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Tertiary Metallurgy

Tertiary metallurgy

Leybold vacuum solutions are used in the wide field of metallurgy, refining and in all the production steps.

Soluzioni per vuoto affidabili e durevoli, efficienza energetica, design compatto

Traditional steam-ejector vacuum systems have been progressively replaced by more energy-efficient and environmentally-friendly mechanical vacuum systems. Through the development of extremely robust dry compressing screw vacuum pumps (DRYVAC) along with booster pumps (RUVAC WH Line), mechanical vacuum systems are currently the best choice for the producing the highest quality steel with the lowest energy requirements and the most modern industry 4.0 control technology!

Leybold provides mechanical vacuum solutions for secondary metallurgy degassing processes to tertiary metallurgy refining steps and final heat treatment processes of machined metals in all vacuum-required processes. (RH; VIT; RHO; VID; VD; VCD; VMD; VAD; VD-OB; VOD; VODC; AOD-Metallurgy)

Secondary steelmaking involves refinement of the crude steel resulting from primary metallurgical production steps. The various operations are normally performed through the use of ladles. In secondary metallurgy, alloying agents are added, dissolved gases in the steel are lowered, carbon content is reduced and inclusions are removed or chemically altered to ensure that high-quality steel is produced after casting. Many process steps are performed under vacuum which is necessary for ensuring the highest quality steel.

We are a supplier of vacuum pumps, systems and accessories for nearly every application. Our vacuum solutions are used in metallurgy, refining and all production steps. Using standard Leybold components such as DRYVAC-, RUVAC WH serial vacuum pumps guarantee robust and long-lasting pump performance. Leybold’s modular and compact steel degassing system design offers the most optimal footprints, service requirements and modern 4.0 Industry standards! The use of just three pump sizes for producing fore-vacuum and high-vacuum reduces service costs and allows an easy exchange or extension of system modules! Three powerful pump stages produce vacuum performance in the lowest pressure range (< 1 mbar) and the use of additional high vacuum pumps such as oil-booster pumps enable approximate pressures of < 0.01 mbar!

 

Our vacuum solutions feature a durable and reliable design. Their proven performance makes them perfect for demanding tertiary metallurgy applications.

Varianti del processo di degasaggio in siviera, processi sottovuoto e spurgo, processi dinamici e statici

RH (RHO) - Ruhrstahl-Heraeus o Ruhrstahl-Heraeus-Oxygen

The melt is suctioned via an immersed up-pipe into the evacuated reactor vessel and flows back into the ladle via a down-pipe. The injection of argon into the up-pipe accelerates the melt and maintains its circulation, which gives the RH-process its alternative name of “Vacuum Circulation Process”. “RH Process”, however, was more commonly used due to its optimal use argon which resulted in better degassing as well as efficient decarburization without requiring the special performance of the vacuum pumps. Leybold-Heraeus produced the first mechanical vacuum system for carrying out this innovation process in the 1960s!

VIT - Colata in lingottiera sottovuoto

The process in which the degassed stream jet is collected in an ingot mold. Vacuum Ingot Teeming is still used for the largest forge ingots of 150t to 600t. Besides hydrogen, nitrogen and oxygen are removed, the latter via the formation of CO.

VD - Degasaggio sottovuoto

A boundary layer phenomenon which occurs at the interface between the molten steel and the reduced-pressure atmosphere. Effective vacuum degassing depends upon sufficient exposed surface area of the molten steel. Vacuum degassing systems employ various methods to maximize this surface area.

VAD VHD - Degasaggio ad arco sottovuoto (riscaldamento)

Arc heating is only possible under rough vacuum (> 600hPa). At lower vacuum pressures, the arc becomes too long. The VAD or VHD plants with arc heating combine both processes, i.e., heating and degassing within same station. This compact layout has since been replaced by the combination of LF and VD.

VCD - Disossidazione del carbonio sottovuoto

Degassing and natural decarburization of semi-killed melts. Metallic deoxidization a is method of deoxidization which involves adding specific metals to the steel. These metals react with the unwanted oxygen, forming a strong oxide which, compared to pure oxygen, reduces the steel's strength and quality by a lesser amount.  

VD - Disossidazione sottovuoto

A method which involves using a vacuum to remove impurities. A portion of the carbon and oxygen in the steel reacts, forming carbon monoxide. CO gas floats up to the top of the liquid steel and is removed by a vacuum system.

VMD - Distillazione del metallo sottovuoto

VMD technology is a metallurgical process under conditions of lower than 1 (NOTE: MEASUREMENT UNIT SEEMS TO BE MISSING HERE?) atmospheric pressure to ultra-high vacuum. It essentially uses the difference of the boiling point and saturated vapor pressure between elements to separate, purify and refine the matter to a certain temperature and vacuum.

VD-OB - VD - Soffiatura di ossigeno

Degassing and forced decarburization or chemical heating. Oxygen blowing is a method of steelmaking where oxygen is blown through pig iron to lower the carbon content. Oxygen forms oxides with the unwanted elements, such as carbon, silicon, phosphorus and manganese, which appear from various states of the manufacturing process.  A VD/VD-OB plant produces steel with low hydrogen and low sulphur content, e.g., for pipeline applications (HIC resistant steel) and high strength steels as well as for ultra-low carbon (ULC) steels.

VOD - Decarburazione dell'ossigeno sottovuoto

Forced decarburization of high chromium melts. The VOD process (Vacuum Oxygen Decarburization) is a decarburization process for RSH steels in which the carbon dissolved in the liquid steel is converted into carbon monoxide by inflated oxygen. This rises to the surface of the bath, leaving the liquid steel due to low pressure. The vacuum environment is created in this way by further treating the ladle with the liquid steel alloy in a vacuum vessel. Burn-off of the alloying elements is minimized under these conditions, and the lowest harmful hydrogen contents are achieved.

Pompe per vuoto per processi di fusione VIM e VAR

VIM - Fusione a induzione sottovuoto

Used to produce stainless steels, VIM involves the melting of metal via an electromagnetic induction field under vacuum. The induction furnace is located inside a vacuum chamber, and the melted metal is refined under vacuum until the precise melt chemistry is achieved. Impurities are then removed via chemical reactions, flotation, disassociation and volatilization. The VIM process is used to produce stainless steel, superalloys and magnetic and battery alloys. 

VAR - Rifusione ad arco sottovuoto

Continuous remelting of a consumable electrode via an arc under vacuum to remove impurities and prevent from oxide formation. High vacuum is maintained during the melting process to remove impurities and prevent oxide formation. The VAR process is used to improve standard air-melted or vacuum induction melted ingots in order to produce clean, homogeneous metals with improved fatigue resistance and fracture strength.

Sistemi DRYVAC e RUVAC per pre-vuoto

DRYVAC/RUVAC systems are robust, reliable, durable and ready to meet the most stringent process requirements. They’re ideally suited for demanding industrial applications and consist of a smart system with integrated power electronics and monitoring devices for the purge gas system. Standard systems, equipped with state-of-the-art mechanical pumps, feature the following:

  • Pumping speeds of 450 to 7,000 m3/h
  • Ultimate pressures as low as 10-3 mbar
  • Flexible modular systems
  • Easy adaptation to customer needs
  • Energy efficient, cost effective
  • Long lifetime of seals, bearing and gear oil via an intelligent purge gas system
  • Minimized annual maintenance
  •  World-wide service support

Vuoto alto per processi VIM o VAR

Oil Booster high vacuum pumps provide the best vacuum performance in their class with a pumping speed 6,000 to 18,000 l/s and an operating range of 10-1 to < 10-4 mbar. They feature optimum pumping speeds in the pressure range of 1 to 10-3 mbar. The EEC (Energy Efficiency Control) unit guarantees optimized power consumption in relation to perfect conditions for pump performance and oil temperature.

  • Highly robust and reliable
  • Modular design
  • Easy to service
  • The modern EEC communicates with PLC and
  • Achieves reductions in cost of up to 30% through energy savings and increased lifespans for oil and heating cartridges

Problemi dei sistema per vuoto

  • Dust in the process gas
  • Residual humidity and aggressive gases
  • Process pressures of 10-4 mbar l/s, depending on the alloy
  • High gas inlet temperatures
  • Process pressures of 10-4 mbar l/s, depending on the alloy
Vacuum Systems for Tertiary Metallurgy

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Mechanical Vacuum Systems

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Heat Treatment Furnaces

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