、to Bell by the U.S. Army Aviation Applied Technology Directorate to develop state-of-the-art drive system technology under the Armys Future Advanced Rotorcraft Drive System (FARDS) program.1QuesTek has been working closely with Bell to further develop the thermal processing and finishing processes o
42、f C64 steel to optimize the combination of strength and hardness in the gear case and core, aiming to achieve the targeted 55% improvement in power-to-weight ratio, 35% reduction in production, operating, and support costs, and other improvements in drive systems for the U.S. Armys current/future fl
43、eet of rotorcraft and for commercial rotorcraft. Successful applications of C61 and C64 steels include off-road racing and NASCAR gearbox applications (see Figure 5). These steels performance is race-proven, with more than 100 ring-and-pinion sets made of C61 steel used in highly demanding SCORE Int
44、ernational off-road races such as the BAJA 1000. This application of C61 steel has shown a 3-4 times improvement in gear set durability versus the incumbent 9310 steel. C61 and C64 steel application has penetrated the oil and gas industry with multiple private industry-funded material development pr
45、ojects. C61 steel is being considered as an upgrade from incumbent oil and gas steels such as 9310, EN36A, EN36B and EN36C, by offering much greater strength and toughness. C64 steel provides a much greater surface hardness, with greater temperature and corrosion resistance versus traditional carbur
46、izing steels. These steels are being applied to down hole transmission components, gears, pinions and components where durability, compactness, weight savings, or high temperature resistance is valued. Ferrium S53 and Ferrium M54 Ferrium S53 alloy (AMS 5922, MMPDS-05) is an ultra-high strength, corr
47、osion-resistant secondary-hardening steel strengthened by an efficient M2C carbide precipitation within a fine ductile lath martensite matrix. Designed with sufficient chromium to provide passivation against general corrosion, S53 alloy has much greater corrosion resistance than 4340 and 300M, and h
48、as significantly improved corrosion fatigue performance (see Table 2 for typical property comparisons). QuesTek designed S53 alloy for the U.S Strategic Environmental Research and Development Program in order to eliminate the need for toxic cadmium plating on corrosion-prone Air Force 300M landing g
49、ear. Due to the limited corrosion resistance and corrosion fatigue life of 300M steel, coatings for corrosion protection are utilized which can become compromised in service or during installation, causing onset of corrosion and resulting in a reduced service life and greater risk of failure. Figure 5. Example of a Ferrium C61 ring-and-pinion set used in a high-performance racing application 1http:/ QuesTek Innovations is a subcontractor to Bell Helicopter for the first two years of this five
