IDEA #2L7PEE Production Of Solderable Chromium-Plated Canned Food Steel Sheet Using The Low-Concentration Electrolytes

APPLIED RESEARCH • MATERIALSAND PROCESS TECHNOLOGY PRODUCTION OOFF SOLDERABLE CHROMIUM(cid:2)(cid:2)PLATED CANNED FOOD STEEL SHEET USING THE LOW(cid:2)(cid:2)CONCENTRATION ELECTROLYTES Description High concentration of chromium anhydride in the chromium(cid:2) plating electrolytes (220(cid:2)280 g/l) is the major impediment for the replacement of the steel sheet tinning process by the process of its chromium(cid:2)plating (for packing of dry and granu(cid:2) lar foodstuffs). According to the proposed production process, a thin (0.01(cid:2)0.03 μm) protective lustrous nanostructurally(cid:2)tex(cid:2) turally(cid:2)composite chromium coat is obtained on the canned food steel sheet using an electrolyte with a lowered concentra(cid:2) tion of chromium anhydride (80(cid:2)120 g/l). Then the chromium(cid:2) plated steel sheet is passivated using an electrolyte with a lowered concentration of chromium anhydride (10(cid:2)15 g/l) and soldered with tin solder during the producing of cans. The basic production items are: • The developed chromium(cid:2)plating technology using the low(cid:2) concentration electrolyte that provides formation on the canned food steel sheet of a textured coat having a nanocrys(cid:2) tal structure. Forming of a nanostructure in chromium coats leads to an increase of their plasticity while maintaining the adhesive strength characteristics. This provides an adequate continuity of the coats after deforming the chromium(cid:2)plated steel sheet, as well as a sufficient level of its mechanical dura(cid:2) bility in the production of foodstuff cans. The texture forming in chromium coats ensures an adequate corrosion resistance of the chromium(cid:2)plated steel sheet in various model and food(cid:2) stuff media. • The developed passivating technology using the low(cid:2)con(cid:2) centration electrolyte that provides forming on the chromium(cid:2) plated steel sheet of a colorless protective film. • The developed technology for soldering chromium(cid:2)plated steel sheet using tin base solder. The basis of this technology is the developed flux that ensures the solder spread coeffi(cid:2) cient 2.2(cid:2)2.5 (the standard norm being not less than 1.0). Innovative Aspect and Main Advantages The proposed chromium(cid:2)plated canned food steel sheet pro(cid:2) duction process is based on three potential inventions that are grounded on the usage of the phenomenon of the structure formation in the metallic materials being electrochemically deposited via a metallic liquid. These inventions are com(cid:2) prised of the development of electrolytes and methods of elec(cid:2) trochemical treatment of steel sheet and are aimed at reduc(cid:2) ing the canned food steel sheet production cost while replac(cid:2) ing the process of its tinning by the chromium(cid:2)plating process. • Decreased of the passivating duration of the chromium(cid:2) plated steel sheet to 2(cid:2)3 seconds. • Increased of the current chromium yield to 25(cid:2)30 % during the chromium(cid:2)plating of canned food steel sheet. • Soldering of chromium(cid:2)plated canned food steel sheet becomes commercially feasible. • The production process does not require any capital expen(cid:2) diture and is applicable on the existing equipment. • The developed additives to the flux, chromium(cid:2)plated and passivating electrolytes are not expensive, readily available and low toxic. Areas ooff Application • Metallurgical industry: production of thin sheet and strip. • Canned food industry: manufacture of food cans. • Foodstuffs industry: production of canned food. • Light industry: manufacturing of packing tare. Economic Effectiveness It is known that more than 300 million of food cans are opened daily in the world, and the share of the tinned steel cans (as the main canned food tare) comprises 2/3 of the total amount of food cans. Let us assume that the quantity of the major tinned sheet producers in the world is about ten, and each producer will shift half of his production facilities to manufacturing of chromium(cid:2)plated steel sheet. In such case the production cost of one food storage can will be brought down by three cents due to the replacement of the tinned steel sheet by the chromium(cid:2)plated steel sheet. Then the economic effectiveness of the proposed new production technology for one company will reach more than 300 thousand USD per day or more than 100 million USD per year. Besides, not less than 20 m t of canned food steel sheet is annually produced in the world, while tinned steel sheet com(cid:2) prises about 2/3 of the total volume. Let us assume that the capacity of one tinned steel sheet producer approximately equals one tenth of the annual world volume, and half of this volume will be shifted by the producer to the output of chromi(cid:2) um(cid:2)plated steel sheet. It is known that the economic effect of producing 1 t of chromium(cid:2)plated steel sheet instead of tinned steel sheet is about 142 USD. Then the economic effect of the implementation of the new technology of producing chromi(cid:2) um(cid:2)plated steel sheet will amount per one producer about 100 million USD per year. The major advantages of the new production technology: Stage ooff Development • The replacement of the canned food steel sheet Patenting of the inventions. tinning process by the process of its chromium plating results in saving expensive and scarce tin. • A reduction of chromium anhydride concentration in the chromium(cid:2)plating electrolyte by 2.5 times (from 220(cid:2)280 g/l to 80(cid:2)120 g/l). • A reduction of chromium anhydride concentration in the passivating electrolyte by 7 times (from 80(cid:2)90 g/l to 10(cid:2)15 g/l). • Decreased of the duration of the steel sheet chromium(cid:2) plating to 1(cid:2)3 seconds. Contact Details Organization: Ukrainian State University of Chemical Engineering Contact person: Prof. Oleg Girin Address: 8, Prospekt Gagarina, Dnipropetrovsk 49005, Ukraine Теl: (38 0562) 68 21 66/67 97 25 Fax: (38 0562) 33 71 36/47 33 16/67 97 25 E(cid:2)mail: girin@ua.fm 182