US20070107817A1 - Method for controlling bright annealing furnace - Google Patents

Method for controlling bright annealing furnace Download PDF

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Publication number
US20070107817A1
US20070107817A1 US10/574,637 US57463704A US2007107817A1 US 20070107817 A1 US20070107817 A1 US 20070107817A1 US 57463704 A US57463704 A US 57463704A US 2007107817 A1 US2007107817 A1 US 2007107817A1
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US
United States
Prior art keywords
furnace
partial pressure
steam
dew point
environment
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/574,637
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English (en)
Inventor
Kenji Kousaka
Morihiko Imada
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chugai Ro Co Ltd
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Chugai Ro Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Chugai Ro Co Ltd filed Critical Chugai Ro Co Ltd
Assigned to CHUGAI RO CO., LTD. reassignment CHUGAI RO CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: IMADA, MORIHIKO, KOUSAKA, KENJI
Publication of US20070107817A1 publication Critical patent/US20070107817A1/en
Abandoned legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
    • C21D1/76—Adjusting the composition of the atmosphere

Definitions

  • the invention relates to method of controlling the generation of white powder within a bright annealing furnace.
  • White ash particles are normally generated within a bright annealing furnace, when a heat-treated steel strip, such as stainless steel strip or the like, is heat treated in the internal furnace environment which is not to oxidize the surface of the strip.
  • a large volume of white powder often accumulates in the cooling zone of the annealing furnace and inside of a cooler for cooling a furnace environment gas. Continuous operation of the furnace over a long period of time results in making the thermally low conductive white powder accumulate in and adhere to the cooler and/or other related mechanisms, thus inhibiting the performance of the cooler. Large amounts of cooling water have been used in an attempt to solve the problem. However, this has been found not to be the desired solution due to limitations on pump capacity.
  • the hardness of the white powder is greater than that of the heat treated steel strip, there are cases where the steel strip is damaged as a result of excessive pressure resulting from the accumulation of the white powder on the skin-pass roller. This can adversely affect the quality of the finished product.
  • the white powder adversely affects the cooling performance of the bright annealing furnace and also has the potential to degrade the quality of the finished product.
  • the bright annealing furnace is correctly installed and operated, it has been found necessary to periodically conduct maintenance by lowering the temperature and opening the furnace for the sole purpose of cleaning out the accumulated white powder.
  • the skin-pass rollers are also removed, polished, and re-installed when this type of maintenance is conducted.
  • a reducing gas of hydrogen and nitrogen is injected into the internal furnace environment while the furnace is operating, the gradual release of oxygen atoms makes it difficult to set the residual oxygen concentration to the required value when the gas is re-injected into the furnace environment, since the internal environment is oxidized by the opening operation of the furnace for maintenance.
  • the operating yield of the bright annealing furnace is also significantly reduced because the furnace cannot be operated while the aforesaid maintenance is being conducted.
  • a conventional bright annealing furnace exhibits the shortcoming of generating a white powder which makes it difficult to maintain the cooling performance of the furnace, reduces production efficiency due to the periodic maintenance required to remove the white powder (during which the furnace may not be operated), and adversely affects the quality of the finished product.
  • it is desirable that a method of reducing the generation of white powder is invented.
  • a selected aspect relates to a method for controlling a bright annealing furnace comprising establishing a partial pressure of steam within the furnace at less than about 1 ⁇ 10 ⁇ 5 to suppress generation of boron oxide.
  • the partial pressure of the steam is established at a value less than about 1 ⁇ 10 ⁇ 5 by lowering the dew point of the internal furnace environment.
  • the method can also include a process wherein a gas having a hydrocarbon component is introduced into the internal environment of the bright annealing furnace to reduce the water vapor pressure to a value of less than about 1 ⁇ 10 ⁇ 5 by lowering the dew point of the internal environment within the furnace.
  • the method can further include another process wherein a chemical compound having a carbon component is introduced into the internal environment of the bright annealing furnace to reduce the water vapor pressure to a value of less than about 1 ⁇ 10 ⁇ 5 by lowering the dew point of the internal environment within the furnace.
  • FIG. 1 is an Ellingham diagram showing the Gibbs standard generated free energy ⁇ G° of the boron oxide, the causative agent of the white powder.
  • FIG. 2 is a logarithmic graph showing the relationship between the partial pressure of methane, carbon monoxide, and steam at 1,400K.
  • the gas may be easily injected into the internal furnace environment without regard as to the type of furnace being used, thus making the invention applicable to various types of bright annealing furnaces.
  • the chemical compound may simply be placed in the heating region of the bright annealing furnace when inspection or maintenance work is conducted. The methods specified by the invention are thus easily applied to a bright annealing furnace.
  • K 1 and K 2 are equilibrium constants.
  • partial pressure P (H 2 ) is unrestricted at a value near 1 due to the approximately 100% concentration of H 2 in the internal environment of the bright annealing furnace. Even if the furnace operates with an internal environment other than pure H 2 (75% H 2 , 25% N 2 , for example), the nitrogen (N 2 ) is not involved in the reaction. Also, of all components, the H 2 component comprises almost the entire environment. Thus, if error is taken into consideration, partial pressure P (H 2 ) may be considered as 1 (as in the following).
  • Equation 3 shows that, in regard to random methane partial pressure P (CH 4 ) as shown in FIG. 2 , the reduction of carbon monoxide partial pressure P (CO) has the effect of reducing steam partial pressure P (H 2 O) to a point below 1 ⁇ 10 ⁇ 5 which thus makes it possible to suppress the generation of boron oxide.
  • Equation 5 The following (equation 5) is derived from equation 4.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Furnace Details (AREA)
US10/574,637 2003-10-17 2004-10-12 Method for controlling bright annealing furnace Abandoned US20070107817A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2003-358078 2003-10-17
JP2003358078A JP2005120448A (ja) 2003-10-17 2003-10-17 光輝焼鈍炉の制御方法
PCT/JP2004/015025 WO2005038059A1 (ja) 2003-10-17 2004-10-12 光輝焼鈍炉の制御方法

Publications (1)

Publication Number Publication Date
US20070107817A1 true US20070107817A1 (en) 2007-05-17

Family

ID=34463278

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/574,637 Abandoned US20070107817A1 (en) 2003-10-17 2004-10-12 Method for controlling bright annealing furnace

Country Status (6)

Country Link
US (1) US20070107817A1 (ja)
EP (1) EP1679385A4 (ja)
JP (1) JP2005120448A (ja)
CN (1) CN1867686A (ja)
TW (1) TWI338052B (ja)
WO (1) WO2005038059A1 (ja)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9581389B2 (en) 2012-03-27 2017-02-28 Kanto Yakin Kogyo Co., Ltd. Method for heat treatment, heat treatment apparatus, and heat treatment system

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5188448B2 (ja) * 2009-05-11 2013-04-24 中外炉工業株式会社 連続焼鈍炉
CN102534182B (zh) * 2012-02-23 2014-02-12 中冶南方工程技术有限公司 一种用于罩式退火炉工艺的控制***
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

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5167735A (en) * 1990-03-29 1992-12-01 Linde Aktiengesellschaft Process for the annealing of steel annealing material
US5814726A (en) * 1996-04-10 1998-09-29 E & E Elektronik Gesellschaft M.B.H. Method for determining the absolute humidity of air

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53110909A (en) * 1977-03-10 1978-09-28 Oriental Engineering Co Control method of furnace atomosphere
JPS6039131B2 (ja) * 1980-08-07 1985-09-04 オリエンタルエンヂニアリング株式会社 光輝熱処理における炉気制御方法
DE3733884A1 (de) * 1987-10-07 1989-04-27 Linde Ag Verfahren zum gluehen von metallteilen in durchlaufoefen
JPH032317A (ja) * 1989-05-29 1991-01-08 Sumitomo Metal Ind Ltd 光輝焼鈍炉の雰囲気ガス調整方法
JP2530580Y2 (ja) * 1991-06-12 1997-03-26 日本酸素株式会社 熱処理雰囲気炉
JPH1072624A (ja) * 1996-08-30 1998-03-17 Nisshin Steel Co Ltd 光輝焼鈍炉におけるホワイトパウダーの削減方法
JPH1150202A (ja) * 1997-07-29 1999-02-23 Sumitomo Metal Ind Ltd 耐銹性に優れたフェライト系ステンレス鋼光輝焼鈍材およびその製造方法
JPH11158559A (ja) * 1997-11-27 1999-06-15 Sumitomo Metal Ind Ltd 連続焼鈍炉の炉内雰囲気制御方法
GB9800528D0 (en) * 1998-01-12 1998-03-11 Boc Group Plc Furnace atmosphere dew point control
JP3882470B2 (ja) * 2000-06-06 2007-02-14 住友金属工業株式会社 オーステナイト系ステンレス鋼板の製造方法
JP2003247787A (ja) * 2002-02-22 2003-09-05 Chugai Ro Co Ltd 連続焼鈍炉におけるホワイトパウダー除去装置

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5167735A (en) * 1990-03-29 1992-12-01 Linde Aktiengesellschaft Process for the annealing of steel annealing material
US5814726A (en) * 1996-04-10 1998-09-29 E & E Elektronik Gesellschaft M.B.H. Method for determining the absolute humidity of air

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9581389B2 (en) 2012-03-27 2017-02-28 Kanto Yakin Kogyo Co., Ltd. Method for heat treatment, heat treatment apparatus, and heat treatment system

Also Published As

Publication number Publication date
TW200526790A (en) 2005-08-16
JP2005120448A (ja) 2005-05-12
EP1679385A4 (en) 2007-05-30
TWI338052B (en) 2011-03-01
WO2005038059A1 (ja) 2005-04-28
EP1679385A1 (en) 2006-07-12
CN1867686A (zh) 2006-11-22

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Owner name: CHUGAI RO CO., LTD.,JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KOUSAKA, KENJI;IMADA, MORIHIKO;REEL/FRAME:018998/0443

Effective date: 20060328

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION