中國德國煉鋼連鑄技術(shù)交流會(huì)的料

1、development of rh refining technology at baosteel cui jian, wang zhe baoshan iron &steel co., ltd october, 2007outline introduction development of rh at baosteel development of rh refining technology at baosteel future research on rh refining technology conclusionsfunction of rh degasser rh dega

2、ssers have functional advanced from only dehydrogenation into a comprehensive steel refining process. with the further study on rh refining process, the scope of steel grades gradually expands, the quality of steel and the efficiency of rh process are also improving. rh vacuum degasser gradually sec

3、ures its position as a predominant vacuum degassing process.main advance of rh technology high efficiency and multi-function. the high efficiency of rh process refers to the promotion of the capacity of rh equipment and the reasonable optimization of rh technology. the multifunction of rh process re

4、fers to the expansion of technology and equipment. the adoption of these technologies could make rh equipment have the functions of heating and temperature compensation, forced decarbonization, desulfurization by powder injection or vessel flux addition, inclusion control, the heating of vacuum cham

5、ber, and skull removal. a setup of rh-mfbmulti-function lance1、oxygen blowing for forced decarburization2、deskull by vacuum chamber combustion heating3、powder injectiondevelopment of rh at baosteel no.1 rh degasser was introduced in 1985 for dehydrogenation and temperature compensation for the molte

6、n steel by oxygen blowing (rh-ob). no.3 rh equipment was developed in the second phase of baosteel building, the snorkel diameter was enlarged to 750 mm and the top oxygen-blowing lance was also equipped. in 1999, baosteel completed no.2 rh degasser with multifunction top lance which has the functio

7、ns of oxygen blowing for forced decarburization and temperature compensation for the molten steel, heating the vessel to remove the skull inside the rh vessel, powder injection for desulfurization. driven by the vigorous demands of the domestic steel market and high value added steel products, no 4

8、rh and no.5 rh were developed in 2006. no.4 rh is under construction and it will put into production this year. the feature of no.4 rh degasser is its high-speed evacuation, it reaches 1500kg/hr at 67 pa, it is very favorable for high-efficiency operation. no.5 rh degasser is a real sense of high ef

9、ficient device and it was put into production in nov. 2006. a twin-vessel system and three stand-by stations was applied.hot metal pretreatment converterccflow chart of baosteel branchrh refiningtab. 1 the process parameters of rh degassers at baosteel branchitemno.1no.3 no.2 no.4 no.5 heat size（ton

10、s）300250300300295snorkel inside diameter（mm）750750750750750lift gas flow rate（nl/min）max4000max3500max4000max4000max4500circulation rate（t/min）max240max230max240max240max270type of oxygen blowingtopktbtoptoptopflow rate of oxygen blowing（nm3/hr）25003000250025002500utmost of vacuum（pa） 25 25 25 25 25

11、evacuation capacity at 67 pa（kg/hr）11001000110015001200circle of total rh treatment (min)3236363527 there are 2 rh degassers being put into production at baosteel, including 160 t rh in stainless branch and 160t rh-ktb in meishan corp., which were innovated and integrated independently by baosteel.

12、the capacity of rh degassers of baosteel has come to account for about 30% of the domestic rh capacity vacuum degassing ratio at baosteel the vacuum degassing ratio of japans converter steel production jumped from 16% at the end of 1970s to over 50% in 1984 and increased to over 60% at the early sta

13、ge of 1990s when baosteel put into production, the vacuum degassing ratio was only 35%. with the completion of no.2 rh and no.3 rh degasser, the vacuum degassing ratio reached nearly 60% in 2006, it will get up to more than 75% when no.4 and no.5 rh degasser are put into operation. development of rh

14、 refining technology at baosteel in the early 1990s, the development of clean steel technology promoted the rh refining technology. moreover, the development of new steel products and the demands for high quality, high-purity of steel products gave an impetus to the rh refining technology. the compl

15、ete set of rh equipment and refining technology was formed. researches on rh process fundamental experiments and simulations were carried out to get in-depth understanding of rh process, and provided a theoretical basis for process optimization vacuum decarburization technology desulphurization in r

16、h process by vessel flux addition or powder injection deoxidation and inclusion control degassing technology fine composition adjustment if molten steel improvement on rh refractory051015202530050100150200250300350carbon content, ppmtime, min before revamping after revampingcomparison of decarburiza

17、tion of no.1 rh before and after equipment revised 0100200300400500600700800199819992000200120022003200420052006production, mt10-2/aauto sheetsrh productiongrowth of steel production amount by rh treatment and auto sheets production since 1998 at baosteel10101516202125263030010203040506070ratio, %co

18、ntent, ppm c n o distribution of to, n and c content in ultra-low carbon if steel produced in no.2 rh degasser in dec. 2006 the average c, n and to content reached 12.1ppm, 14.9ppm and 24.8ppm respectively. the if steel grade production with the carbon content less than 13ppm meets with the requirem

19、ents of low-temperature annealing technology. the production of if steel with the nitrogen content below 15 ppm achieve 58.3%. the production with to content less than 25 ppm achieved only 57%, further technological improvement should be taken to get better results. 02040608010001010202050inclusion

20、size，m2ratio，%calcium treatment 1calcium treatment 2conventionaltechnology 1conventionaltechnology 2inclusion distribution of tin plate steel with the development of calcium treatment technology in rh process desulphurization in rh process the method of vessel flux addition or powder injection using

21、 pre-melted flux and highly reactive powder in rh process was developed to enable the rh process to perform desulphurization. the technology was successfully applied to the production of pipeline steel, high-grade non-oriented silicon steel. the sulphur content of steel products produced by rh degas

22、ser achieved less than 15 ppm, the lowest sulphur content reached less than 10 ppm. the rh refractory erosion during desulfurization process has been improved a lot. future research on rh refining technology baosteel obtains a perfect engineering ability of independent technical integration, design,

23、 manufacture, erection, commissioning and production of rh degasser. high efficiency, quality and production stability and the process line optimization still need to be improved improvement on high efficiency is to match the needs of continuous casting production, to achieve better logistics contro

24、l. adoption of twin-vessel system to reduce the rh assisted operations will be more and more important. to improve the production and quality stability, the impact of experience should be reduced. the model control and automatic refining technology should be conducive to the control of production an

25、d quality stability. in the process line optimization, according to steel grade and degassing process, refining process should be operated in a fixed process production line within a certain period, it is favorable for stable quality, high production efficiency and lower costs. conclusions driven by the vigorous demands of the domestic steel market, the developments of new steel products and the demands for high quality, high-purity of steel products, the rh refining technologies and equipments at baosteel have made remarkable progress for more than 20