The basic principle and technical advantages of RH refining furnace
RH refining equipment includes vacuum chamber, immersion tube and ladle, as shown in Fig. 1. The degassing process of molten steel is carried out in the vacuum chamber. The operation procedure is as follows: the vacuum chamber leaves from the preheating device and stops baking; The nozzle of the immersion pipe is sleeved with a slag retaining cap; Install the alloy hopper on the top cover of the vacuum chamber. At this time, place the ladle with molten steel in the treatment position with a crane, rotate the RH vacuum chamber to the upper square of the ladle, and take samples of molten steel for temperature measurement. During degassing, the immersion tube is inserted into the steel water. When the vacuum chamber is evacuated, the molten steel rises to the differential pressure level through the immersion tube. The driving gas is blown into the molten steel from the bottom of the immersion tube to push the molten steel and form bubble cores in the molten steel. The gas in the molten steel diffuses into the bubbles, and the bubbles expand rapidly. The molten steel is sprayed into the vacuum chamber in the form of first spray, and the degassing of the molten steel is completed at the same time. The degassed molten steel has a relatively high density and flows back to the ladle along the downcomer due to gravity. The vacuum circulation process of molten steel is realized.
Compared with other secondary refining processes, RH technology has the following advantages:
(1) It has the advantages of fast processing speed, short reaction period and low temperature loss. The slag on the molten steel has a good thermal insulation effect, and the temperature drop of the molten steel is small during the treatment process. The temperature drop during normal treatment is only 30 ~ 50 ℃;
(2) The degassing effect is good, the molten steel reacts in the vacuum chamber, and the molten steel entering the vacuum chamber splashes to form very fine particles, which greatly increases the surface area of the molten steel and greatly improves the degassing efficiency;
(3) Strong applicability. One RH equipment can handle this volume of molten steel, and it can also be carried out in induction furnace and electric arc furnace.
(4) Strong processing ability. The continuous circulation of molten steel treatment makes it possible to get rid of the restrictions of the vacuum chamber and the clear height and size of the ladle, so that it can be applied to the treatment of a large amount of molten steel and has a large production capacity.