One Minute Mentor: Control of Nitriding Potential at Low Temperatures
March 31, 2017
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The graph shows the case thickness for fluidized-bed nitrided 316L samples after 8 hours of treatment. The treatment temperature must be kept, ideally, below 430°C (805°F). The dissociation of NH3, and thus the nitriding potential, is controlled by the addition of H2, N2, and CH4 (which dissociates into carbon and hydrogen and also promotes nitrocarburizing) in the treatment atmosphere.
The addition of H2 and CH4 decreases the NH3 dissociation, and the addition of N2 increases the NH3 dissociation according to the following relationship:
%N = k[p(NH3)/p(H2)3/2]
where k is the equilibrium constant, and p is the partial pressure of NH3 and H2.
The final result is that, after 8 hours of nitriding treatment, the fluidized bed is able to produce a case approximately 8 µm at its thickest, as shown in the graph. In contrast, plasma nitriding of 316L samples for 8 hours would result in a layer thickness on the order of 18 to 20 µm.
Volume 4D, Heat Treating of Irons and Steels ⇒ Heat Treated High-Alloy Steels ⇒ Nitriding of Stainless Steels ⇒ Thermochemical Nitriding Treatments
The graph shows the case thickness for fluidized-bed nitrided 316L samples after 8 hours of treatment.
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Praxair to apply Tribomet protective coatings to Rolls-Royce jet engine parts
March 30, 2017
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Praxair Inc., Danbury, Conn., announces that its subsidiary Praxair Surface Technologies, Indianapolis, has been awarded a ten-year contract by Rolls-Royce to apply its Tribomet abrasive coatings to rotating components in jet engines for wide-body aircraft. The coatings help prevent frictional heating, increase fuel efficiency ,and extend component life. The project, which will begin in mid-2017, will be serviced from PST's coating operations in Indianapolis and Weston-super-Mare, England.
Tribomet MCrAlY coatings are produced by co-deposition of alloyed powders of specific particle size distribution with nickel and/or cobalt from conventional electroplating solutions, followed by a vacuum heat treatment.
"We are proud to extend our relationship with Rolls-Royce, a leading aerospace producer," said Freddie Sarhan, vice president for the Americas at Praxair Surface Technologies. "This is just the latest example of the type of long-term business relationships we develop with our customers to support their business growth in the United States and around the world. It also further builds on PST's long and successful history of serving the aerospace industry."
"We are very pleased to collaborate with Praxair Surface Technologies, a key supply chain partner, to expand our in-state relationships and contribute to the overall growth of the aerospace sector," said Jeff McInerney, Rolls-Royce vice president of supply chain, Americas.
Rolls-Royce is a major aerospace company in Indiana. However, this contract supports coating operations for Rolls-Royce Crosspointe, a facility located south of Richmond, Virginia, which manufactures engine components for its large Trent engine family.
www.praxair.com
Praxair Inc., Danbury, Conn., announces that its subsidiary Praxair Surface Technologies, Indianapolis, has been awarded a ten-year contract by Rolls-Royce to apply its Tribomet abrasive coatings to rotating components in jet engines for wide-body aircraft.
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Medical manufacturer chooses Ipsen Titan vacuum heat treating system
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Ipsen, Cherry Valley, Ill., recently shipped a Titan H2 vacuum heat-treating system with 2-bar gas quenching to Costa Rica, where it will be used to manufacture surgical components. With its compact dimensions and superior quality, the Titan helps companies accelerate the pace of innovation while satisfying the strict legal requirements of the medical industry. The company also utilized Ipsen's full-scale support offerings with Ipsen U training, a spare parts kit, and installation/start-up support to advance their equipment and maximize uptime.
This standardized vacuum furnace features an 18x24x18-inch all-metal hot zone with a 1000-pound load capacity. It is capable of operating at temperatures of 1000 to 2400°F with ±10°F temperature uniformity.
Equipped with the PdMetrics platform for predictive maintenance – which securely connects to a network of integrated sensors on the furnace to gather and analyze data, run algorithms and provide real-time diagnostics – the Titan furnace provides sophisticated monitoring of critical systems and key parameters that improve the health and integrity of the equipment. They also received a gas backfill reservoir, a loader with a 2000-pound load capacity, and a complete air-cooled, closed-loop water system.
The manufacturer decided to take a proactive approach to preventive maintenance by ordering one of Ipsen's spare parts kits. These kits help ensure equipment uptime and keep the furnace running smoothly. They also opted for technical support and training, including installation supervision, start-up service and seats at Ipsen U – a three-day course that provides a broad overview of furnace equipment, processes, and maintenance using a hands-on approach to learning.
www.IpsenUSA.com/TITAN
Ipsen, Cherry Valley, Ill., recently shipped a Titan H2 vacuum heat-treating system with 2-bar gas quenching to Costa Rica, where it will be used to manufacture surgical components.
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Lindberg/MPH ships gas fired zinc melting, holding furnace for diecasting
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Lindberg/MPH, Riverside, Mich., has shipped a gas-fired melting and holding furnace with a maximum temperature of 850°F for melting and holding up to 45,000 pounds of molten zinc for diecasting. The furnace incorporates seven immersion tubes, each with its own burner and ratio regulator control.
The system is rated at 2,300,000 BTU/hr. The furnace temperature controller includes a PID loop and LED display. The furnace includes an adjacent pump well with stainless steel weir to isolate dross. A splash shield was added to protect combustion piping from molten metal contact. The 180°F exhaust deflector improves efficiency and reduces noise.
"The design of this system facilitates energy-efficient melting and holding of the zinc and precise temperature control. Lindberg/MPH also supplied control and power wiring." – Andrew Paul
This Lindberg/MPH furnace features individually operable spark ignited burners with flame rod flame safety. Each burner has its own gas/air ratio regulator assuring the correct air and gas mixture for dependable ignition and efficient combustion. On-off firing allows for a wide input range virtually eliminating temperature creep.
www.Lindbergmph.com
Lindberg/MPH, Riverside, Mich., has shipped a gas-fired melting and holding furnace with a maximum temperature of 850°F for melting and holding up to 45,000 pounds of molten zinc for diecasting.
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Wisconsin Oven four-zone conveyor furnace heat-treats AR-15 forged aluminum parts
March 29, 2017
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Wisconsin Oven Corp., East Troy, Wis., has shipped a natural gas-fired four-zone solution treatment conveyor furnace for treating forged aluminum parts for AR-15 rifles prior to quenching in water. The maximum operating temperature is 1100°F, and the work chamber dimensions are 4 1/6 ft. wide x 60 ft. long X 1 ft. high.
Each of the four work zones has dimensions of 4 1/6 ft. wide X 15 ft. long X 1 ft. high. The design capacity of the furnace is 1500 pounds per hour of aluminum. The equipment achieves temperature uniformity of +/-10°F at 750°F and 1100°F.
The conveyor furnace shell features "CAN" type, double-wall construction and includes two inches of 14# density high temperature industrial mineral wool insulation, backed with six inches of 6# density, industrial board type insulation, for a total of eight inches. The shell, including the roof, consists of Wisconsin Oven's patented high-efficiency Expandable Surface Design. The solution treatment furnace utilizes a flat wire belt to transfer parts through the work zones.
"Temperature control and uniformity was a critical feature in the design of this system," says Mike Grande, Sales Manager. The equipment achieves the tightest temperature tolerances available in the industry for a furnace of its type."-
The conveyor furnace was fully factory tested and adjusted prior to shipment from our facility. All safety interlocks are checked for proper operation and the equipment is operated at the normal and maximum operating temperatures. An extensive quality assurance check list was completed to ensure the equipment met all Wisconsin Oven quality standards.
www.wisoven.com
Wisconsin Oven Corp., East Troy, Wis., has shipped a natural gas-fired four-zone solution treatment conveyor furnace for treating forged aluminum parts for AR-15 rifles prior to quenching in water.
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Instron website explains new ISO 6892-1:2016 for ambient tensile testing of metals
March 22, 2017
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Instron, Norwood, Mass., reports that the newly released ISO 6892-1:2016 standard for ambient tensile testing of metallic materials provides greater clarity of the major changes that were introduced in the previous version, ISO 6892-1:2009.
The 2009 version of the standard introduced testing rates based on strain rate (Method A). Method A was based on maintaining a strain rate around the area of interest (yield), whereas traditional testing was based on having a constant stress rate during the elastic region (Method B).
As some metals are strain-rate sensitive, Method A provides improved repeatability and allows for more comparable results by reducing the variation of test rates at the time when strain-rate sensitive parameters are determined. The introduction of Method A caused confusion. Many understood this as only being achievable by using equipment capable of closed-loop strain control, but this is not true. It is possible to conform to Method A of ISO 6892-1:2009 by using a constant crosshead speed.
To better clarify, the requirements of Method A, ISO 6892-1:2016 now includes two clearly defined approaches, Method A1 (closed-loop strain control) and Method A2 (constant crosshead separation rate).
The Instron website also features a video that demonstrates the changes.
www.instron.com
Instron, Norwood, Mass., reports that the newly released ISO 6892-1:2016 standard for ambient tensile testing of metallic materials provides greater clarity of the major changes that were introduced in the previous version, ISO 6892-1:2009.
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One Minute Mentor: Nitriding in Fluidized-Bed Reactors at Low Temperatures
March 16, 2017
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In nitriding treatment furnaces, the heating is done electrically, and the fluidizing gas composition is chosen to provide the optimum chemistry for the desired surface treatment (usually a mixture of NH3 + N2, with CH4 added when nitrocarburizing is desired). The granular solid is considered inert and does not react with the part being treated but is fundamental in establishing the fluidized bed and its outstanding properties.
For stainless steel nitriding, treatment temperature must be kept below 840°F to prevent the precipitation of chromium nitride. The lower treatment temperature increases the efficiency of the Cr2O3 barrier against nitriding; even after the acid treatment, there is still some oxide layer left at the steel surface.
The result is lower diffusion rates and lower nitriding potential (less dissociation of NH3, which is the mean supplier of atomic nitrogen needed for the nitriding treatment), as shown in the graph. The NH3 dissociation effect is controlled by changing the composition of the atmosphere, but the oxide layer would dissociate or become permeable only at much higher temperatures, which would cause the precipitation of nitrides and carbides in the case.
Volume 4D, Heat Treating of Irons and Steels ⇒ Heat Treated High-Alloy Steels ⇒ Nitriding of Stainless Steels ⇒ Thermochemical Nitriding Treatments
In nitriding treatment furnaces, the heating is done electrically, and the fluidizing gas composition is chosen to provide the optimum chemistry for the desired surface treatment (usually a mixture of NH3 + N2, with CH4 added when nitrocarburizing is desired).
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Wisconsin Oven composite curing ovens feature temperature uniformity of ±5°F
March 15, 2017
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Wisconsin Oven Corp., East Troy, Wis., has shipped three electrically heated, heavy-duty walk-in ovens with temperature uniformity of ±5°F for composite curing. The maximum temperature rating for each oven is 500°F, with chamber dimensions of 10x24x10 feet. The customer required guaranteed temperature uniformity of ±5°F at 150°F, 250°F, and 350°F, which was verified through a fifteen-point profile test conducted in an empty chamber under static operating conditions.
The composite curing ovens feature combination airflow to maximize heating rates and temperature uniformity. The oven bodies are constructed of tongue-and-groove panels that feature high-efficiency panel seams. These panels provide 25% better efficiency than standard panels.
"For this project, our customer required guaranteed temperature uniformity," says Jim Lucas, Senior Sales Engineer. "Now in use, the customer is very pleased with the consistent uniformity at all three temperature marks."
These composite curing ovens include a reinforced insulated two-inch thick floor with wheel guides; a 35,000 CFM @ 25 HP recirculation blower; and one thermocouple check port and three vacuum ports on the side wall.
The combination airflow provides both horizontal and vertical upward airflow. The digital programmable temperature controller includes Ethernet communications, and the paperless chart recorder has four inputs.
The composite curing ovens were fully factory tested and adjusted prior to shipment. All safety interlocks were checked for proper operation, and the equipment was operated at the normal and maximum operating temperatures. An extensive quality assurance check list was completed to ensure the equipment met all Wisconsin Oven quality standards.
The ovens are backed by Wisconsin Oven's exclusive and unprecedented five-Year WOW warranty. This warranty covers all materials for all components (less wear items).
www.wisoven.com
Wisconsin Oven Corp., East Troy, Wis., has shipped three electrically heated, heavy-duty walk-in ovens with temperature uniformity of ±5°F for composite curing.
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Seco Warwick enables constant control of temperature in multi-chamber heat-treat furnaces
March 14, 2017
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Seco Warwick, Meadville, Pa., announces that its engineering team has designed an innovative way to continuously control the heating and cooling of the entire cycle in multi-chamber heat treating furnaces. The company says that this is a unique technological solution on a global scale that could revolutionize the heat treatment process and exceed the aerospace sector's standards.
"All of our customers set the bar high," says Katarzyna Sawka, Global Marketing Director. "Nevertheless, the aerospace industry sets the bar the highest."
The patented solution, designed to meet the highest AMS standard, is based on thermocouples that move between chambers during the heat treatment cycle. Temperature control is achieved based on a special construction that allows the operator to monitor the temperature in both chambers. This provides full temperature control of the processed parts in multi-chamber vacuum furnaces during the entire process.
The technology has already been successfully implemented in a two-chamber vacuum furnace, the CaseMaster Evolution, which enables precise vacuum case-hardening for the most challenging industries. It has been successful in applications for aerospace, automotive, machinery, wind energy, and commercial heat treating facilities.
In 2016, Seco Warwick received a number of prestigious awards and nominations. The company won the Symbol of Innovation 2016, for implementing research and development projects with technical universities, and for developing an innovative graphene production line. Seco Warwick was also one of the first companies in the world to introduce augmented reality technology into heavy industry (SECO/LENS).
www.secowarwick.com
Seco Warwick, Meadville, Pa., announces that its engineering team has designed an innovative technology for continuous control over the heating and cooling of the entire cycle in multi-chamber furnaces.
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Lucifer Furnaces benchtop furnace heat-treats BeCu pins in nitrogen atmosphere
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Lucifer Furnaces, Warrington, Pa., has shipped a customized benchtop heat-treating furnace to R. Hueter Co., Beverly, Mass., a CNC machine shop, to harden beryllium-copper pins. With a chamber size of 9x12x12 inches, Model 42GT-H12 is insulated with five inches of both insulating firebrick and mineral wool backup. Four kilowatts of power allow fast heat-up to 1200°F.
Hueter plans to use the furnace primarily at around 600°F for two-hour cycles, to achieve a specific Rockwell hardness on small lots of beryllium-copper pins. They will be treated under a nitrogen atmosphere to reduce surface oxidation and achieve a scale-free, bright finish.
The GT ovens, built for operation with an inert atmosphere, are crafted with a continuously welded outer steel shell and gasketed roof plate. A strong seal on the double-pivot door is achieved with a square gasket around the door perimeter to form a tight seal to the oven face-plate. Swing bolts with T handles make clamping easy.
The stainless-steel liner baffles the work chamber from the side wall heating elements, and directs the air flow horizontally through the chamber for uniform heating. Hueter chose a Honeywell DC2500 temperature controller with a soak timer to shut off heating elements at the end of a programmed cycle, in addition to a flowmeter mounted and piped to the oven for easy connection to the atmosphere supply.
www.luciferfurnaces.com
Lucifer Furnaces, Warrington, Pa., has shipped a customized benchtop heat-treating furnace to R. Hueter Co., Beverly, Mass., a CNC machine shop, to harden beryllium-copper pins.
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