GB1572231A - Cooling element for a metallurgical furnace - Google Patents

Cooling element for a metallurgical furnace Download PDF

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Publication number
GB1572231A
GB1572231A GB15377/78A GB1537778A GB1572231A GB 1572231 A GB1572231 A GB 1572231A GB 15377/78 A GB15377/78 A GB 15377/78A GB 1537778 A GB1537778 A GB 1537778A GB 1572231 A GB1572231 A GB 1572231A
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GB
United Kingdom
Prior art keywords
layer
cast iron
iron body
cooling element
metallic
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.)
Expired
Application number
GB15377/78A
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.)
Thyssen AG
Original Assignee
Thyssen AG
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 Thyssen AG filed Critical Thyssen AG
Publication of GB1572231A publication Critical patent/GB1572231A/en
Expired legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B7/00Blast furnaces
    • C21B7/10Cooling; Devices therefor
    • 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
    • F27D1/00Casings; Linings; Walls; Roofs
    • F27D1/12Casings; Linings; Walls; Roofs incorporating cooling arrangements
    • 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
    • F27D9/00Cooling of furnaces or of charges therein
    • F27D2009/0002Cooling of furnaces
    • F27D2009/0045Cooling of furnaces the cooling medium passing a block, e.g. metallic
    • F27D2009/0048Cooling of furnaces the cooling medium passing a block, e.g. metallic incorporating conduits for the medium
    • 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
    • F27D9/00Cooling of furnaces or of charges therein
    • F27D2009/0002Cooling of furnaces
    • F27D2009/0051Cooling of furnaces comprising use of studs to transfer heat or retain the liner

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)
  • General Induction Heating (AREA)
  • Laminated Bodies (AREA)

Description

(54) COOLING ELEMENT FOR A METALLURGICAL FURNACE (71) We, THYSSEN AKTIENGESBLL- SCHAFT, a Company organised according to the laws of the Federal Republic of Germany of 4100 Duisburg, Federal Republic of Germany, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: The present invention relates to a cooling element for a metallurgical furnace, in particular for a blast furnace, with steel tubes which are integrally cast in a cast iron body for conveying cooling means, and an additional metallic layer arranged on the steel tube between the tube and the cast iron body of the cooling element.
The inner walling of a continuous furnace, in particular of a blast furnace, is formed from such cooling elements. The cooling elements are provided with a refractory lining on the side facing the inside of the furnace. In order to enable the heat to be discharged, each cooling element is provided with tubes, through which cooling means flows. It is known to diminish the danger of cracking in the steel tubes which are integrally cast in the cast iron body by providing an intermediate layer of metal or metallic oxide on the steel tube, i.e. between the steel tube and the cast iron body.
A layer composed of a mixture of dimethyl polysiloxane and silicon dioxide (German Offenlegungschrift 21 28 827) has been preferred in such a case. Tests carried out by the Applicants have shown that neither the known metallic layers nor the known metallic oxide layers lead to a satisfactory solution. For example, if the intermediate layer is composed of a nickel layer, it has been shown that cracks appear which partly reach up to the tube body - independently of the thickness of, layer applied.
These cracks can lead to carbonisation (cementation) of the steel tube, as the carbon can diffuse from the cast iron body into the steel tubes. Due to the cementation the steel tube loses its inherent high tenacity. An aluminium layer was shown to be unsatisfactory as aluminium is easily oxidised and the cohesive metallic layer is hereby broken up, so that carbonisation also results in the area of the damaged point of the metallic layer. In contrast, an oxidic intermediate layer is often not thermoshock resistant, i.e. cracks appear in the oxide layer during casting and operation due to the different coefficients of expansion of the tube body and the oxide layer. In these cases a disadvantageous carbonisation of the tube also occurs.
It would therefore be desirable to produce a cooling element for a metallurgical furnace in which the steel tubes are protected from carbonisation, the steel tubes are prevented from caking on the cast iron body during casting and by which a good transfer of heat is attained between the cast iron body and the steel tube.
According to the present invention there is provided a cooling element for a metallurgical furnace having steel tubes which are integrally cast in a cast iron body for conveying cooling means, and an additional metallic layer arranged on the steel tube between the tubes and the cast iron body of the cooling element, wherein the metallic layer is composed of at least one of Ni, Co, Mn and Ag and a metallic oxide layer is provided on the metallic layer, the free standard enthalpy of formation of the metallic oxide layer amounting to less than -145 kcal under normal pressure conditions and at a temperature of 6000C.
The metallic oxide layer must be stable, i.e. the free oxide standard enthalpy of formation must be below - 145 kcal under normal pressure conditions and at a temperature of 600"C. The chromium oxides for example, belong to these stable oxides.
However, highly stable metallic oxides are particularly preferred, i.e. metallic oxides whose standard enthalpy of formation is below - 180 kcal at a temperature of 600"C and normal pressure. Thus, the oxides of the metals aluminium, titanium, zirconium are particularly preferred.
The metals selected for the metallic layer or their metal alloys were selected due to their not being inclined to form metal carbides either in the production of the cooling element or during the temperatures of the later use. The metallic layer is pre ferably applied onto the steel tube at a thickness of 40 to 100 microns.
The metal oxide layer is subsequently applied onto the metallic layer at a thickness of preferably 30 to 100 microns. The metallic layer and the metal oxide layer should as a whole have a thickness of 200 microns at maximum. A total thickness of layer of 100 to 200 microns, in particular of 100 to 150 microns, is preferred. Sufficient transfer of heat between the cooled steel tube and the cast iron body is still guaranteed with this thickness of the layer.
An embodiment of cooling element within the present invention has a long service life as the selected first layer effectively prevents the steel tube from carbonising while the tube is being integrally cast in the cast iron body and also during later operation. This protective function is guaranteed from the outset as the second layer (metal oxide layer) is not susceptible to damage and therefore cracks and fractures are prevented from occuring in the first layer (metal layer). Moreover, the second layer Drevents the steel tube from caking on the cast iron body. It also supports the first layer in its Drotective function as it hinders both the diffusion of carbon and the diffusion of oxygen into the steel tube.At the same time, a good transfer of heat is guaranteed as even when the total thickness of the intermediate layer amounts to 100-200 microns, preferably up to 150 microns, the oxide layer, which deteriorates the transfer of heat, only amounting to a part of the intermediate layer.
A particular embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Fig. 1 shows a top view of a cooling element: Fig. 2 shows a cross-section according to line I-I of Fig. 1; Fig. 3 shows an enlarged section of the cross-section of Fig. 2.
A cooling element is composed of a boxshaped cast iron body 1 bearing ribs 2 on one side to anchor refractory material.
Cooling tubes 3 curved in the shape of a "U" are integrally cast in the cast iron body, the inlets and outlets 4, 5 of the tubes 3 projecting out of the cast iron body 1 on the side opposing said ribs 2. The tubes 3 are of steel.
A multilayered intermediate layer is arranged between the walls of the tube 3 and the cast iron body 1. The first layer 6 composed of a metal which does not form carbides, in the present case nickel or cobalt, or alloys thereof, is arranged directly on the tube 3. The second layer 7 composed of highly stable metal oxides, in particular oxides of the metals Al, titanium, zirconium or mixtures thereof, is arranged on said first layer 6. The layers are sprayed on.
The first layer is approximately 70 microns thick and the second layer approximately 50 microns thick.
The cast iron body of a cooling element according to the present invention may be composed of the material described and claimed in our copending application no.
15378/78, 1572232 of the same date and/ or provided with a refractory lining as described therein.
WHAT WE CLAIM IS: 1. A cooling element for a metallurgical furnace having steel tubes which are integrally cast in a cast iron body for conveying cooling means, and an additional metallic layer arranged on the steel tube between the tubes and the cast iron body of the cooling element, wherein the metallic layer is composed of at least one of Ni, Co, Mn and Ag and a metallic oxide layer is provided on the metallic layer, the free standard enthalpy of formation of the metallic oxide layer amounting to less than -145 kcal under normal pressure conditions and at a temperature of 600"C.
2. A cooling element according to claim 1 wherein the metal oxide layer is composed of an oxide of at least one of the metals Al, Ti, or Zr.
3. A cooling element substantially as herein described with reference to and as illustrated in the accompanying drawings.
4. A metallurgical furnace provided with cooling elements as claimed in any one of the prece goTTET T'T
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

  1. **WARNING** start of CLMS field may overlap end of DESC **.
    for example, belong to these stable oxides.
    However, highly stable metallic oxides are particularly preferred, i.e. metallic oxides whose standard enthalpy of formation is below - 180 kcal at a temperature of 600"C and normal pressure. Thus, the oxides of the metals aluminium, titanium, zirconium are particularly preferred.
    The metals selected for the metallic layer or their metal alloys were selected due to their not being inclined to form metal carbides either in the production of the cooling element or during the temperatures of the later use. The metallic layer is pre ferably applied onto the steel tube at a thickness of 40 to 100 microns.
    The metal oxide layer is subsequently applied onto the metallic layer at a thickness of preferably 30 to 100 microns. The metallic layer and the metal oxide layer should as a whole have a thickness of 200 microns at maximum. A total thickness of layer of 100 to 200 microns, in particular of 100 to 150 microns, is preferred. Sufficient transfer of heat between the cooled steel tube and the cast iron body is still guaranteed with this thickness of the layer.
    An embodiment of cooling element within the present invention has a long service life as the selected first layer effectively prevents the steel tube from carbonising while the tube is being integrally cast in the cast iron body and also during later operation. This protective function is guaranteed from the outset as the second layer (metal oxide layer) is not susceptible to damage and therefore cracks and fractures are prevented from occuring in the first layer (metal layer). Moreover, the second layer Drevents the steel tube from caking on the cast iron body. It also supports the first layer in its Drotective function as it hinders both the diffusion of carbon and the diffusion of oxygen into the steel tube.At the same time, a good transfer of heat is guaranteed as even when the total thickness of the intermediate layer amounts to 100-200 microns, preferably up to 150 microns, the oxide layer, which deteriorates the transfer of heat, only amounting to a part of the intermediate layer.
    A particular embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, in which: Fig. 1 shows a top view of a cooling element: Fig. 2 shows a cross-section according to line I-I of Fig. 1; Fig. 3 shows an enlarged section of the cross-section of Fig. 2.
    A cooling element is composed of a boxshaped cast iron body 1 bearing ribs 2 on one side to anchor refractory material.
    Cooling tubes 3 curved in the shape of a "U" are integrally cast in the cast iron body, the inlets and outlets 4, 5 of the tubes 3 projecting out of the cast iron body 1 on the side opposing said ribs 2. The tubes 3 are of steel.
    A multilayered intermediate layer is arranged between the walls of the tube 3 and the cast iron body 1. The first layer 6 composed of a metal which does not form carbides, in the present case nickel or cobalt, or alloys thereof, is arranged directly on the tube 3. The second layer 7 composed of highly stable metal oxides, in particular oxides of the metals Al, titanium, zirconium or mixtures thereof, is arranged on said first layer 6. The layers are sprayed on.
    The first layer is approximately 70 microns thick and the second layer approximately 50 microns thick.
    The cast iron body of a cooling element according to the present invention may be composed of the material described and claimed in our copending application no.
    15378/78, 1572232 of the same date and/ or provided with a refractory lining as described therein.
    WHAT WE CLAIM IS: 1. A cooling element for a metallurgical furnace having steel tubes which are integrally cast in a cast iron body for conveying cooling means, and an additional metallic layer arranged on the steel tube between the tubes and the cast iron body of the cooling element, wherein the metallic layer is composed of at least one of Ni, Co, Mn and Ag and a metallic oxide layer is provided on the metallic layer, the free standard enthalpy of formation of the metallic oxide layer amounting to less than -145 kcal under normal pressure conditions and at a temperature of 600"C.
  2. 2. A cooling element according to claim 1 wherein the metal oxide layer is composed of an oxide of at least one of the metals Al, Ti, or Zr.
  3. 3. A cooling element substantially as herein described with reference to and as illustrated in the accompanying drawings.
  4. 4. A metallurgical furnace provided with cooling elements as claimed in any one of the prece goTTET T'T
GB15377/78A 1977-04-21 1978-04-19 Cooling element for a metallurgical furnace Expired GB1572231A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2717641A DE2717641C3 (en) 1977-04-21 1977-04-21 Cooling element for a metallurgical furnace, in particular for a blast furnace

Publications (1)

Publication Number Publication Date
GB1572231A true GB1572231A (en) 1980-07-30

Family

ID=6006866

Family Applications (1)

Application Number Title Priority Date Filing Date
GB15377/78A Expired GB1572231A (en) 1977-04-21 1978-04-19 Cooling element for a metallurgical furnace

Country Status (8)

Country Link
BE (1) BE866239A (en)
DE (1) DE2717641C3 (en)
FR (1) FR2388233A1 (en)
GB (1) GB1572231A (en)
IT (1) IT1094125B (en)
LU (1) LU79471A1 (en)
NL (1) NL7804071A (en)
ZA (1) ZA781922B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2719166C3 (en) * 1977-04-29 1981-03-19 Thyssen AG vorm. August Thyssen-Hütte, 4100 Duisburg Cooling element for a metallurgical furnace
DE2804544C3 (en) * 1978-02-03 1981-05-07 M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 4200 Oberhausen Cooling plate for a metallurgical furnace, in particular a blast furnace
DE2951640C2 (en) * 1979-12-21 1982-10-14 M.A.N. Maschinenfabrik Augsburg-Nürnberg AG, 4200 Oberhausen Cooling plate for a metallurgical furnace, in particular a blast furnace, and a method for producing it

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE230058C (en) *
FR2053891A5 (en) * 1969-07-22 1971-04-16 Inst Ochistke Tekhno Long life heat exchanger members
FR2096059A5 (en) * 1970-06-10 1972-02-11 Ishikawajima Harima Heavy Ind
PL95965B1 (en) * 1974-11-26 1977-11-30 THE COOLER, ESPECIALLY BLOCK FURNACE

Also Published As

Publication number Publication date
FR2388233B1 (en) 1984-02-03
DE2717641B2 (en) 1980-08-14
DE2717641C3 (en) 1981-05-21
IT1094125B (en) 1985-07-26
LU79471A1 (en) 1978-09-29
NL7804071A (en) 1978-10-24
BE866239A (en) 1978-08-14
FR2388233A1 (en) 1978-11-17
ZA781922B (en) 1979-03-28
DE2717641A1 (en) 1978-11-02
IT7822592A0 (en) 1978-04-21

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Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PCNP Patent ceased through non-payment of renewal fee