Induction Heatable Coated Multi-Layer Metal Cooking Vessels

Abstract

The present invention relates to a coated multi-layer metal cooking vessel compatible with induction heating, comprising a heating surface coated with a protective coating and a cooking surface coated with an anti-stick coating, forming a cooking surface. According to the invention, the metal body comprises a metallurgically assembled aluminum plate having a double-sided aluminized low-carbon ferromagnetic steel plate forming the heating surface, a double-sided aluminized low-carbon ferromagnetic steel plate comprising a low-carbon ferromagnetic steel substrate having an outer layer comprising an aluminum-based matrix on each of its two sides, and an intermediate layer comprising an iron / aluminum intermetallic compound disposed between the low-carbon ferromagnetic steel substrate and the outer layer, wherein the outer layer has a thickness of less than 27 μm, preferably less than 20 μm, more preferably less than 18 μm, at least at the bottom of the heating surface. The invention also relates to cooking articles, electric cooking appliances, and methods for obtaining the coated metal cooking vessel.

Description

[Technical field]

[0001] The present invention relates to the technical field of induction heating compatible metal cooking vessels for cooking or heating food, which can be used with induction heating devices such as induction hobs installed or built into a worktop, or induction heaters built into electric cookware.

[0002] The present invention more specifically relates to coated multi-layer metal cooking vessels that are compatible with induction heating.

[0003] The present invention relates particularly, but not exclusively, to coated multi-layer metal cooking supports forming cooking vessels.

[0004] The present invention also relates to a cooking utensil that includes a coated multi-layer metal cooking vessel associated with at least one gripping element. If desired, the gripping element(s) can be detached or disassembled from the coated multi-layer metal cooking vessel.

[0005] The present invention also relates to an electric cooking appliance having a coated multi-layer metal cooking vessel associated with an induction heater. [Background technology]

[0006] It is known from US Pat. No. 5,399,633 to produce a coated cookware article compatible with induction heating, in which a metal plate forming the cooking surface is joined to a ferritic stainless steel plate using an inserted aluminium plate to obtain a metallurgical bond of the different plates. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] European Patent No. 2554080 Summary of the Invention [Problem to be solved by the invention]

[0008] The disadvantage of this type of design is that such coated metal cooking vessels have a relatively high cost price, especially due to the presence of stamping operations to obtain the metallurgical assembly of the various plates.

[0009] Another drawback of this design is that such coated metal cooking vessels are relatively heavy due to the presence of the interposed aluminum and ferritic stainless steel plates.

[0010] Various aspects of the present invention are intended to overcome the shortcomings of the prior art by providing a coated multi-layer metal cooking vessel that is compatible with induction heating and has limited cost. [Means for solving the problem]

[0011] A first aspect of the invention relates to a coated multi-layer metal cooking vessel adapted for induction heating, comprising a metal body including a heating surface and a cooking surface, the heating surface having a bottom adapted to rest on an induction heating device, the heating surface carrying a protective coating and the cooking surface carrying an anti-adhesion coating forming the cooking surface, the metal body being formed of an aluminum plate metallurgically assembled with a double-sided aluminized low-carbon ferromagnetic steel plate forming the heating surface, and if desired together with another double-sided aluminized low-carbon ferromagnetic steel plate, the double-sided aluminized low-carbon ferromagnetic steel plate being formed of a low-carbon ferromagnetic steel substrate having an outer layer with an aluminum-based matrix on each of its two sides, an intermediate layer comprising an iron / aluminum intermetallic compound being disposed between the low-carbon ferromagnetic steel substrate and the outer layer, the outer layer having a thickness of less than 27 μm, preferably less than 20 μm, even more preferably less than 18 μm, at least at the bottom of the heating surface. The low-carbon steel used for the ferromagnetic substrate is sensitive to magnetic fields and can be heated by induction. On the other hand, aluminum is a magnetic field impediment material used for induction heating. However, during the aluminization of steel sheets, an intermetallic reaction layer is formed at the interface between the steel and the aluminum. The intermetallic compounds of the intermediate layer do not have the obstructive properties of aluminum to the magnetic field used for induction heating. Therefore, for aluminum-based coatings used for aluminization, the thickness of the outer layer containing the aluminum-based matrix appears to be the main relevant parameter for obtaining compatibility with the induction plate. The use of such a coated metal body provides a coated multi-layer metal cooking vessel that is compatible with induction heating and is more economical to produce than a coated metal cooking vessel that includes an aluminum body combined with a ferromagnetic steel element. The use of such a coated metal body provides a coated multi-layer metal cooking vessel that is compatible with induction heating and is lighter than a coated metal cooking vessel made from cast steel. The aluminum plate helps to limit hot spots and therefore reduces the risk of overheating the anti-adhesive coating that forms the cooking surface.

[0012] The outer layer may contain Al-Fe-Si needles in an aluminum-silicon matrix. The use of an aluminizing bath containing aluminum and silicon facilitates the production of the outer layer during the aluminization of the steel sheet. Silicon does not have the destructive properties of aluminum to the magnetic fields used in induction heating.

[0013] The low carbon ferromagnetic steel substrate may have a thickness of 0.3 to 1 mm, preferably 0.3 to 0.5 mm, and the aluminum plate may have a thickness of 0.3 to 3 mm, preferably 0.5 to 1.5 mm.

[0014] The low carbon ferromagnetic steel substrate may be made of a steel grade having a maximum of 0.3% by weight carbon, preferably 0.1-0.2% by weight carbon.

[0015] The protective coating can be applied directly to the heating surface of the metal body. The protective coating may consist of one or more layers.

[0016] The anti-adhesion coating can be applied directly to the cooking surface of the metal body. The anti-adhesion coating can have one or more layers. Optionally, an intermediate coating can be placed between the anti-adhesion coating and the metal body to provide a hard base.

[0017] In particular, the protective coating may be a PTFE type coating, or an enamel type coating, or a lacquer type coating, or a ceramic type coating, or a sol-gel type coating.

[0018] According to one embodiment, the protective coating is a PTFE type coating, or a lacquer type coating, or a ceramic type coating, or a sol-gel type coating, and the metal body may comprise an aluminium-based deposit having a thickness of less than 30 μm, preferably less than 20 μm, at least on the bottom of the heating surface.

[0019] According to another embodiment, the protective coating may be an enamel-type coating, in which the metal body comprises an aluminium-based deposit having a thickness of less than 40 μm, preferably less than 30 μm, at least on the bottom of the heating surface.

[0020] The anti-adhesion coating may be a PTFE type coating, or a ceramic type coating, or a sol-gel type coating.

[0021] The coated multi-layer metal cooking support may have sidewalls that rise around the bottom of the heating surface to form a cooking vessel.

[0022] In particular, the coated multi-layer metal cooking vessel can have pinched edges, or rolled edges, or open rolled edges, which arrangement allows the ends of the metal body to be hidden from view.

[0023] A second aspect of the present invention relates to a cookware article that includes a coated multi-layer metal cooking vessel and a gripping element attached to the coated multi-layer metal cooking vessel, such that the coated multi-layer metal cooking vessel complies with at least one of the aforementioned characteristics.

[0024] A third aspect of the present invention relates to an electric cookware having a coated metal cooking vessel associated with an induction heater, in that the coated multi-layer metal cooking vessel complies with at least one of the aforementioned characteristics.

[0025] A fourth aspect of the invention relates to a method for obtaining a coated metal cooking vessel suitable for induction heating according to at least one of the above characteristics, comprising the following steps: Cutting or providing a multi-layer shape from a double sided aluminized low carbon ferromagnetic steel sheet metallurgically assembled with an aluminium sheet, the double sided aluminized low carbon ferromagnetic steel sheet having a first free surface and the aluminium sheet having a second free surface; stamping the multi-layer shape to form the metal body with the heating surface corresponding to the first free surface and the cooking surface corresponding to the second free surface; applying a protective coating to the heating surface; Applying an anti-stick coating to the cooking surface to form a cooking surface.

[0026] A fifth aspect of the invention relates to a method for obtaining a coated multi-layer metal cooking vessel suitable for induction heating according to at least one of the above characteristics, comprising the following steps: cutting or providing a multi-layer shape from an aluminum plate metallurgically assembled with a double-sided aluminized low carbon ferromagnetic steel plate and another double-sided aluminized low carbon ferromagnetic steel plate, the double-sided aluminized low carbon ferromagnetic steel plate having a first free surface and the other double-sided aluminized low carbon ferromagnetic steel plate having a second free surface; stamping the multi-layer shape to form the metal body with the heating surface corresponding to the first free surface and the cooking surface corresponding to the second free surface; applying a protective coating to the heating surface; Applying an anti-stick coating to the cooking surface to form a cooking surface.

[0027] According to any of these aspects, after imaging the multilayer form and before the protective and anti-adhesion coatings are applied, the method may include a step of treating a peripheral portion of the multilayer form to obtain a pinched edge, or a rolled edge, or an open rolled edge.

[0028] In particular, the protective coating may be a PTFE type coating, or an enamel type coating, or a lacquer type coating, or a ceramic type coating, or a sol-gel type coating.

[0029] The anti-adhesion coating may be a PTFE type coating, or a ceramic type coating, or a sol-gel type coating.

[0030] A sixth aspect of the invention relates to a method for obtaining a coated multi-layer metal cooking vessel suitable for induction heating according to at least one of the above characteristics, comprising the following steps: cutting or providing a multi-layer shape from an aluminum plate metallurgically assembled with a double-sided aluminized low carbon ferromagnetic steel plate and another double-sided aluminized low carbon ferromagnetic steel plate, the double-sided aluminized low carbon ferromagnetic steel plate having a first free surface and the other double-sided aluminized low carbon ferromagnetic steel plate having a second free surface; - obtaining a coated multi-layer shape by producing a protective coating on a first free surface and an adhesive coating on a second free surface; Stamping the coated multi-layer shape to form a coated metal body including a heating surface having a protective coating and a cooking surface having an anti-adhesion coating to form a cooking surface.

[0031] After the protective and anti-adhesion coatings have been applied, and after the coated form has been imaged, the method may include a step of treating a peripheral portion of the coated form to obtain a pinched edge, or a rolled edge, or an open rolled edge.

[0032] In particular, the protective coating may be a PTFE type coating or a lacquer type coating.

[0033] The anti-adhesion coating may be a PTFE type coating.

[0034] According to one embodiment, the shape may be disc-shaped, although other shapes are possible. [Brief description of the drawings]

[0035] Other features and attributes of the present invention will become more apparent from the following detailed description of illustrative embodiments and variants thereof, which are illustrated in the accompanying drawings, without being limiting. [Figure 1] 1 shows a partial schematic view of an example of a metal body used to make a coated metal cooking vessel. [Diagram 2] 2 shows a schematic cross-sectional view of the metal body shown in FIG. 1. [Diagram 3] 3 is an enlarged cross-sectional view of a surface portion of the metal body shown in FIG. 2. [Figure 4] 2 shows an enlarged schematic cross-sectional view of the metal body shown in FIG. 1 after a protective coating and an anti-adhesion coating have been applied. [Diagram 5] 1 shows a partial schematic view of an example of a metal body used to make a coated multi-layer metal cooking vessel according to the present invention. [Figure 6] 6 shows a schematic cross-sectional view of the metal body shown in FIG. 5 after application of a protective coating and an anti-adhesion coating. [Figure 7] 1 shows a partial schematic view of another example of a metal body used to make a coated multi-layer metal cooking vessel according to the present invention. [Figure 8] 8 shows a schematic cross-sectional view of the metal body shown in FIG. 7 after a protective coating and an anti-adhesion coating have been applied. [Figure 9] FIG. 9 shows a schematic cross-sectional view of one example of an embodiment of a coated multi-layer metal cooking vessel according to the present invention comprising the metal body shown in FIG. 6 or FIG. 8. [Figure 10] 1 shows a schematic cross-sectional view of a first embodiment of a peripheral portion of a coated multi-layer metal cooking vessel of the present invention having a pinched edge. [Figure 11] 2 shows a schematic cross-sectional view of a second embodiment of a peripheral portion of a coated metal cooking vessel of the present invention having a rolled edge. [Figure 12] 1 shows a schematic cross-sectional view of a third embodiment of a peripheral portion of a coated multi-layer metal cooking vessel of the present invention having an open rolled edge. [Figure 13] 1A-1D show schematic elevation and vertical cross-sectional views of an exemplary embodiment of a cookware article having a coated multi-layer metal cooking vessel according to the present invention. [Figure 14]1A-1D show schematic elevation and vertical cross-sectional views of an exemplary embodiment of an electric cooking appliance having a coated multi-layer metal cooking vessel according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] FIG. 1 illustrates an exemplary embodiment of a metal body 110 used to make a coated metal cooking vessel that is compatible with induction heating.

[0037] The metal body 110 is made of a low-carbon ferromagnetic steel sheet 101, which is aluminized on both sides. The aluminization of the low-carbon ferromagnetic steel sheet on both sides is achieved by immersion in an aluminized bath based on aluminization, achieving an aluminized deposit 115. The aluminized bath may contain silicon, in particular 8 to 13% by weight of silicon, in order to facilitate the deposition on the steel. In particular, AS-type aluminum-silicon alloys can be used, for example AS alloys with 8 to 13% by weight of silicon. However, the use of aluminized baths with a lower proportion of silicon or without silicon is conceivable. The amount of material deposited on the low-carbon ferromagnetic steel sheet can be evaluated by weighing. The additional mass thus obtained makes it possible to define the thickness of the aluminized deposit 115 on the steel sheet. Typically, such an aluminized deposit 115 can reach several tens of μm.

[0038] As shown in FIG. 2, the double-sided aluminum-coated low-carbon ferromagnetic steel plate 101 used to make the induction-heat compatible coated metal cooking vessel includes a low-carbon ferromagnetic steel substrate 111 having an aluminum-based outer layer 112 on each of its two sides.

[0039] The low carbon ferromagnetic steel substrate 111 may have a thickness of 0.7-3 mm, in particular a thickness of 1-2 mm. The material of the low carbon ferromagnetic steel substrate 111 is selected so as to be compatible with induction heating. The low carbon ferromagnetic steel substrate may be made of a steel grade having a maximum of 0.3% by weight carbon, preferably 0.1-0.2% by weight carbon. In particular, the ferromagnetic substrate 111 made of low carbon steel may be made of grades DX51-DX56, which contain 0.12-0.18% by weight carbon and maximum 0.5% by weight silicon.

[0040] As best seen in Figure 3, the intermediate layer 113 is disposed between the low carbon ferromagnetic steel substrate 111 and the outer layer 112. The intermediate layer 113 is an intermetallic reaction layer that includes iron / aluminum intermetallic compounds, specifically FeAl3 and Fe2Al5. Thus, not all of the aluminum-based deposits 115 made on the steel sheet are found in the outer layer 112. Some of the aluminum-based deposits 115 are in the intermediate layer 113.

[0041] The thickness of this intermediate layer 113 is usually 3-5 μm. However, heat treatment above 500° C. can contribute to increasing the thickness of this intermediate layer 113 and to the detriment of the thickness of the outer layer 112, which can then be subdivided into several sub-layers with different aluminum / iron ratios, these ratios increasing from the ferromagnetic substrate 111 made of low carbon steel towards the outer layer 112.

[0042] The aluminum-based outer layer 112 may include silicon if the aluminizing bath includes silicon, particularly 8-13% silicon by weight. As can be seen in the exemplary embodiment shown in FIG. 4, the outer layer 112 may then include Al-Fe-Si needles 114 within an aluminum-silicon matrix 116.

[0043] 5 and 6 show two exemplary embodiments of a metal body 110 used to make the induction heating compatible coated multi-layer metal cooking vessel 100 shown in FIG.

[0044] The metal body 110 shown in FIG. 5 differs from the metal body 110 shown in FIG. 1 in that it includes an aluminum plate 102 metallurgically assembled with a double-sided aluminum-coated low-carbon ferromagnetic steel plate 101. The aluminum plate 102 is made of a forged aluminum alloy. For example, the placage of the metallurgically assembled aluminum plate 102 with the double-sided aluminum-coated low-carbon ferromagnetic steel plate 101 can be performed by rolling or diffusion. The thickness of the double-sided aluminum-coated low-carbon ferromagnetic steel plate 101 is, for example, 0.3-1 mm, preferably 0.3-0.5 mm. The thickness of the aluminum plate 102 is, for example, 0.3-3 mm, preferably 0.5-1.5 mm.

[0045] The metal body 110 shown in FIG. 6 differs from the metal body 110 shown in FIG. 5 in that it includes another double-sided aluminum-coated low-carbon ferromagnetic steel plate 103 metallurgically assembled with the aluminum plate 102. The coating of the metallurgically assembled aluminum plate 102 with the double-sided aluminum-coated low-carbon ferromagnetic steel plate 101 and the double-sided aluminum-coated low-carbon ferromagnetic steel plate 103 can be performed, for example, by rolling or diffusion. The thickness of the double-sided aluminum-coated low-carbon ferromagnetic steel plate 101 is, for example, 0.3 to 1 mm, preferably 0.3 to 0.5 mm. The thickness of the aluminum plate 102 is, for example, 0.3 to 3 mm, preferably 0.5 to 1.5 mm. The thickness of the other double-sided aluminum-coated low-carbon ferromagnetic steel plate 103 is, for example, 0.3 to 1 mm, preferably 0.3 to 0.5 mm.

[0046] 9, metal body 110 includes a heating surface 120 and a cooking surface 130. Heating surface 120 has a bottom 122 configured to rest on an induction heating device, particularly an induction plate or induction heater.

[0047] As shown in FIG. 9, the heating surface 120 has a protective coating 121 and the cooking surface 130 has an anti-adhesive coating 131 that forms a cooking surface 132 .

[0048] The coated multi-layer metal cooking vessel 100 compatible with induction heating according to the invention shown in Figure 6 or Figure 8 includes a metal body 110, a protective coating 121, and an anti-adhesion coating 131. The metal body 110 has a protective coating 121 and an anti-adhesion coating 131.

[0049] 5 and 6, in the embodiment of FIG. 1 the heating surface 120 is formed by a low carbon ferromagnetic steel plate 101 which is aluminized on both sides.

[0050] In the embodiment of Figure 6, the cooking surface 130 is formed by an aluminium plate 102. The thickness of the aluminium plate 102 is, for example, 1.2 mm, and the thickness of the double-sided aluminized low carbon ferromagnetic steel plate 101 is, for example, about 0.3 mm.

[0051] In the embodiment of Figure 8, the cooking surface 130 is formed by the other double-sided aluminized low-carbon ferromagnetic steel plate 103. The thickness of the aluminum plate 102 is, for example, 1.2 mm, and the thicknesses of the double-sided aluminized low-carbon ferromagnetic steel plate 101 and the other double-sided aluminized low-carbon ferromagnetic steel plate 103 are, for example, about 0.3 mm.

[0052] If desired, the protective coating 121 can be applied directly to the heating surface 120 of the metal body 110, in particular to the outer layer 112 on the bottom 122. If necessary, a surface treatment can be performed on the heating surface 120 before the protective coating 121 is applied. In particular, the protective coating 121 can be a PTFE type coating, or an enamel type coating, or a lacquer type coating, or a ceramic type coating, or a sol-gel type coating.

[0053] If desired, the anti-adhesion coating 131 can be applied directly to the cooking surface 130 of the metal body 110. If necessary, a surface preparation can be performed on the cooking surface 130 before the protective coating 121 is applied. In particular, the anti-adhesion coating 131 can be a PTFE type coating, or a ceramic type coating, or a sol-gel type coating.

[0054] 9, the coated multi-layer metal cooking vessel 100 may include a sidewall 123 that rises around the bottom 122 of the heating surface 120 to form a cooking vessel 124. Alternatively, the coated multi-layer metal cooking support 100 does not necessarily form a cooking vessel 124. In particular, the coated multi-layer metal cooking surface 100 may form a cooking plate.

[0055] Tests with several induction plates have shown that the relevant parameter for achieving compatibility with induction heating on different induction heating devices is the thickness of the outer layer 112 on the bottom 122 of the heating surface 120, and not the thickness of the aluminum-based deposit 115 on the bottom 122 of the heating surface 120. The induction plates used are listed in Table 1.

[0056] [Table 1]

[0057] In fact, these tests show that the limit value for the thickness of the aluminum-based deposit 115 on the bottom 122 of the heated surface 120 to obtain a bond on the induction plate is about 30 μm when the protective coating 121 is a PTFE-type coating, a lacquer-type coating or a ceramic-type coating, or a sol-gel-type coating, but the limit value for the thickness of the aluminum-based deposit 115 on the bottom 122 of the heated surface 120 to obtain a bond on the induction plate is about 40 μm when the protective coating 121 is an enamel-type coating. These tests also showed that a satisfactory coupling was obtained with a thickness of the aluminum-based deposit 115 on the bottom 122 of the heated surface 120 of less than about 20 μm when the protective coating 121 is a PTFE-type coating, or a lacquer-type coating, or a ceramic-type coating, or a sol-gel-type coating, and with a thickness of the aluminum-based deposit 115 on the bottom 122 of the heated surface 120 of less than about 30 μm when the protective coating 121 is an enamel-type coating. The use of enamel type coatings requires firing temperatures in the range of 550° C. to 600° C. Above 500° C., diffusion phenomena occurring at the steel / aluminum interface favor the formation of iron / aluminum intermetallic compounds, which displace the interface between the intermediate layer 113 and the outer layer 112 and reduce the thickness of the outer layer 112. The thickness of the intermediate layer 113 is typically around 3-5 μm, but can be greater if necessary in the form of several sublayers and / or in the reduction of the thickness of the outer layer 112, especially in the case of heat treatments that favor a growth in the thickness of the intermediate layer 113.

[0058] The thickness of the outer layer 112 on the bottom 122 of the heating surface 120 is important for the compatibility of the coated multi-layer metal cooking vessel 100 with induction heating. A thickness of less than 27 μm for the outer layer 112 on the bottom 122 of the heating surface 120 is considered a limiting value for achieving bonding on the induction plate. For the outer layer 112 on the bottom 122 of the heating surface 120, a thickness of less than 26 μm provides better results than a thickness of less than 27 μm, a thickness of less than 25 μm provides better results than a thickness of less than 26 μm, a thickness of less than 24 μm provides better results than a thickness of less than 25 μm, a thickness of less than 23 μm provides better results than a thickness of less than 24 μm, a thickness of less than 22 μm provides better results than a thickness of less than 23 μm, a thickness of less than 21 μm provides better results than a thickness of less than 22 μm, a thickness of less than 20 μm provides better results than a thickness of less than 21 μm, a thickness of less than 19 μm provides better results than a thickness of less than 20 μm, a thickness of less than 18 μm provides better results than a thickness of less than 19 μm, and a thickness of less than 17 μm provides better results than a thickness of less than 18 μm. A thickness of less than 20 μm for the outer layer 112 on the bottom 122 of the heating surface 120 allows a fairly satisfactory bond with the induction plate. A thickness of less than 18 μm for the outer layer 112 on the bottom 122 of the heating surface 120 allows a fairly satisfactory bond with the induction plate. The efficiency (power absorbed by the coated multi-layer metal cooking vessel 100 / power emitted by the induction plate) can approach 100%. The heating rate is very fast.

[0059] 9, the coated multi-layer metal cooking vessel 100 compatible with induction heating has an exposed end 128. The end 128 is generally free of the outer layer 112 by cutting the metal body 110 to create a multi-layer shape suitable for making the coated multi-layer metal cooking vessel 100. The end 128 may be at least partially covered by a protective coating 121 and / or an anti-adhesion coating 131. Preferably, the exposed end 128 is covered by the protective coating 121 and / or the anti-adhesion coating 131.

[0060] As shown in Figure 10, the induction heating compatible coated multi-layer metal cooking vessel 100 can have pinched edges 125. As shown in Figure 11, the induction heating compatible coated multi-layer metal cooking vessel 100 can have rolled edges 126. As shown in Figure 12, the induction heating compatible coated multi-layer metal cooking vessel 100 can have open rolled edges 127. Thus, edges 128 are not visible on the top side of the coated multi-layer metal cooking vessel 100.

[0061] FIG. 13 shows a cooking article 140 having a coated multi-layer metal cooking vessel 100 and a gripping element 150 attached to the coated multi-layer metal cooking vessel 100. The coated multi-layer metal cooking vessel 100 forms the cooking vessel 124 shown in FIG. 9. In the exemplary embodiment shown in FIG. 9, the gripping element 150 is attached to the cooking vessel 124 by at least one rivet 151. For this purpose, the rivet 151 is attached to a hole in the side wall 123. If desired, multiple rivets 151 can be used to secure the gripping element 150 to the cooking vessel 124. Preferably, two to four rivets 151 are used to secure the gripping element 150 to the cooking vessel 124. Alternatively, the gripping element 150 can be attached to the side wall 123 by being welded or screwed to a stud welded to the side wall 123. If desired, further gripping elements can be attached to the side wall 123 of the cooking vessel 124 by at least one further rivet, by welding, or by screwing onto studs welded to the side wall 123 .

[0062] FIG. 14 shows an electric cookware 160 having a coated multi-layer metal cooking vessel 100 associated with an induction heater 170. The coated multi-layer metal cooking vessel 100 forms the cooking vessel 124 shown in FIG. 9. The cooking vessel 124 is placed on a heating base 175 that includes an induction heater 170. The bottom 122 rests on the induction heater 170. Optionally, the cooking vessel 124 may include at least one gripping element 155. In the exemplary embodiment shown in FIG. 14, the cooking vessel 124 has two opposing gripping elements 155. One or each gripping element 155 is attached to the cooking vessel 124 by at least one rivet 156. For this purpose, the rivet 156 is attached to a hole in the side wall 123. Optionally, multiple rivets 156 can be used to fasten the gripping element 155 to the cooking vessel 124. Preferably, two to four rivets 156 are used to secure one or each gripping element 155 to the cooking vessel 124. Alternatively, the or at least one of the gripping elements 155 can be attached to the sidewall 123 by welding or screwing to a stud welded to the sidewall 123.

[0063] The induction heating compatible coated multi-layer metal cooking vessel 100 according to the present invention can be obtained by a variety of methods.

[0064] A first method for obtaining a coated multi-layer metal cooking vessel 100 that is compatible with induction heating includes the following steps. cutting or providing a multi-layer shape from a double sided aluminized low carbon ferromagnetic steel sheet 101 metallurgically assembled with an aluminium sheet 102, said double sided aluminized low carbon ferromagnetic steel sheet 101 having a first free surface and said aluminium sheet 102 having a second free surface; stamping the multi-layer shape to form the metal body 110 with the heating surface 120 corresponding to the first free surface and the cooking surface 130 corresponding to the second free surface; Producing a protective coating 121 on the heating surface 120; An anti-adhesive coating 131 is applied to cooking surface 130 to form cooking surface 132.

[0065] A second method for obtaining a coated multi-layer metal cooking vessel 100 that is compatible with induction heating includes the following steps. cutting or providing a multi-layer shape from an aluminum plate 102 metallurgically assembled with a double-sided aluminized low carbon ferromagnetic steel plate 101 and another double-sided aluminized low carbon ferromagnetic steel plate 103, the double-sided aluminized low carbon ferromagnetic steel plate 101 having a first free surface and the other double-sided aluminized low carbon ferromagnetic steel plate 103 having a second free surface; stamping the multi-layer shape to form the metal body 110 with the heating surface 120 corresponding to the first free surface and the cooking surface 130 corresponding to the second free surface; Producing a protective coating 121 on the heating surface 120; An anti-adhesive coating 131 is applied to cooking surface 130 to form cooking surface 132.

[0066] In particular, the multi-layer shape can be disk-shaped. Optionally, after imaging the multi-layer shape and before creating the protective coating 121 and the anti-adhesion coating 131, the first method or the second method may include a step of processing a peripheral portion of the multi-layer shape to obtain a pinched edge 125 or a rolled edge 126 or an open rolled edge 127.

[0067] In this first method or this second method, the molding operation is followed by a protective coating 121 and an anti-adhesion coating 131. A wide range of coatings can be used. In particular, the protective coating 121 can be a PTFE-type coating, or an enamel-type coating, or a lacquer-type coating, or a ceramic-type coating, or a sol-gel-type coating. In particular, the anti-adhesion coating 131 can be a PTFE-type coating, or a ceramic-type coating, or a sol-gel-type coating.

[0068] A third method for obtaining a coated multi-layer metal cooking vessel 100 that is compatible with induction heating includes the following steps. cutting or providing a multi-layer shape from an aluminum plate 102 metallurgically assembled with a double-sided aluminized low carbon ferromagnetic steel plate 101 and another double-sided aluminized low carbon ferromagnetic steel plate 103, the double-sided aluminized low carbon ferromagnetic steel plate 101 having a first free surface and the other double-sided aluminized low carbon ferromagnetic steel plate 103 having a second free surface; - obtaining a coated multi-layer shape by producing a protective coating 121 on a first free surface and an anti-adhesion coating 131 on a second free surface; Stamping the coated form to form a coated metal body 110 comprising a heating surface 120 having a protective coating 121 and a cooking surface 130 having an anti-adhesion coating 131 forming a cooking surface 132.

[0069] In particular, the multi-layer shape can be a disk. After the protective coating 121 and the anti-adhesion coating 131 are applied and after the coated form is imaged, the method can include processing a peripheral portion of the coated form to obtain a pinched edge 125, or a rolled edge 126, or an open rolled edge 127.

[0070] In this third method, the protective coating 121 and the anti-adhesion coating 131 are applied before the forming operation. As a result, the range of coatings that can be used is more limited. The protective coating 121 and the anti-adhesion coating 131 should make it possible to form the shape by stamping. In particular, the protective coating 121 can be a PTFE type coating or a lacquer type coating. In particular, the anti-adhesion coating 131 can be a PTFE type coating.

[0071] The use of a metal body 110 consisting of one side of a double-sided aluminized low carbon ferromagnetic steel plate 101 to make the coated multi-layer metal cooking vessel 100 makes it possible to use conventional manufacturing processes, limiting the required investment.

[0072] The coated multi-layer metal cooking vessel 100 is mechanically very strong. The efficiency (power input / power output of the induction heater) is very high, especially when the thickness of the aluminum-based deposit 115 is less than 20 μm. The heating rate is high: 15 seconds for a 28 cm diameter pan, compared to about 1 minute 30 seconds for a standard aluminum pan of the same diameter with a stainless steel insert for compatibility with induction heating. Energy savings can be achieved because the power delivered by the induction heater can be lower.

[0073] In the two-layer structure according to the embodiment of FIG. 6 or the three-layer structure according to the embodiment of FIG. 8, the presence of an aluminum plate 102 metallurgically assembled with a double-sided aluminized low-carbon ferromagnetic steel plate 101 makes it possible to improve the thermal homogeneity of the cooking surface 132.

[0074] In its two-layer construction according to the example embodiment of FIG. 6, the coated multi-layer metal cooking vessel 100 remains fairly light while providing better thermal uniformity.

[0075] In the three-layer construction according to the embodiment of Figure 8, it is possible to use a method of forming after the coating operation due to the presence of another double-sided aluminized low carbon ferromagnetic steel sheet 103 metallurgically assembled with the aluminium sheet 102. The coated multi-layer metal cooking vessel 100 remains relatively light.

[0076] Various modifications and / or improvements apparent to those skilled in the art can be made to the exemplary embodiments of the invention set forth in this description without departing from the scope of the invention as defined by the appended claims.

Claims

1. A coated multi-layer metal cooking vessel (100) compatible with induction heating, comprising a metal body (110) including a heating surface (120) and a cooking surface (130), said heating surface (120) having a bottom (122) configured to rest on an induction heating device, said heating surface (120) carrying a protective coating (121), and said cooking surface (130) carrying an anti-adhesion coating (131) forming a cooking surface (132); 1. A coated multi-layer metal cooking vessel (100) compatible with induction heating, wherein the metal body (110) is formed of a metallurgically assembled aluminum plate (102) with a double-sided aluminum-coated low-carbon ferromagnetic steel plate (101) forming the heating surface (120), the double-sided aluminum-coated low-carbon ferromagnetic steel plate (101) being formed of a low-carbon ferromagnetic steel substrate (111) having on each of its two sides an outer layer (112) with an aluminum-based matrix, an intermediate layer (113) comprising an iron / aluminum intermetallic compound being disposed between the low-carbon ferromagnetic steel substrate (111) and the outer layer (112), and wherein, at least at the bottom (122) of the heating surface (120), the outer layer (112) has a thickness of less than 27 μm, preferably less than 20 μm, even more preferably less than 18 μm.

2. 2. The coated multi-layer metal cooking vessel (100) compatible with induction heating according to claim 1, characterized in that the metal body (110) formed of the aluminum plate (102) metallurgically assembled with the double-sided aluminum-coated low-carbon ferromagnetic steel plate (101) forming the heating surface (120) further comprises another double-sided aluminum-coated low-carbon ferromagnetic steel plate (103).

3. The coated multi-layer metal cooking vessel (100) compatible with induction heating according to claim 1 or 2, characterized in that the outer layer (112) comprises Al-Fe-Si needles in an aluminum-silicon matrix.

4. The coated multi-layer metal cooking vessel (100) suitable for induction heating according to any one of claims 1 to 3, characterized in that the low carbon ferromagnetic steel substrate (111) has a thickness of 0.3 to 1 mm, preferably 0.3 to 0.5 mm, and the aluminium plate (102) has a thickness of 0.3 to 3 mm, preferably 0.5 to 1.5 mm.

5. The coated multi-layer metal cooking vessel (100) suitable for induction heating according to any one of claims 1 to 4, characterized in that the low carbon ferromagnetic steel substrate (111) is made of a steel grade having a maximum of 0.3% by weight carbon, preferably 0.1-0.2% by weight carbon.

6. The coated multi-layer metal cooking vessel (100) compatible with induction heating according to any one of claims 1 to 5, characterized in that the protective coating (121) can be applied directly to the heating surface (120) of the metal body (110).

7. The coated multi-layer metal cooking vessel (100) suitable for induction heating according to any one of claims 1 to 6, characterized in that the protective coating (121) is a PTFE type coating, or an enamel type coating, or a lacquer type coating, or a ceramic type coating, or a sol-gel type coating.

8. 8. The coated multi-layer metal cooking vessel (100) suitable for induction heating according to claim 7, characterized in that the protective coating (121) is a PTFE type coating, or a lacquer type coating, or a ceramic type coating, or a sol-gel type coating, and the metal body (110) comprises an aluminum-based deposit (115) having a thickness of less than 30 μm, preferably less than 20 μm, at least on the bottom part (122) of the heating surface (120).

9. 8. The coated multi-layer metal cooking vessel (100) adapted for induction heating according to claim 7, characterized in that the protective coating (121) is an enamel-type coating and the metal body (110) comprises an aluminum-based deposit (115) having a thickness of less than 40 μm, preferably less than 30 μm, at least on the bottom (122) of the heating surface (120).

10. The coated multi-layer metal cooking vessel (100) compatible with induction heating according to any one of claims 1 to 9, characterized in that the anti-adhesion coating (131) is a PTFE type coating, or a ceramic type coating, or a sol-gel type coating.

11. The coated multi-layer metal cooking vessel (100) suitable for induction heating according to any one of claims 1 to 10, characterized in that a side wall (123) rises around a bottom (122) of the heating surface (120) to form a cooking vessel (124).

12. The coated multi-layer metal cooking vessel (100) suitable for induction heating according to any one of claims 1 to 11, characterized in that it has folded edges (125), or rolled edges (126), or open rolled edges (127).

13. A cooking article (140) comprising a coated multi-layer metal cooking vessel (100) and a gripping element (150) attached to the coated multi-layer metal cooking vessel (100), characterized in that the coated multi-layer metal cooking vessel (100) is the coated multi-layer metal cooking vessel (100) according to any one of claims 1 to 12.

14. An electric cooking appliance (160) having a coated multi-layer metal cooking vessel (100) associated with an induction heater (170), characterized in that the coated multi-layer metal cooking vessel (100) is a coated multi-layer metal cooking vessel (100) according to any one of claims 1 to 12.

15. A method for obtaining a coated multi-layer metal cooking vessel (100) suitable for induction heating according to claim 1 or any one of claims 3 to 12 not dependent on claim 2, comprising the steps of cutting or providing a multi-layer shape from said aluminium plate (102) metallurgically assembled with said double-sided aluminized low carbon ferromagnetic steel plate (101), said double-sided aluminized low carbon ferromagnetic steel plate (101) having a first free surface and said aluminium plate (102) having a second free surface; stamping the multi-layer shape to form the metal body (110) with the heating surface (120) corresponding to the first free surface and the cooking surface (130) corresponding to the second free surface; forming said protective coating (121) on said heating surface (120); and applying the anti-adhesion coating (131) to the cooking surface (130) to form a cooking surface (132).

16. A method for obtaining a coated multi-layer metal cooking vessel (100) suitable for induction heating according to any one of claims 2 to 12, comprising the steps of: cutting or providing a multi-layer shape from said metallurgically assembled aluminum sheet (102) comprising said double-sided aluminized low carbon ferromagnetic steel sheet (101) and another double-sided aluminized low carbon ferromagnetic steel sheet (103), said double-sided aluminized low carbon ferromagnetic steel sheet (101) having a first free surface and said another double-sided aluminized low carbon ferromagnetic steel sheet (103) having a second free surface; stamping the multi-layer shape to form the metal body (110) with the heating surface (120) corresponding to the first free surface and the cooking surface (130) corresponding to the second free surface; forming a protective coating (121) on said heating surface (120); and applying an anti-adhesive coating (131) to the cooking surface (130) to form a cooking surface (132).

17. The method for obtaining a coated multi-layer metal cooking vessel (100) compatible with induction heating according to claim 15 or claim 16, wherein after stamping the multi-layer shape and before applying the protective coating (121) and the anti-adhesion coating (131), the method includes a step of treating a peripheral portion of the multi-layer shape to obtain a folded edge (125) or a rolled edge (126) or an open rolled edge (127).

18. A method for obtaining a coated multi-layer metal cooking vessel (100) compatible with induction heating according to any one of claims 15 to 17, characterized in that the protective coating (121) is a PTFE type coating, or an enamel type coating, or a lacquer type coating, or a ceramic type coating, or a sol-gel type coating.

19. A method for obtaining a coated multi-layer metal cooking vessel (100) compatible with induction heating according to any one of claims 15 to 18, characterized in that the anti-adhesion coating (131) is a PTFE type coating, or a ceramic type coating, or a sol-gel type coating.

20. A method for obtaining a coated multi-layer metal cooking vessel (100) suitable for induction heating according to any one of claims 1 to 12, comprising the steps of: cutting or providing a multi-layer shape from a metallurgically assembled aluminum sheet (102) having a double-sided aluminized low carbon ferromagnetic steel sheet (101) and another double-sided aluminized low carbon ferromagnetic steel sheet (103), the double-sided aluminized low carbon ferromagnetic steel sheet (101) having a first free surface and the other double-sided aluminized low carbon ferromagnetic steel sheet (103) having a second free surface; - obtaining a coated multi-layer shape by producing a protective coating (121) on said first free face and an anti-adhesion coating (131) on said second free face; and stamping the coated multi-layer shape to form a coated metal body (110) including a heating surface (120) having the protective coating (121) and a cooking surface (130) having the anti-adhesion coating (131) to form a cooking surface (132).

21. 21. The method for obtaining a coated multi-layer metal cooking vessel (100) compatible with induction heating as claimed in claim 20, characterized in that after the protective coating (121) and the anti-adhesion coating (131) are applied and after the coated multi-layer shape is stamped, the method includes a step of treating a peripheral portion of the coated multi-layer shape to obtain a folded edge (125), or a rolled edge (126), or an open rolled edge (127).

22. A method for obtaining a coated multi-layer metal cooking vessel (100) compatible with induction heating according to claim 20 or claim 21, characterized in that the protective coating (121) is a PTFE type coating or a lacquer type coating.

23. A method for obtaining a coated multi-layer metal cooking vessel (100) compatible with induction heating according to any one of claims 20 to 22, characterized in that said anti-adhesion coating (131) is a PTFE type coating.

24. A method for obtaining a coated multi-layer metal cooking vessel (100) suitable for induction heating according to any one of claims 15 to 23, characterized in that said shape is disc-shaped.

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