US20150114528A1 - Method of lowering dew point of amibient gas within annealing furnace, device thereof, and method of producing cold-rolled annealed steel sheet - Google Patents

Method of lowering dew point of amibient gas within annealing furnace, device thereof, and method of producing cold-rolled annealed steel sheet Download PDF

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Publication number
US20150114528A1
US20150114528A1 US14/391,022 US201314391022A US2015114528A1 US 20150114528 A1 US20150114528 A1 US 20150114528A1 US 201314391022 A US201314391022 A US 201314391022A US 2015114528 A1 US2015114528 A1 US 2015114528A1
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gas
temperature
zone
ambient
heat exchanger
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Takamasa Fujii
Masato Iri
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JFE Steel Corp
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JFE Steel Corp
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    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54Furnaces for treating strips or wire
    • C21D9/56Continuous furnaces for strip or wire
    • C21D9/561Continuous furnaces for strip or wire with a controlled atmosphere or vacuum
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D17/00Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/004Systems for reclaiming waste heat
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27FURNACES; KILNS; OVENS; RETORTS
    • F27DDETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D7/00Forming, maintaining, or circulating atmospheres in heating chambers
    • F27D7/06Forming or maintaining special atmospheres or vacuum within heating chambers
    • F27D2007/063Special atmospheres, e.g. high pressure atmospheres

Definitions

  • This disclosure relates to advantageous production of a steel strip that can lower the dew point of an ambient gas in a continuous annealing furnace and has high wettability and, in particular, relates to a method of lowering the dew point of an ambient gas in an annealing furnace, a device for the method, and a method of producing a cold-rolled and annealed steel sheet.
  • the low-temperature gas is directly introduced into the high-temperature furnace.
  • a large amount of thermal energy is required to maintain the steel strip temperature in the furnace, the gas temperature cannot be controlled, and the energy efficiency is very low.
  • the temperature of a gas to be returned to the furnace is not sufficiently increased and, as described in JP '622, the water adsorption filter having a low dehumidification capacity lowers the dew point only to approximately ⁇ 30° C. and cannot lower the dew point to ⁇ 45° C. or less.
  • known techniques to lower the dew point of the atmosphere of a continuous annealing furnace have problems that they cannot achieve a low dew point of ⁇ 45° C. or less and that they have very low energy efficiency.
  • a dryer for example, of a desiccant method or a compressor method that allows a dew point of ⁇ 45° C. or less to lower the dew point of an annealing furnace ambient gas and a circulator to lower the dew point to ⁇ 45° C., installing a heat exchanger in the circulator to increase or decrease the temperature of the gas, and modifying a gas inflow (gas introduction) into a heating zone and a cooling zone of the furnace to improve energy efficiency.
  • Part of an ambient gas in the heating zone and/or the soaking zone is sucked out and is cooled through a high-temperature gas passage of the heat exchanger by heat exchange with a gas in a low-temperature gas passage, is then further cooled by mixing with part of an ambient gas of the cooling zone, is then further cooled through the gas cooler, is then dehumidified to a dew point of ⁇ 45° C. or less in the dryer, is then heated through the low-temperature gas passage of the heat exchanger by heat exchange with a gas in the high-temperature gas passage, and is returned to the heating zone and/or the soaking zone.
  • part of gas flowing from the dryer toward the low-temperature gas passage of the heat exchanger is returned directly to the cooling zone without passing through the heat exchanger.
  • FIG. 1 is a schematic view of Conventional Example 1.
  • FIG. 2 is a schematic view of Conventional Example 2.
  • FIG. 3 is a schematic view of a circulation system according to Conventional Example 2.
  • FIG. 4 is a schematic view of Conventional Example 3.
  • FIG. 5 is a schematic view of a circulation system according to Conventional Example 3.
  • FIG. 6 is a schematic view of Comparative Example 1.
  • FIG. 7 is a schematic view of a circulation system according to Comparative Example 1.
  • FIG. 8 is a schematic view of our Example 1.
  • FIG. 9 is a schematic view of a circulation system according to Example 1.
  • FIG. 10 is a schematic view of our Example 2.
  • FIG. 11 is a schematic view of a circulation system according to Example 2.
  • a large amount of Mn oxide is produced on the surface of the steel strip and inhibits the adhesion of plating.
  • a circulator equipped with a dryer that allows a dew point of ⁇ 45° C. or less to achieve a very low dew point to prevent concentration of Mn oxide on the surface of the steel strip.
  • the desired ambient gas temperature in the annealing furnace is different in a heating zone, a soaking zone, and a cooling zone. More specifically, the sucked gas is cooled to approximately room temperature in a gas cooler before entering the dryer, dehumidified in the dryer, and returned to the furnace.
  • a low-temperature gas is directly introduced into a high-temperature region such as the heating zone or the soaking zone, a high temperature required to anneal the steel strip cannot be maintained. For this reason, the temperature of the introduced gas from the circulator must be increased.
  • a heat exchanger between the furnace and the gas cooler. More specifically, a high-temperature gas sucked from the heating zone or the soaking zone of the furnace (sucked gas) is cooled in the cooler before entering the dryer. Utilizing thermal energy resulting from the temperature difference, therefore, the gas cooled in the gas cooler and dehumidified in the dryer can be heated. Thus, thermal energy discharged from the gas cooler can be effectively utilized.
  • a high-temperature gas sucked from the heating zone or the soaking zone of the furnace is passed through the heat exchanger, cooled in the gas cooler, dehumidified in the dryer, heated in the heat exchanger, and then returned to the heating zone or the soaking zone of the furnace.
  • the temperature of the high-temperature gas sucked from the heating zone or the soaking zone after the heat exchange is sometimes higher than the gas temperature in the cooling zone.
  • the gas after the heat exchange can advantageously be mixed with a low-temperature gas sucked from the cooling zone to lower energy required to further cool the gas in the downstream gas cooler.
  • the gas temperature after cooling with the gas cooler is lower than the temperature of the cooling zone of the furnace, part of gas cooled in the gas cooler, dehumidified in the dryer, and returned directly to the cooling zone without passing through the heat exchanger can lower the temperature and the dew point of the cooling zone, thus further improving energy efficiency.
  • a dryer for use herein preferably has a high dehumidification capacity, for example, of a desiccant method for continuous dehumidification using calcium oxide, zeolite, silica gel, or calcium chloride or a compressor method using an alternative chlorofluorocarbon.
  • FIGS. 1 to 11 illustrate the structure and gas passages of a continuous annealing furnace having a heating zone and a cooling zone according to Examples, Comparative Example, and Conventional Examples.
  • FIG. 1 illustrates Conventional Example 1 described in JP '953.
  • Ambient gas supply equipment 12 directly supplies another low-temperature ambient gas to a heating zone 1 and a cooling zone 2.
  • FIGS. 2 and 3 illustrate Conventional Example 2 described in JP '830.
  • a gas sucked from a cooling zone 2 enters a circulator 8 through a flow path 15 , passes through a heat exchanger 9 to heat a gas from ambient gas supply equipment 12 , and returns to the cooling zone 2 through a flow path 16 .
  • the low-temperature ambient gas supplied from the gas supply equipment 12 is heated in the heat exchanger 9 and introduced into a heating zone 1 through an ambient gas pipe 7 .
  • FIGS. 4 and 5 illustrate Conventional Example 3 described in JP '622.
  • a gas sucked from heating zone 1 is introduced into a circulator 8 through a flow path 15 , cooled in a heat exchanger 9 with a gas from a water adsorption filter 18 , dehumidified with the water adsorption filter 18 made of activated alumina, heated in the heat exchanger 9 , and returned to the heating zone 1 through a flow path 16 .
  • Each device includes three water adsorption filters 18 alternately operated at intervals of three hours.
  • FIGS. 6 and 7 illustrate Comparative Example 1.
  • a gas sucked from a heating zone 1 is introduced into a circulator 8 through a flow path 15 , cooled in a heat exchanger 9 with a gas that has been dehumidified in a dryer 11 , further cooled in a gas cooler 10 , dehumidified in the dryer 11 , heated in the heat exchanger 9 with a gas from the heating zone 1, and returned to the heating zone 1 through a flow path 16 .
  • FIGS. 8 and 9 illustrate our Example 1.
  • a gas sucked from a heating zone 1 is introduced into a circulator 8 through a flow path 15 , cooled in a heat exchanger 9 with a dehumidified gas from a dryer, mixed in a mixer 20 with another gas sucked from a cooling zone 2 through a flow path 19 , further cooled in a cooler 10 , dehumidified in a dryer 11 , heated with a gas from the heating zone 1, and returned to the heating zone 1 through a flow path 16 .
  • FIGS. 10 and 11 illustrate our Example 2.
  • the gas dehumidified in the dryer 11 is distributed with a gas distributor 13 .
  • One part of the distributed gas is introduced into the heat exchanger 9 , heated therein with a gas from the heating zone 1 and returned to the heating zone 1 through a flow path 16 .
  • the other part of the distributed gas is returned directly to a cooling zone 2 through a flow path 17 .
  • Table 1 shows the dew points of the sucked gases and the dew points of the introduced gases passing through the gas passages and exhausted heat energy during the passage in Examples and Conventional Examples.
  • Table 1 shows that the dew points of the gases introduced into the annealing furnaces in No. 1 to No. 3 of Example 1 and No. 4 to No. 6 of Example 2 are satisfactorily lower than the target temperature of ⁇ 45° C., as compared with Conventional Examples No. 7 to No. 10.
  • the dew points in the furnaces measured upstream from an annealing furnace outlet 21 are also satisfactorily lower than ⁇ 45° C.
  • No. 1 to No. 3 of Example 1 and No. 4 to No. 6 of Example 2 exhausted less heat energy and have very high energy efficiency.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
US14/391,022 2012-04-09 2013-04-05 Method of lowering dew point of amibient gas within annealing furnace, device thereof, and method of producing cold-rolled annealed steel sheet Abandoned US20150114528A1 (en)

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JP2012-088089 2012-04-09
JP2012088089 2012-04-09
PCT/JP2013/002353 WO2013153791A1 (ja) 2012-04-09 2013-04-05 焼鈍炉内雰囲気ガスの露点低減方法、その装置及び冷延焼鈍鋼板の製造方法

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US (1) US20150114528A1 (ja)
EP (1) EP2837700B1 (ja)
JP (1) JP5742950B2 (ja)
KR (1) KR101564870B1 (ja)
CN (1) CN104245972B (ja)
WO (1) WO2013153791A1 (ja)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150076751A1 (en) * 2012-04-09 2015-03-19 Jfe Steel Corporation Method of reducing dew point of atmosphere gas in annealing furnace, apparatus for the same and method of producing cold-rolled and annealed steel sheet
US10233526B2 (en) * 2012-12-04 2019-03-19 Jfe Steel Corporation Facility having a continuous annealing furnace and a galvanization bath and method for continuously manufacturing hot-dip galvanized steel sheet

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105018714B (zh) * 2014-04-17 2017-02-22 宝山钢铁股份有限公司 连续退火炉内气氛增湿方法
JP6008007B2 (ja) * 2015-03-23 2016-10-19 Jfeスチール株式会社 連続溶融亜鉛めっき装置及び溶融亜鉛めっき鋼板の製造方法
CN109990569B (zh) * 2019-04-09 2020-08-11 中冶赛迪工程技术股份有限公司 一种基于降温除湿的退火炉烘干方法
JP7402372B1 (ja) 2023-06-06 2023-12-20 日本碍子株式会社 熱処理炉

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JPH11124622A (ja) * 1997-10-21 1999-05-11 Daido Steel Co Ltd 熱処理方法
US6228321B1 (en) * 1998-07-28 2001-05-08 Kawasaki Steel Corporation Box annealing furnace method for annealing metal sheet using the same and annealed metal sheet
US20120111416A1 (en) * 2009-01-28 2012-05-10 Uhde Gmbh Method for supplying an entrained -flow gasification reactor with fuel from a storage container
US20150076751A1 (en) * 2012-04-09 2015-03-19 Jfe Steel Corporation Method of reducing dew point of atmosphere gas in annealing furnace, apparatus for the same and method of producing cold-rolled and annealed steel sheet

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Publication number Priority date Publication date Assignee Title
JPH11124622A (ja) * 1997-10-21 1999-05-11 Daido Steel Co Ltd 熱処理方法
US6228321B1 (en) * 1998-07-28 2001-05-08 Kawasaki Steel Corporation Box annealing furnace method for annealing metal sheet using the same and annealed metal sheet
US20120111416A1 (en) * 2009-01-28 2012-05-10 Uhde Gmbh Method for supplying an entrained -flow gasification reactor with fuel from a storage container
US20150076751A1 (en) * 2012-04-09 2015-03-19 Jfe Steel Corporation Method of reducing dew point of atmosphere gas in annealing furnace, apparatus for the same and method of producing cold-rolled and annealed steel sheet
US9657366B2 (en) * 2012-04-09 2017-05-23 Jfe Steel Corporation Method of reducing dew point of atmosphere gas in annealing furnace, apparatus for the same and method of producing cold-rolled and annealed steel sheet

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20150076751A1 (en) * 2012-04-09 2015-03-19 Jfe Steel Corporation Method of reducing dew point of atmosphere gas in annealing furnace, apparatus for the same and method of producing cold-rolled and annealed steel sheet
US9657366B2 (en) * 2012-04-09 2017-05-23 Jfe Steel Corporation Method of reducing dew point of atmosphere gas in annealing furnace, apparatus for the same and method of producing cold-rolled and annealed steel sheet
US10233526B2 (en) * 2012-12-04 2019-03-19 Jfe Steel Corporation Facility having a continuous annealing furnace and a galvanization bath and method for continuously manufacturing hot-dip galvanized steel sheet

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JPWO2013153791A1 (ja) 2015-12-17
CN104245972A (zh) 2014-12-24
EP2837700B1 (en) 2019-06-05
EP2837700A1 (en) 2015-02-18
KR101564870B1 (ko) 2015-10-30
EP2837700A4 (en) 2015-12-02
KR20140139590A (ko) 2014-12-05
JP5742950B2 (ja) 2015-07-01
WO2013153791A1 (ja) 2013-10-17
CN104245972B (zh) 2016-03-16

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