HRP930001A2

HRP930001A2 - Method for manufacturing a cooking vessel

Info

Publication number: HRP930001A2
Authority: HR
Inventors: Alfred Galle
Original assignee: Amc Int Alfa Metalcraft Corp
Priority date: 1993-01-04
Filing date: 1993-01-04
Publication date: 1994-10-31

Description

Izum se odnosi na postupak za proizvodnju jedne kuhinjske posude koja obuhvaća jednu okruglu posudu za hranu koja ima dno, ploču od toplinsko provodljivog materijala i vanjsko dno koje pokriva ploču, pri čemu je vanjsko dno načinjeno od limenog diska i ima konveksno zakrivljenje prema posudi, a također ima prirubnicu koja naliježe na posudu u jednom zakrivljenom prelaznom području između dna i omotača posude, pri čemu su posuda i vanjsko dno načinjeni od nehrđajućeg čelika a ploča je intermetalno spojena sa dnom posude i sa vanjskim dnom. Poznata su razna izvođenja ovih kuhinjskih posuda. The invention relates to a process for the production of a kitchen container comprising a round food container having a bottom, a plate made of heat-conducting material and an outer bottom covering the plate, wherein the outer bottom is made of a sheet metal disk and has a convex curvature towards the container, and also has a flange that abuts the vessel in a curved transition region between the bottom and the shell of the vessel, wherein the vessel and the outer bottom are made of stainless steel and the plate is intermetallic connected to the bottom of the vessel and to the outer bottom. Various versions of these kitchen utensils are known.

Izum se zasniva na postupku kod koga se ploča, limeni disk i dno posude centriraju i spajaju elektrootpornim zagrijavanjem da bi se ostvarilo središnje točkasto zavarivanje, poslije čega se ostvaruje intermetalni spoj jednostrukim ili višestrukim udarnim pritiskom i plastičnom deformacijom, pa se pri tome tvori prirubnica vanjskog dna na limenom disku a njen rub je postavljen oko posude. Svakako da se proces na kome se zasniva izum, a prema tome i postupak prema izumu može izvoditi i na temperaturi okolne sredine i uz zagrijavanje. Energija udara će biti prilagođena temperaturi posude, bar u području dna, vanjskog dna i ploče. Obično se te temperature biraju tako da su blizu, ali dovoljno ispod temperature topljenja materijala ploče. Aluminij u vidu industrijski čistog aluminija vrlo je pogodan materijal za ploču. Bakar je također pogodan materijal za ploču. Kuhinjske posude mogu biti lonci, zdjele, tave i slično, a posebno lonci za kuhanje i tzv. ekspres lonci. Ploča služi da poboljša prijenos topline od ploče kuhala ili ploče štednjaka do hrane. Na prenošenje topline nepovoljno utječe ako dođe do oštećenja intermetalnog spoja. To posebno vrijedi kada je oštećenje u području prirubnice vanjskog dna, jer iskustvo pokazuje da se ono može odavde širiti kada se posuda koristi. The invention is based on a process in which the plate, tin disk and the bottom of the vessel are centered and joined by electrical resistance heating to achieve central spot welding, after which an intermetallic connection is achieved by single or multiple impact pressure and plastic deformation, thus forming the flange of the outer bottom on a tin disk and its edge is placed around the container. Certainly, the process on which the invention is based, and therefore the procedure according to the invention, can be performed at ambient temperature and with heating. The impact energy will be adapted to the temperature of the vessel, at least in the area of the bottom, outer bottom and plate. Typically, these temperatures are chosen to be close to, but sufficiently below, the melting temperature of the plate material. Aluminum in the form of industrially pure aluminum is a very suitable material for the plate. Copper is also a suitable material for the plate. Kitchen utensils can be pots, bowls, pans and the like, especially cooking pots and so-called pressure cookers. The plate serves to improve the transfer of heat from the hob or stove top to the food. Heat transfer is adversely affected if the intermetallic connection is damaged. This is especially true when the damage is in the area of the outer bottom flange, as experience shows that it can spread from here when the vessel is in use.

Poznati postupak na kome se zasniva izum (DE-PS 22 58 795) ne daje kuhinjsku posudu koja ima donji dio vanjskog dna s konveksnim zakrivljenjem prema posudi. Umjesto toga, proces daje uglavnom ravno vanjsko dno. Koristi se ravan limeni disk čiji rub ne može, a nije ni konstruiran, da se trajno deformira i na-legne uz posudu kada se na vanjskom dnu stvori prirubnica. Teži se samo da se rub limenog diska oblikuje ili zakosi da bi dobro nalegla uz posudu. U tom je cilju promjer diska manji od nominalnog vanjskog promjera lonca. Udarni pritisak oblikuje ravno vanjsko dno i tvori prirubnicu u istoj operaciji. U praksi se pokazalo da to ne može osigurati potpuno korektan intermetalni spoj između vanjskog dna, njegovog donjeg dijela, prirubnice vanjskog dna i ploče, ili između ploče i dna posude. Često se centriranje ostvareno prije udarnog pritiska remeti i proizvod se mora odbaciti. The known process on which the invention is based (DE-PS 22 58 795) does not provide a kitchen vessel having a lower part of the outer bottom with a convex curvature towards the vessel. Instead, the process produces a mostly flat outer bottom. A flat sheet metal disk is used, the edge of which cannot, and is not designed, to be permanently deformed and lie against the vessel when a flange is formed on the outer bottom. The aim is only to shape or bevel the edge of the tin disk so that it fits well against the container. For this purpose, the diameter of the disc is smaller than the nominal outer diameter of the pot. Impact pressure forms a flat outer bottom and forms a flange in the same operation. In practice, it has been shown that this cannot ensure a completely correct intermetallic connection between the outer bottom, its lower part, the flange of the outer bottom and the plate, or between the plate and the bottom of the vessel. Often, the centering achieved before the impact pressure is disturbed and the product has to be discarded.

Kod jednog drugog poznatog postupka (EP 0 209 745), procedura se odvija na sljedeći način: ploča se pričvrsti na sredini unaprijed izrađenog vanjskog dna točkastim zavarivanjem. Sklop, koji sačinjavaju vanjsko dno, ploča i dno posude ili Do-suda, zagrijava se do temperature koja je blizu, ali ispod temperature topljenja materijala ploče. Početna debljina ploče je najmanje 20% veća od krajnje debljine ploče, nakon što se načini intermetalni spoj. U prvoj fazi udarnog pritiska, pritisak se prenosi postupno od središta ka rubu sklopa, tako da se dobiva posebna koveksnost, tj. takva da je ukupna zakrivljenost udubljenja oblikovane ploče i posude ne manja od 0,5% prosječnog promjera dna posude kada dostigne konačan oblik. To je postupak istiskivanja zraka od središta prema van, iz sklopa koji čine dno posude, ploča i vanjsko dno. Poznati postupak, međutim, ima ograničenja koja umanjuju pogodnost naprijed opisanih stupnjeva obrade. To je zbog postavljenih uvjeta, tj. s jedne strane da početna debljina ploče mora biti najmanje 20% veća od njene konačne debljine nakon ostvarivanja intermetalnog spoja, i s druge strane, da se udubljenje mora prilagoditi kako je naprijed opisano. Također nije rečeno da spoj točkastim zavarivanjem treba biti u središtu i biti otporan na udarni pritisak. Ako se u tijeku udarnog pritiskanja taj spoj prekine, ne može se izbjeći pomicanje ploče u tijeku udarnog pritiskanja. Zbog toga nema garancije da će se ostvariti intermetalni spoj koji će zadovoljiti sve uvjete i kod ruba ploče i kod prirubnice vanjskog dna. In another known method (EP 0 209 745), the procedure takes place as follows: the plate is fixed in the middle of the pre-made outer bottom by spot welding. The assembly, consisting of the outer bottom, the plate and the bottom of the vessel or Do-vessel, is heated to a temperature close to but below the melting temperature of the plate material. The initial thickness of the plate is at least 20% greater than the final thickness of the plate, after the intermetallic joint is made. In the first stage of impact pressure, the pressure is transferred gradually from the center to the edge of the assembly, so that a special convexity is obtained, i.e. such that the total curvature of the depression of the formed plate and the vessel is not less than 0.5% of the average diameter of the vessel bottom when it reaches its final shape . It is the process of squeezing air from the center outwards, from the assembly that makes up the bottom of the container, the plate and the outer bottom. The known process, however, has limitations that reduce the convenience of the processing steps described above. This is due to the set conditions, i.e. on the one hand that the initial thickness of the plate must be at least 20% greater than its final thickness after achieving the intermetallic connection, and on the other hand, that the recess must be adjusted as described above. It also did not say that the spot weld joint should be centered and be impact resistant. If this connection is broken during impact pressing, the movement of the plate cannot be avoided during impact pressing. For this reason, there is no guarantee that an intermetallic connection will be achieved that will satisfy all conditions both at the edge of the plate and at the flange of the outer bottom.

U stvarnosti je, međutim, vrlo vezno imati u cjelini interrnetalni spoj bez bilo kakvih grešaka, posebno u području donjeg dijela vanjskog dna (usporediti časopis "Materialprüfung" 33 (1991) 4, str. 89 do 91). In reality, however, it is very important to have an overall interrnetal connection without any defects, especially in the area of the lower part of the outer bottom (compare the journal "Materialprüfung" 33 (1991) 4, pp. 89 to 91).

Do sada nije bio poznat neki postojeći, uglavnom automatiziran postupak za osiguravanje takvog spoja, osim ako početni materijal nije bio relativno ravan limeni disk umjesto unaprijed oblikovanog vanjskog dna. Until now, no existing, largely automated process for providing such a joint was known, unless the starting material was a relatively flat sheet metal disc instead of a preformed outer bottom.

Cilj je izuma da se preusmjeri naprijed opisan postupak (DE 22 58 795) tako da se može izraditi kuhinjska posuda koja ina naprijed opisanu konstrukciju, a sa donjim dijelom i pri-rubnicom vanjskog dna koji će imati konveksnu krivinu prema dnu posude i zadovoljiti sve zahtjeve. U tom se cilju, prema izumu, koristi limena kružna ploča, ili disk, koji ima rub koji se može, u toku stvaranja prirubnice vanjskog poklopca, trajno deformirati dok se pritište uz posudu, pri čemu su limeni disk, ploča i dno posude centrirani elektrootpornim zavarivanjem, tako da su otporni na udarni pritisak, pri čemu udarni pritisak djeluje tako da osigurava konveksnu zakrivljenost u donjem dijelu vanjskog dna, a u tijeku udarnog pritiska zrak se prvo istisne iz područja između diska i vanjskog dna u procesu oblikovanja, nakon čega se ostvaruje brtvljenje trajnim deformiranjem u odnosu na plastičnu deformaciju materijala ploče, a na materijalu ploče se stvara jedna prirubnica i utiskuje se u područje brtvljenja. Svakako da se alati, tj. kalup i pritiskivao, za izvođenje udarnog pritiska u preši, moraju namjestiti tako da se dobije ranije naglašen, blago konveksan oblik donjeg dijela vanjskog dna. Obično je posuda malo ispupčena prema van. Svakako da geometrijski uvjeti u pogledu dna posude, vanjskog dna i ploče moraju biti ugođeni tako da kod gotove kuhinjske posude ploča potpuno ispunjava prostor između dna posude i vanjskog dna, tj. u toku intermetalnog spajanja ploča stvara jednu prirubnicu koja se pruža brtvljujuće, ili vrlo brtvljujuće u spomenuto područje brtvljenja. Definiran, neporemećen tijek materijala ploče važan je za ostvarivanje intermetalnog spoja. Ploča može biti ravna, ili može imati lećast ili stupnjevit poprečni presjek. Prema izumu, površina vanjskog dna i dna posude mogu, ako se želi, biti konstruirani tako da potpomognu stvaranje intermetalnog spoja, na primjer nagrizanjem, hrapavljenjem, ili sličnim. Posebno je važno da rub prirubnice vanjskog dna naliježe bez greške na posudu. Ako se materijal ploče ovdje probije van, posuda će biti odbačena iz estetskih razloga i da bi se izbjegla korozija. Ako tu postoji procjep, može prodrijeti voda u toku upotrebe ili kod pranja, i stvarati probleme izazivajući koroziju. The aim of the invention is to redirect the process described above (DE 22 58 795) so that it is possible to create a kitchen container that has the structure described above, and with the lower part and the flange of the outer bottom, which will have a convex curve towards the bottom of the container and meet all requirements . For this purpose, according to the invention, a tin circular plate, or disc, is used, which has an edge that can, during the creation of the flange of the outer cover, be permanently deformed while being pressed against the container, whereby the tin disc, plate and bottom of the container are centered with an electro-resistant by welding, so that they are resistant to impact pressure, whereby the impact pressure acts to ensure a convex curvature in the lower part of the outer bottom, and during the impact pressure, air is first squeezed out of the area between the disc and the outer bottom in the forming process, after which sealing is achieved by permanent deformation in relation to the plastic deformation of the plate material, and one flange is created on the plate material and pressed into the sealing area. It is certain that the tools, i.e. the mold and the pressing tool, for performing the impact pressure in the press, must be adjusted in such a way as to obtain the previously emphasized, slightly convex shape of the lower part of the outer bottom. Usually the bowl is slightly bulging outwards. Of course, the geometric conditions regarding the bottom of the container, the outer bottom and the plate must be adjusted so that in the finished kitchen container the plate completely fills the space between the bottom of the container and the outer bottom, i.e. during the intermetallic connection of the plates, it creates one flange that extends sealingly, or very sealant into the mentioned sealing area. A defined, undisturbed flow of the sheet material is important for achieving an intermetallic connection. The plate can be flat, or it can have a lenticular or stepped cross-section. According to the invention, the surface of the outer bottom and the bottom of the container can, if desired, be designed to facilitate the formation of an intermetallic compound, for example by etching, roughening, or the like. It is especially important that the edge of the flange of the outer bottom rests on the container without error. If the plate material breaks through here, the vessel will be discarded for aesthetic reasons and to avoid corrosion. If there is a gap there, water can penetrate during use or when washing, and cause problems by causing corrosion.

Prema izumu ima više mogućnosti da se dalje razvija prikazani postupak. Pogodno je da se koristi ploča koja ima debljinu, u hladnom stanju prije plastične deformacije, koja je veća za manje od 16% od debljine nakon plastične deformacije. Mada je ovaj višak debljine ploče relativno mali, izum daje besprijekoran intermetalni spoj. Naprijed spomenuto oblikovanje prirubnice vanjskog dna sa trajnim deformiranjem uz posudu u toku udarnog pritiska može se ostvariti bez teškoće, ako se koristi limeni disk promjera većeg od nominalnog vanjskog promjera lonca. Poželjno je da je debljina lima približno jednaka debljini metala od koga je načinjena posuda. Disk može biti čak za 20% tanji od lima od koga je načinjeno dno posude. According to the invention, there are more possibilities to further develop the presented procedure. It is convenient to use a plate that has a thickness, in the cold state before plastic deformation, which is greater by less than 16% than the thickness after plastic deformation. Although this excess plate thickness is relatively small, the invention provides a flawless intermetallic joint. The above-mentioned shaping of the flange of the outer bottom with permanent deformation next to the vessel during the impact pressure can be achieved without difficulty, if a tin disk with a diameter larger than the nominal outer diameter of the pot is used. It is desirable that the thickness of the sheet is approximately equal to the thickness of the metal from which the container is made. The disk can be even 20% thinner than the sheet from which the bottom of the container is made.

Kako je već rečeno, postupak prema izumu može se izvoditi na temperaturi okolne sredine, ili uz deformiranje zagrijavanjem. U ovom drugom slučaju, jedno preporučljivo izvođenje izuma karakteristično je po tome, što se na posudu, vanjsko dno i ploču djeluje udarnim pritiskom kada su ovi elementi na temperaturi koja je bliska temperaturi topljenja ploče, a alati za oblikovanje se koriste zagrijani na temperaturu u opsegu između 100 i 350°C. As already mentioned, the process according to the invention can be performed at ambient temperature, or with deformation by heating. In this second case, one recommended embodiment of the invention is characterized by the fact that the vessel, the outer bottom and the plate are subjected to impact pressure when these elements are at a temperature close to the melting temperature of the plate, and the molding tools are used heated to a temperature in the range between 100 and 350°C.

Neočekivano se postupak prema izumu može koristiti za izradu posude opisane vrste, koja ima vanjsko dno, prirubnicu vanjskog dna i donji dio istog koji je konveksan prema posudi, a koja zadovoljava sve uvjete, mada je, u toku udarnog pritiska, vanjsko dno načinjeno od limenog diska bez prirubnice, tako da nema potrebe da se prethodno izrađuje vanjsko dno sa prirubnicom. To je zbog toga što su ranije opisani stupnjevi kombinirani u toku izvođenja. Trajna deformacija se javlja točno na mjestu određenom konstrukcijom i može biti veoma precizna, jer je zavaren spoj otporan na udarni pritisak. Zavaren spoj otpor-m na udarni pritisak može se načiniti elektrootpornim zavarivanjem, ako se dovede dovoljna količina energije. To je moguće posebno zbog toga, što se, prema izumu, koristi relativno tanka ploča. Deformiranje ploče plastičnim pritiskom, uz istovremeno oblikovanje vanjskog dna, dovodi do krajnje čvrstog, jakog intermetalnog spoja u ovom važnom području, a bez poremećaja centriranja. Rub vanjskog dna dodiruje i brtvi posudu, kako u toku izrade, tako i nakon hlađenja. Nema procjepa između dna posude i vanjskog dna, tako da voda ne može prodrijeti u toku upotrebe ili pri pranju, i nisu primijećene neke posljedice izazvane korozijom. Izum će biti detaljnije opisan sa pozivom na crteže jednog izvođenja, prikazanog samo kao primjer. Na shematskim crtežima: Unexpectedly, the process according to the invention can be used to produce a container of the described type, which has an outer bottom, a flange of the outer bottom and a lower part of it that is convex towards the container, and which meets all the conditions, although, during the impact pressure, the outer bottom is made of tin disc without a flange, so there is no need to make the outer bottom with a flange beforehand. This is because the stages described earlier are combined during execution. Permanent deformation occurs exactly at the place determined by the construction and can be very precise, because the welded joint is resistant to impact pressure. A welded joint resistance-m to impact pressure can be made by electric resistance welding, if a sufficient amount of energy is supplied. This is possible especially because, according to the invention, a relatively thin plate is used. Deforming the plate by plastic pressure, while simultaneously forming the outer bottom, leads to an extremely strong, strong intermetallic connection in this important area, without centering disturbances. The edge of the outer bottom touches and seals the container, both during production and after cooling. There is no gap between the bottom of the container and the outer bottom, so that water cannot penetrate during use or when washing, and no consequences caused by corrosion have been observed. The invention will be described in more detail with reference to the drawings of one embodiment, shown only as an example. On the schematic drawings:

- slika 1 prikazuje vertikalan presjek kroz kuhinjsku posudu izrađenu prema izumu, korištenjem postupka prema izumu, - figure 1 shows a vertical section through a kitchen vessel made according to the invention, using the method according to the invention,

- slika 2 prikazuje komponente sa slike 1, a nakon centriranja elektrootpornim zavarivanjem, sa središnjom točkom zavarivanja, - picture 2 shows the components from picture 1, and after centering by electric resistance welding, with the central point of welding,

- slika 3 prikazuje predmet sa slike 2 u alatima, također u vertikalnom presjeku, jedne preše za izvođenje procesa prema izumu, - figure 3 shows the object from figure 2 in tools, also in a vertical section, of a press for carrying out the process according to the invention,

- slika 4 prikazuje dio vertikalnog presjeka kroz dobivenu kuhinjsku posudu, i - Figure 4 shows part of the vertical section through the resulting kitchen vessel, i

- slika 5 prikazuje, u uvećanom srazmjeru, dio A predmeta sa slike 4. - picture 5 shows, in an enlarged scale, part A of the item from picture 4.

Na slikama 1 do 3 prikazane komponente za izradu jedne kuhinjske posude koja obuhvaća okruglu posudu 1 za hranu. Crteži prikazuju dno 2 posude, ploču 3 od toplinoprovodljivog materijala, vanjsko dno 4 preko ploče 3. Vanjsko dno 4 je načinjeno od limenog diska 5. Kako je prikazano na slici 4, donji dio 6 vanjskog dna 4 ima konveksno zakrivljenje K prema dnu 2 posude i ima prirubnicu 7 koja naliježe na okruglu posudu 1 u zakrivljenom prelaznom području 8 između dna 2 posude i omotača 9 posude. Posuda 1 i vanjsko dno 4 načinjeni su od nehrđajućeg čelika. Ploča 3 je intermetalno spojena, sa dnom 2 posude i s vanjskim dnom 4. Figures 1 to 3 show the components for making one kitchen container, which includes a round container 1 for food. The drawings show the bottom 2 of the container, the plate 3 of heat-conducting material, the outer bottom 4 over the plate 3. The outer bottom 4 is made of a tin disk 5. As shown in Figure 4, the lower part 6 of the outer bottom 4 has a convex curvature K towards the bottom 2 of the container and has a flange 7 which rests on the round container 1 in the curved transition area 8 between the bottom 2 of the container and the shell 9 of the container. The container 1 and the outer bottom 4 are made of stainless steel. The plate 3 is intermetallic connected to the bottom 2 of the container and to the outer bottom 4.

Kao što pokazuje usporedba slika 1 i 2, koristi se ravan limeni disk 5 da bi se dobilo potpuno vanjsko dno 4 postupkom prema izumu. Limeni disk 5 je oblikovan i dimenzioniran tako, da kada se prirubnica 7 načini na vanjskom dnu, rub 10 diska je pritisnuta uz trajnu deformaciju 11 na posudu 1. As a comparison of Figures 1 and 2 shows, a flat sheet metal disc 5 is used to obtain a complete outer bottom 4 by the process according to the invention. The tin disk 5 is shaped and dimensioned in such a way that when the flange 7 is made on the outer bottom, the edge 10 of the disk is pressed with permanent deformation 11 on the container 1.

Zbog toga je njegov promjer veći od nominalnog vanjskog promjera lonca, kao što je prikazano u preuveličanom obliku na slici 1 i 2. U praksi je razlika promjera nekoliko milimetara, na primjer 3 do 5 mm. Kako je prikazano na slici 5, ploča 3 i dno 2 posude zavareni su elektrootpornim zavarivanjem, na pogodno dimenzioniranoj točki 12 zavarivanja u središtu, tako da budu otporni na udarni pritisak. Radi jasnoće, to je prikazano u preuveličanom obliku na slikama 2 i 3. Therefore, its diameter is larger than the nominal outer diameter of the pot, as shown in exaggerated form in Figure 1 and 2. In practice, the diameter difference is a few millimeters, for example 3 to 5 mm. As shown in Figure 5, the plate 3 and the bottom 2 of the container are welded by electro-resistance welding, at a suitably dimensioned welding point 12 in the center, so that they are resistant to impact pressure. For clarity, this is shown in exaggerated form in Figures 2 and 3.

Kao što je prikazano na slici 3i udarni pritisak se primjenjuje, ili se može primijeniti tako, da stvara konveksnu zakrivljenost K na donjem dijelu 6 vanjskog dna. Kao rezultat procesa oblikovanja, u toku udarnog pritiska zrak se prvo istiskuje iz područja između diska 5 i prirubnice 7 u procesu oblikovanja, u tijeku koga, ili poslije koga nastaje trajna deformacija 11 (vidjeti sliku 5). Trajna deformacija 11 djeluje kao brtvilo u odnosu na plastičnu deformaciju materijala ploče. Uslijed toga, materijal ploče stvara prirubnicu 13 koja se utiskuje u područje brtvljenja u zoni 11 (vidjeti slike 4 i 5). Debljina ploče 3 prije deformiranja i kada je hladna, može biti do 16% veća nego nakon plastične deformacije. Kako primjer pokazuje, korišten je limeni disk 5 debljine skoro jednake debljini lima koji čini posudu 1. Što se tiče temperaturnih uvjeta, vidjeti zahtjev 6. As shown in Figure 3i the impact pressure is applied, or can be applied, to create a convex curvature K on the lower part 6 of the outer bottom. As a result of the molding process, during the impact pressure, air is first forced out of the area between the disc 5 and the flange 7 in the molding process, during which, or after which permanent deformation 11 occurs (see Figure 5). The permanent deformation 11 acts as a sealant in relation to the plastic deformation of the panel material. Consequently, the plate material forms a flange 13 which is pressed into the sealing area in the zone 11 (see figures 4 and 5). The thickness of plate 3 before deformation and when it is cold, can be up to 16% greater than after plastic deformation. As the example shows, a tin disk 5 with a thickness almost equal to the thickness of the sheet forming the container 1 was used. As for the temperature conditions, see claim 6.

Claims

1. A method for producing a kitchen container comprising one round food container, wherein the container has a bottom, a plate of heat-conducting material and an outer bottom covering the plate, and the outer bottom itself is made of a sheet metal disk and has a base formed by a convex curvature directed towards the container , and also has a flange that adheres to the circular vessel in a curved transition region between the bottom of the vessel and its shell, wherein the vessel and the outer bottom are made of stainless steel and the plate is intermetallic connected to the bottom of the vessel and to the outer bottom, the plate being , the sheet metal disk and the bottom of the container are centered and joined by electric resistance welding to obtain a central point of welding, after which an intermetallic connection is achieved by single or multiple impact pressure and plastic deformation, so the flange of the outer bottom is formed on the sheet metal disk and its edge is placed around the container , indicated by the fact that a tin disc is used that has an edge that, within the shape anja, the flanges of the outer bottom, can be permanently deformed as it is pushed against the pan, and that the sheet metal disc, plate and bottom of the pan are centered by electro-resistance welding to resist the impact pressure, that the impact pressure is applied so as to produce a convex curvature in the lower part of the outer bottom, and that, in relation to the impact pressure, air is first squeezed out of the area between the disc and the outer bottom, during the molding process, after which sealing is achieved by permanent deformation during the plastic deformation of the plate material, and that one flange is made on material of the panel and pressed into the area of the sealant.

2. The method according to claim 1, characterized in that a plate is used with a thickness that, in the cold state before plastic deformation, is not more than 16% greater than the thickness after plastic deformation.

3. The method according to claim 1 or 2, characterized in that a tin disk with a diameter greater than the nominal outer diameter of the pot is used.

4. The method according to any one of claims 1 to 3, characterized in that a sheet metal disc with a thickness approximately equal to the thickness of the sheet forming the container is used.

5. The method according to any one of claims 1 to 2, characterized in that a sheet metal disk no more than 20% thinner than the sheet forming the container is used.

6. The method according to any one of claims 1 to 5, characterized in that impact pressure is applied to the vessel, outer bottom and plate at a temperature close to the melting point of the plate, and the impact pressure tools are used at a temperature in the range between 100 and 350 °C.