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Secondary metallurgy

Metallurgy
Innovative and efficient liquid steel refining

There are various types of plant concepts for the secondary metallurgical refining of liquid steel available from SMS group. These state-of-the-art production tools enable you to meet today's and tomorrow's demands for final product quality. Following your specific requirements, we design tailor-made solutions that accomplish your metallurgical, logistics, and productivity operations.

Concepts

RH (Ruhrstahl-Heraeus) Process Recirculation degassing

The RH (Ruhrstahl-Heraeus) or recirculating degassing process is one of the partial degassing processes.

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Recirculation degassing

Our RH process offers you distinctive benefits:

Excellent degassing

Removal of hydrogen from liquid steel in a short time

Outstanding decarburization

Fast, reliable and reproducible achievement of lowest carbon contents for the production of thin sheet to produce DDQ and EDDQ (Deep Drawing and Extra Deep Drawing Quality)

Low temperature losses under vacuum

To minimize temperature losses of the circulating steel, the vacuum vessel is preheated. The ladle top slag on the liquid steel remains completely closed and insulated against heat losses during the vacuum treatment.

Short treatment times

The RH process enables a high throughput of lift gas and thus a high steel circulation rate. The bath surface directly exposed to the vacuum is as large as possible due to an optimized vessel design, thus making optimum use of the reaction space: This results in intensive metallurgical reactions and short treatment times. For this reason, the RH process is particularly suitable for converter steelworks with short cycle times and for long continuous casting sequences with correspondingly short casting times.

No extra ladle freeboard

A vacuum treatment in which the mass transfer surface is outside the ladle does not require an additional ladle freeboard. This applies in the case that the amount of alloying elements added... and leads to maximum productivity for a given ladle design.

No ladle plugs required

The special feature of the RH process is that the inert lift gas is injected directly into the RH snorkel. This means that no bottom purging plugs are required in the ladle during the RH process. In case of a downstream atmospheric treatment, ladle purging plugs can be switched on. This is done by using purging equipment typically belonging to the plant, which is located upstream of the RH unit.

Atmospheric and vacuum process technologies

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Atmospheric processes

SMS group's atmospheric ladle treatment processes are used to set the optimum temperature and chemical analysis of the steel as precisely as possible prior to vacuum treatment or casting. In order to increase the steel temperature, heating can be achieved either by an electric arc with electrical energy or by an oxidation reaction with chemical energy. Slag formers and alloying elements can be added under almost inert conditions if required. The most important units in atmospheric processes are ladle furnaces, chemical heating stations and ladle treatment stations.

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Vacuum processes

In the last 20 years two processes have established themselves at the top of secondary metallurgical vacuum processes: the RH process with the variants RH-TOP (Temperature-Oxygen-Powder) and RH-OB (Oxygen Blowing) as well as the VD process (Vacuum Degassing) with the variants VD-OB and VOD (Vacuum Degassing + Oxygen Blowing or Vacuum Oxygen Decarburization). In VD-OB and VOD processes, oxygen blowing lances are additionally used either to optimize the C-O ratio during decarburization or to blow carbon out of the steel as CO with the aid of oxygen.

In the RH process a stream of liquid steel is continuously circulated under vacuum between vacuum vessel and ladle and undesirable elements are removed via the gas phase.

In the VD process, the entire ladle is placed under vacuum in a tank that is vacuum-tightly closed, and steel circulation within the ladle is enabled by bottom stirring through porous plugs in the ladle bottom.

The RH and RH-TOP plants from SMS group are typically installed in steel making plants with batch sizes from 80 to 400 tons. VD and VD-OB plants typically cover batch sizes from 20 to 350 tons, VOD plants from 10 to 180 tons. RH plants and VD plants can be used in both electric and converter steelworks. VOD plants are required in stainless steel production to achieve particularly low carbon contents in an economical way.

Technology

Advanced steel quality A package of superior solutions

SMS group's program covers the complete range of technologies and services for advanced steel quality. This package of metallurgical solutions is an important factor in helping to continuously deliver products with superior benefits for the final customer. These true assets give you maximum capacity and flexibility in constantly supporting leading industries with the most appropriate advanced steel quality. And the demand for quality steels in future-oriented markets is growing.

We coordinate each component of your metallurgical plant individually with you and adapt it accordingly. Our total commitment to technology and services contributes to your competitiveness.

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CMS

CMS stands for Condition Monitoring System. In vacuum metallurgy, it is used primarily for the optimized monitoring of vacuum systems.

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TOP lances

Multi-functional TOP lance systems are indispensable for efficient and cost-effective RH operation.

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Ladle handling

Optimized ladle handling from arrival to departure is as important as the vacuum treatment itself.

To immerse the immersion tubes in the liquid steel, either the treatment ladle must be raised or the vacuum vessel lowered. Systems for lifting the ladle are used in systems with fixed vacuum vessel. This is the majority of the RH plants. They typically have a hydraulic lifting cylinder built into the foundation under the ladle. However, due to the potential risk of breakthrough, some customers would like to do without hydraulic equipment under the ladle. They prefer vascular lifting systems.

Splash control

SC stands for Splash Control. With our RH-SC® technology, advanced control of the vacuum pump prevents steel splashes in the RH vessel. Variable steam nozzles are used to directly control the speed at which the pressure is reduced.

Selected References

Service

Emergency support - Remote Service

For easy identification of defects and malfunctions and quick initiation of measures for fault elimination.

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Long-term service agreement

As a reliable partner, we provide for a highly productive plant, which operates economically and serves the cycle times of the entire production process.

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Safety Locator

Protect your most valuable asset - your employees - with the SMS group Safety Locator!

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Smart Maintenance

Digitalize your maintenance with SMS group!

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Downloads

Plant technology
New secondary steel treatment options implemented at TerniumSiderar (ARG)
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Increased plant availiability
Quick coupling systems for all fluid connections in the steel meltshop
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TBK laser measurement equipment
Electrical and Automation Systems
A new steel plant complex for SDI

Contact

SMSgroup Luven, Michael

Michael Luven

SMS group GmbH
Head of Technical Sales and Project Planning - Secondary & Tertiary Metallurgy, Metallurgical Plants and Environmental Technology
Eduard-Schloemann-Straße 4
40237 Düsseldorf
Germany

Phone : +49 211 881-8164
Fax : +49 211 881-8264

SMSgroup Eggert, Rüdiger

Rüdiger Eggert

SMS group GmbH
Senior Manager Technical Sales - Secondary & Tertiary Metallurgy, Metallurgical Plants and Environmental Technology
Eduard-Schloemann-Straße 4
40237 Düsseldorf
Germany

Phone : +49 211 881-8139
Fax : +49 211 881-8239