US3718510A - Method for increasing the heating rate in continuous annealing processes - Google Patents
Method for increasing the heating rate in continuous annealing processes Download PDFInfo
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- US3718510A US3718510A US00115456A US3718510DA US3718510A US 3718510 A US3718510 A US 3718510A US 00115456 A US00115456 A US 00115456A US 3718510D A US3718510D A US 3718510DA US 3718510 A US3718510 A US 3718510A
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- strip
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- heating rate
- heating
- emissivity
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 22
- 238000000034 method Methods 0.000 title claims description 19
- 238000000137 annealing Methods 0.000 title description 9
- 238000000576 coating method Methods 0.000 claims abstract description 32
- 239000011248 coating agent Substances 0.000 claims abstract description 20
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 239000000243 solution Substances 0.000 claims description 4
- POWFTOSLLWLEBN-UHFFFAOYSA-N tetrasodium;silicate Chemical compound [Na+].[Na+].[Na+].[Na+].[O-][Si]([O-])([O-])[O-] POWFTOSLLWLEBN-UHFFFAOYSA-N 0.000 claims description 4
- 239000007864 aqueous solution Substances 0.000 claims description 2
- 239000004615 ingredient Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 abstract description 13
- 238000001816 cooling Methods 0.000 abstract description 11
- 229910000831 Steel Inorganic materials 0.000 abstract description 7
- 239000010959 steel Substances 0.000 abstract description 7
- 229910052910 alkali metal silicate Inorganic materials 0.000 abstract description 3
- 238000012360 testing method Methods 0.000 description 11
- 238000001953 recrystallisation Methods 0.000 description 5
- 238000001035 drying Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 3
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 3
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 3
- 229910052605 nesosilicate Inorganic materials 0.000 description 3
- 150000004762 orthosilicates Chemical class 0.000 description 3
- 239000011591 potassium Substances 0.000 description 3
- 229910052700 potassium Inorganic materials 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- 229910052708 sodium Inorganic materials 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 230000001680 brushing effect Effects 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 2
- QLOKJRIVRGCVIM-UHFFFAOYSA-N 1-[(4-methylsulfanylphenyl)methyl]piperazine Chemical compound C1=CC(SC)=CC=C1CN1CCNCC1 QLOKJRIVRGCVIM-UHFFFAOYSA-N 0.000 description 1
- 229910021555 Chromium Chloride Inorganic materials 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 241000276498 Pollachius virens Species 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000010425 asbestos Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- QSWDMMVNRMROPK-UHFFFAOYSA-K chromium(3+) trichloride Chemical compound [Cl-].[Cl-].[Cl-].[Cr+3] QSWDMMVNRMROPK-UHFFFAOYSA-K 0.000 description 1
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Substances OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 1
- 238000004320 controlled atmosphere Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 239000002320 enamel (paints) Substances 0.000 description 1
- 239000012065 filter cake Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- FBAFATDZDUQKNH-UHFFFAOYSA-M iron chloride Chemical compound [Cl-].[Fe] FBAFATDZDUQKNH-UHFFFAOYSA-M 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 235000021110 pickles Nutrition 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 229910052895 riebeckite Inorganic materials 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000011775 sodium fluoride Substances 0.000 description 1
- PUZPDOWCWNUUKD-UHFFFAOYSA-M sodium fluoride Inorganic materials [F-].[Na+] PUZPDOWCWNUUKD-UHFFFAOYSA-M 0.000 description 1
- 235000013024 sodium fluoride Nutrition 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Images
Classifications
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
- C21D9/54—Furnaces for treating strips or wire
- C21D9/56—Continuous furnaces for strip or wire
-
- 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
- C21D1/68—Temporary coatings or embedding materials applied before or during heat treatment
- C21D1/70—Temporary coatings or embedding materials applied before or during heat treatment while heating or quenching
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C24/00—Coating starting from inorganic powder
Definitions
- This invention relates to a method of continuous annealing, whereby both the heat-up rate and cooling rate of the steel sheet material undergoing recrystallization is markedly increased.
- Continuous annealing is employed extensively in the production of recrystallized sheet and strip material.
- the strand of light-gage cold reduced metal travels at high speed through a radiant heating zone, under a non-oxidizing atmosphere, where it is brought to desired temperature in a short time, held at temperature for a period of a few seconds, passed through a cooling zone and then emerges into the air at a temperature below that at which it rapidly oxidizes.
- both the heating and cooling of the strip are effected primarily by radiation, the heating and cooling rates are dependent on the emissivity of the surface of the strip.
- An ideal black body has an emissivity of 1.0, whereas the ordinary steel strip employed in such continuous annealing processes has an emissivity below 0.2, resulting in much slower heat transfer rates than could be obtained with surfaces having higher emissivities. Consequently, a considerable length of heating and cooling section is required to achieve the desired temperature; and for commercial lines operating at speeds of about 1,500 ft/min., these sections are necessarily large and expensive. If the emissivity of the strip could be effectively increased prior to its entry into the heating zone of the furnace, continuous annealing lines operating at a fixed speed could be reduced in size and cost.
- the di, meta, and ortho silicates of sodium and potassium have been found to possess a combination of properties (hereinafter described) which make them particularly suitable as coating materials for increasing e. they are able to withstand roll contact without chipping or flaking and are therefore amenable to thickness control; and
- the coatings may be applied as a wet cake, by brushing, by spraying of an aqueous mixture or by passage through a bath.
- the cold reduced strip is conveyed through a tank containing an aqueous mixture (slurry, suspension, or solution) of the silicate. It is then passed through rolls to control the uniformity and thickness of the coating, followed by drying jets to remove the greater part of the water.
- the rolls may be eliminated, and the drying jets may be employed to serve both functions, by serving as an air knife (analogous to the procedure of, for example, U.S. Pat. No. 3,459,587).
- the strip with the proper thickness of coating on the surface thereof is passed to the annealing furnace, to effect recrystallization of the cold reduced material.
- the strip passes to a cooling section, where it is permitted to cool under a controlled atmosphere with the high emissivity coating still intact.
- the strip emerges from the cooling section at a temperature cool enough to avoid oxidation, it is cooled by water jets, which serve a dual function by dissolving and removing the silicate coating.
- thermocouples were attached to both the coated and uncoated portions of the same sample; both temperatures being simultaneously and continuously recorded-In other tests, separate samples of coated and uncoated strip were prepared and tested.
- the heating rate ratio (the heating rate of coated strip, divided by the heating rate of uncoated strip) also increases. However, as evidenced by the FIGURE, this ratio increases rapidly above a thickness of about 5 milliounceslft reaching a maximum at about milliounces/ft of strip surface, and thereafter decreases, but more slowly.
- coatings greater than about 20 milliounces/ft would be less desirable both because of increased material cost as well as increased cost of removal. Coatings within a range of about 9-15 milliounces/ft being preferred, for providing both maximum heat-up rates as well as minimum cost.
- Pilot line tests have been run to compare the service performance of control strip with that of strip annealed with the sodium orthosilicate coating of this invention. These comparison strips were both chrome plated and tin plated and then processed through standard quality performance tests. For the chromium plated product, these tests included the stack rust test, humid storage test, salt-citric acid test and accelerated salt-water test, whereas for tin plated strip, the tests included the stack rust test, iron solution value, alloy tin couple and pickle lag testing. In all cases, the precoated annealed strip of this invention was equal to or better in quality performance than that of the control, untreated annealed strip. It is clear, therefore, that these emissivity coatings do not change the surface chemistry of annealed strip in any manner which would deleteriously affect the end use of the annealed product.
- strand as used herein and in the appended claims is to be understood as including flat rolled metal articles of various dimensions, as well as wire, rod, or other elongated articles amenable to continuous radiation heat treatment.
- the improvement which comprises: applying to the surface of the strand, a coating selected from the group consisting essentially of the di, meta and ortho silicates of sodium or potassium, and mixtures thereof, in a thickness of from about 5 to about 20 milliounces per square foot of strand surface; thereafter, rapidly heating said strand to a temperature above the lower critical to effect recrystallization, passing said strand to a cooling zone and subsequently removing said coating from the strand surface.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Abstract
Alkali metal silicate coatings are applied to steel sheet or strip material to increase the emissivity of the material undergoing heating and/or cooling under substantially radiative conditions. The heating rate of the sheet material is markedly increased with the application of coating thicknesses within the range of about 5 to 20 milliounces/ft2.
Description
O United States Patent 1 1 11 1 3,718,510 Patula et al. 1 1 Feb. 27, 1973 [54] METHOD FOR INCREASING THE 3,582,409 6/1971 Kohler ..l48/1 13 X HEATING E [N N INU 3,301,702 1/1967 Amcs et al.... ....148/14 X 3,480,486 11/1969 Tanaka et al..... ..l48/l4 X ANNEALING PROCESSES 2,906,649 9/1959 Keuth et al. ..l 17/ 135.] X [75] Inventors: Edward J. Patula, Monroeville; 2,628,175 2/1953 Henderson ..1 17/ 135.1 X Robert R. Somers, Penn Hills 2,462,763 2/1949 Nightingall ..1 17/ 135.1 X Township; William L. Roberts, 1,856,751 3/1932 Prefahl ..148/14 X Franklin Township, Westmoreland 1,750,305 3/1930 Gross ..1 17/ 135.1 X Cty., all of Pa. Primary Examiner-Charles N. Lovell [73] Assignee. Umted States Steel Corporation Atmmey Arthur J. Greif [22] Filed: Feb. 16, 1971 21 Appl.'No.: 115,456 [571 ABSTRACT Alkali metal silicate coatings are applied to steel sheet 521 US. Cl. ..14s/14, 117/1351, 148/18 strip material increase the emissivity the 148/28 148/29 material undergoing heating and/r cooling under sub- 51 Int. Cl. ..C2ld 1/48 Stamially radiative eenditiens- The heating rate of the 58 Field of Search ..14s 12.1, 14, 18, 122, 113, sheet material is markedly increased with the pp 148/28, 29; 117/135 1 tion of coating thicknesses within the range of about to 20 milliounceslft 56 R t d l 1 e 4 Claims, 1 Drawing Figure UNITED STATES PATENTS 3,208,874 9/1965 Conner, Jr ..1 17/1351 STRIP SPEED -/0 FPM HEflT/IVG RATE RATIO OF COATED T0 UNCOATED STRIP 60A TIA/G wE/aHr, MIL L IOUNCES/F r 2 STRIP THICKNESS 0.0066" HEAT/N6 ZONE TEMPERATURE-IJQOVI TO 1500",.
PATENTED FEBZYIQYS nttkm 0 3 E 0 w w w 0 T F a 0 w -2 3 4 E H 6 0 A 0 1w mm P mow ww 0 MDK E0 2 m P MS 0 WWW E 5 arr H88 0 COAT/N6 WEIGHT; MILL/OUA/CES/FT INVENTORS.
I EDWARD J. PATULA, WILL/AM L. ROBERTS 5 ROBERT R. OMERS METHOD FOR INCREASING THE HEATING RATE IN CONTINUOUS ANNEALING PROCESSES This invention relates to a method of continuous annealing, whereby both the heat-up rate and cooling rate of the steel sheet material undergoing recrystallization is markedly increased.
Continuous annealing is employed extensively in the production of recrystallized sheet and strip material. In this treatment, the strand of light-gage cold reduced metal, travels at high speed through a radiant heating zone, under a non-oxidizing atmosphere, where it is brought to desired temperature in a short time, held at temperature for a period of a few seconds, passed through a cooling zone and then emerges into the air at a temperature below that at which it rapidly oxidizes.
Since both the heating and cooling of the strip are effected primarily by radiation, the heating and cooling rates are dependent on the emissivity of the surface of the strip. An ideal black body has an emissivity of 1.0, whereas the ordinary steel strip employed in such continuous annealing processes has an emissivity below 0.2, resulting in much slower heat transfer rates than could be obtained with surfaces having higher emissivities. Consequently, a considerable length of heating and cooling section is required to achieve the desired temperature; and for commercial lines operating at speeds of about 1,500 ft/min., these sections are necessarily large and expensive. If the emissivity of the strip could be effectively increased prior to its entry into the heating zone of the furnace, continuous annealing lines operating at a fixed speed could be reduced in size and cost. Conversely, lines could be made to operate at even higher speeds and on thicker strip. It has now been found that certain alkali metal silicates, when applied to the steel surface, in certain critical coating thicknesses, not only effectively increase the emissivity of the surface, but also possess a combination of other properties desirable for the commercial utilization of such a technique.
It is therefore an object of this invention to provide a method for coating strip material to markedly increase the emissivity of the surface thereof.
It is another object of this invention to provide such a coating method with a minimum of additional cost.
It is still another object of this invention to provide a coating method which does not affect appearance or end use of the strip.
These and other objects will be more apparent when read in conjunction with the following description, taken in conjunction with the appended claims, and the FIGURE which shows the critical effect of sodium orthosilicate coating thickness on strip heating rate.
The di, meta, and ortho silicates of sodium and potassium have been found to possess a combination of properties (hereinafter described) which make them particularly suitable as coating materials for increasing e. they are able to withstand roll contact without chipping or flaking and are therefore amenable to thickness control; and
f. they provide significant increases in heat-up and cooling rates.
The coatings may be applied as a wet cake, by brushing, by spraying of an aqueous mixture or by passage through a bath. In the latter, preferred method, the cold reduced strip is conveyed through a tank containing an aqueous mixture (slurry, suspension, or solution) of the silicate. It is then passed through rolls to control the uniformity and thickness of the coating, followed by drying jets to remove the greater part of the water. In an alternate procedure, the rolls may be eliminated, and the drying jets may be employed to serve both functions, by serving as an air knife (analogous to the procedure of, for example, U.S. Pat. No. 3,459,587). Subsequent to drying, the strip with the proper thickness of coating on the surface thereof, is passed to the annealing furnace, to effect recrystallization of the cold reduced material. Following recrystallization, the strip passes to a cooling section, where it is permitted to cool under a controlled atmosphere with the high emissivity coating still intact. As the strip emerges from the cooling section at a temperature cool enough to avoid oxidation, it is cooled by water jets, which serve a dual function by dissolving and removing the silicate coating.
In the investigation which led to this invention, potential coatings were evaluated, using a muffle furnace with a specially designed protective atmosphere chamber. Samples were evaluated for their ease in the application and removal of the coating as well as for their emissivity. In this regard, it should be noted that materials need not be dark in appearance to have high values of emissivity. For example, asbestos, glass, and white enamel paint, although light in appearance had significantly increased emissivities. Coatings were applied by brushing and then drying completely.
Samples (4 X 8 X 0.0085 inches) were screened by determining the heating rates from F to a temperature of l,l00 F. In some tests, thermocouples were attached to both the coated and uncoated portions of the same sample; both temperatures being simultaneously and continuously recorded-In other tests, separate samples of coated and uncoated strip were prepared and tested. Of the coatings tested, which included: MgO slurry; CaSO 2I-I O; H PO,; BOP furnace filter cake; phosphate cleanser; potassium chromate, iodide and fluoride; sodium chloride, and fluoride; iron chloride; chromium chloride; and sodium silicate (water glass) only the di, meta, and ortho silicates of sodium and potassium possess the ability to significantly increase the emissivity of the strip without marring its finish, and to be easily and economically removable by simple rinsing.
Although even a very thin coating of silicate would effect at least some increase in emissivity, it has been found that there exists a critical minimum thickness for achieving a significant increase in heat-up rate. Referring to the FIGURE, it may be seen that as coating weight increases, the heating rate ratio (the heating rate of coated strip, divided by the heating rate of uncoated strip) also increases. However, as evidenced by the FIGURE, this ratio increases rapidly above a thickness of about 5 milliounceslft reaching a maximum at about milliounces/ft of strip surface, and thereafter decreases, but more slowly. Thus, while very thick coatings would still provide significant increases in heat-up ratio, coatings greater than about 20 milliounces/ft would be less desirable both because of increased material cost as well as increased cost of removal. Coatings within a range of about 9-15 milliounces/ft being preferred, for providing both maximum heat-up rates as well as minimum cost.
Pilot line tests have been run to compare the service performance of control strip with that of strip annealed with the sodium orthosilicate coating of this invention. These comparison strips were both chrome plated and tin plated and then processed through standard quality performance tests. For the chromium plated product, these tests included the stack rust test, humid storage test, salt-citric acid test and accelerated salt-water test, whereas for tin plated strip, the tests included the stack rust test, iron solution value, alloy tin couple and pickle lag testing. In all cases, the precoated annealed strip of this invention was equal to or better in quality performance than that of the control, untreated annealed strip. It is clear, therefore, that these emissivity coatings do not change the surface chemistry of annealed strip in any manner which would deleteriously affect the end use of the annealed product.
The term strand as used herein and in the appended claims is to be understood as including flat rolled metal articles of various dimensions, as well as wire, rod, or other elongated articles amenable to continuous radiation heat treatment.
We claim:
1. In the continuous recrystallization annealing of steel strand, wherein radiative heating is employed to supply at least a major portion of the required rapid increase in temperature, the improvement which comprises: applying to the surface of the strand, a coating selected from the group consisting essentially of the di, meta and ortho silicates of sodium or potassium, and mixtures thereof, in a thickness of from about 5 to about 20 milliounces per square foot of strand surface; thereafter, rapidly heating said strand to a temperature above the lower critical to effect recrystallization, passing said strand to a cooling zone and subsequently removing said coating from the strand surface.
2. The method of claim 1, wherein the coating is applied as an aqueous mixture of said silicate, and substantially all the water is eliminated from said coating prior to said rapid heating.
3. The method of claim 2, wherein said mixture consists essentially of an aqueous solution of said silicate.
4. The method of claim 3, in which the major ingredient in said solution is sodium orthosilicate, and said thicknesses from about 9 to about l5 milliounces per square foot.
Claims (3)
- 2. The method of claim 1, wherein the coating is applied as an aqueous mixture of said silicate, and substantially all the water is eliminated from said coating prior to said rapid heating.
- 3. The method of claim 2, wherein said mixture consists essentially of an aqueous solution of said silicate.
- 4. The method of claim 3, in which the major ingredient in said solution is sodium orthosilicate, and said thicknesses from about 9 to about 15 milliounces per square foot.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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US11545671A | 1971-02-16 | 1971-02-16 |
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Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3839256A (en) * | 1973-05-11 | 1974-10-01 | Steel Corp | Silicate-resin coating composition |
US3908066A (en) * | 1973-05-11 | 1975-09-23 | United States Steel Corp | Protecting metal and metal products |
US4209366A (en) * | 1977-07-01 | 1980-06-24 | Centre De Recherches Metallurgiques Centrum Voor Research In De Metallurgie | Process for improving the surface cleanliness of sheet steel |
EP0466491A2 (en) * | 1990-07-12 | 1992-01-15 | Kawasaki Steel Corporation | Anti-oxidation agent for continuous annealing of stainless steel strip and anti-oxidation method using the same |
US20150360444A1 (en) * | 2014-06-13 | 2015-12-17 | Thyssenkrupp Rasselstein Gmbh | Method for the production of an aluminized packaging steel |
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US1856751A (en) * | 1930-03-17 | 1932-05-03 | Grasselli Chemical Co | Process of preparing metal sheets for annealing |
US2462763A (en) * | 1937-03-20 | 1949-02-22 | Met Proprietary Ltd Di | Protectively coated ferrous metal surfaces and method of producing same |
US2628175A (en) * | 1948-05-24 | 1953-02-10 | Colin Stewart Ltd | Coated sheet metal |
US2906649A (en) * | 1955-04-07 | 1959-09-29 | Siemens Ag | Heat-resistant electric insulation and method of manufacture |
US3208874A (en) * | 1964-12-03 | 1965-09-28 | Allegheny Ludlum Steel | Surface finishing of stainless steel |
US3301702A (en) * | 1963-05-09 | 1967-01-31 | Allegheny Ludlum Steel | Coating for the protection of ferrous base alloys at elevated temperatures |
US3480486A (en) * | 1965-06-18 | 1969-11-25 | Kokusai Electric Co Ltd | Heating method for local annealing or stress relieving of parts of metal articles |
US3582409A (en) * | 1968-01-02 | 1971-06-01 | Armco Steel Corp | Method of producing potassium silicate glass coating for ferrous magnetic sheet stock |
-
1971
- 1971-02-16 US US00115456A patent/US3718510A/en not_active Expired - Lifetime
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
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US1750305A (en) * | 1927-11-19 | 1930-03-11 | Westinghouse Electric & Mfg Co | Insulating material |
US1856751A (en) * | 1930-03-17 | 1932-05-03 | Grasselli Chemical Co | Process of preparing metal sheets for annealing |
US2462763A (en) * | 1937-03-20 | 1949-02-22 | Met Proprietary Ltd Di | Protectively coated ferrous metal surfaces and method of producing same |
US2628175A (en) * | 1948-05-24 | 1953-02-10 | Colin Stewart Ltd | Coated sheet metal |
US2906649A (en) * | 1955-04-07 | 1959-09-29 | Siemens Ag | Heat-resistant electric insulation and method of manufacture |
US3301702A (en) * | 1963-05-09 | 1967-01-31 | Allegheny Ludlum Steel | Coating for the protection of ferrous base alloys at elevated temperatures |
US3208874A (en) * | 1964-12-03 | 1965-09-28 | Allegheny Ludlum Steel | Surface finishing of stainless steel |
US3480486A (en) * | 1965-06-18 | 1969-11-25 | Kokusai Electric Co Ltd | Heating method for local annealing or stress relieving of parts of metal articles |
US3582409A (en) * | 1968-01-02 | 1971-06-01 | Armco Steel Corp | Method of producing potassium silicate glass coating for ferrous magnetic sheet stock |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3839256A (en) * | 1973-05-11 | 1974-10-01 | Steel Corp | Silicate-resin coating composition |
US3908066A (en) * | 1973-05-11 | 1975-09-23 | United States Steel Corp | Protecting metal and metal products |
US4209366A (en) * | 1977-07-01 | 1980-06-24 | Centre De Recherches Metallurgiques Centrum Voor Research In De Metallurgie | Process for improving the surface cleanliness of sheet steel |
EP0466491A2 (en) * | 1990-07-12 | 1992-01-15 | Kawasaki Steel Corporation | Anti-oxidation agent for continuous annealing of stainless steel strip and anti-oxidation method using the same |
EP0466491A3 (en) * | 1990-07-12 | 1992-03-04 | Kawasaki Steel Corporation | Anti-oxidation agent for continuous annealing of stainless steel strip and anti-oxidation method using the same |
US20150360444A1 (en) * | 2014-06-13 | 2015-12-17 | Thyssenkrupp Rasselstein Gmbh | Method for the production of an aluminized packaging steel |
CN105316595A (en) * | 2014-06-13 | 2016-02-10 | 蒂森克虏拉塞斯坦有限公司 | Method for production of aluminized packaging steel and related application of aluminized steel sheet |
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Legal Events
Date | Code | Title | Description |
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AS | Assignment |
Owner name: USX CORPORATION, A CORP. OF DE, STATELESS Free format text: MERGER;ASSIGNOR:UNITED STATES STEEL CORPORATION (MERGED INTO);REEL/FRAME:005060/0960 Effective date: 19880112 |