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.

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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. 

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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

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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Evolution on the microstructure and mechanical properties of a new multicomponent near-Alpha Titanium Alloy after rolling and heat treatments

Beijing University of Technology, China, presented the microstructure and mechanical properties of a new type of multi-component near-α titanium alloy sheet after rolling, 700°C aging, and 800°C aging in a new paper.

 The results show that the strength of the alloy after aging at 700°C increases from 1156 MPa to 1304 MPa, respectively, but decreases to 1246 MPa with the aging temperature increasing. The ductility of the alloy aged at 700°C is lower than that of the rolled state, but the ductility increases slightly with the aging temperature increasing. The effect of aging heat treatment on the microstructure and precipitation behavior of alloy plates has been studied and compared with alloys before aging. 

After heat treatment, the content of primary α decreases from 25% to 5%, respectively. Two kinds of silicide precipitate at different positions, with the large-size spherical silicide being (Ti, Zr, Nb)5Si3, and the small-size fusiform silicide being (Ti, Zr, Nb)6Si3, respectively. Ti3Al was precipitated in the primary α phase, during the aging process. The silicides exhibit the strengthening effect on the alloy, but the effect weakens when the silicides grow up. The loss in ductility is mainly attributed to the precipitation of the α2 phase after aging treatment. However, ductility is improved after applying higher aging temperatures as the size of the α2 phase becomes smaller, and the distribution of them tends to become dispersed.

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A ‘green’ Seco/Warwick vacuum furnace for wind power plants

Seco/Warwick, Meadville, Pa., has been chosen by a recognized manufacturer of wind power plants to deliver a vertical vacuum furnace designed to perform low-pressure carburizing for the large structural elements (gearboxes) used in wind power plants. 

The solution on order combines the advantages of two technologies: atmospheric and vacuum processing. The furnace is designed for low-pressure carburizing oversized parts, made possible due to a very large, vertical heating chamber, while the furnace pit structure saves space in the production facility. The Pit-LPC technology is a modern alternative to atmosphere carburizing. Its main advantage is the ability to carry out efficient and effective carburizing in a much shorter time than in atmospheric furnaces. The vacuum processing solution provides more than twice the productivity, and consequently lower process costs and a quick investment return.

The main advantage of this furnace is the ability to open the furnace at process temperature at the end of the cycle. This is the advantage of atmospheric furnace technology implemented within a vacuum furnace. This type of solution combines the advantages of an atmospheric furnace with the advantages of a vacuum furnace, which include: elimination of the oxidation effect at the grain boundary, process purity, and heating uniformity. The product solves the problem of high energy and process gas consumption by the partner’s old furnaces, and shortens the carburizing process, which significantly improves efficiency and production costs.

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Lindberg/MPH ships mesh belt conveyor furnace for use with powdered metal

Lindberg/MPH, Mich., has announced the shipment of an electrically heated, full muffle, mesh belt conveyor furnace. This furnace is designed for treating pressed powdered material.

The furnace is designed for applications with a maximum process temperature of 1000° C (1832° F) that utilize a nitrogen or clean dry filtered air process atmosphere. The unit is configured with 9 temperature control zones and includes a water-cooling section. The conveyor system features a 14 inch wide mesh belt with belt stop alarm to provide an audible and visual indication in case of a conveyor stoppage.

There are purge chambers at the entrance and exit of this conveyor furnace. In these chambers purge gas flows from perforated plenum chambers above and below the belt and exhaust stacks with adjustable butterfly valves are located at the inner ends of each chamber. Load and unload tables at the entrance and exit of the conveyor provide ease of product transfer for the operator.

The furnace zone temperatures are controlled by Eurotherm controllers. These controllers have advanced PID control with variable overshoot inhibition. A hi-limit Eurotherm controller guards against over temperature conditions in each zone of temperature control.  A visual and audible alert and removal of power to the heating element occur in the event the monitor temperature exceeds a desired set point. 

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Confluent Medical Technologies announces grand opening of Costa Rica expansion

Confluent Medical Technologies, Scottsdale, Ariz., has announced the grand opening of the latest addition to their large scale manufacturing center of excellence in Alajuela, Costa Rica, expanding their capacity for Nitinol processing and catheter manufacturing.

This new facility will be co-located with the existing Confluent Costa Rica facility and will add an additional 66,000 square feet to this location. The new site greatly expands Confluent’s capacity to process Nitinol components, as well as produce complex catheters using a combination of clean rooms and white-space manufacturing.

“Confluent has experienced consistent and strong growth in recent years,” said Confluent president & CEO, Dean Schauer. “This expansion supports our new product pipeline which continues to grow at a rate greater than Confluent has previously experienced.”

Confluent supports some of the fastest growing medical device markets such as interventional neurovascular, electrophysiology, structural heart, and peripheral vascular. As a result of the double-digit growth of these currently served markets, a substantial number of new products are coming into production and will utilize this new facility space immediately. Additionally, Confluent is considering additional expansion options beyond this new facility.

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