OMM: Controlled Atmosphere Furnaces

In the past, atmospheric furnaces were used quite often for heat treatment of tool steels. Due to the improved furnace technology of vacuum furnaces and their increased distribution in the market, the percentage of tools heat treated in atmospheric furnaces has fallen significantly over the last 20 to 30 years.

Furthermore, most of the atmospheric furnaces show a maximum temperature of 1100 °C (2000 °F). Therefore, the application of atmospheric furnaces is limited, with the maximum hardening temperature of the tool steel at or below 1050 °C (1925 °F).

However, for atmospheric furnaces it is essential to select an atmosphere that will protect the surface of the tool steel against the addition or the depletion of carbon during heat treatment. Therefore, it is desirable to choose one that requires no adjustment of composition to suit various steels. Ammonia-based atmospheres meet this requirement due to the ammonia dissociation at high temperatures, leading to an excess of hydrogen with the advantage of a sufficient reduction of oxidation even of high-chromium steels.

For more information, click on the link below (subscription required). Then scroll to Figure 4.

R Schneider; R. Mesquita; W Schützenhöfer, Distortion in Tool Steels, ASM International, 2014, https://doi.org/10.31399/asm.hb.v04d.a0005958

Nanoindentation testing results found inconsistent

Nanoindentation testing is a high-precision indentation test technique that has advantages for nondestructive testing. However, researchers found that when testing the same sample with different Berkovich indenters, inconsistency still arises even if the indenters are regularly calibrated. This inconsistency poses challenges in accurately testing material hardness and comparing data from different laboratories.

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Fusion power breakthrough successfully repeated

For the second time, U.S. researchers have achieved net energy gain in a nuclear fusion reaction. The amazing feat, which uses lasers to fuse two atoms, brings investigators one step closer to discovering a near-limitless, safe, and clean source of energy.

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One Minute Mentor: Distortion in Tool Steels

Distortion in tool steels encompasses all irreversible dimensional changes. There are two main types: size distortion and shape distortion. Size distortion involves expansion or contraction in volume or linear dimensions without changes in geometrical form. Shape distortion entails changes in curvature or angular relations, as in twisting, bending, and/or nonsymmetrical changes in dimensions. In most cases both types of distortion occur during a heat-treatment operation.

Some of the main interactions occur between temperature, microstructure, and stress/strain. Especially for tool steels these interactions are mainly influenced by the carbon content in the steel matrix, the types and relative amounts of the alloying elements, and the carbide formation/transformation/precipitation characteristics of the alloy system.

For more information, click on the link below (subscription required). Then scroll to Figure 1..

R Schneider; R. Mesquita; W Schützenhöfer, Distortion in Tool Steels, ASM International, 2014, https://doi.org/10.31399/asm.hb.v04d.a0005958

One Minute Mentor: Plasma Nitriding Equipment

Cold-walled (double-walled water-cooled) systems were the first generation of plasma nitriding furnaces. This technology is also a vacuum-based process but employs the principle of glow discharge to provide energy for heating and nitriding at one time. Therefore, the independent control of the temperature stability and the nitriding intensity is not possible because both processes are using the same energy source—the plasma.

The hot-wall plasma nitriding furnaces, the next generation of cold-wall ion nitriding systems, are mainly used and built now. This system ensures optimal nitriding quality by fulfilling the highest demands on temperature and nitriding process control. The big advantage of this technology is the separation of the control of the heating and the plasma nitriding parameters. 

For more information, click on the link below (subscription required). Then scroll to Figure 26

R Schneider; R. Mesquita; H. Altena; T. Müller; P. Seemann, Processes and Furnace Equipment for Heat Treating of Tool Steels, ASM International, 2014, https://doi.org/10.31399/asm.hb.v04d.a0005958

Spray Tips: Spray drying

Spray drying, a method that rapidly dries aqueous or solvent-based solutions or slurries to particulate form by atomizing the liquid in a heated chamber, can be used to agglomerate fine powders and is an important method for the dehydration of fluid foods, such as milk, coffee, and egg powder extensively used in the pharmaceutical and chemical industries.

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Constellium to sell three german extrusion plants to Vaessen Aluminium

Constellium, Paris,  announced that it signed a binding agreement with Vaessen Aluminium for the sale of three of Constellium’s soft alloy extrusion facilities located in Landau, Crailsheim and Burg in Germany for a total cash consideration of €48.8 million.

With nearly 450 employees, the three Constellium plants specialize in soft alloy extruded products for the Building & Construction, Transportation and Industry markets in Europe.

Vaessen Aluminium belongs to a longstanding family-owned industrial group, headquartered in Belgium, active in aluminum billets and profiles (E-Max), in lighting and ceiling (Kreon) and in wall cladding (Limeparts Drooghmans).

The transaction is expected to close in the second half of 2023 and is subject to customary closing conditions and regulatory approval.

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Seco/Warwick delivers Vector vacuum furnace to revolver manufacturer

Seco/Warwick, Meadville, Pa.,  received another order for the supply of a Vector vacuum furnace to a South American international manufacturer of weapons and military equipment. The furnace will process various components including barrels, reels, locks, and firearm magazines, which are expected to be reliable, of the highest quality, and perform with outstanding resistance to negative external conditions.

This will be the second solution of this type in the South American defense industry leader’s internal hardening plant. It is a single-chamber gas-cooled vacuum furnace which can be used for a variety of metal heat treatment processes and applications. This solution has been adapted to the customer’s requirements so that it is as effective as possible at delivering the precision heat treatment results required for quality weaponry.

Thanks to the large working space (900x900x1200 mm), the Vector system is designed to process quite large elements. A characteristic feature of the design is convection heating, which improves heat transfer efficiency when heating at lower temperatures, and directional cooling, which enables differentiated cooling of problematic parts in terms of shapes.

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Lehigh’s summer engineering institute students tour Solar Atmospheres

Solar Atmospheres, Souderton, Pa., hosted over 40 high school students enrolled in the Summer Engineering Institute (SEI) at Lehigh University. The SEI program, under the guidance of Director Dr. Laura Moyer, is a two-week residential program, running two sessions back to back. 

Students are nominated by faculty of local high schools, and the program specifically targets under-represented groups including girls, first-generation students, and students who might otherwise have limited opportunities to study in the fields of science, technology, engineering, and math (STEM).

Solar Atmospheres provided a tour of the campus, exhibiting materials and processes for intriguing applications in a variety of markets. The students experienced a manufacturing setting encompassing related topics from their curriculum, gaining a better understanding of heat treating and manufacturing, and how cutting edge technology reshapes centuries-old processes.

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Deep learning uses surface image to look inside

According to researchers at Massachusetts Institute of Technology (MIT), Cambridge, Mass., engineers may now be able to figure out what’s going on inside a part—from an airplane wing to a medical implant—simply by observing properties of the material’s surface.

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Nitrex provides nitrocarburizing system to New Zealand heat treater

Nitrex, Quebec, has announced that they have provided a nitrocarburizing system to Heat Treatments, a leading provider of commercial heat treatment services in New Zealand and one of Nitrex’s earliest customers.

Heat Treatments’ partnership with Nitrex dates to 1992 when they purchased its first Nitrex system with Nitreg nitriding capabilities. As operations grew, the company later added a second system in 2004 for nitrocarburizing and post-oxidation treatments. Contrary to the first two systems, which are identical pit furnaces, the latest addition, an NXK series, features the furnace and control panel mounted on an integral platform. Delivery, installation, and startup time and costs are reduced with this design. The NXK-812 model is designed to treat workloads weighing up to 1200 kg, with a diameter of 800 mm (31.5″) and a height of 1200 mm (47.25″). The system is equipped with advanced process technologies, including Nitreg-C controlled nitrocarburizing and ONC post-oxidation, which provide precise control and consistent results.

https://www.nitrex.com/