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1. 发明专利

JPH07316633A METHOD FOR PREVENTING ABSORPTION OF NITROGEN IN RH VACUUM DEGASSING TREATMENT 失效
公开(公告)号：JPH07316633A
公开(公告)日：1995-12-05
申请号：JP10395794
申请日：1994-05-18
申请人： SHINAGAWA REFRACTORIES CO , NIPPON KOKAN KK
发明人： KAMEMIZU AKIRA , TERAOKA TAKUJI , KOMATSU YOSHIMI , TOYODA KOJI , NISHIO HIDEAKI , TAKESHITA YASUO , NAKAISO SHINJI , SHIMIZU HIROAKI
IPC分类号： C21C7/10
摘要： PURPOSE:To perfectly prevent the absorption of nitrogen into molten steel, to restrain the development of spalling phenomenon, crack, shortage of joint, etc., of a refractory forming the inner and the outer cylinders of an immersion tube, to prolong the service life of the immersion tube and to prevent the stickiness of a large quantity of slag to the outer periphery of the non-immersion part of the immersion tube and a flange part by restraining spatter of the slag. CONSTITUTION:At the time of executing vacuum degassing by dipping the immersion tube of an RH vacuum degassing apparatus into molten steel, and inert gas filling member 7 is embedded and arranged at the upper part from the molten steel surface M in the outer periphery of the seal member of the immersion tube, and while holding the pressure at an area of the inert gas filling member higher than the atmosphere, the degassing treatment is executed to the molten steel to be treated to prevent the absorption of the nitrogen in the RH vacuum degassing treatment. Further, in some case, the inert gas filling member is divided and embedded and arranged to the outer periphery of the seal member, and further, the pressure at the area of the inert gas filling member is made to be in the range of 0.1-1MPa.

2. 发明专利

JPH0925507A METHOD FOR REFINING MOLTEN STEEL 失效
公开(公告)号：JPH0925507A
公开(公告)日：1997-01-28
申请号：JP17352695
申请日：1995-07-10
申请人： NIPPON KOKAN KK
发明人： KAMEMIZU AKIRA , FURUNO YOSHIKATSU , FUKUMI JUNICHI , TOYODA KOJI
IPC分类号： C21C7/00 , C21C7/04 , C21C7/06 , C21C7/068 , C21C7/10
摘要： PROBLEM TO BE SOLVED: To efficiently produce a high clean aluminum killed extra-low carbon steel by adding CaO during tapping molten steel roughly decarburized steel to lower the m.p. of slag, further executing an Al deoxidation after executing a vacuum decarburization and successively, executing a stirring refining. SOLUTION: The molten steel roughly decarburized steel in a refining furnace is tapped into a ladle and the molten steel in this ladle is vacuum-decarburized and refined in RH degassing equipment. At this time, CaO is added during tapping to lower the m.p. of slag and successively, the Al deoxidation is executed after vacuum deoxidizing in the condition of undeoxidation. The composition of ladle slag during modifying and after modifying the slag is desirable to be made into 5±0.2 basicity CaO/SiO2 and 1.5±0.1 CaO/Al2 O3 by charging the CaO. Thereafter, the molten steel is sufficiently stirred with the slag in simple refining equipment capable of the gas stirring and an alloy addition, and refined. By this method, the adjustment of components in the molten steel is executed, and also iron oxide in the slag is reduced to execute the slag modification.

3. 发明专利

JPH068451B2 失效
公开(公告)号：JPH068451B2
公开(公告)日：1994-02-02
申请号：JP20781488
申请日：1988-08-22
申请人： NIPPON KOKAN KK
发明人： MYAHARA HIROAKI , YAMADA KAORU , TOYODA KOJI , ISHIKAWA HIROAKI
IPC分类号： C21C5/46

4. 发明专利

JPH0515967A UPPER NOZZLE FOR SLIDING NOZZLE 失效
公开(公告)号：JPH0515967A
公开(公告)日：1993-01-26
申请号：JP16989791
申请日：1991-07-10
申请人： NIPPON KOKAN KK
发明人： TAKASUGI HIDETO , TOYODA KOJI , TAKAOKA TAKASHI
IPC分类号： B22D11/10 , B22D41/42
摘要： PURPOSE:To prevent sticking of Al2O3 to stagnating part in a sliding nozzle. CONSTITUTION:On an upper nozzle 10 forming part in contact with a fixed plate 1 with permeable refractory 16, an annular header 29 connected with an inert gas feeding pipe 18 in this permeable refractory 16 is provided and also, plural penetrated holes 30 having 0.3mm diameter, are provided on half- circular part at the opening side of the sliding gate in the porous refractory 16 at the inside of the annular header.

5. 发明专利

JPH0347662A SEMI-IMMERSION NOZZLE FOR CONTINUOUS CASTING 失效
公开(公告)号：JPH0347662A
公开(公告)日：1991-02-28
申请号：JP17900489
申请日：1989-07-13
申请人： NIPPON KOKAN KK
发明人： HARADA SHOJI , SAWAI KENJI , TOYODA KOJI
IPC分类号： B22D11/10
摘要： PURPOSE:To reduce involution of powder by forming thickness of immersing part of a semi-immersion nozzle thicker than that of non-immersing part by the specific thickness at the time of continuous casting. CONSTITUTION:Molten steel 2 is poured into a mold 6 from a tundish 1 through the semi-immersion nozzle 7. Then, by drawing means, a cast slab formed, after solidifying, in the mold 6 is continuously drawn downward to execute continuous casting. In the case the semi-immersion nozzle 7 is melted off during pouring the molten steel 2, this is exchanged for the fresh one. At this time, as the thickness of immersing part of the semi-immersion nozzle 7 is thicker than that of non-immersing part by >=10%, the semi-immersion nozzle 7 is made difficult to melt off. Therefore, frequency for exchanging the semi- immersion nozzles 7 is made few and the involution of powder 9 into solidified shell 11 can be reduced and defect in the quality can be reduced.

6. 发明专利

JPH0347661A SEMI-IMMERSION NOZZLE FOR CONTINUOUS CASTING 失效
公开(公告)号：JPH0347661A
公开(公告)日：1991-02-28
申请号：JP17900389
申请日：1989-07-13
申请人： NIPPON KOKAN KK
发明人： HARADA SHOJI , SAWAI KENJI , TOYODA KOJI
IPC分类号： B22D11/10
摘要： PURPOSE:To reduce the development of splash at the time of exchanging by forming thickness at upper end part of a semi-immersion nozzle thinner than that of the other part by the specific quantity at the time of continuous casting. CONSTITUTION:Molten steel 2 is poured into a mold 6 from a tundish 1 through the semi-immersion nozzle 7. Then, by drawing means, a cast slab formed, after solidifying, in the mold 6 is continuously drawn downward to execute continuous casting. In the case the semi-immersion nozzle 7 is melted off during pouring the molten steel 2, this is exchanged for the fresh one. At this time, as the thickness of the upper end part of semi-immersion nozzle 7 is formed thinner than that of the other part by >=50%, the development of splash at the time of exchanging can be reduced.

7. 发明专利

JPH0285334A REFINING METHOD OF HIGH CHROME AND HIGH NICKEL STEEL 失效
公开(公告)号：JPH0285334A
公开(公告)日：1990-03-26
申请号：JP23688388
申请日：1988-09-21
申请人： NIPPON KOKAN KK
发明人： TABATA YOSHIAKI , OKIMOTO SHINICHI , WATANABE ATSUSHI , SUZUKI KATSUNORI , HASEGAWA TERUYUKI , TOYODA KOJI
IPC分类号： C22C33/04
摘要： PURPOSE:To obtain the title steel having good blowing characteristics by combinedly charging a molten steel of which stainless steel scraps and Ni are melted and hot metal to a converter, carburizing it, adding Cr thereto and furthermore adding stainless steel scraps to the formed molten steel. CONSTITUTION:A molten steel of which steel scraps consisting essentially of a stainless steel and Ni and hot metal are combinedly charged to a converter and are carburized as well as Cr is added thereto. At the end of blowing, as a cold charge, stainless steel scraps are added thereto. The molten steel in the converter is discharged into a ladle. On the other hand, steel scraps consisting essentially of a stainless steel are preliminarily melted by an electric furnace or the like and the molten metal and the molten metal discharged from the converter are mixed. The mixture is then fed to a secondary refining stage and is furthermore cleaned. In this way, the quality of steel scraps to be used can be increased and the manufacturing cost can be reduced.

8. 发明专利

JPH01252721A OXYGEN NOZZLE FOR SECONDARY COMBUSTION OF CONVERTER 失效
公开(公告)号：JPH01252721A
公开(公告)日：1989-10-09
申请号：JP8048788
申请日：1988-03-31
申请人： NIPPON KOKAN KK
发明人： MURAKI YASUNORI , HASEGAWA TERUYUKI , TOYODA KOJI
IPC分类号： C21C5/46
摘要： PURPOSE:To perfectly carry out the secondary combustion of the CO-contg. gas in a converter and to improve the heat efficiency by inserting a nozzle tip having many small holes into the secondary-combustion oxygen nozzle at the tip of a lance at the time of decarburizing and refining molten iron in the converter having a top-blowing oxygen lance to produce molten steel. CONSTITUTION:The moten iron, which has been desulfurized, dephosphorized, etc., is charged into an top-blown converter, oxygen is blown into the converter from the oxygen nozzle 11 of an oxygen top-blowing lance 10 to oxidize the C in the molten iron, and then molten iron is decarburized to produce molten steel. In this case, the gaseous CO generated by the oxidation of C in the molten iron is secondarily burned to improve heat efficiency. For the purpose, the nozzle tip 1 obtained by embedding small pipes 3 made of heat-resistant metal into a refractory material 4 is inserted into the secondary-combustion oxygen nozzle 12 opened obliquely downward at the tip of the lance 10. Gaseous O2 for the secondary combustion of CO is rapidly diffused into a CO-contg. atmosphere, CO is secondarily burned with high efficiency, and the heat efficiency of the steelmaking oxygen top-blown converter is remarkably improved.

9. 发明专利

JPH01247526A METHOD FOR CONTROLLING CARBON CONTENT AT END POINT IN CONVERTER 失效
公开(公告)号：JPH01247526A
公开(公告)日：1989-10-03
申请号：JP7475188
申请日：1988-03-30
申请人： NIPPON KOKAN KK
发明人： YAMADA KAORU , MIYAHARA HIROAKI , TOYODA KOJI , ISHIKAWA HIROAKI
IPC分类号： C21C5/30
摘要： PURPOSE:To control the aimed carbon content in molten steel at end point in a converter at good accuracy by refining dephosphorized molten iron in the converter, measuring the carbon content and temp. in the molten steel at end stage of blowing and finding the necessary blowing oxygen rate with the specific decarbonizing equation. CONSTITUTION:At the time of refining the dephosphorized molten iron with less-slag in the converter, the carbon content and temp. in the molten steel in the converter are measured at the end stage of the blowing. By using these measured values, the decarbonizing model (in the equation, C: carbon content in the molten steel, Q: blowing oxygen rate, CT: transition point of decarbonization, CL: limiting point of decarbonization, alpha, beta: the content) is integrated with relation between the present carbon content and the aimed carbon content, and the necessary blowing oxygen rage is found to execute the blowing. Further, the decarbonizing transition point of this corresponding heat is calculated from the actual blowing data and feed-back thereof is executed to the next heat as the decarbonizing transition point CT. By this method, the carbon content and temp. at the end point in the converter is controlled at high accuracy.

10. 发明专利

JPS6346124B2 失效
公开(公告)号：JPS6346124B2
公开(公告)日：1988-09-13
申请号：JP11594685
申请日：1985-05-29
申请人： NIPPON KOKAN KK
发明人： HASEGAWA TERUYUKI , TOYODA KOJI , KAWASE YUKIO , TABATA YOSHIAKI
IPC分类号： C21C1/02 , C21C1/00 , C21C1/04 , C21C5/28

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