Rapid degassing method of vacuum induction furnace

Abstract

The invention discloses a rapid degassing method of a vacuum induction furnace. The method comprises the following steps: (1) according to the requirements of steel components, calculating weight of the needed scrap steel raw material and pre-deoxidizer as well as various alloys, weighing the materials, and pre-drying the pre-deoxidizer and the alloys; (2) placing the scrap steel raw material in a crucible, and placing the pre-deoxidizer and the alloys in a storage bin; (3) closing a vacuum chamber of the vacuum induction furnace and vacuumizing for 3-8 minutes; (4) transferring electrochemical steel into an inductor, then keeping vacuum degree at 0.05-0.1Pa, and continuously vacuumizing for 10-20 minutes; (5) stopping vacuumizing, charging argon into the vacuum chamber until pressure reaches 500-700Pa, starting a vacuum pump for vacuumizing to 0.05-0.1Pa, and then maintaining the vacuum degree for 10-20 minutes; (6) stopping vacuumizing, and then filling argon into the vacuum chamber until pressure reaches 500-700Pa; (7) adding the pre-deoxidizer and the alloys in the storage bin to molten steel for full circulation; and (8) naturally cooling the molten steel for 5-10 minutes in a vacuum state and then performing vacuum breaking and demoulding. Practices prove that, in the molten steel treated by the degassing method, the contents of the carbon element, the nitrogen element and the oxygen element are extremely low and are respectively not more than 15ppm, not more than 15ppm and not more than 20ppm.

Description

technical field [0001] The invention belongs to the technical field of vacuum induction furnace smelting, and specifically refers to a method for rapid degassing of a vacuum induction furnace. Background technique [0002] Gas in steel not only reduces the mechanical properties of steel, but also is the main cause of defects such as cracks, subcutaneous bubbles, and loose centers. Therefore, reducing the gas content in steel to a minimum is an important measure to improve steel quality and reduce costs. [0003] The basic principle of the existing RH vacuum degassing device is to blow argon gas through the argon channel installed in the riser, and drive the molten steel in the ladle into the riser under the action of vacuuming, and then pass through the vacuum chamber, and then the downcomer Back to the ladle to complete a cycle, so as to realize the batch processing of molten steel. The Chinese invention patent with application number 02147730.2 discloses a method for vacu...

AI Technical Summary

Problems solved by technology

However, because the RH vacuum degassing level mainly depends on its equipment capability, the ultimate vacuum degree that can be achieved by general equipment is about 0.067Pa. When investing in a vacuum pump with a larger capacity, the degassing ability of this method is only suitable for the production of ultra-low carbon high-quality steel with a carbon content of less than 15ppm, and the ability to remove the oxygen and nitrogen elements in the steel is very small

[0004] A Chinese invention patent with application number 01126597.3 discloses a method of vacuum degassing and refining. The dipping tube at the bottom of the vacuum chamber is inserted into the molten steel in the ladle, and driving gas is passed into one of the dipping tubes, and the steel in the ladle The liquid passes through the dipping tube and flows through the vacuum chamber to complete the circulation. The special feature is that at least one magnetic field generator is installed on the periphery of at least one dipping tube. The magnetic field generator can generate an electromagnetic force that is consistent with the circulation direction of the molten steel. , so that the driving gas is set to drive the molten steel circulation together to improve the degassing ability, but this invention increases the degassing ability by increasing the molten steel circulation flow rate, and its equipment is complicated, the investment is large, and it is difficult to adapt to large-scale production