RH Vacuum Degassing Technology Oct07

RH Vacuum Degassing Technology...

RH Vacuum Degassing Technology Vacuum degassing is an important secondary steel making process. This process was originally used for hydrogen removal from the liquid steel but presently it is also being used for secondary refining and has become increasingly important process of secondary steel making. Pressure dependent reactions are the reason for the treatment of liquid steel in this process.  There are many vacuum degassing systems but RH type degassers are very popular. The RH process has been named after Ruhrstahl and Heraeus where this process was initially developed. The RH degassing technology was first introduced in the late 1950s and presently it has become an important tool of secondary metallurgy in most of the modern steel plants. The RH circulation degassing process has proved its vast suitability in large number of shops worldwide, for operation with short tap to tap times covering heat sizes up to 400 tons. The vacuum treatment in RH plants produces steel which fulfills the demand of high steel qualities. To achieve this, the liquid steel is allowed to circulate in a vacuum chamber where a considerable drop in pressure causes it to disintegrate into the smallest of the parts. The increase in the surface area allows the liquid steel to degas to the best possible extent. The process needs reliable vacuum units since it should be able to suck off very large flow rates under very difficult conditions of dusty atmosphere and high temperatures. The mechanism of the vacuum treatment of liquid steel in RH process is shown in Fig 1. Fig 1 Mechanism of the vacuum treatment of liquid steel in the RH process RH degassing process The process mainly consists of a refractory lined cylindrical reaction vessel with two steel pipes attached to the bottom of...