The first ever Nadcap accreditation for Aero Structure Assembly has been awarded to an aerospace company based in Wichita, Kansas.
Lee Aerospace Inc., which designs, manufactures, installs, and repairs aerospace parts and assemblies for the aerospace industry, recently received the accreditation following a 2018 pilot audit that validated the audit criteria developed by the Nadcap Aero Structure Assembly Task Group and rigorously assessed the company’s compliance to the applicable industry standards and customer requirements.
Christopher Lowe of Spirit AeroSystems, Nadcap Aero Structure Assembly Task Group Chair
“There are more companies than ever involved in aerostructure assembly as activity is delegated through the supply chain by the airframers,” explained Christopher Lowe of Spirit AeroSystems, Nadcap Aero Structure Assembly Task Group Chair. “As a result, the need for supply chain oversight in this area was recognized as being of growing importance. Nonconforming assembly practices can cause serious escapes such as unseen product defects, delivery delays and rectification costs.
“Congratulations to Lee Aerospace Inc. for their notable achievement in being the first in the world to gain this prestigious accreditation. I am pleased to have had the opportunity, through Nadcap, to work with my peers at Airbus, Airbus Defense and Space, Arconic, BAE Systems, Helicomb International, Lee Aerospace Inc., Leonardo, Lockheed Martin, Northrop Grumman and Spirit AeroSystems to address this issue and I encourage others in the industry to get involved in this activity.”
Technologies covered in the Aero Structure Assembly audit criteria currently extend to fastening, electrical bonding, bushing and bearing installation, and sealant application.
Tommy Howland, Director of Quality for Lee Aerospace
Issuing the first accreditation is a significant step in the maturation of the newest Nadcap Task Group, whose members have been working towards this point since 2015 when the Nadcap Management Council approved Aero Structure Assembly as one of the specialized technologies that Nadcap accredits. Aero Structure Assembly now joins both long-standing practices such as heat treating, welding, and non-destructive testing, as well as newer activities such as composites and electronics in the Nadcap program.
“As an active member of Nadcap, when the opportunity to be the first company for accreditation in a pilot program presented itself, we literally jumped at the chance,” said Tommy Howland, Director of Quality for Lee Aerospace. “At Lee Aerospace, we strive to be the best in all aspects of our manufacturing processes, including transparencies, composites, and aerostructure assembly.”
The space industry is growing fast and is predicted to be worth over a trillion dollars by 2040.
Keith Ferguson, Senior Business Development Manager at Morgan Advanced Materials’ Braze Alloys Business, explains how braze alloys play their part in safe, reliable and sustainable space exploration.
A Braze New World
The saying goes, “one small step for man, one giant leap for mankind.” This famous phrase uttered by Neil Armstrong is the perfect advertisement for space exploration and its importance to the future.
Less than a century old, space exploration has come on leaps and bounds since the first artificial satellite, Sputnik 1, was propelled into space in 1957. Since then, the world has witnessed marvels such as landing on the moon, the space shuttle program of the 1970s, and the launch of the International Space Station.
The importance of these missions and their subsequent value is immeasurable. Many might not realize on a day-to-day basis how space exploration has improved lives and the global economy to no end. This includes simple weather forecasting, broadcasting TV and radio, predicting natural disasters, monitoring for fertile land, forecasting sea level patterns, and even aiding research in muscular atrophy.
It’s little wonder then that this industry has significant value. The space industry was reportedly worth $384 million USD in 2017, growing at a rate of 7.4 percent. According to Morgan Stanley, it sees the industry growing to be worth $1.1 trillion USD by 2040.
However, there are challenges. Many believe that the millions of dollars and resources used to explore space could be better used on immediate threats to society like clean water, famine, poverty and more. Outside of external opinion though, there are internal operational challenges. Namely, space exploration needs to become safer and more sustainable.
A huge part of solving this challenge is in brazing alloys.
A Brief History on Brazing in Space
In simple terms, brazing joins two metals by heating and melting a filler (alloy) that bonds to the two pieces of metal and joins them. The filler must have a melting temperature below that of the metal pieces.
The use of braze alloys in space equipment is mission critical, as they allow sensors to be mounted as close as possible to engines to measure and monitor output and feed data back to operators. Indeed, they’ve already aided successful missions. Two of Morgan Advanced Materials’ braze alloys, RI-46 and RI-49, were specifically engineered and used by NASA on the Space Shuttle Main Engine, also known as the RS25.
Braze Alloys (Morgan in Space)
RI-46 specifically was developed as a replacement for the existing Nioro braze alloy, which is comprised of 82/18 Au/Ni (gold/nickel). RI-46 contains much less gold, adding in copper and manganese instead. This helped make the braze alloy significantly less dense and provided crucial weight savings, but also still operable from a wide range of temperatures, between -400°F to 1292°F (-240°C to 700°C).
These alloys have not only been critical for past space missions, but also for future missions. RI-46 and RI-49 have been adopted for NASA’s Space Launch System (SLS), a vehicle that is planned to take a crewed mission to Mars.
As alluded to already, developing new braze alloys is as much about performance as well as sustainability.
The Need for Non-Precious Alloys
It needs no mention that space exploration is a costly exercise. According to NASA, the average cost to launch a Space Shuttle is $450 million per mission. The Space Shuttle Endeavour, the orbiter built to replace the Space Shuttle Challenger, cost an eye-watering $1.7 billion USD.
Wire Form Braze Alloys (Morgan in Space)
Bringing costs down is clearly required to keep space missions feasible. One key part of cost reduction is in reducing the use of precious metal braze alloys.
Precious metals like gold and palladium are becoming increasingly scarce. Of course, the cost of producing alloys from these precious metals is also increasing as a result.
However, there can be a reluctance to come away from using precious metal alloys. Years of research, development, and data mean these alloys are tested and reliable. When dealing with missions and equipment that run into the hundreds of millions of dollars and, more importantly, the lives of crew members, reliability becomes an overarching objective, and failures must be prevented.
To solve this issue, Morgan’s Braze Alloys business has been researching and developing non-precious metal alloys over many years. As seen from the RI-46 and RI-49 alloys, these solutions are just as strong as their equivalent high precious-metal counterparts, but at a fraction of the cost.
Non-precious metal alloys can be made from metals like nickel, chromium, and cobalt. Their success has already been seen in the aerospace sector, and now research is being pioneered into making them fit for going into orbit and beyond.
Space, for All to Enjoy
Space travel is not just for highly trained astronauts and public benefit; there is also a growing commercial aspect. Satellite TV and radio have already been mentioned, but billionaire entrepreneurs such as Richard Branson and Elon Musk have also been pioneering private space travel. The hope is that civilians might one day be able to enjoy outer space as well, albeit at potentially high prices.
Achieving this dream is of course hinged on safety and reliability, given that lives will be at stake. The key to improving these factors is being able to place sensors as close as possible to the spacecraft’s engine.
By enabling sensors to be placed near the spacecraft’s engine, mission control and crew can then accurately read and measure data and output. This includes fuel efficiency, temperature, gas flow and monitoring for fire detection or abnormalities. If these sensors are placed too far away from the engines, then data readings become inaccurate and missions can be compromised.
Recent news highlights why sensor technologies are critical, as a two-man space crew had to abort their flight to the ISS after a post-rocket launch failure. The Soyuz spacecraft started to experience failure 119 seconds into the flight, and seemingly, problems were reported by the crew first, not by mission control. The crew described feelings of weightlessness, an indication of a problem during that stage of the flight. Luckily, they aborted, ejected their capsule from the rocket, and returned safely to Earth.
While the cause of the failure is still to be identified at the time of writing, clearly, such a situation should not be happening. Any problems should be picked up by mission control, and not be reliant on crew judgment.
Active Alloys join ceramic sensors to engines. (Morgan in Space)
The challenge though is that some sensors are made from ceramic due to the need to resist corrosion and high temperatures, typically up to 1742°F (950°C ). However, these ceramic sensors then need to be joined to metallic parts of the engine.
This is where “active alloys” come in. Unlike regular braze alloys that join metal to metal, these alloys can join metal to ceramic, or even ceramic to ceramic. Industry standard active alloys like Incusil®-ABA and Ticusil® from Morgan’s range were developed up to 40 years ago but are still in use today. New alloys are also currently in development to withstand much higher temperatures.
A Never-Ending Journey
Morgan Metals and Joining Center of Excellence in Hayward, California (Morgan in Space)
Much like how there is still so much to learn and explore about space, so too is Morgan’s journey with braze alloys. Morgan Advanced Materials is not just committed to making the space industry more sustainable and safer, but it is helping with applications across all industries.
A key pillar of this is through Morgan’s highly specialized Metals and Joining Centre of Excellence (CoE), based in Hayward, California, as well as Morgan’s Brazing Department.
With highly trained researchers and scientists, Morgan’s Braze Alloys business can custom cater alloys to specific applications, run trials to test materials, braze cycles and fixturing. The whole operation, from powder atomization, to preform fabrication and brazing trials, can be looked after from start to finish.
Flexicore® (Morgan in Space)
One of the latest developments being pioneered at the Metals and Joining CoE is Flexicore®. This new technology transforms traditionally brittle alloys (such as AMS4777) into a flexible wire form. In many cases, this will be far superior to pastes in terms of repeatability and ease of use. Along with the operational benefits, Flexicore® will also allow for the use of nickel-based alloys to replace precious-metal alloys. Again, this will help to bring costs down for operators and manufacturers.
Watch This Space
Space travel, as Richard Branson predicts for his own Virgin Galactic programme, is only two or three flights away. We’re truly not far away from entering a new world, and brazing alloys will have their say on how the space industry turns out.
Morgan’s Braze Alloy solutions, like RI-46 and RI-49, as well as others like Palniro-1 and Palniro-7, can already be found across the various programmes and spacecraft. Through more research and development, who knows where this important industry could lead us to.
Morgan Advanced Materials plc is a global engineering company headquartered in Windsor, UK , and is a world leader in advanced materials science and engineering of ceramics, carbon, and composites, engineering high-specification materials, components, and sub-assembly parts to solve challenging technical problems. Markets that Morgan work in include healthcare, petrochemicals, transport, electronics, energy, defense, security and industrial.
Sourcing activity by users of a leading online platform is up in the category of Aerospace Heat Treating.
Tony Uphoff, President and CEO of Thomas
The recent Thomas Index Report, the online platform for supplier discovery and product sourcing in the US and Canada, focuses on sourcing activity for Aerospace Heat Treating as well as related aerospace categories by users of the Thomasnet.com platform. Besides data for Aerospace Contract Manufacturing,
"[O]ur data shows that sourcing activity is also up 18% or more in the related categories of Aerospace Heat Treating and Aerospace Machining." ~ Tony Uphoff
Space technology has caught the attention of dreamers and investors recently, with the launch of Elon Musk’s SpaceX Crew Dragon capsule, which successfully docked with the international space station, and the restart of the mission to the moon.
A heat treating equipment manufacturer based in Carroll, Ohio, recently announced plans to expand its facility and broaden its capability to produce furnaces for aerospace manufacturers equipping in-house heat treat operations.
Delta H Technologies LLC’s investments will cover the purchase of machinery and equipment for the design and production of furnaces for aerospace components. The expansion confirms the company’s nearly 30-year commitment to providing state-of-the-art heat treat equipment manufacturing to keep pace with the growth in aerospace technology and production.
“Richard Conway, director and chief technology officer, started the company in 1990 while attending Ohio State University to get his bachelors of science in industrial engineering. He did maintenance and tuning work for industrial furnaces and ovens. . . . Richard’s wife, Mary Conway, is a retired teacher who taught honors chemistry and physics at Pickerington North High School. And she was the one who came up with the name Delta H as it is a math symbol for change of heat.” ~ Lancaster Eagle-Gazette
An independent provider of engine and airframe maintenance, repair, and overhaul (MRO) services was recently selected by a Ghana-based airline to provide a tailored package of engine services for its fleet of Q400 regional turboprop aircraft.
Under the multi-year contract, StandardAero, based in Scottsdale, Arizona, will provide MRO services for PassionAir’s Pratt & Whitney Canada (P&WC) PW150A turboprop engines from its Designated Overhaul Facility (DOF) in Seletar, Singapore.
The contract will also authorize StandardAero to provide PassionAir with a range of rental engine, engineering and engine condition trend monitoring (ECTM) support services. StandardAero is uniquely placed to offer ECTM analysis expertise as both a P&WC designated overhaul facility (DOF) and a CAMP Systems Designated Analysis Center (DAC).
Peter Turner, President of Airlines & Fleets for StandardAero
“After evaluating prospective service providers on our shortlist, we are happy to engage StandardAero as the engine maintenance provider for our Q400 fleet,” said Charles Richardson, Director of Maintenance for PassionAir. “We found the engine care package offered to be comprehensive and competitive, and it is my belief and hope that we will experience complete satisfaction with the service and support that we anticipate to receive from them.”
“We are pleased to add PassionAir to the list of Ghanaian operators supported by StandardAero,” said Peter Turner, President of Airlines & Fleets for StandardAero. “PassionAir joins a growing list of customers who benefit from service excellence provided by our start-of-the-art facility in Singapore, backed up by our extensive engineering and ECTM capabilities. We look forward to meeting and exceeding the airline’s expectations for on-time support over the coming years.”
The aerospace team at a heat treating company based in Orange, California, is partnering with NASA to launch manned missions to deep space.
Senator Ted Cruz (R- TX), Chair, Senate Space Subcommittee with Thermal-Vac Administrative Director Heather Falcone after he spoke to suppliers about the commitment to fund deep space exploration in years to come through bipartisan legislation.
Thermal-Vac Technology, which provides brazing, heat treating, and finishing services at its southern California facility, is working with NASA’s exclusive exploration-class space systems: NASA’s Space Launch System (SLS) rocket, Orion spacecraft and the Exploration Ground Systems that launch these vehicles. Thermal-Vac’s aerospace division joins with NASA and aerospace leaders “to return Americans to the Moon and send astronauts to Mars in the early 2030s.”
“Our team is honored to be part of the American efforts to continue being leaders in space exploration,” said Steve Driscol, CEO of Thermal-Vac. “It is a vital part our humanity that we invest in and support these projects to ensure their success now and for years into the future.”
With suppliers in all 50 states, NASA’s journey to deep space is a national effort. 2019 marks the final integration and testing of the rocket and spacecraft leading up to the first integrated launch to the Moon late next year. Aerospace companies across the country are helping to meet NASA’s visionary plan and contribute to America’s unmatched legacy in space.
Photo credit / caption: Thermal-Vac Technology / Eight astronauts from multiple missions to the moon and ISS pose with Congresswoman Kendra Horn (D-OK), Chair, House Space Subcommittee during a reception for SLS-Orion suppliers.
Modern rotary-wing aircraft propulsion systems rely on different types of gears to transmit power from the turbine engines to the rotors. The basic requirements of these gears are that they are high strength, sustain long life, meet weight considerations, and have a high working temperature and low noise and cost, among others.
Most importantly, these gears require a hard, wear-resistant surface with a ductile core.
Gas carburizing is the current heat treat method used to produce these aircraft quality gears, but this method of heat treatment is costly due to the large number of process steps, huge footprints, energy consumption, and environmental issues. Moreover, the final grinding of gear teeth to correct distortion produced during quenching reduces effective surface compressive stresses.
An investigation into low-cost alternatives for surface hardening aerospace spur gears was conducted where specimens of the selected gears were induction hardened using a patented process. Dimensional and microstructural analyses were conducted, and residual stress studies were performed. This article is a summary of the steps and observations of the case study that resulted from this investigation, which can be summarized this way:
The proposed induction process is a low-cost alternative to conventional gas carburization. In some applications, a 25% savings is estimated.
The first step to gear manufacturing demands a total understanding of aerospace gear requirements. As the gear transmits torque, the teeth are subjected to a combination of cyclic bending, contact stresses, and different degrees of sliding or contact behavior. It is, therefore, critical for a gear to have the proper case and core structure to withstand these loading conditions.
With every revolution, a cyclic bending load is applied, resulting in tensile stress at the root region of the gear. The core of the gear has to be soft to absorb impact load and prevent brittle failure. Due to high-speed contact between adjacent gear teeth, peak shear stresses generated at the surface act in the normal direction to the surface. Pitting, spalling, or case crushing types of failures can occur due to low residual stress or inadequate case depth.
For aircraft quality gears, typical surface hardness is around 58Rc to 60Rc. The case depth is in reference to 50Rc and is controlled by diametral pitch.
Carburization
Carburization hardening is the most widely used technique for surface hardening of aerospace quality gears. A brief introduction to carburization is necessary to understand the potential benefits of this process and how other surface transformation can improve on some of the drawbacks of this commonly used process.
After raw material is received, it is forged to achieve proper grain structure and core hardness. The alloy most commonly used is ASM 6260 (AISI 9310). This low carbon alloy steel exhibits high core toughness and ductility.
Parts are loaded in a furnace and heated to 1650ºF – 1750ºF in a carbon rich atmosphere, where approximately 1% carbon potential is maintained. The depth and level of carbon absorption depend on carbon potential, temperature, time inside the furnace, and the alloy content of the material. After the desired carbon gradient is achieved, the gears are cooled slowly. Then the parts are heated to austenitizing temperature and quenched.
The process depends on the size, geometry, dimension tolerances, and other gear requirements.
The heat treat cycles shown above are two commonly used carburization processes. The difference in post carburization steps depends on the alloy used and final product requirement.
The characteristic of carburization is the inherent distortion associated due to the difference in cooling rates between the thin web and thicker rim. Distortion can occur as a size growth, a change in involute profile, or the loss of crown in spur gears.
Case Hardening by Selective Heat Treatment
The number of process steps required to case carburize a gear can be significantly reduced only if the gear tooth surface areas are heat treated.
Processes for locally heating only the tooth surface include induction, flame, laser, and electron beam.
In order to use induction, steel with a minimum of 0.5% carbon must be used. Several different alloy steels were experimented with, such as AMS 6431, AlSl 6150, and AlSl 4350/4360/4370. These steels were selected due to their combination of toughness, temper resistance, hardenability, and strength. The hardened case is obtained by heating a specific volume of the tooth surface above the transformation temperature for that material. Rapid contour heating produced a case of martensitic structure around the profile-hardened area, resulting in high compressive residual stress at the surface at the root fillet. This compressive stress increases the tooth bending fatigue life, where tensile stress exists due to tooth bending.
Transformation hardening allows a significant reduction in process steps and associated fabrication costs, due to two different factors:
Since sufficient carbon is already present in the base material, copper masking, plating, stripping and carburization steps are eliminated.
In selective hardening, the area of the heated zone is limited to only the hardened sections, and distortion is minimal and predictable.
Surface hardening applications are generally controlled by three process parameters, namely frequency, power level, and time. In this respect, several different hardening processes have been used for gear hardening. The proposed method discussed in this presentation is known as Dual Pulse Induction Hardening (DPIH).
DPIH Process
The DPIH is a patented process (U.S. patent #4,639,279). The process uses single frequency for both the preheat and final heat cycles. Two different power levels are used. This allows the entire process to be performed in one setup, using a single solid-state power supply.
The DPIH process consists of the steps described below:
The heat treatment process steps for both the carburized and DPIH processes for the aircraft gear are compared below:
An 85% reduction in heat treat process steps occurs when the gear hardening method is changed from conventional gas carburization to DPIH.
Conclusion:
Comparison of the above data and the conventional carburization process to DPIH process.
Carburizing grade material has to be changed from low carbon to medium carbon steel for induction hardening. In both the processes, surface hardness achieved is comparable, but the characteristic of induction hardening is that the gear section maintains a constant hardness value from the surface up to the transition zone, where it rapidly drops to core hardness levels, unlike a more gradual decrease in hardness in case of carburized gears. Low distortion of induction hardening gear is also a major cost reducing factor.
Acknowledgment:
This work was performed at AGT, Division of General Motors.
Madhu Chatterjee is founder and president of AAT Metallurgical Services LLC in Michigan with extensive experience in advanced engineering, research and development, and process and product improvement. He is also one of the original dozen consultants that inaugurated Heat TreatToday’sHeat TreatConsultants resource page. You can learn more about Madhu Chatterjee here.
Look for more on aerospace heat treating in the upcoming special aerospace manufacturing edition of Heat TreatToday.
A nickel-based heat resistant alloy that is very strong, corrosion resistant, and can be used at temperatures between -422°F and 1300°F has recently been released by a German specialist in custom prototypes and low-volume production parts.
Inconel 718 and Maraging Steel 1.2709 will expand Protolabs’ list of Direct Metal Laser Sintering (DMLS) materials that make up a wide range of metals available for rapid prototyping and the manufacture of functional end-use parts with complex geometries.
The high-temperature strength of Inconel 718 is derived from its ability to create a thick, stable passivating oxide layer at high temperatures, protecting the material from further attack. Inconel, which has good tensile, fatigue, creep and rupture strength, is thus ideal for the aerospace and heavy industries–particularly, in the production of jet engines, rocket engine components, gas turbine parts, instrumentation parts, power and process parts and related equipment that are exposed to extreme environments.
Photo credit/caption: Protolabs/Inconel 718 is a superalloy used in the development of turbojet engines for aircraft, among a variety of other applications.
The demand in aerospace manufacturing for brazing technology is likely to increase as the alloys developed and manufactured through the process are used for more applications — from turbine blades to rocket nozzles to hydraulic assemblies.
“Brazing is used just about everywhere—it’s difficult to classify.” ~ Ed Arata, brazing engineer, Morgan Advanced Materials
Brazing may be difficult to classify, but the process can be explained, and its subsequent value to aerospace design and manufacturing groups is explored in this Best of the Web article from MRO-Network.com
When the U.S. Air Force flies its new advanced pilot trainer from Boeing and Saab, it will be equipped with an ACES 5® ejection seat along with a fully integrated landing gear system.
John “Barney” Fyfe, Air Force programs director for Collins Aerospace
Both will be supplied by Collins Aerospace, the entity that resulted from the recent merging of UTC Aerospace Systems and Rockwell Collins. Collins is a unit of United Technologies Corp, headquartered in Farmington, Connecticut, and provides heat treating capabilities among its high-technology systems and services to the building and aerospace industries.
ACES 5 offers passive head and neck protection, arm and leg flail prevention, and a load-compensating catapult rocket that varies its thrust based on the occupant’s weight. In addition to ACES 5, Collins will supply the aircraft’s fully integrated landing gear system, including structure, actuation, dressings, hydraulics, and wheels and brakes. The system boasts several technological innovations designed to help reduce maintenance costs while improving operational performance.
“Collins Aerospace is honored to be a supplier for Boeing in support of the U.S. Air Force’s next-generation trainer program and proud to provide a host of integral content, including our ACES 5 ejection seat and fully integrated landing gear system,” said John “Barney” Fyfe, Air Force programs director for Collins Aerospace. “Our innovative technologies will play a critical role in helping to keep aircrews safe, reducing maintenance costs, and improving operational performance. Our support for Boeing military aircraft dates back to 1932 with the P-26, and we look forward to continuing to work with the Boeing and Saab team on the T-X program in the years to come.”
