EP0431250A1 - Scale removing composition and method - Google Patents
Scale removing composition and method Download PDFInfo
- Publication number
- EP0431250A1 EP0431250A1 EP90112692A EP90112692A EP0431250A1 EP 0431250 A1 EP0431250 A1 EP 0431250A1 EP 90112692 A EP90112692 A EP 90112692A EP 90112692 A EP90112692 A EP 90112692A EP 0431250 A1 EP0431250 A1 EP 0431250A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- scale
- composition
- acid
- metal substrate
- group
- 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.)
- Ceased
Links
- 239000000203 mixture Substances 0.000 title claims abstract description 54
- 238000000034 method Methods 0.000 title claims description 5
- 239000000758 substrate Substances 0.000 claims abstract description 44
- 229910052751 metal Inorganic materials 0.000 claims abstract description 42
- 239000002184 metal Substances 0.000 claims abstract description 42
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 19
- 238000010438 heat treatment Methods 0.000 claims abstract description 17
- 239000000945 filler Substances 0.000 claims abstract description 14
- 230000004907 flux Effects 0.000 claims abstract description 13
- -1 alkaline earth metal carbonates Chemical class 0.000 claims abstract description 11
- 229910019142 PO4 Inorganic materials 0.000 claims abstract description 7
- 150000001875 compounds Chemical class 0.000 claims abstract description 7
- 238000002844 melting Methods 0.000 claims abstract description 7
- 230000008018 melting Effects 0.000 claims abstract description 7
- 235000021317 phosphate Nutrition 0.000 claims abstract description 7
- 150000003013 phosphoric acid derivatives Chemical class 0.000 claims abstract description 7
- 229910052783 alkali metal Inorganic materials 0.000 claims abstract description 6
- 150000001340 alkali metals Chemical class 0.000 claims abstract description 6
- 229910052736 halogen Inorganic materials 0.000 claims abstract description 6
- 150000002367 halogens Chemical class 0.000 claims abstract description 6
- 150000002823 nitrates Chemical class 0.000 claims abstract description 6
- 150000002826 nitrites Chemical class 0.000 claims abstract description 6
- LSNNMFCWUKXFEE-UHFFFAOYSA-L sulfite Chemical class [O-]S([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-L 0.000 claims abstract description 6
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims abstract description 6
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims abstract description 4
- 150000004679 hydroxides Chemical class 0.000 claims abstract description 4
- DLYUQMMRRRQYAE-UHFFFAOYSA-N tetraphosphorus decaoxide Chemical compound O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 claims description 8
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 6
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 4
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 4
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims description 4
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 4
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical compound [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 claims description 4
- 235000012245 magnesium oxide Nutrition 0.000 claims description 4
- 239000000395 magnesium oxide Substances 0.000 claims description 4
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 4
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 claims description 4
- JHJLBTNAGRQEKS-UHFFFAOYSA-M sodium bromide Chemical compound [Na+].[Br-] JHJLBTNAGRQEKS-UHFFFAOYSA-M 0.000 claims description 4
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 claims description 4
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical compound [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 claims description 4
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 3
- 235000012255 calcium oxide Nutrition 0.000 claims description 3
- 239000000292 calcium oxide Substances 0.000 claims description 3
- 239000011521 glass Substances 0.000 claims description 3
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims description 2
- 229910020261 KBF4 Inorganic materials 0.000 claims description 2
- 239000007836 KH2PO4 Substances 0.000 claims description 2
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 claims description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 2
- DWAQJAXMDSEUJJ-UHFFFAOYSA-M Sodium bisulfite Chemical compound [Na+].OS([O-])=O DWAQJAXMDSEUJJ-UHFFFAOYSA-M 0.000 claims description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 2
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 2
- 229910052925 anhydrite Inorganic materials 0.000 claims description 2
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 claims description 2
- 239000004327 boric acid Substances 0.000 claims description 2
- 150000001642 boronic acid derivatives Chemical class 0.000 claims description 2
- 229910052791 calcium Inorganic materials 0.000 claims description 2
- 235000010216 calcium carbonate Nutrition 0.000 claims description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 2
- 239000001110 calcium chloride Substances 0.000 claims description 2
- 235000011148 calcium chloride Nutrition 0.000 claims description 2
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims description 2
- 229910052681 coesite Inorganic materials 0.000 claims description 2
- 229910052593 corundum Inorganic materials 0.000 claims description 2
- 229910052906 cristobalite Inorganic materials 0.000 claims description 2
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 claims description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 2
- 229910052749 magnesium Inorganic materials 0.000 claims description 2
- 239000001095 magnesium carbonate Substances 0.000 claims description 2
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 claims description 2
- 235000014380 magnesium carbonate Nutrition 0.000 claims description 2
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims description 2
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 claims description 2
- 239000000347 magnesium hydroxide Substances 0.000 claims description 2
- 235000012254 magnesium hydroxide Nutrition 0.000 claims description 2
- 229910001862 magnesium hydroxide Inorganic materials 0.000 claims description 2
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Inorganic materials [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 claims description 2
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims description 2
- 235000019341 magnesium sulphate Nutrition 0.000 claims description 2
- 229910052748 manganese Inorganic materials 0.000 claims description 2
- 150000002739 metals Chemical class 0.000 claims description 2
- 229910000402 monopotassium phosphate Inorganic materials 0.000 claims description 2
- 235000019796 monopotassium phosphate Nutrition 0.000 claims description 2
- 235000011007 phosphoric acid Nutrition 0.000 claims description 2
- 229910052700 potassium Inorganic materials 0.000 claims description 2
- 239000011736 potassium bicarbonate Substances 0.000 claims description 2
- 229910000028 potassium bicarbonate Inorganic materials 0.000 claims description 2
- 235000015497 potassium bicarbonate Nutrition 0.000 claims description 2
- CHKVPAROMQMJNQ-UHFFFAOYSA-M potassium bisulfate Chemical compound [K+].OS([O-])(=O)=O CHKVPAROMQMJNQ-UHFFFAOYSA-M 0.000 claims description 2
- 229910000343 potassium bisulfate Inorganic materials 0.000 claims description 2
- 235000015320 potassium carbonate Nutrition 0.000 claims description 2
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 2
- GNSKLFRGEWLPPA-UHFFFAOYSA-M potassium dihydrogen phosphate Chemical compound [K+].OP(O)([O-])=O GNSKLFRGEWLPPA-UHFFFAOYSA-M 0.000 claims description 2
- 235000010259 potassium hydrogen sulphite Nutrition 0.000 claims description 2
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 claims description 2
- 235000010333 potassium nitrate Nutrition 0.000 claims description 2
- 235000010289 potassium nitrite Nutrition 0.000 claims description 2
- 229910052939 potassium sulfate Inorganic materials 0.000 claims description 2
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 claims description 2
- 235000019252 potassium sulphite Nutrition 0.000 claims description 2
- 239000000377 silicon dioxide Substances 0.000 claims description 2
- 235000012239 silicon dioxide Nutrition 0.000 claims description 2
- 229910052708 sodium Inorganic materials 0.000 claims description 2
- 235000017557 sodium bicarbonate Nutrition 0.000 claims description 2
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims description 2
- WBHQBSYUUJJSRZ-UHFFFAOYSA-M sodium bisulfate Chemical compound [Na+].OS([O-])(=O)=O WBHQBSYUUJJSRZ-UHFFFAOYSA-M 0.000 claims description 2
- 229910000342 sodium bisulfate Inorganic materials 0.000 claims description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 2
- 235000017550 sodium carbonate Nutrition 0.000 claims description 2
- 239000011780 sodium chloride Substances 0.000 claims description 2
- 235000010267 sodium hydrogen sulphite Nutrition 0.000 claims description 2
- 235000011121 sodium hydroxide Nutrition 0.000 claims description 2
- 235000010344 sodium nitrate Nutrition 0.000 claims description 2
- 235000010288 sodium nitrite Nutrition 0.000 claims description 2
- 229910052682 stishovite Inorganic materials 0.000 claims description 2
- 229910052905 tridymite Inorganic materials 0.000 claims description 2
- 229910001845 yogo sapphire Inorganic materials 0.000 claims description 2
- 229910020440 K2SiF6 Inorganic materials 0.000 claims 1
- 239000000463 material Substances 0.000 claims 1
- 150000003016 phosphoric acids Chemical class 0.000 claims 1
- 238000005406 washing Methods 0.000 abstract description 20
- 206010040844 Skin exfoliation Diseases 0.000 abstract description 8
- 229910000831 Steel Inorganic materials 0.000 abstract description 4
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 229910001220 stainless steel Inorganic materials 0.000 abstract description 4
- 239000010959 steel Substances 0.000 abstract description 4
- 239000002253 acid Substances 0.000 description 31
- 239000004615 ingredient Substances 0.000 description 11
- 239000000843 powder Substances 0.000 description 11
- 238000009472 formulation Methods 0.000 description 10
- 238000000227 grinding Methods 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 4
- 238000009749 continuous casting Methods 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 239000007832 Na2SO4 Substances 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000008199 coating composition Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- GEHJYWRUCIMESM-UHFFFAOYSA-L sodium sulfite Chemical compound [Na+].[Na+].[O-]S([O-])=O GEHJYWRUCIMESM-UHFFFAOYSA-L 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 235000010265 sodium sulphite Nutrition 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 210000002268 wool Anatomy 0.000 description 1
Classifications
-
- 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
- C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
- C23G5/00—Cleaning or de-greasing metallic material by other methods; Apparatus for cleaning or de-greasing metallic material with organic solvents
-
- 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
Definitions
- the present invention relates to a scale removing composition, which is coated on the surface of a metal substrate during or before heat treatment of the substrate in order that the scale as already formed on the surface of the said substrate is made easily removable due to heat of the heat treatment.
- a metal substrate such as a high-temperature slab in continuous casting or a high-temperature coil after hot-rolled is always exposed to an aerial atmosphere, the surface thereof is extremely easily oxidized to form a metal oxide scale thereon.
- the scale as fomed on the surface of a metal substrate is, after cooled, removed by washing with an acid or the like.
- a scale as formed, for example, on the surface of a stainless steel during heating contains a large amount of non-iron components and is therefore dense and hard, so that removal of such a scale is extremely difficult.
- the present invention has been accomplished by finding a fact that a composition containing a flux component having a particular melting temperature, a filler comprising particular alkali metal or alkaline metal compounds or salts and an attacking agent comprising particular compounds or salts has a function of making a scale as formed on a metal substrate easily removable therefrom by mecahnical peeling and/or acid washing when coated on the surface of a high-temperature slab or a metal substrate during or before heat treatment thereof.
- the flux component (A) acts to form a glassy coat layer over the surface of a scale layer-having metal substrate, when coated over the surface of the substrate during heat treatment, due to the heat of the said substrate to rapidly melt the component (A) thereon. It also forms the same glassy coat layer when the composition is coated over a high-temperature slab in continuous casting.
- the component (A) is to melt in the subsequent heat-treatment step to also form the same glassy coat layer over the substrate.
- the filler component (B) in the composition has a function of an acid-permeation medium, which dissolves in an acid to improve the permeability of the acid, when the heat-treated metal substrate is washed with an acid. Accordingly, the acid as used for acid-washing may penetrate into the scale layer through the coat layer of the composition of the invention via the filler to be able to peel, dissolve and remove the coat layer along with the scale.
- the scale-attacking agent (C) in the composition melts or decomposes by heat singly or along with the dissolved flux to thereby attack the scale as formed on the surface of the metal substrate to make it brittle so as to capture the resulting scale as a form of being mechanically easily peelable or of being easily removable by acid washing, such as an iron halide.
- composition of the invention to the surface of a scale layer-having metal substrate, it is possible to rapidly and effectively remove the scale as formed on the surface of a metal substrate of being heat-treated at a high temperature, by mechanical peeling and/or acid-washing means. As a result, it is possible to noticeably improve the production efficiency in the process of producing metal products such as steel plates and the like, by the present invention.
- the scale removing composition of the invention to a metal substrate the scale of which is hardly removed, such as a stainless steel under heat treatment, the time necessary for acid-washing of the metal substrate may be shortened and the production efficiency of metal products may remarkably be elevated.
- Examples of the flux component to be in the scale removing composition of the invention include glass compositions which contain SiO2 as an essential ingredient and additionally other oxide components of Al2O3, Fe2O3, CaO, MgO, Na2O, B2O3, TiO2, P2O5, ZnO, BaO, PbO and others; phosphates or borates of metals such as K, Na, Li, Ca, Mg, Mn, Al, Fe and the like; as well as boric acid and others.
- the component has a melting point of 1000°C or lower, especially falling within the range of from 400 to 800°C.
- the flux component (A) is one to form a glassy coat layer by heat, and the content thereof is preferably from 15 to 98 % by weight, more preferably from 18 to 95 % by weight, on the basis of the three components comprising the component (A) along with the other filler component (B) and scale-attacking agent (C) which will be explained below.
- the filler to be employed in the present invention comprises one or more selected from the group consisting of alkali metal or alkaline earth metal carbonates, hydroxides and oxides, such as Na2CO3, NaHCO3, K2CO3, KHCO3, MgCO3, CaCO3, MgO, CaO1 NaOH, Mg(OH)2 and the like.
- the filler is employed for the purpose of dissolving in an acid during the procedure of acid-washing so as to improve the permeability of the acid into the scale layer, and the content thereof in the composition is preferably from 0 to 70 % by weight, more preferably from 3 to 68 % by weight, on the basis of the three components comprising the component (B) along with the above-mentioned component (A) and the component (C) which will be explained below.
- the effect of the scale attaching agent would be retarded though the acid washability could be improved.
- the scale-attacking agent (C) to be in the composition of the invention dissolves or decomposes by heat, as mentioned above, to attack the scale on the surface of a metal substrate to thereby make the scale layer brittle, whereby the resulting scale layer is converted into a form of being mechanically easily peelable or of being easily washed with an acid and, as a result, the layer is to be easily removed.
- the agent (C) comprises one or more selected from the group consisting of halogen-containing compounds, nitrates, nitrites, sulfates, sulfites and phosphates.
- halogen-containing compounds include NaCl, NaBr, CaCl2, K2SIF6, KBF4, Na3AlF5 and the like; those of nitrates include NaNO3, KNO3, Ca(NO3)2, Mg(NO3)2 and the like; those of nitrites include KNO2, NaNO2 and the like; those of sulfates include K2SO4, KHSO4, Na2SO4, NaHSO4, CaSO4, MgSO4 ; those of sulfites include K2SO3, KHSO3, Na2SO3, NaHSO3 and the like; and those of phosphates include P2O4, P2O5, H3PO4, KH2PO4 and the like.
- the content of the scale-attacking agent in the composition is preferably from 2 to 80 % by weight, on the basis of the three components (A), (B) and (C). If it is less than 2 % by weight, the composition could not have a sufficient scale-attacking capacity so that the scale would still be tough, even after the composition has been applied thereto, and the scale layer could not be removed after acid-washing for a long period of time. On the contrafy, however, if the content of the scale-attacking agent is more than 80 % by weight, not only the scale layer but also the surface of the metal substrate below the scale layer would be corroded by the composition.
- the scale removing composition of the invention which comprises the above-mentioned components, is applied to the surface of a metal substrate already having scale thereon during or before heat treatment. Additionally, the composition may also be applied to a high-temperature slab in continuous casting. Regarding the form of the scale removing composition of the invention when it is actually used as above, the composition of itself may be used as such, or it may be dispersed in a pertinent vehicle to give a coating composition which is used as above.
- the flux component (A) in the composition may rapidly dissolve due to the heat of the substrate to give a glassy coat layer over the scale layer.
- the composition may also be applied to an already scale layer-having metal substrate before heat treatment at room temperature. In the latter case, the flux component (A) in the composition coated can dissolve in the subsequent heat-treating step to also give a glassy coat layer over the scale layer.
- the scale layer on the metal substrate is thereby made brittle due to the action of the scale-attacking agent component (C) as being in the thus formed molten glassy coat layer and is then captured in the said composition as a form of being easily removable by acid washing, such as an iron halide or the like.
- the glassy coat layer of the composition which has captured the scale therein is cracked due to the difference in the thermal expansion between the metal substrate and the glassy coat layer during the cooling step to be effected after heat treatment and, as a result, it becomes easily mechanically peelable. Additionally, since the scale layer on the metal substrate after completion of heat treatment has become brittle and is therefore in the form of being easily peelable due to the action of the scale-attacking agent component (A) as mentioned above, the scale-captured glassy coat layer may be peeled off from the surface of the metal substrate by means of a mechanical scale-peeling treatment, for example, by bending the metal substrate or by roll-brushing the same.
- the metal substrate is generally subjected to washign with a mineral acid such as HCl, H2SO4 or the like, after the above-mentioned mechanical scale peeling treatment.
- a mineral acid such as HCl, H2SO4 or the like
- the glassy coat layer may easily be removed along with the scale.
- the filler component (B) such as an alkali metal, carbonate which is in the glassy coat layer is attacked by an acid and is dissolved out to the liquid.
- the glassy coat layer is made brittle and mechanically easily breakable while the acid used in acid-washing is to penetrate into the inside of the glassy coat layer from the filler-dissolved site.
- the scale layer on the surface of the metal substrate is corroded by the scale-attacking agent component (C) and is then made mechanically brittle or is converted into a form of being easily washed with an acid, such as an iron halide, and after all the scale is removed from the surface of the metal substrate along with the above-mentioned glassy coat layer.
- an acid such as an iron halide
- removal of the scale-captured glassy coat layer may completely be effected by the previous mechanical peeling treatment only, the subsequent acid-washing treatment may be omitted.
- removal of the scale-captured glassy coat layer may be effected only by the acid-washing treatment without the previous mechanical peeling treatment.
- removal of scale by acid-washing and/or mechanical peeling treatment may efficiently and rapidly be effected by the present invention.
- test sample of SUS430 stainless steel sheet (4 mm x 50 mm x 100 mm) was used.
- a 8 wt.% HCl was used as an acid for acid-washing treatment.
- a test sample was first heated at 900°C for 30 minutes, and, while hot, 0.8 to 1.0 g of a powder as obtained from Formulation No. 4 was coated over the surface scale layer of the hot sample by the use of a spraying gum. Thereafter the coated sample was spontaneously cooled to room temperature in air. After thus cooled, the surface of the test sample was observed and it was found that the formed glassy coat layer peeled off from the test sample along with the scale and therefore the scale was completely removed.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
Disclosed is a scale removing composition containing (A) a flux component having a melting point of 1000°C or lower, (B) a filler comprising one or more selected from the group consisting of alkali metal or alkaline earth metal carbonates, hydroxides and oxides, and (C) a scale-attacking agent comprising one or more selected from the group consisting of halogen-containing compounds, nitrates, nitrites, sulfates, sulfites and phosphates., By applying the composition to the surface of a scale layer-having metal substrate, the scale as formed on the metal substrate to be heat-treated at a high temperature may be removed rapidly and effectively from the surface of the metal substrate by mechanical peeling treatment and/or acid-washing treatment. As a result, the production efficiency of producing steel plates and other metal products may be improved noticeably. The composition may also be applied to heat-treatment of stainless steels from which removal of scale is difficult, so that the time for acid-washing treatment may remarkably be shortened and the production efficiency may thereby be improved noticeably.
Description
- The present invention relates to a scale removing composition, which is coated on the surface of a metal substrate during or before heat treatment of the substrate in order that the scale as already formed on the surface of the said substrate is made easily removable due to heat of the heat treatment.
- Since a metal substrate such as a high-temperature slab in continuous casting or a high-temperature coil after hot-rolled is always exposed to an aerial atmosphere, the surface thereof is extremely easily oxidized to form a metal oxide scale thereon. The scale as fomed on the surface of a metal substrate is, after cooled, removed by washing with an acid or the like. However, a scale as formed, for example, on the surface of a stainless steel during heating contains a large amount of non-iron components and is therefore dense and hard, so that removal of such a scale is extremely difficult.
- Accordingly, in order to completely remove such a scale, a long time is required for washing the metal substrate with an acid to cause a problem that the efficiency of producing metal products noticeably lowers.
- The present invention has been accomplished by finding a fact that a composition containing a flux component having a particular melting temperature, a filler comprising particular alkali metal or alkaline metal compounds or salts and an attacking agent comprising particular compounds or salts has a function of making a scale as formed on a metal substrate easily removable therefrom by mecahnical peeling and/or acid washing when coated on the surface of a high-temperature slab or a metal substrate during or before heat treatment thereof.
- Specifically, there is provided in accordance with the present invention a scale removing composition containing:
- (A) a flux component having a melting point of 1000°C or lower;
- (B) a filler comprising one or more selected from the group consisting of alkali metal or alkaline earth metal carbonates, hydroxides and oxides; and
- (C) a scale-attacking agent comprising one or more selected from the group consisting of halogen-containing compounds, nitrates, nitrites, sulfates, sulfites and phosphates.
- Among the three components of constituting the scale removing composition of the present invention, the flux component (A) acts to form a glassy coat layer over the surface of a scale layer-having metal substrate, when coated over the surface of the substrate during heat treatment, due to the heat of the said substrate to rapidly melt the component (A) thereon. It also forms the same glassy coat layer when the composition is coated over a high-temperature slab in continuous casting. When the composition is coated over the surface of a metal substrate before heat treatment, the component (A) is to melt in the subsequent heat-treatment step to also form the same glassy coat layer over the substrate.
- The filler component (B) in the composition has a function of an acid-permeation medium, which dissolves in an acid to improve the permeability of the acid, when the heat-treated metal substrate is washed with an acid. Accordingly, the acid as used for acid-washing may penetrate into the scale layer through the coat layer of the composition of the invention via the filler to be able to peel, dissolve and remove the coat layer along with the scale.
- The scale-attacking agent (C) in the composition melts or decomposes by heat singly or along with the dissolved flux to thereby attack the scale as formed on the surface of the metal substrate to make it brittle so as to capture the resulting scale as a form of being mechanically easily peelable or of being easily removable by acid washing, such as an iron halide.
- Accordingly, by applying the composition of the invention to the surface of a scale layer-having metal substrate, it is possible to rapidly and effectively remove the scale as formed on the surface of a metal substrate of being heat-treated at a high temperature, by mechanical peeling and/or acid-washing means. As a result, it is possible to noticeably improve the production efficiency in the process of producing metal products such as steel plates and the like, by the present invention.
- Additionally, by applying the scale removing composition of the invention to a metal substrate the scale of which is hardly removed, such as a stainless steel under heat treatment, the time necessary for acid-washing of the metal substrate may be shortened and the production efficiency of metal products may remarkably be elevated.
- Examples of the flux component to be in the scale removing composition of the invention include glass compositions which contain
SiO2
as an essential ingredient and additionally other oxide components of
Al₂O₃, Fe₂O₃, CaO, MgO, Na₂O, B₂O₃,
TiO₂, P₂O₅, ZnO, BaO, PbO
and others; phosphates or borates of metals such as K, Na, Li, Ca, Mg, Mn, Al, Fe and the like; as well as boric acid and others. The component has a melting point of 1000°C or lower, especially falling within the range of from 400 to 800°C. - If it has a melting point higher than the defined range, it would hardly form a glassy coat layer on the surface of a metal substrate when the composition has been coated on the surface thereof during heat treatment and, as a result, the effect as the scale-attacking agent would lower.
- As mentioned above, the flux component (A) is one to form a glassy coat layer by heat, and the content thereof is preferably from 15 to 98 % by weight, more preferably from 18 to 95 % by weight, on the basis of the three components comprising the component (A) along with the other filler component (B) and scale-attacking agent (C) which will be explained below.
- The filler to be employed in the present invention comprises one or more selected from the group consisting of alkali metal or alkaline earth metal carbonates, hydroxides and oxides, such as
Na₂CO₃, NaHCO₃, K₂CO₃, KHCO₃, MgCO₃, CaCO₃,
MgO, CaO₁ NaOH, Mg(OH)₂
and the like. - As mentioned above, the filler is employed for the purpose of dissolving in an acid during the procedure of acid-washing so as to improve the permeability of the acid into the scale layer, and the content thereof in the composition is preferably from 0 to 70 % by weight, more preferably from 3 to 68 % by weight, on the basis of the three components comprising the component (B) along with the above-mentioned component (A) and the component (C) which will be explained below.
- If the content of the filler is more than the defined range, the effect of the scale attaching agent would be retarded though the acid washability could be improved.
- The scale-attacking agent (C) to be in the composition of the invention dissolves or decomposes by heat, as mentioned above, to attack the scale on the surface of a metal substrate to thereby make the scale layer brittle, whereby the resulting scale layer is converted into a form of being mechanically easily peelable or of being easily washed with an acid and, as a result, the layer is to be easily removed. Precisely, the agent (C) comprises one or more selected from the group consisting of halogen-containing compounds, nitrates, nitrites, sulfates, sulfites and phosphates. Examples of halogen-containing compounds include
NaCl, NaBr, CaCl₂, K₂SIF₆,
KBF₄, Na₃AlF₅
and the like; those of nitrates include
NaNO₃, KNO₃, Ca(NO₃)₂, Mg(NO₃)₂
and the like; those of nitrites include
KNO₂, NaNO₂
and the like; those of sulfates include
K₂SO₄, KHSO₄, Na₂SO₄, NaHSO₄, CaSO₄, MgSO₄
; those of sulfites include
K₂SO₃, KHSO₃, Na₂SO₃, NaHSO₃
and the like; and those of phosphates include
P₂O₄, P₂O₅, H₃PO₄, KH₂PO₄
and the like. - The content of the scale-attacking agent in the composition is preferably from 2 to 80 % by weight, on the basis of the three components (A), (B) and (C). If it is less than 2 % by weight, the composition could not have a sufficient scale-attacking capacity so that the scale would still be tough, even after the composition has been applied thereto, and the scale layer could not be removed after acid-washing for a long period of time. On the contrafy, however, if the content of the scale-attacking agent is more than 80 % by weight, not only the scale layer but also the surface of the metal substrate below the scale layer would be corroded by the composition.
- Next, the method of removing scale by the use of the above-mentioned scale removing agent of the invention will be explaiend below.
- The scale removing composition of the invention, which comprises the above-mentioned components, is applied to the surface of a metal substrate already having scale thereon during or before heat treatment. Additionally, the composition may also be applied to a high-temperature slab in continuous casting. Regarding the form of the scale removing composition of the invention when it is actually used as above, the composition of itself may be used as such, or it may be dispersed in a pertinent vehicle to give a coating composition which is used as above.
- After the scale removing composition of the invention has been applied to a metal substrate having a scale layer on the surface thereof during heat treatment, the flux component (A) in the composition may rapidly dissolve due to the heat of the substrate to give a glassy coat layer over the scale layer. Alternatively, the composition may also be applied to an already scale layer-having metal substrate before heat treatment at room temperature. In the latter case, the flux component (A) in the composition coated can dissolve in the subsequent heat-treating step to also give a glassy coat layer over the scale layer.
- Accordingly, the scale layer on the metal substrate is thereby made brittle due to the action of the scale-attacking agent component (C) as being in the thus formed molten glassy coat layer and is then captured in the said composition as a form of being easily removable by acid washing, such as an iron halide or the like.
- The glassy coat layer of the composition which has captured the scale therein is cracked due to the difference in the thermal expansion between the metal substrate and the glassy coat layer during the cooling step to be effected after heat treatment and, as a result, it becomes easily mechanically peelable. Additionally, since the scale layer on the metal substrate after completion of heat treatment has become brittle and is therefore in the form of being easily peelable due to the action of the scale-attacking agent component (A) as mentioned above, the scale-captured glassy coat layer may be peeled off from the surface of the metal substrate by means of a mechanical scale-peeling treatment, for example, by bending the metal substrate or by roll-brushing the same.
- After completion of heat treatment, the metal substrate is generally subjected to washign with a mineral acid such as
HCl, H₂SO₄
or the like, after the above-mentioned mechanical scale peeling treatment. By the acid-washing treatment, the glassy coat layer may easily be removed along with the scale. Precisely, by the above-mentioned acid-washing, the filler component (B) such as an alkali metal, carbonate which is in the glassy coat layer is attacked by an acid and is dissolved out to the liquid. As a result, the glassy coat layer is made brittle and mechanically easily breakable while the acid used in acid-washing is to penetrate into the inside of the glassy coat layer from the filler-dissolved site. Accordingly, as mentioned above, the scale layer on the surface of the metal substrate is corroded by the scale-attacking agent component (C) and is then made mechanically brittle or is converted into a form of being easily washed with an acid, such as an iron halide, and after all the scale is removed from the surface of the metal substrate along with the above-mentioned glassy coat layer. However, if removal of the scale-captured glassy coat layer may completely be effected by the previous mechanical peeling treatment only, the subsequent acid-washing treatment may be omitted. Alternatively, removal of the scale-captured glassy coat layer may be effected only by the acid-washing treatment without the previous mechanical peeling treatment. - As mentioned above in detail, removal of scale by acid-washing and/or mechanical peeling treatment may efficiently and rapidly be effected by the present invention.
- Next, the present invention will be explained in more detail by way of the following examples, which, however, are not intended to restrict the scope of the present invention.
- Using three kinds of glass composition (a), (b) and (c) each having the composition as shown in Table 1 below, eleven kinds of samples (Nos. 1 to 11) as shown in Table 2 below were prepared.
- A test sample of SUS430 stainless steel sheet (4 mm x 50 mm x 100 mm) was used.
-
- Ingredients of Fromulation No. 1 of Table 2 above were ground in a ball mill, and 1 g of the resulting powder was coated on the surface of a test sample and heated at 700°C for 30 minutes. Next, the test sample was cooled and acid-treated at 80°C for 30 seconds. As a result, the glassy coat layer formed peeled off from the test sample along with the scale to give a scale-free surface.
- 1 g of a powder obtained by grinding the ingredients of Formulation No. 2 was coated on a test sample and heated at 750°C for 20 minutes. The formed glassy coat layer was in the form of a semi-molten state. Next, after cooled, it was acid-treated in the same manner as in Example 1. However, only the glassy coat layer dissolved in the acid but almost all the scale layer remained.
- 1 g of a powder obtained by griding the ingredients of Formulation No. 3 was coated on a test sample and heated at 800°C for 20 minutes. The formed glassy coat layer was in the form of a semi-molten state. Next, after cooled, it was acid-treated in the same manner as in Example 1. However, only the glassy coat layer dissolved in the acid but almost all the scale layer remained.
- A test sample was first heated at 900°C for 30 minutes, and, while hot, 0.8 to 1.0 g of a powder as obtained from Formulation No. 4 was coated over the surface scale layer of the hot sample by the use of a spraying gum. Thereafter the coated sample was spontaneously cooled to room temperature in air. After thus cooled, the surface of the test sample was observed and it was found that the formed glassy coat layer peeled off from the test sample along with the scale and therefore the scale was completely removed.
- 1 g of a powder obtained by grinding the ingredients of Formulation No. 5 was coated on a test sample and heated at 700°C for 30 minutes. Next, the test sample was cooled and then acid-treated at 80°C for one minutes, whereby the formed glassy coat layer was peeled off from the surface of the test sample along with the scale to give a scale-free surface.
- 1 g of a powder obtained by grinding the ingredients of Formulation No. 6 was coated on a test sample and heated at 800°C for 30 minutes. Next, after cooled, the coated sample was acid-treated in the same manner as in Example 1. As a result, the glassy coat layer was completely dissolved to give a scale-free surface.
- 1 g of a powder obtained by griding the ingredients of Formulation No. 7 was coated on a test sample and heated at 700°G for 30 minutes. Next, the coated sample was then acid-treated in the same manner as in Example 1. As a result, almost all the glassy coat layer was dissolved in the acid, but the scale layer was not removed.
- 1 g of a powder obtained by grinding the ingredients of Formulation No. 8 was coated on a test sample and heated at 900°C for 30 minutes. The thus formed glassy coat layer was a semi-molten state. Next, the test sample was mechanically bend to peel the glassy coat layer and the surface of the test sample was observed. It was found that the surface was free from scale but was corroded into the inside of the steel substrate.
- 1 g of a powder obtained by grinding the ingredients of Formulation No. 9 was coated on a test sample and heated at 700°C for 30 minutes. After cooled, the surface of the test sample was observed and it was found that a part of the formed glassy coat layer peeled off. The coat layer was removed by the use of a steel wool to give a substrate surface having little scale.
- 1 g of a powder obtained by grinding the ingredients of Formulation No. 10 was coated on a test sample and heated at 650°C for one hour. Next, after cooled, the coated sample was acid-treated in the same manner as in Example 1. As a result, the formed classy coat layer was peeled off from the metal substrate along with scale to give a scale-free surface.
- 1 g of a powder obtained by grinding the ingredients of Formulation No. 11 was coated on a test sample and heated at 700°C for 30 minutes. Next, after cooled, the coated sample was acid-treated in the same manner as in Example 1. As a result, the formed glassy coat layer was dissolved in the acid to give a clean surface having little scale.
- While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
Claims (7)
- A scale removing composition, which is characterized by containing:(A) a flux component having a melting point of 1000°C or lower;(B) a filler comprising one or more selected from the group consisting of alkali metal or alkaline earth metal carbonates, hydroxides and oxides; and(C) a scale-attacking agent comprising one or more selected from the group consisting of halogen-containing compounds, nitrates, nitrites, sulfates, sulfites and phosphates.
- The composition as claimed in claim 1, in which the flux component (A) comprises one or more selected from the group consisting of glass compositions which contain
SiO₂
as a main component and additionally other oxide components of
Al₂O₃, Fe₂O₃, CaO, MgO, Na₂O, B₂O₃, TiO₂, P₂O₅, ZnO,
BaO, PbO
and the like, phosphates or borates of metals of K, Na, LI, Ca, Mg, Mn, Al, Fe and the like, and boric acid, the materials of the group having a melting point of 1000°C or lower. - The composition as claimed in claim 1, in which the filler (B) comprises one or more selected from the group consisting of
Na₂CO₃, NaHCO₃, K₂CO₃, KHCO₃, MgCO₃, CaCO₃, MgO,
CaO, NaOH, Mg(OH)₂
and the like. - The composition as claimed in claim 1, in which the scale-attacking agent (C) comprises one or more selected from the group consisting of halogen-containing compounds such as
NaCl, NaBr, CaCl₂, K₂SiF₆, KBF₄, Na₃AlF₅
and the like, nitrates such as
NaNO₃, KNO₃, Ca(NO₃)₂, Mg(NO₃)₂
and the like, nitrites such as
KNO₂, NaNO₂
and the like, sulfates such as
K₂SO₄, KHSO₄,
NaSO₄, NaHSO₄, CaSO₄, MgSO₄
and the like, sulfites such as
K₂SO₃, KHSO₃, Na₂SO₃₁ NaHSO₃
and the like, and phosphoric acid compounds such as
P₂O₄, P₂O₅, H₃PO₄, KH₂PO₄
and the like. - The composition as claimed in claim 1, in which the content of the flux component (A) is from 15 to 98 % by weight, that of the filler (B) is from 0 to 70 % by weight and that of the scale attacking agent (C) is from 2 to 80 % by weight, on the basis of the total weight of the three components (A) , (B), (C).
- A metal coated structure, which is composed of a metal substrate and a glassy coat layer derived from a scale removing composition as claimed in claim 1, the glassy coat layer being formed on the surface of the substrate.
- A method of removing scale from the surface of a metal substrate, in which a scale removing composition as claimed in claim 1 is applied to a metal substrate during or before heat treatment thereof.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1315013A JPH0765201B2 (en) | 1988-12-07 | 1989-12-04 | Descaling composition |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0431250A1 true EP0431250A1 (en) | 1991-06-12 |
Family
ID=18060373
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP90112692A Ceased EP0431250A1 (en) | 1989-12-04 | 1990-07-03 | Scale removing composition and method |
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EP (1) | EP0431250A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102418110A (en) * | 2010-09-26 | 2012-04-18 | 通用电气公司 | Method for removing oxides |
WO2013116615A1 (en) * | 2012-02-02 | 2013-08-08 | Malloy James C | Caustic application for metal surface scale modification |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1061806A (en) * | 1963-12-16 | 1967-03-15 | Babcock & Wilcox Co | Method and apparatus for descaling ferrous billets |
US3415691A (en) * | 1963-11-07 | 1968-12-10 | Foseco Int | Method of protecting metal surfaces during heat treatment |
-
1990
- 1990-07-03 EP EP90112692A patent/EP0431250A1/en not_active Ceased
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3415691A (en) * | 1963-11-07 | 1968-12-10 | Foseco Int | Method of protecting metal surfaces during heat treatment |
GB1061806A (en) * | 1963-12-16 | 1967-03-15 | Babcock & Wilcox Co | Method and apparatus for descaling ferrous billets |
Non-Patent Citations (4)
Title |
---|
CHEMICAL ABSTRACTS, vol. 83, no. 1, 14th July 1975, page 256, abstract no. 14313e, Columbus, Ohio, US; & JP-A-74 122 436 (MITSUBISHI HEAVY INDUSTRIES, LTD) 22-11-1974 * |
CHEMICAL ABSTRACTS, vol. 92, no. 20, May 1980, page 230, abstract no. 167493z, Columbus, Ohio, US; & JP-A-79 36 901 (NIPPON STEEL CORP.) 12-11-1979 * |
CHEMICAL ABSTRACTS, vol. 94, no. 13, 1981, page 276, abstract no. 107545z, Columbus, Ohio, US; & JP-A-80 125 283 (NIPPON STEEL CORP.) 26-09-1980 * |
SOVIET INVENTIONS ILLUSTRATED, week 8503, section chemistry, 27th Febraury 1985, accession no. 85-017874/03, Derwent Publications Ltd, London, GB; & SU-A-1097 714 (CEMENT IND. RES. INST.) 01-11-1982 * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102418110A (en) * | 2010-09-26 | 2012-04-18 | 通用电气公司 | Method for removing oxides |
CN102418110B (en) * | 2010-09-26 | 2015-06-10 | 通用电气公司 | Method for removing oxides |
WO2013116615A1 (en) * | 2012-02-02 | 2013-08-08 | Malloy James C | Caustic application for metal surface scale modification |
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