US3827922A - Method of retarding metal scale formation with carbon-containing mgo-b2o3 coatings - Google Patents

Method of retarding metal scale formation with carbon-containing mgo-b2o3 coatings Download PDF

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Publication number
US3827922A
US3827922A US00291849A US29184972A US3827922A US 3827922 A US3827922 A US 3827922A US 00291849 A US00291849 A US 00291849A US 29184972 A US29184972 A US 29184972A US 3827922 A US3827922 A US 3827922A
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US
United States
Prior art keywords
percent
coating
mgo
coatings
solids
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 - Lifetime
Application number
US00291849A
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English (en)
Inventor
W Linderman
R Snow
W Boggs
F Borough
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.)
United States Steel Corp
Original Assignee
Steel Corp
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 Steel Corp filed Critical Steel Corp
Priority to US00291849A priority Critical patent/US3827922A/en
Priority to BE135730A priority patent/BE804948A/fr
Priority to GB4355573A priority patent/GB1451235A/en
Priority to DE19732347728 priority patent/DE2347728A1/de
Priority to CA181,736A priority patent/CA1006186A/en
Priority to IT69810/73A priority patent/IT999582B/it
Priority to FR7334371A priority patent/FR2200339B1/fr
Priority to JP48107089A priority patent/JPS503931A/ja
Priority to PL1973165419A priority patent/PL86828B1/pl
Priority to US05/473,543 priority patent/US3956028A/en
Application granted granted Critical
Publication of US3827922A publication Critical patent/US3827922A/en
Assigned to USX CORPORATION, A CORP. OF DE reassignment USX CORPORATION, A CORP. OF DE MERGER (SEE DOCUMENT FOR DETAILS). Assignors: UNITED STATES STEEL CORPORATION (MERGED INTO)
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/27—Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.]
    • Y10T428/273—Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.] of coating

Definitions

  • the composition is admixed with a suitable vehicle and is applied to the metal surface in the form of a dispersion, suspension or as a slurry.
  • This invention is directed to a composition for reducing oxidation and scaling of ferrous articles during high temperature heat treatments.
  • the oxida tion and growth of scale on the surface thereof, and its subsequent removal prior to hot rolling results in a loss of metal that can be quite substantial.
  • the economic loss is even more significant if the article contains appreciable amounts of expensive alloying additions.
  • additional problems are encountered.
  • the nickel-bearing grades develop scales that are abnormally tenacious and extremely ditficult to remove. If such scale is rolled-in during the hot-rolling procedure, the removal of the resulting inclusions results in pits which must be subsequently removed by grinding. This results in even further material loss as Well as significantly increased processing cost.
  • the figure is a graph depicting the protective value of a steel article utilizing the composition of this invention in comparison to that of bare steel and one covered with asbestos.
  • compositions of this invention are admixed in a suitable vehicle and applied in any convenient manner.
  • they may be admixed in the form of slurry or they may be suspended by the use of a suitable dispersant.
  • a suitable dispersant A number of particularly e'ifective vehicles are reported in the examples below.
  • a computer program was written to process the experimental data obtained from each coating tested, and to compare these data with that obtained from oxidation of bare and asbestos covered, 3 Ni steel, heated in air at 1300 C. for 1, 2, 4, and 6 hours.
  • the weight loss for the asbestos covered specimens was divided by the weight loss in the particular test and multiplied by 100. This produced an empirical graduated system of protection values in which asbestos is rated at and bare steel at 67 (see the figure).
  • the protection numbers for the 1, 2, 4 and 6 hour exposures of each coating formulation were added and divided by 4 to provide an average protection value.
  • Such coatings are normally composed of refractory oxides, e.g. alumina, silica, magnesia and fluxes, e.g. silicates, borates, phosphates in combination with a variety of other ingredients.
  • refractory oxides e.g. alumina, silica, magnesia and fluxes, e.g. silicates, borates, phosphates in combination with a variety of other ingredients.
  • protective sheets of refractory materials e.g., asbestos, have been employed to retard oxidation during heating. These expedients have been useful in many instances.
  • these refractory coat- The superiority of the B O -periclase coatings, especially at exposure periods greater than about two hours is clearly evident.
  • the borate should be supplied either as (anhydrous) B 0 or as boric acid.
  • C in any amount up to about 15% will provide enhanced protection, it is preferable to employ greater than about 6%.
  • Any well known source of finely divided C e.g. lamp black, coke breeze, is acceptable.
  • the C burns out of the coating. Therefore, to prevent undue porosity, C in excess of about 12 percent (solids fraction) or particle sizes in excess of 60 mesh should preferably be avoided. Maxiumum benefit is achieved if the particle size is finer than 200 mesh.
  • TiO additions within the range of about 11 to about 17% TiO is especially marked for short (e.g. less than three hours) annealing times. For periods of four hours and greater the TiO;, containing coatings are about equal in protection value to those in which no TiO is employed.
  • compositions of this invention may therefore be formulated in the following manner.
  • the MgO content of the solids fraction may range from about 65 to 80 percent. Significantly lower values of TiO- e.g. 1 to 8 percent, may be detrimental to the basic (MgO-B O -C) coating. When TiO within the preferred range is not employed, the MgO content of the solids fraction should always be greater than about 75 percent, and preferably greater than about 82 percent (depending somewhat on the concentration of the other ingredients).
  • MgO magnesite and precipitated magnesia
  • the denser grained periclase has been found to provide significantly enhanced protection. Because of the above-mentioned detrimental effect of SiO' the periclase should be as pure as possible. In all cases, the SiO content should be below 2 percent and preferably less than 1 percent. It is desirable that the particles be finer than 60 mesh, especially if the coating is to be sprayed (as opposed to painting). For some unknown reason, if the periclase particle sizes are within the very narrow range of 120-140 mesh, the protection afforded is markedly increased.
  • borate content is less than about 2 percent in the solids fraction, there is a loss of coating adherence at high temperatures and the protection afforded is inferior to that of asbestos.
  • the vehicle itself, may be either organic or water base.
  • a water-base vehicle may be preferable.
  • solids content may vary from as low as 10% to as high as a more limited range, e.g. 40-70% is preferable, especially if spraying is employed.
  • a solids content below about 40% excessive heating would be required to evaporate the vehicle, while a solids content in excess of 70% could be difficult to spray.
  • the suspension of solids in water requires a thickener to increase the viscosity and a dispersant to keep the particles in suspension.
  • a binder is required to provide green strength (low temperature cohesion) for the coating.
  • the coating in some instances tended to pull away from the substrate, even though the binder provided excellent cohesion of the particles.
  • the vehicle-binder system consisted of the following:
  • the coating should be applied in a thickness ranging from at least about 0.04 gm./cm. to no greater than about 0.25 gm./cm. Below 0.04 gm./cm. protection is totally insufficient. To insure adequate protection for a period greater than about three hours, it is preferable to employ a coating of at least about 0.08 gm./cm. in thickness.
  • the upper limit of 0.25 gm./ cm. is dictated by the tendency of thicker coatings to spell-off due to thermal shock. To further minimize this tendency, a more preferred upper limit is about 0.15 grn./cm. in thickness.
  • a coating composition consisting essentially of from 40 to 70% solids in a suitable vehicle, wherein said solids consist'essential- 1y of (a) 75 to 95 percent MgO,
  • a coating composition consisting essentially of from 40 to about percent solids in a suitable vehicle, wherein said solids consist essentially of (a) 65 to percent MgO,
  • ferrous article is a steel containing Ni as a purposeful alloy addition and said heat-treatment is conducted at temperatures in excess of about 2300 F. for a period less than about 3 hours.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Paints Or Removers (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Chemical Treatment Of Metals (AREA)
  • Fireproofing Substances (AREA)
US00291849A 1972-09-25 1972-09-25 Method of retarding metal scale formation with carbon-containing mgo-b2o3 coatings Expired - Lifetime US3827922A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
US00291849A US3827922A (en) 1972-09-25 1972-09-25 Method of retarding metal scale formation with carbon-containing mgo-b2o3 coatings
BE135730A BE804948A (fr) 1972-09-25 1973-09-17 Revetements temporaires retardant l'oxydation
GB4355573A GB1451235A (en) 1972-09-25 1973-09-17 Temporary scale retardant coatings
DE19732347728 DE2347728A1 (de) 1972-09-25 1973-09-21 Ueberzugsmasse fuer die verzoegerung der zunderbildung bei temperaturen oberhalb 1177 grad c
IT69810/73A IT999582B (it) 1972-09-25 1973-09-24 Composizione e procedimento per ridurre l ossidazione di articoli ferrosi durante trattamenti termici
CA181,736A CA1006186A (en) 1972-09-25 1973-09-24 Temporary scale retardant coatings
FR7334371A FR2200339B1 (fr) 1972-09-25 1973-09-25
JP48107089A JPS503931A (fr) 1972-09-25 1973-09-25
PL1973165419A PL86828B1 (fr) 1972-09-25 1973-09-25
US05/473,543 US3956028A (en) 1972-09-25 1974-05-28 Temporary scale retardant coatings

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00291849A US3827922A (en) 1972-09-25 1972-09-25 Method of retarding metal scale formation with carbon-containing mgo-b2o3 coatings

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US05/473,543 Division US3956028A (en) 1972-09-25 1974-05-28 Temporary scale retardant coatings

Publications (1)

Publication Number Publication Date
US3827922A true US3827922A (en) 1974-08-06

Family

ID=23122118

Family Applications (1)

Application Number Title Priority Date Filing Date
US00291849A Expired - Lifetime US3827922A (en) 1972-09-25 1972-09-25 Method of retarding metal scale formation with carbon-containing mgo-b2o3 coatings

Country Status (9)

Country Link
US (1) US3827922A (fr)
JP (1) JPS503931A (fr)
BE (1) BE804948A (fr)
CA (1) CA1006186A (fr)
DE (1) DE2347728A1 (fr)
FR (1) FR2200339B1 (fr)
GB (1) GB1451235A (fr)
IT (1) IT999582B (fr)
PL (1) PL86828B1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3930905A (en) * 1972-10-26 1976-01-06 Allmanna Svenska Elektriska Aktiebolaget Method of manufacturing an object of silicon steel
US3956028A (en) * 1972-09-25 1976-05-11 United States Steel Corporation Temporary scale retardant coatings
US3959028A (en) * 1972-11-20 1976-05-25 The International Nickel Company, Inc. Process of working metals coated with a protective coating
US4096000A (en) * 1973-04-11 1978-06-20 Nippon Steel Corporation Annealing separator for silicon steel sheets
US4511124A (en) * 1983-05-03 1985-04-16 Lone Star Steel Company Method and composition for fluidization of accumulated pit scrap in soaking pits

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2164665B (en) * 1984-09-24 1988-06-08 Honda Motor Co Ltd Spacers for use in brazing

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3956028A (en) * 1972-09-25 1976-05-11 United States Steel Corporation Temporary scale retardant coatings
US3930905A (en) * 1972-10-26 1976-01-06 Allmanna Svenska Elektriska Aktiebolaget Method of manufacturing an object of silicon steel
US3959028A (en) * 1972-11-20 1976-05-25 The International Nickel Company, Inc. Process of working metals coated with a protective coating
US4096000A (en) * 1973-04-11 1978-06-20 Nippon Steel Corporation Annealing separator for silicon steel sheets
US4511124A (en) * 1983-05-03 1985-04-16 Lone Star Steel Company Method and composition for fluidization of accumulated pit scrap in soaking pits

Also Published As

Publication number Publication date
FR2200339A1 (fr) 1974-04-19
GB1451235A (en) 1976-09-29
PL86828B1 (fr) 1976-06-30
IT999582B (it) 1976-03-10
DE2347728A1 (de) 1974-04-04
BE804948A (fr) 1974-03-18
CA1006186A (en) 1977-03-01
FR2200339B1 (fr) 1978-11-10
JPS503931A (fr) 1975-01-16

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Legal Events

Date Code Title Description
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