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Controlling process gases for reproducible steel qualities

Are you looking for a simple solution to modernise your molten metal treatment process? Do you need to control the gases of your molten metal treatment precisely and reproducibly? Bürkert mass flow controllers can be integrated quickly and make your plant fit for the future

Challenges of molten metal treatment

Molten metal treatment in secondary metallurgy places extensive demands on the converters or ladle furnaces.

  • Task: Producing required steel qualities with a high level of repeat accuracyChallenge: 
  • Controlling inert gases such as nitrogen and argon in the converter exactly and
  • reproducibly
  • Mixing the molten metal constantly and thoroughly
  • Solution: Controlling the flow of gases with future-compliant mass flow controllers (MFCs)
Farbik die verschiedene Metallprodukte ausgibt

Controlling gas in the ladle furnace

Exact control of gases in molten metal treatment:
✓ Allows reproducible and time-saving processes
✓ Increases the service life of your ladle furnace
✓ Enables you to produce a wide range of steel qualities

Secondary metallurgy (ladle metallurgy)
Post-treatment of steel, refining crude steels
Molten metal treatment
Molten metal treatment enables the production of new types of steel and the production of higher steel qualities. With the right MFCs, the entire process can become more effective, resulting in enormous savings.
Argon purging / Nitrogen purging
The steel must achieve a castable condition and meet the desired requirements. During the entire treatment, inert gases such as argon or nitrogen are introduced into the molten metal through special ceramics (purging plugs) in the floor of the ladle in order to ensure it is mixed continuously.

Conventional solution and possible sources of error

Manual gas control during molten metal treatment
is complex and not reproducible:

  • If the flow demand increases, the steel operator adds more purging gas.
  • A high-pressure bypass is used in case of increased back pressure in the ladle caused for example by clogged purging plugs.

Possible problems:

  • If the slag breaks open during purity purging, the process is prolonged.
  • Stress causes the furnace walls to clog and leads to wear and tear.
  • Spatter poses a danger to people and machines
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Solution: Mass flow controllers for molten metal treatment

Bürkert’s mass flow controllers (MFCs) make your gas control processes reproducible. This allows you to set the flow rate of your gases automatically and with a high
level of repeat accuracy. This guarantees consistent quality and also protects your purging plugs. The digital version provides you with additional diagnostic functions and increases the efficiency of your processes.
 
High setting range: Control the mass flow of large gas quantities precisely.
High pressures: If required, the MFC also controls high levels of pressure, thereby eliminating the need for a high-pressure bypass.

MFC Type 8745
with solenoid valve Type 2875

Mass flow controller with Ethernet interface
MFC Type 8745
with motor valve Type 3280

Mass flow controller with high pressure valve and analogue interface

 

Added values for ladle metallurgy

 

Flow control without a high-pressure bypass

Bürkert analogue mass flow controllers modernise your molten metal treatment process. A high-pressure bypass is no longer required – the high-pressure MFCs perform this task easily and quickly.

Die Bürkertlösung schafft die Durchflussregelung ohne Hochdruckbypass mit MFCs

 

Advantages of digital flow control

Make your gas control fit for the future. To do so, simply connect your mass flow controllers (MFCs) via the Bürkert interface. Digitisation allows you to benefit from further advantages:

1.    Reproducible processes: All data and measured values are available and documented at all times.
2.    Save resources: You can monitor several plants at the same time.
3.    Minimise expenditure: Less cabling and low maintenance.
4.    Cut down on process gases: Consumption is reduced by controlling your gases very precisely

Programmable logic controller
Fieldbus gateway
Several MFCs with Bürkert 
system bus interface (büS)

Controlling gas with a plug-and-play system

Why install individual mass flow controllers when you can utilise a tailored system for your molten metal treatment in steel production?

Save time and money with Bürkert: We assemble your gas mixing unit exactly according to your requirements. Be it a distributed solution or installed in a robust control cabinet – you receive a compact unit that can be integrated into your plant quickly and easily.

Grafik zeigt eine konfigurierte Einheit aus Massendurchflussreglern inklusive Ventile.

A unit configured to your requirements using space-saving mass flow controllers arranged side by side, including valves.

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Learn in the video how you can permanently optimise your melt treatment process and thus save the high-pressure bypass

Example calculations: Molten metal treatment savings

Automation saves time: Bürkert mass flow controllers allow you to accurately control the flow of purging gases such as argon. Manual intervention is eliminated, allowing you to produce more batches each day.

The conventional method requires about nine manual interventions. This increases the processing time for each batch to 70 minutes. In other words, you can only produce a total of ten batches a day.

                                        Conventional solution                           Bürkert solution

Grafik zeigt die Beispielberechnung für manuellen Eingriffe im Prozess, mit der herkömmlichen und der Bürkert Lösung

 

The Bürkert solution eliminates manual interventions. The processing time for each batch is reduced to 45 minutes. In other words, you can produce six additional batches a day.

Automation saves gas: Compared to the conventional solution, the automated control system saves around a quarter of the purging gas. Shown here using argon as an example. You can use the saved gas for further batches – thereby optimising your profit.

Conventionally, 12 Nm³/ Ar per ton of steel are required for processing. In this case, the production of 95 t of steel would require 1140 Nm³/ Ar.

                                         Conventional solution                              Bürkert solution

Grafik zeigt die Beispielberechnung für Argonverbrauch im Prozess, mit der herkömmlichen und der Bürkert Lösung

 

With the Bürkert solution, gases can be controlled much more precisely. Accordingly, only 9 Nm³/ Ar are required. This results in a saving of 285 Nm³/ Ar when processing 95 t of steel. The amount of argon saved is enough to process three more batches.

Do you want to optimise your molten metal treatment and make your gas control system fit for the future? Contact us.