Refining submerged arc of the slag ladle furnace (60 t (LF) molten steel warming the influence of speed

With the speeding up of the steelmaking rhythm and lowering cost increased demand, how to improve thermal efficiency, reduce LF refractory erosion to reduce cost for many research focus problem. Through the LF made slag foaming realize submerged arc operation become solve the problem in an effective way. The research and development of a LF submerged arc can satisfy the requirements of industrial production slag.

1 experimental LF refining submerged arc of slag thermal simulation experiment

Experiment with the ladle furnace dc power supply heating, early in the steelmaking by a line to provide water DianZhaLu, steel water quantity is 55 to 75 kg, steel for 20, carbon steel.

Test result, the conclusion of the (%) for 50 to 60 lime, 25 to 35 high bauxite, 8 to 12 industrial aluminum oxide F type refining foundation are good slag desulfurization effect, desulfurization rate was 43% ~ 70%.

In order to further improve the slag desulphurization ability, in the basis of this slag to enhance the lime scale, increased to 60% from 70%, but considering the slag melt temperature increase, therefore, by adding 5% to reduced melting temperature of fluorite and regulate liquidity, called G type refining basic slag, composition (%) : 65 ~ 75 lime, 20 ~ 27 high bauxite and 0 ~ 5 fluorite. And the traditional 70% ~ 75% CaO, 20% ~ 30% CaF2 slag series (H) for the contrast test. The results show that G type refining desulphurization performance of the slag than F type, and with the traditional CaO-CaF2 slag removal efficiency of quite. At the same time, the slag foaming G models refining effect than traditional H, close to F type slag level.

2 60 tLF refining submerged arc slag and process

Industrial experiment in 60 tLF ladle. The technological process for UHP electric arc furnace LF-VD, and molded. The molten steel UHP electric arc furnace from the EBT steel ladle out into, in the steel while debris for electric arc furnace high by the steel slag ladle silo join mix rushed to the desulfurization of fast purpose. At the same time, to join a certain amount of ferroalloy rough in the ingredients tone. Into the ladle location, the first for temperature measurement sampling, and immediately electrify heats. Add foaming agent and diffusion deoxidizer. Used in the test for foaming agent and diffusion SiC deoxidizer. And then carry on the multiple temperature sampling to adjust the molten steel temperature and composition, the steel is inserted before final Al deoxidization. The steel from electric arc furnace have been pouring to ladle has been for the whole before blowing Ar mixing.

According to the research results of laboratory work, determined the 60 tLF refining submerged arc slag industrial test arrangement, see table 1. Considerations include three slag series, namely to lime, high bauxite clinker is given priority to, add a small amount of fluorite S1 type, the raw materials of lime 68% ~ 70%; High bauxite 24% ~ 25%, 5% ~ 8% of fluorite; The second kind of slag type S2 from 60% of the lime, 15% of clay brick blocks and 25% of fluorite is composed; The third kind of slag series S3 type of from 55% ~ 65% lime, and 35% ~ 45% of fluorite composition. Based on the laboratory research results, SiC foaming agent in a leading role, at the same time it can spread on the role of deoxidizer. In order to make the test simplified, foaming agent used a single component SiC. Experiment mainly is to compare slag series between the effect and refining submerged arc effect. Refining effect is to look at the main desulfurization rate. And submerged arc the main effect is relatively early stage of heating rate of temperature, slag layer thickness and the voice of the arc of the size. And slag layer thickness due to the different debris for stove to join the difference of the amount of oxide residue of slag and the different control, thus can only as a reference. Usually every batch of water control in 50 ~ steel between 60 t. But individual cases because operation problem of water, sometimes partial steel scarce. xk

Steel slag series of debris for group (%) into

Lime high bauxite fluorite fire bricks

40 Cr S1 70 25 5

40 Cr S1 63.6 22.7 13.6

GCr15 * S2 60 25 15

* * * * 66.7 20.8 12.5 GCr15 S2

35 CrMoA S1 66.4 23.4 10.3

40 Cr S3 65 35

20 S3 65 35

40 Cr S3 55.5 44.5

20 S1 68.3 24.7 6.9

20 G S3 60 40

20 G S1 68.3 24.7 6.9

20 G S1 68.3 24.0 7.7