During the production of high-quality steels Aerzen Vacuum Blowers are used for further processing of the melt, the so-called steel degassing.
Vacuum Blowers are used after the so-called “refresh“ of the steel, where oxygen is blasted into the pig iron. During this metallurgic further processing of the melt, the so-called secondary metallurgy, gases are removed, including argon, carbon monoxide, oxygen and carbon dioxide, which can negatively influence the properties of the steel. Aerzen Vacuum Blowers ensure safe suction of these harmful gases under vacuum conditions.
Different procedures in the secondary metallurgy are used for steel production with dry compressing Aerzen Vacuum Blowers.
RH- (=Ruhrstahl-Heraeus) and RH- OB-procedure (=Ruhrstahl-Heraeus-Oxygen-Blowing)
In the so-called vacuum circulation procedure, a partial quantity of the liquid steel is sucked into a vacuum vessel. This is effected via two pipes on the under side of the reservoir dipping from above into the melt. The reservoir is evacuated and the melt rises up via both channels. Argon is continuously blasted in so that the melt is decarbonized (carbon is removed) and degassed, and afterwards it flows back into the melt pan. The purpose of these operations is to produce steel with greater purity. Due to the removal of hydrogen the hydrogen brittleness is reduced. The first Rh-treatment of steel was carried out in the steel works of Henrichshütte in June 1958. Later, the Rh-OB-procedure (Rh-Oxygen Blowing) was refined whereby the degassed melt is decarbonized by additional blown-in oxygen thereby producing steels of higher-quality.
VD (= Vacuum Degassing) and VOD- Procedure (= Vacuum Oxygen Decarbu- risation)
Aerzener Maschinenfabrik has been well-represented in these applications for over 60 years with the large Roots Blowers. Energy saving and an improvement in the environmental balance are the main focus worldwide. Applications for production of vacuum with dry- compressing vacuum blowers are divided into three areas:
Aerzen vacuum blower series HV in a steel works.
1. New installations for higher steel qualities.
2. Modernisation of existing large-scale units in substitution for steam cleaners.
3. New installations for smaller steel works producing new semi-finished products out of steel scrap (mini mills, micro mills).
The reliability of Aerzen large blowers with a suction volume of 10,000 to 97,000 cubic metres per hour, and the technical support available, are appreciated world- wide. For smaller volume flows (mini mills or micro mills) and quick processes, Aerzen Canned Motor Blowers are also used including the GM 9500 HM-Y with suction volume of up to 15,600 cubic metres per hour. As usual, Aerzener Maschinenfabrik has the right solution for each type of application.