GB1574814A - Hot-dip coating of steel substrates - Google Patents
Hot-dip coating of steel substrates Download PDFInfo
- Publication number
- GB1574814A GB1574814A GB52783/76A GB5278376A GB1574814A GB 1574814 A GB1574814 A GB 1574814A GB 52783/76 A GB52783/76 A GB 52783/76A GB 5278376 A GB5278376 A GB 5278376A GB 1574814 A GB1574814 A GB 1574814A
- Authority
- GB
- United Kingdom
- Prior art keywords
- coating
- aluminium
- silicon
- steel
- substrate
- 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
Links
- 239000000758 substrate Substances 0.000 title claims description 38
- 229910000831 Steel Inorganic materials 0.000 title claims description 33
- 239000010959 steel Substances 0.000 title claims description 33
- 238000003618 dip coating Methods 0.000 title description 3
- 238000000576 coating method Methods 0.000 claims description 67
- 239000011248 coating agent Substances 0.000 claims description 63
- 239000000463 material Substances 0.000 claims description 39
- 239000004411 aluminium Substances 0.000 claims description 36
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 36
- 229910052782 aluminium Inorganic materials 0.000 claims description 32
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 18
- 239000010703 silicon Substances 0.000 claims description 18
- 229910052710 silicon Inorganic materials 0.000 claims description 18
- 229910045601 alloy Inorganic materials 0.000 claims description 15
- 239000000956 alloy Substances 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 15
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- 238000005260 corrosion Methods 0.000 claims description 7
- 230000007797 corrosion Effects 0.000 claims description 7
- 229910000676 Si alloy Inorganic materials 0.000 claims description 6
- 239000008199 coating composition Substances 0.000 claims description 6
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 239000012768 molten material Substances 0.000 claims description 5
- 229910000838 Al alloy Inorganic materials 0.000 claims description 4
- 239000000274 aluminium melt Substances 0.000 claims description 4
- 230000000694 effects Effects 0.000 claims description 3
- 238000007654 immersion Methods 0.000 claims description 3
- 229910000789 Aluminium-silicon alloy Inorganic materials 0.000 claims description 2
- 238000011109 contamination Methods 0.000 claims description 2
- 238000004090 dissolution Methods 0.000 claims description 2
- 230000005496 eutectics Effects 0.000 claims description 2
- 238000002474 experimental method Methods 0.000 claims description 2
- 239000000155 melt Substances 0.000 claims description 2
- 238000005192 partition Methods 0.000 claims description 2
- 229910000765 intermetallic Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- CSDREXVUYHZDNP-UHFFFAOYSA-N alumanylidynesilicon Chemical compound [Al].[Si] CSDREXVUYHZDNP-UHFFFAOYSA-N 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000010301 surface-oxidation reaction Methods 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
- 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
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/12—Aluminium or alloys based thereon
-
- 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
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Coating With Molten Metal (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
Description
(54) HOT-DIP COATING OF STEEL SUBSTRATES
(71) We, UNIVERSITY COLLEGE
CARDIFF of C.U.I.C. University College,
P.O. Box 78, Cardiff, CF1 1XL, and CO
ATED METALS LIMITED, Glamorgan
Works, Pontardulais, Swansea, a British
University and a British Company respectively, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:
This invention relates to a method and means for applying hot-dip coatings on to a steel substrate. The invention is particularly, but not exclusively, concerned with applying metal or alloy coatings on to steel substrates in order to improve the formability and corrosion resistance of the substrates. Known coating processes include hot dip galvanising, tinning and aluminising.
Hot dip aluminised steel strip for corrosion and heat resistant applications is produced in two grades which are known commercially as Type 1 and Type 2. In the case of Type 1 the coating is an aluminium 5-12% silicon alloy whereas in the case of
Type 2 the coating is pure aluminium. In practice the coating material used in the production of Types 1 and 2 is normally contained in a bath which in use becomes contaminated with iron to an extent of about 3% during a hop dip campaign. The iron arises from solution of the ferrous processing hardware immersed in the coating material.
It is generally acknowledged that Type 1 coated steel is more formable but less corrosion resistant than Type 2 coated steel.
By formability in this specification is meant the ability of the coating to deform with the steel substrate whilst remaining integral with the substrate. A cross section taken through a hot dipped aluminised steel substrate indicates an aluminium rich outer coating, a layer comprising an iron aluminium intermetallic compound, which is generally referred to as an alloy layer, and finally the substrate. During deformation the alloy layer behaves like a typical low ductility metallic compound and tends to crack and so reduce the degree of cohesion between the outer coating and the substrate.
The forming properties can, however, be improved by reducing the thickness of the alloy layer as much as possible and we have found that the effect of silicon additions to aluminium in the coating material is markedly to reduce the thickness of the alloy layer developed during a given time of immersion at a predetermined temperature.
However, the presence of appreciable quantities of silicon in Type 1 coatings tends to impair the corrosion resistance by increasing the number of heterogeneities in the coatings at which corrosion attack can occur. On the other hand, the
According to the present invention there is provided a method of coating a steel substrate, comprising the steps of feeding the substrate through, or immersing the substrate in, a first molten coating material comprising mainly an aluminum-silicon alloy, and subsequently feeding the so coated substrate through, or immersing the so coated substrate in, a second molten material comprising mainly aluminium, whereby the second coating material is overlaid upon the first coating material on the substrate.
In order to prevent contact between the substrate bearing the first coating material and the ambient atmosphere, the so coated substrate is preferably passed from the first coating material to the second coating material via an inert atmosphere or environment which may be liquid or gaseous. Passage through an inert atmosphere or environment is advantageous in that surface oxidation of the first coating material is inhibited, if not prevented, prior to application of the second coating material. The first and second coating materials are preferably floatingly supported on a layer of molten material which is inert relative to the two coating materials, and the two coating materials are preferably separated from one another by a partition. To aluminise the steel substrate, for example a steel strip, the first and second coating compositions are preferably aluminium/silicon alloy containing between 5 and 12% silicon and aluminium respectively.
One form of apparatus for carrying out the present invention is shown in Figure 1 of the drawings accompanying the Provisional
Specification. The apparatus comprises a bath 1 containing a quantity 2 of molten lead. Floatingly supported on the molten lead are quantities of an aluminium/silicon melt 3 and an aluminium melt 4. The melts 3 and 4 are, as shown, separated from one another by a divider 5. A steel roll 6 is mounted in the bath 1 in the position shown and steel substrate, in the form of a strip 7, is firstly fed through the aluminium/silicon melt into the molten lead around the steel roll 6 and exits from the bath through the aluminium melt 4. The immersed steel roll 6 serves to change the direction of travel of the strip and allow a double coating to be applied to the strip in a single operation. An added advantage of the apparatus is that the steel roll 6 is protected by the lead melt from the dissolution effect of molten aluminium and consequently it is expected that the roll will have an increased service life. Similarly, the molten aluminium on the exit side will be subject to less iron contamination and as such is expected to produce a more corrosion resistant coating on the steel strip.
Our experiments using the above apparatus for applying a double coating on to a steel substrate have shown. after a 5 second immersion in a pure aluminium bath at 700or a specimen previously treated in an aluminium/silicon bath to produce a 6-8 llm thick alloy layer will experience restricted alloy layer growth to a thickness of 8-10 tim i.e. only 2 llm approximately more than the initial alloy layer thickness. An uncoated steel specimen dipped into a pure aluminium bath at 700"C will develop an alloy layer 20 tim thick after 5 seconds. Thus a first or preliminary alloy coating produced in an aluminium/silicon bath appears to act very strongly to restrict the rate of further growth in any subsequent coating step.
Figure 2 shows the microstructure of hot dip aluminised steel after prior treatment in an aluminium/silicon bath and Figure 3 shows the microstructure of this material after it has been further dipped for 5 seconds in aluminium at 700 C. The thicker aluminium coating of Figure 3 reveals an absence of the eutectic silicon network seen in Figure 2.
WHAT WE CLAIM IS:- 1. A method of coating a steel substrate, comprising the steps of feeding the substrate through or immersing the substrate in, a first molten coating material comprising mainly an aluminium - silicon alloy, and subsequently feeding the so coated substrate through, or immersing the so coated substrate in, a second moten material comprising mainly aluminium, whereby the second coating material is overlaid upon the first coating material on the substrate.
2. A method according to claim 1, including the step of feeding the substrate from the first coating composition to the second coating composition through an inert environment.
3. A method according to claim 1 or claim 2, wherein the first and second coating materials are floatingly supported on a layer of molten material which is inert relative to the coating materials.
4. A method according to claim 3, wherein the first coating material is an aluminium/silicon alloy containing between 5 and 12 wt.% silicon and the second coating is carried out at a temperature within the range 600-800"C.
6. A method according to claim 4, wherein the coating of the first coating material has a thickness of between 6 and 8 Fm and'the coating of the second coating material has a thickness of up to 10 ltm.
7. A method according to claim 6 wherein the coating of the second coating material has a thickness of between 8 and 10 tim.
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (7)
1. A method of coating a steel substrate, comprising the steps of feeding the substrate through or immersing the substrate in, a first molten coating material comprising mainly an aluminium - silicon alloy, and subsequently feeding the so coated substrate through, or immersing the so coated substrate in, a second moten material comprising mainly aluminium, whereby the second coating material is overlaid upon the first coating material on the substrate.
2. A method according to claim 1, including the step of feeding the substrate from the first coating composition to the second coating composition through an inert environment.
3. A method according to claim 1 or claim 2, wherein the first and second coating materials are floatingly supported on a layer of molten material which is inert relative to the coating materials.
4. A method according to claim 3, wherein the first coating material is an aluminium/silicon alloy containing between
5 and 12 wt.% silicon and the second coating is carried out at a temperature within the range 600-800"C.
6. A method according to claim 4, wherein the coating of the first coating material has a thickness of between 6 and 8 Fm and'the coating of the second coating material has a thickness of up to 10 ltm.
7. A method according to claim 6 wherein the coating of the second coating material has a thickness of between 8 and 10 tim.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB52783/76A GB1574814A (en) | 1976-12-17 | 1976-12-17 | Hot-dip coating of steel substrates |
| FR7737826A FR2374093A1 (en) | 1976-12-17 | 1977-12-15 | PROCESS FOR APPLYING AT LEAST ONE COATING LAYER ON A SUBSTRATE |
| DE19772756437 DE2756437A1 (en) | 1976-12-17 | 1977-12-17 | COATED OR ENVELOPED SUBSTRATE AND METHOD FOR MANUFACTURING IT |
| JP15228877A JPS53102233A (en) | 1976-12-17 | 1977-12-17 | Coating method by molten metal and its device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB52783/76A GB1574814A (en) | 1976-12-17 | 1976-12-17 | Hot-dip coating of steel substrates |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1574814A true GB1574814A (en) | 1980-09-10 |
Family
ID=10465295
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB52783/76A Expired GB1574814A (en) | 1976-12-17 | 1976-12-17 | Hot-dip coating of steel substrates |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS53102233A (en) |
| DE (1) | DE2756437A1 (en) |
| FR (1) | FR2374093A1 (en) |
| GB (1) | GB1574814A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2118211A (en) * | 1982-04-01 | 1983-10-26 | Nisshin Steel Co Ltd | Aluminized steel support for a planographic plate |
| GB2122650A (en) * | 1982-06-28 | 1984-01-18 | Nisshin Steel Co Ltd | Aluminium coated steel sheet and process for producing the same |
| WO1993018197A1 (en) * | 1992-03-13 | 1993-09-16 | Mannesmann Ag | Process for coating elongated materials with multiple layers |
| WO2014121956A1 (en) * | 2013-02-05 | 2014-08-14 | Thyssenkrupp Steel Europe Ag | Metal flat product, preferably consisting of steel, with a surface improved by hot-dip coating |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4310574A (en) * | 1980-06-20 | 1982-01-12 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Method of protecting a surface with a silicon-slurry/aluminide coating |
| JPS57178642A (en) * | 1981-04-27 | 1982-11-02 | Shin Nippon Koki Kk | Measuring device in machine tool |
| RU1831448C (en) * | 1990-12-19 | 1993-07-30 | И.Н.Селезнев | Method of manufacturing artricles |
| FR2758571B1 (en) * | 1997-01-21 | 1999-02-12 | Lorraine Laminage | STEEL SHEET WITH AN ALUMINUM COATING |
| DE102013101132A1 (en) * | 2013-02-05 | 2014-08-07 | Thyssenkrupp Steel Europe Ag | Process for hot dip coating of metal strip, in particular steel strip |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR543587A (en) * | 1921-11-15 | 1922-09-05 | Process for coating sheet steel or sheet steel objects and resulting products with aluminum | |
| US1741388A (en) * | 1926-09-13 | 1929-12-31 | American Rolling Mill Co | Metal coating metal sheets |
| FR743843A (en) * | 1931-10-23 | 1933-04-07 | ||
| US2111826A (en) * | 1935-12-09 | 1938-03-22 | Northwestern Barb Wire Company | Galvanizing process |
| US2156331A (en) * | 1937-05-05 | 1939-05-02 | Clad Metals Ind Inc | Method of coating steel strips |
| US2276232A (en) * | 1939-07-06 | 1942-03-10 | Du Pont | Metal coating process |
| US2937435A (en) * | 1956-08-11 | 1960-05-24 | Ver Leichtmetallwerke Gmbh | Clad metal body and method of making the same |
| PL94340B1 (en) * | 1974-11-30 | 1977-07-30 |
-
1976
- 1976-12-17 GB GB52783/76A patent/GB1574814A/en not_active Expired
-
1977
- 1977-12-15 FR FR7737826A patent/FR2374093A1/en not_active Withdrawn
- 1977-12-17 DE DE19772756437 patent/DE2756437A1/en not_active Withdrawn
- 1977-12-17 JP JP15228877A patent/JPS53102233A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2118211A (en) * | 1982-04-01 | 1983-10-26 | Nisshin Steel Co Ltd | Aluminized steel support for a planographic plate |
| GB2122650A (en) * | 1982-06-28 | 1984-01-18 | Nisshin Steel Co Ltd | Aluminium coated steel sheet and process for producing the same |
| WO1993018197A1 (en) * | 1992-03-13 | 1993-09-16 | Mannesmann Ag | Process for coating elongated materials with multiple layers |
| AU674304B2 (en) * | 1992-03-13 | 1996-12-19 | I.P. Bardin Central Research Institute Of Iron And Steel Industry | Process for coating elongated materials with multiple layers |
| WO2014121956A1 (en) * | 2013-02-05 | 2014-08-14 | Thyssenkrupp Steel Europe Ag | Metal flat product, preferably consisting of steel, with a surface improved by hot-dip coating |
| US10081857B2 (en) | 2013-02-05 | 2018-09-25 | Thyssenkrupp Steel Europe Ag | Metallic flat product which is subjected to surface finishing by hot-dip coating and which is preferably composed of steel |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS53102233A (en) | 1978-09-06 |
| DE2756437A1 (en) | 1978-06-22 |
| FR2374093A1 (en) | 1978-07-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed [section 19, patents act 1949] | ||
| PCNP | Patent ceased through non-payment of renewal fee |