One Minute Mentor: The Passive Layer in Stainless Steels
December 1, 2016
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The presence of chromium causes the buildup of a chromium oxide layer that is impermeable and adherent to the alloy substrate, protecting it from any further oxidation or corrosion. Any scratch on this protective layer exposes the substrate to oxygen, and a new protective oxide layer is produced.
One important aspect of this layer is that it must be homogeneous throughout the surface of the alloy. Any differences from place to place could generate a difference of electrochemical potential, which could trigger a corrosion process.
Under normal conditions, the thickness of the protective passive layer is in the range of 1.5 to 2.5 nm, composed mostly of chromium oxide/hydroxide and iron/iron oxide. The strong affinity of chromium for oxygen promotes a very stable compound (Cr2O3) that suppresses any other reactions and thus stops corrosion.
The chemical stability of the passive layer depends on the type of surface-finishing treatment. Processes such as electrochemical polishing increase the surface concentration of chromium, promoting a thicker and more stable passive layer when compared to mechanically processed surfaces
Volume 4D, Heat Treating of Irons and Steels ⇒ Heat Treated High-Alloy Steels ⇒ Nitriding of Stainless Steels ⇒ Stainless Steels
The presence of chromium causes the buildup of a chromium oxide layer that is impermeable and adherent to the alloy substrate, protecting it from any further oxidation or corrosion.
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MTS electrodynamic test systems feature intuitive and energy-efficient operation
November 26, 2016
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MTS Systems Corp., Eden Prairie, Minn., offers Acumen electrodynamic test systems, which are streamlined, highly intuitive platforms for dynamic and static testing of materials and components. Acumen test systems provide the flexibility of electrodynamic actuation, giving test professionals an easy and energy-efficient way to expand in-house test capabilities with minimal impact in the lab.
Each system features excellent lateral stiffness, highly rigid load frames, a unique high-performance direct-drive motor, and an industry-leading load cell. They provide integrated tools for highly precise load and motion control, no matter which frame is chosen.
Unique integration with MTS TestSuite Multipurpose Software also enables automatic setup, smooth task flow, simplified actuator control and intuitive limit setting, reducing the risk of human error.
Tests include fatigue and fracture, component strength and durability, tension, compression, flex/bend, and FDA regulatory tests for biomaterials and components. Equipped with a Bionix EnviroBath, MTS Acumen test systems enable efficient, accurate testing of biomedical and general material specimens in fluids heated to body temperature.
MTS Acumen test systems consume far less energy than other technologies. They can be installed rapidly, without the need for hydraulic pumps or related infrastructure. All that is needed is a single conventional electrical outlet, and once installed, they provide clean, quiet, and extremely cost-effective operation.
Designed for safe, user-friendly operation, the instruments include a standard T-slot table, an optional integrated enclosure, streamlined cabling, and a universal power supply. They perform consistently and accurately, test after test, yet they require very little maintenance.
http://www.mts.com/acumen
MTS Systems Corp., Eden Prairie, Minn., offers Acumen electrodynamic test systems, which are streamlined, highly intuitive platforms for dynamic and static testing.
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Electric pit furnace features two-stage gas nitriding system for high hardness
November 23, 2016
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Lindberg MPH, Riverside, Mich., has shipped an electrically heated gas nitriding pit furnace with an ammonia dissociator system for heat treating steel parts. It features a two-stage nitriding process to achieve high surface hardness. The ammonia dissociator provides dissociated ammonia during the nitriding cycle second stage. All of the equipment needed has been provided with the system, and is backed by the installation and start-up support of knowledgeable service personnel.
The cylindrical pit furnace has a maximum temperature rating of 1250°F and work chamber diameter of 28 inches and depth of 36 inches. A state of the art operator interface controls process parameters and is used to observe/archive historical data. The system monitors and controls the furnace temperature, fan speed, atmosphere flow, and cooling throughout the entire cycle. Accelerated cooling cuts down on overall cycle time. The advanced control system solves the problems of controlling furnace atmospheres, storing batch data, tracking alarm trending, and complying with AMS2750E specifications.
Unique features include low iron brick insulation to prevent reactivity with furnace atmosphere; heater coils designed with low surface watt density for extended service life; and a thermocartridge fan for increased heat and atmosphere recirculation. A nitriding gas flow control system has full automatic recipe control for each stage of the two-stage nitriding process.
Lindberg MPH is owned by Thermal Product Solutions, a leading American manufacturer of custom industrial ovens for heat treating, finishing, drying, curing, manufacturing automation and process control. TPS is a global leader in thermal processing products and test solutions with brands including Baker Furnace, BlueM, Gruenberg, Tenney, Lindberg MPH, and Wisconsin Oven.
www.lindbergmph.com
Lindberg MPH, Riverside, Mich., has shipped an electrically heated gas nitriding pit furnace with an ammonia dissociator system for heat treating steel parts.
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Lucifer Furnaces dual-chamber furnace heat treats CPM high speed steel
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Lucifer Furnaces, Warrington, Pa., reports that it has delivered a dual-chamber high-temperature furnace to Compacting Tooling Inc., McKeesport, Pa., to heat treat Crucible particle metallurgy (CPM) high speed steel tooling. Powered with 42 kW, this furnace is ideal for heat treating high-speed steel, as it reaches 2450°F in the upper chamber and 1200°F in the lower tempering oven.
A combined 6.5 inches of ceramic fiber modules with mineral wood backup insulation allows for faster heating/cooling cycles. Silicon carbide heating elements operate off-the-line through an SCR power supply with a current limiting circuit that automatically adjusts the voltage to elements as their resistance increases, resulting in longer element life.
Heat treating recipes can be stored in the Honeywell digital temperature controllers with a seven-day timer. High limit controllers were added for safety.
CTI, an ISO 9001-2008 certified shop, is a specialized Tool & Die company manufacturing high-quality tooling for the powder compaction industry. CTI does most of its heat treating in-house for faster turnaround. This furnace will supplement the other Lucifer furnaces currently in use.
www.luciferfurnaces.com
Lucifer Furnaces, Warrington, Pa., reports that it has delivered a dual chamber high-temperature furnace to Compacting Tooling Inc. (CTI), McKeesport, Pa., to heat treat Crucible particle metallurgy (CPM) high speed steel.
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Harper rotary furnace processes iron phosphate powders for lithium-ion batteries
November 22, 2016
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Harper International, Buffalo, N.Y., has been awarded a contract for a high-volume rotary furnace system for drying and calcining advanced iron phosphate powders for lithium-ion batteries at Prayon Technologies, Belgium. Iron phosphate powder is a key component of lithium iron phosphate (LiFePO4) cathode materials used in rechargeable batteries for electric vehicles, and is a part of Prayon's recently announced new plant investment to supply the lithium-ion battery market.
The gas-fired Harper rotary kiln will support high volume operations with features to maximize Prayon's production, including advanced tube features to provide enhanced reaction kinetics, gas-tight and dust-tight design, and internal heat recovery within the furnace chamber to improve energy efficiency.
Prayon collaborated with Harper through the Ignite process during the development phase by supporting scale-up planning and analysis. The Ignite program offers scale-up expertise and testing resources to help minimize risk and maximize efficiency for pilot and production level outputs.
"Harper is focused on supporting the next generation of materials in advanced markets, and this project for the lithium iron phosphate market is a great representation of that," commented Brian Fuller, Sales Manager for Harper International. "The material is an ideal solution for many of today's most advanced technologies for electric power and storage battery systems, and we are proud to be a part of Prayon's solution to supply this market."
www.harperintl.com
Harper International, Buffalo, N.Y., has been awarded a contract for a high-volume rotary furnace system for drying and calcining advanced iron phosphate powders in lithium-ion batteries by Prayon Technologies, Belgium.
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Arconic’s aluminum Micromill technology wins R&D 100 award
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Arconic (formerly Alcoa), Pittsburgh, announces that R&D magazine has named Arconic's aluminum Micromill technology an R&D 100 Award winner. The technology reduces the production time to create rolled coil from hot metal from 20 days to 20 minutes. The Micromill's unique production process significantly changes the microstructure of the metal, allowing for higher formability, greater strength, and lighter weight at the same time. It produces metal that is 40% more formable and 30% stronger than today's incumbent automotive aluminum alloys, while meeting stringent surface quality requirements.
Automotive parts made with Micromill material are twice as formable and at least 30% lighter than parts made from high-strength steel.
"Arconic's Micromill material offers a unique combination of strength, weight reduction, and increased formability that was previously impossible," says Ray Kilmer, Arconic Chief Technology Officer. "Bringing these material benefits together changes the paradigm for auto makers, offering them unparalleled design freedom."
Micromill material debuted on Ford's best-selling vehicle, the 2016 F-150, and Ford continues to collaborate with Arconic under a joint development agreement announced last year.
Arconic received an R&D 100 Award in 2014 for its A951 bonding technology that enabled the historic shift to aluminum-intensive vehicles. Arconic estimates that it will grow its automotive sheet revenue approximately sixfold, from $229 million in 2013 to $1.3 billion in 2018.
This year's R&D 100 Awards were presented during the R&D 100 Conference in Washington, D.C., where top innovators in the R&D community come together each year to review the developments of the past year, provide insight into future forecasting, and foster a collaborative environment to share ideas and network with industry peers.
www.arconic.com
Arconic (formerly Alcoa), Pittsburgh, announces that R&D magazine has named Arconic’s aluminum Micromill technology an R&D 100 Award winner.
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All-Metal Planes for Coast-to-Coast Transport
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Classic article from July 1933 Metal Progress
Classic article from July 1933 Metal Progress
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Computationally Optimized Heat Treatment Process wins R&D 100 Award
November 18, 2016
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The National Energy Technology Laboratory (NETL), Pittsburgh, announces that its Computationally Optimized Homogenization Heat Treatment Process has been named a winner of the 2016 R&D 100 Awards. NETL's technology provides an easy method to optimize heat treatment to achieve the required degree of homogenization with a minimum of furnace time.
Conventional processes for homogenizing metal alloys are trial-and-error in their approach, resulting in increased process cost and limits to the possible paths that may be explored. The primary application for this technology is for alloys that are exposed to extreme environments, including heat-resistant alloys or those needing corrosion/oxidation resistance. A properly homogenized alloy will not only function better, but also will have an extended life cycle.
During solidification of any alloy, the elements segregate unevenly. This chemical segregation is unavoidable and results in non-uniform regions that negatively impact mechanical and physical properties. Even distribution of the alloying elements is necessary to achieve optimal performance for the specified application.
The computational approach to homogenization is based on kinetics of the chemical diffusion coefficient of each element to determine the homogenization cycle necessary to evenly distribute the elements that are susceptible to segregation. Conventional homogenization processes rely on a trial-and-error approach that results in the need for more experimentation and analysis. If the selected times and temperatures do not achieve the correct degree of homogenization, additional experimentation become necessary.
The Computationally Optimized Homogenization Heat Treatment Process is designed especially for alloys exposed to extreme environments, including heat-resistant alloys and those that require corrosion/oxidation resistance. Such alloys are typically in industries that service the aerospace, military, petrochemical, power generation, nuclear, structural, automotive. and instrumentation sectors.
www.netl.doe.gov
The National Energy Technology Laboratory (NETL), Pittsburgh, announces that its Computationally Optimized Homogenization Heat Treatment Process has been named a winner of a 2016 R&D 100 Award.
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Customized MetalMaster heat treating furnaces process a range of materials
November 17, 2016
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Ipsen, Cherry Valley, Ill., announces that in the past few weeks it has shipped five customized MetalMaster vacuum furnaces to companies in locations around the world: Washington, South Carolina, Mexico, and China. Comprised of both horizontal- and vertical-loading systems, these shipments will be used to process parts for the commercial heat treating and aerospace industries .
The customized furnaces also vary in size, ranging from 36 x 48 x 30 inches with all-graphite hot zones and a 2000-pound load capacity, all the way up to a 72 x 156 x 92-inch all-metal hot zone with moly heating elements and a 20,000-pound load capacity. These heat-treating systems are also capable of providing tight temperature tolerances with DigiTrim controls settings, while meeting applicable AMS 2750E requirements.
The MetalMaster furnace design has demonstrated ultimate performance and reliability for more than 45 years, with 500+ installations worldwide. It delivers the cleanliness and uniform cooling that customers request, while also providing a cost-effective, versatile, and adaptable vacuum furnace system.
MetalMaster furnaces may also be ordered with several high-productivity options such as Specialized instrumentation; Increased pumping capability; and Material handling systems.
www.IpsenUSA.com/MetalMaster
Ipsen, Cherry Valley, Ill., announces that in the past few weeks it has shipped five customized MetalMaster vacuum furnaces to companies in locations around the world: Washington, South Carolina, Mexico, and China.
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One Minute Mentor: Effect of Cold Work on Grain Growth
November 14, 2016
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Larger amounts of cold work refine the grain size during solution treatment, but smaller amounts of cold work can lead to critical grain growth. The effect of varying amounts of cold work on grain growth in A-286 during solution treating is illustrated in the graph.
The initial material was solution treated with a maximum grain size of ASTM 5. Cold working in the range of 1 to 5% caused excessive grain growth during subsequent solution treating at 1650°F. Above about 5% of cold work, critical grain growth does not occur, and the recrystallized grain size decreases with increasing cold work. Excessive grain growth, especially excessive localized grain growth, would likely degrade tensile properties.
Therefore, on parts subjected to cold or hot work prior to solution treating, the critical amount of work (about 1 to 6% cold work, depending on the alloy, and about 10% hot work) must be exceeded in all areas to avoid the growth of abnormally large grains. This rule applies to parts such as cold-headed bolts, spun or stretch-formed sheets, and parts formed by simple bending.
Volume 4D, Heat Treating of Irons and Steels ⇒ Heat Treated High-Alloy Steels ⇒ Heat Treating of Precipitation-Hardenable Stainless Steels and Iron-Base Superalloys ⇒ Iron-Nickel Precipitation-Hardenable Superalloys
Larger amounts of cold work refine the grain size during solution treatment, but smaller amounts of cold work can lead to critical grain growth.
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