Method for preventing cold steel in vacuum tank from bonding in RH vacuum cycle degassing process

Abstract

The invention provides a method for preventing cold steel in a vacuum tank from bonding in the RH vacuum cycle degassing process. The method comprises the steps that (1) a steel ladle adopts a normaltransfer ladle and the transfer time is less than 60 minutes; (2) molten steel enters an RH refining furnace, the temperature of deoxidized molten steel is controlled to be greater than 1620 DEG C, and the temperature of non-deoxidized molten steel is controlled to be greater than 1600 DEG C; (3) when the RH refining furnace is subjected to OB temperature rise or OB forced decarburization, the vacuum degree in the vacuum tank is 5-15 kpa and the circulation gas flow is 1400 NL / min; (4) in 5 mins when the decarburization of the RH refining furnace is carried out, the circulation gas flow is controlled at 1600 NL / min, and during the period from the 5 mins to the time the decarburization is finished, the circulation gas flow is controlled at 2000 NL / min; (5) 3 mins after aluminum is added tothe molten steel for deoxidation, other alloys are added; (6) after the molten steel is alloyed, 200 kg desulfurizing agent is added; (7) the temperatures of an upper part tank and a hot bending pipeare increased by employing a top gun to heat, wherein the gun position of the top gun is 8.5 m, the flow of gas is 200 NM<3> / h, and the flow of oxygen is 220 NM<3> / h; and (8) when the pure degassing cycling time of the molten steel is greater than 8 mins, treatment is finished. The cold steel in the vacuum tank can be prevented from bonding effectively, and the operation rate of the RH refining furnace is raised.

Description

Technical field: [0001] The invention relates to a method for preventing cold steel from adhering in a vacuum tank during the RH vacuum cycle degassing process, and belongs to the technical field of steelmaking. Background technique: [0002] The RH vacuum degassing refining method was jointly developed by Ruhrstahl and Heraeus, a subsidiary of Tyssen in Germany, and the vacuum molten steel circulation degassing method was successfully developed. The two companies used their company names This molten steel refining method is named RH vacuum degassing refining method. This method can further reduce [O] and [N] in molten steel, and is used for smelting steel with high cleanliness in molten steel composition. RH vacuum degassing furnace has become an essential process for high-end products, especially for ultra-low carbon steel smelting. [0003] In the existing production process, a large amount of molten steel splashes during the vacuum degassing process, causing a large amo...

AI Technical Summary

Problems solved by technology

The main disadvantages of this process of removing cold steel are: the furnace must be shut down, which affects normal production operations, the steel laundering tank operation must be arranged after baking and discharging, and the temperature and composition of the laundering steel tank after long-term baking are difficult to control

[0012] This method is also used to remove cold steel that has formed in the vacuum tank, and cannot effectively prevent the formation of cold steel

[0013] Using the incomplete combustion product CO in the decarburization period and the oxygen blown in to heat the inner wall of the vacuum tank will inevitably affect the rapid decrease of the vacuum degree, which affects the decarburization rate and depth to a certain extent.

[0014] Failure to effectively control the factors affecting the formation of cold steel, the circulation gas flow rate and the timing of alloy addition, will inevitably lead to the formation of cold steel