Tin-free Steel Research Articles

Production Optimization of Premium Food Can with Distortion Printing under Waving Requirement

This research aims to propose a novel approach for evaluating and minimizing scraps in an industrial production of premium food cans with distortion printing. Beyond conventional formability criteria, a waving requirement is introduced to ensure aesthetic quality of the printed graphics. The research focuses on real production conditions, specifically involving double-cold-reduced (DR) low-carbon steel sheets and chromium-coated tin-free steel with a thickness of 0.16 mm. The sheets are laminated on both sides with a plastic film prior to undergoing distortion printing on the exterior. Subsequently, a blank is subjected to a drawing-redrawing process to form a food can. To address challenges associated with characterizing these thin sheets, a material parameter identification method is proposed and demonstrated. The thickness profile and flange length are identified as key criteria for this identification process. Measurements of thickness distribution and flange length are obtained using digital image correlation (DIC) and microscopy techniques. Within the manufacturing system, uncertainties related to material properties and forming processes can result in scraps or defects. To analyze these processes, finite element analysis (FEA) is employed and validated through experiments. For the evaluation of scrap rates, uncertainty propagation is conducted using a metamodeling technique, specifically employing radial basis function (RBF) neural networks. The study concludes by offering process optimization recommendations aimed at reducing the scrap rate.

Bio-based lacquers from industrially processed tomato pomace for sustainable metal food packaging

Bio-based lacquers prepared from an underutilized tomato processing residue such as pomace have been investigated as sustainable alternatives to bisphenol A (BPA)-based coatings for metal food packaging. The fabrication methodology consisted of a two-step process: spray-coating of a paste of the lipid fraction of tomato pomace with a mixture ethanol:H2O (3:1, v:v) on common metal substrates, used for food canning, such as aluminum (Al), chromium-coated tin-free steel (TFS), and electrochemically tin-plated steel (ETP), followed by the self melt-polycondensation of such lipid fraction. The polymerization reaction was conducted at 200 °C for different times (10, 20, 30, 40, 50, and 60 min) and was monitored by specular infrared spectroscopy, resulting in maximum degrees of esterification of ∼92% for Al and ∼85% for TFS and ETP substrates. The anticorrosion performance of the coatings was studied by electrochemical impedance spectroscopy at different immersion times (time intervals of 2–5 h during an overall stability test up to 170 h) in an aqueous solution of 1 wt% NaCl. The degree of polymerization and the physical properties of the coatings showed a strong dependence on the metal substrate used. In general, the best results were found for tomato pomace-based lacquers applied on aluminum, achieving higher mechanical strength (critical load of 1739 ± 198 mN for Al, 1078 ± 31 mN for ETP, and 852 ± 206 mN for TFS), hydrophobicity (water contact angle ∼95° for Al, ∼91° for ETP, and ∼88° for TFS), and improved anticorrosion performance (coating resistance of 0.7 MΩcm2 after 170 h of immersion for Al, 0.7 MΩcm2 after 70 h of immersion for TFS, and negligible coating resistance for ETP). In view of the technical innovation proposed in the present paper, the estimation of the environmental sustainability of the process has been considered relevant to fit the circular economy target. For this purpose, a life cycle analysis (LCA) was applied to the overall process, revealing multiple advantages for both the environment and human health.

Microstructural Defects of Epoxy–Phenolic Polymers on Metal Substrates during Acidic Corrosion

This study uses confocal microscopy and image processing to investigate the microstructural changes of coating–metal systems immersed in a heated acidic bath. Unlike standard optical microscopy techniques, 3D confocal microscopy images can quantitatively reveal microscopic defects formed at early stages of cathodic delamination. The coatings are made of fluorescent epoxy–phenolic resins cured at high temperatures onto tinplate (T23) and tin-free steel (TFS) substrates. When the coated metal substrates are immersed in acetic acid, a series of microscopic corrosion events occur at the polymer–metal interface. These events are quantified by changes in the thickness distribution of the degraded samples relative to that of intact coatings. The degradation rate is highest for epoxy–phenolic polymers on TFS substrates, represented by multiple orders of magnitude increase in the number density of defect sites. Higher molecular weight coatings provide slightly better resistance against delamination. The coating thickness dictates the rate of oxygen diffusion and ion transport along the polymer–coating interface, where raised asperities serve as localized sites for metal oxidation and formation of alkaline species, leading to subsequent delamination of the cured polymers from the surfaces. The results show that the metal surface topology is as important as chemistry when designing the corrosion resistance of products containing acidic liquids, and that confocal microscopy is useful in quality control through early detection of mesoscale polymer failure.

A STUDY ON DIFFERENT TYPES OF EDIBLE PACKAGING MATERIALS (PLANTS BASED)

The food and pharmaceutical industries recognized edible packaging as a useful alternative or addition to conventional packaging to reduce waste and to create novel applications for improving product stability, quality, safety, variety and convenience for consumers. This study was done to compare the different types of edible packaging materials, their classifications and their applications. The aim of this study was to better understand the potential of fruits and vegetables to be used as components of edible packaging materials is discussed. Such application of fruits and vegetables is possible to the presence of matrix-forming polysaccharides and proteins in their composition. The development of edible fruit and vegetable packaging materials is a promising way of combining the barrier and mechanical properties of biopolymers with the nutritional and sensory properties. The application of fruits and vegetables as a component of edible packaging materials enables the utilization of raw materials with low commercial value. Edible packaging materials are a new method of their utilizing. There is also the possibility of just decreasing the amount of synthetic packaging waste by application of fruit and vegetable packaging materials simply as a passive or active layer partially replacing the non‐renewable materials. The dynamic forces behind the keen chase includes scientific innovation in the functionality of new materials, increased demand for novel foods and increased consciousness for environmental protection and conservation. In this study we’ll know about the different characteristics of edible packaging materials like light weight, low cost with significant strength, good oil and chemical resistance, moderation of elongation, good tensile strength, and act as good oxygen barriers, retard moisture loss, flexible and generally have no taste or flavor. Materials that have traditionally been used in food packaging include glass, metals (aluminum, foils and laminates, tinplate, and tin-free steel), paper and paperboards, and plastics. Moreover, a wider variety of plastics have been introduced in both rigid and flexible forms

What makes epoxy-phenolic coatings on metals ubiquitous: Surface energetics and molecular adhesion characteristics

HypothesisWetting characteristics of epoxy and phenolic resins on metals depend on the molecular interactions between resins’ functional groups and metal surface. Those interactions affect the practical adhesion strength of epoxy-phenolic coatings on metals. Estimation of the theoretical adhesion energies can reveal this system’s microscopic adhesion mechanisms. ExperimentsAdhesion is estimated theoretically based on resins’ wettability on metals, and experimentally through pull-off adhesion testing of cured coatings. The effect of various functional groups on adhesion is decoupled using epoxy and phenolic resins with different functionalities. To assess the impact of the metal passivation on adhesion, tinplated and tin-free steel substrates are used. Differences in their surface chemical composition and polarity are investigated using XPS. FindingsTheoretical adhesion results reveal a superior adhesion of epoxy compared to phenolic resins. Moreover, epoxy resins having a higher content of epoxide-to-hydroxyl groups show improved theoretical and practical adhesion. The importance of epoxides in driving resins’ initial adhesion on metals is attributed to the formation of direct chemical bonds with active hydrogen on metal surfaces. The adhesion of coatings on tin-free steel is found to be higher than on tinplated steel. This is associated to the increased hydroxyl fraction on tin-free steel surface leading to more hydrogen bonds formation.

Effect of thermal processing on quality of tender jackfruit in tin-free-steel cans.

Thermal processing is the most efficient and economical technique for the long-term preservation of tender jackfruit in ready-to-cook form on a commercial-scale. Although, thermal processing primarily focus on microbiological safety of the product, the associated quality changes need to be examined as it is decisive of consumer acceptance. The present study investigated the effect of two pasteurization (90 and 100°C) and sterilization temperatures (110 and 121°C) at different lethality on microbiological, colour, texture, ascorbic acid (AA), total flavonoid (TFC) and phenol (TPC) contents of tender jackfruit processed in tin-free-steel (TFS) cans. Time required for thermal processing was computed from respective heat penetration curve. Thermal processing improved both the TFC and TPC of tender jackfruit, while colour, texture and AA had degraded. Based on microbiological and physicochemical quality analyses, the study adjudged pasteurization at 90°C for 19min and sterilization at 121°C for 8min as the best temperature-time combination for thermal processing of tender jackfruit in TFS cans.

The Bonding Mechanism of the Micro-Interface of Polymer Coated Steel.

As food and beverages require more and more green and safe packaging products, the emergence of polymer coated steel (PCS) has been promoted. PCS is a layered composite strip made of metal and polymer. To probe the bonding mechanism of PCS micro-interface, the substrate tin-free steel (TFS) was physically characterized by SEM and XPS, and cladding polyethylene terephthalate (PET) was simulated by first-principles methods of quantum mechanics (QM). We used COMPASS force field for molecular dynamics (MD) simulation. XPS pointed out that the element composition of TFS surface coating is Cr(OH)3, Cr2O3 and CrO3. The calculation results of MD and QM indicate that the chromium oxide and PET molecules compound in the form of acid-base interaction. The binding energies of Cr2O3 (110), (200), and (211) with PET molecules are −13.07 eV, −2.74 eV, and −2.37 eV, respectively. We established a Cr2O3 (200) model with different hydroxyl concentrations. It is proposed that the oxygen atom in C=O in the PET molecule combines with –OH on the surface of TFS to form a hydrogen bond. The binding energy of the PCS interface increases with the increase of the surface hydroxyl concentration of the TFS. It provides theoretical guidance and reference significance for the research on the bonding mechanism of PCS.

Bio-Based Coatings for Food Metal Packaging Inspired in Biopolyester Plant Cutin.

Metals used for food canning such as aluminum (Al), chromium-coated tin-free steel (TFS) and electrochemically tin-plated steel (ETP) were coated with a 2–3-µm-thick layer of polyaleuritate, the polyester resulting from the self-esterification of naturally-occurring 9,10,16-trihydroxyhexadecanoic (aleuritic) acid. The kinetic of the esterification was studied by FTIR spectroscopy; additionally, the catalytic activity of the surface layer of chromium oxide on TFS and, in particular, of tin oxide on ETP, was established. The texture, gloss and wettability of coatings were characterized by AFM, UV-Vis total reflectance and static water contact angle (WCA) measurements. The resistance of the coatings to solvents was also determined and related to the fraction of unreacted polyhydroxyacid. The occurrence of an oxidative diol cleavage reaction upon preparation in air induced a structural modification of the polyaleuritate layer and conferred upon it thermal stability and resistance to solvents. The promoting effect of the tin oxide layer in such an oxidative cleavage process fosters the potential of this methodology for the design of effective long-chain polyhydroxyester coatings on ETP.

Study on evolution law of lateral thickness difference of polymer-coated steel in laminating process

In order to meet people's requirements for materials saving and environmental protection, the metal packaging industry has proposed a new functional composite material: the polymer-coated steel, which is designed to replace the tinplate in the traditional packaging industry. In this paper, the three-dimensional contour of the Tin free steel (TFS) surface was measured by a white light interference three-dimensional shape analyzer and the endothermic exothermic curve during Polyethylene terephthalate (PET) heating was measured by TG-DSC. The numerical simulation model of the laminating roll-PET-TFS is established according to the difference of the transverse melting thickness of the polymer film during the laminating process. The numerical results showed that the difference of the transverse melting thickness of the PET film gradually decreases with the increase of the initial temperature of TFS and the increase of the filming speed. The optimum film temperature range is found according to the transverse melting thickness difference of PET film. The model of optimum laminating temperature and allowable laminating temperature is established. The optimum process parameters are proposed to control the thickness difference of the film transverse melting with the initial temperature of TFS is 628.15 K and the laminating speed is 100 m / min.

Effect of tin addition on corrosion behavior of a low-alloy steel in simulated costal-industrial atmosphere

The effect of tin addition on the atmospheric corrosion behavior of a low-alloy steel in simulated coastal-industrial atmosphere has been investigated by indoor wet/dry cyclic corrosion test (CCT). The results indicate that tin addition can obviously make the steel substrate more resistant to atmospheric corrosion by suppressing the cathodic H+ reduction reaction, and but tin addition is not of obvious beneficial effect when the steel is covered with a thicker rust layer during long-term corrosion process. The reason lies in the fact that the presence of un-reduced H+ can lower the electrolyte pH value and lead to a loose and porous rust layer on tin-containing steel sample than that on tin-free steel sample. In addition, the 120 CCT cycles corrosion process of the two steels can be divided into three stages. Both the tin-free and tin-containing steels show an increasing corrosion rate during the initial corrosion stage and then exhibit a decreasing corrosion rate during the second and third corrosion stages. Moreover, tin addition makes the tin-containing steel rust layer have a higher amount of α-FeOOH and lower amount of γ-FeOOH and Fe3O4 than the tin-free steel rust layer.

Modeling corrosion trends in tin‐free steel and tinplate cans containing tomato paste via adaptive‐network‐based fuzzy inference system

AbstractCorrosion process in metallic cans is one of the most significant issues, which is of utmost importance in food packaging; meanwhile, it can be studied through both economical and hygienic aspects. Designing a method to determine this process in an acidic food like tomato paste might be a good standard to monitor this phenomenon in food products. Accordingly, in this article, tin‐free steel (TFS) and tinplate (TIN) cans containing tomato paste were incubated at three different temperatures (25, 35, and 45 °C) and three filling percentages (85, 90, and 95%). Corrosion rate was then studied via image processing method within six months, thereupon corrosion modeling was carried out using adaptive‐network‐based fuzzy inference system (ANFIS). Time, temperature and filling percentage were considered as the input parameters, on the other hand the corrosion rate was assumed as the output. Multiple training cycles and various membership functions were used in the form of trial and error to have the models optimized. Having the models been examined, trapezoidal membership functions with 3–3–3 functions for TFS cans and 2–2–2 functions in Tin cans were determined as the best models. High coefficients of determination (R2 = 0.97) between experimental and predicted values by optimum models presented a robust method for monitoring corrosion in metallic cans.Practical applicationsFood products might be preserved in metallic cans for more than 2 years without any significant changes in organoleptic properties. One disadvantage is that cans are more susceptible to corrosion compared with other packaging materials. The absence of appropriate methods and the high costs of analytical instruments are major problems encountered in evaluating the corrosion process. On the other hand, developing straightforward and modern techniques may be an efficient solution in this area. This study was devoted to the prediction of the corrosion process using two prevalent can plates employed in the food industry. ANFIS modeling was implemented in tomato paste, which exhibits acidic and corrosive behavior. ANFIS modeling may be an onset for further research in this area to engineer and manufacture intelligent sensors by which on‐line monitoring in complex and nonlinear interactions is undertaken.

Lasting high surface energy co‐polyester ionomer and its application in laminated tin‐free steel

ABSTRACTA lasting high surface energy co‐polyester poly[ethylene terephthalate‐co‐ethylene isophthalate sodiosulfonate‐co‐poly(ethylene glycol)] polyester (PEPST) was synthesized and applied in laminated tin‐free steel (TFS). The structures and properties of the co‐polyester were characterized by nuclear magnetic spectra (1H‐NMR), thermogravimetry, differential scanning calorimetry, polarized optical microscopy, and surface energy tests. Meanwhile, the peel strength and corrosion resistance of the co‐polyester film were also measured. The results confirm that an improvement in the lamination temperature leads to PEPST film peel strength increases, and crystalline and corrosion resistance decrease. Based on the purpose of reducing a detrimental effect on corrosion resistance, a reasonable lamination temperature was determined. Scanning electron microscope and energy dispersive X‐ray analysis prove the interface combination morphology of laminated TFS. Anticorrosion property analysis shows PEPST film has good anticorrosion performance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45174.

X-ray TV study of the penetration of tin into a steel melt

A technique is developed and an X-ray TV study is performed to investigate the penetration of spherical tin samples into the steel 40Kh melt at a temperature of 1550°C. Cold spherical tin particles 1–2 in weight are found to dissolve in the tin-free steel at an initial rate of 180 ± 50 mol/(m2 s). A sample dissolves fully in less than 2 s. When a sample reaches the steel–gas phase interface, its dissolution rate decreases by many times. Separation with the formation of a two-phase system occurs at 1.6–1.9 mol % tin in steel. The density of the iron-based alloy is lower than that of the tin-based alloy. Pure tin and the saturated solution of iron in tin wet Al2O3-based refractory ceramic better than pure iron or its alloy with tin.

Correlation of Acoustic Emission and Corrosion Resistance of Lacquer Coatings on Tin-Free Steel

Acoustic emission (AE) is a non-destructive technique which is well known for crack monitoring. Moreover, it has been widely used for corrosion and erosion damage on metallic structures. In this study, AE technique was applied for quick monitoring of corrosion resistance of lacquer coatings on tin free steel and laminated steel for food can-packaging. There were three types of coatings: (A) BPA-NI lacquer, (B) BPA-complied lacquer, and (C) PET lamination. These coatings were investigated in flat-sheet and in deformed sheet. Cathodic disbonding (CD) technique was carried out to cause separation between the coating and the metal substrate and initialize corrosion damage. AE signals was detected immediately with potential excitation, and showed good correlation with coating corrosion resistance during corrosion development. AE count signal matched with resulting current during CD, and proportional to corroded areas. In addition, coatings properties were measured before and after the CD process by electrochemical impedance spectroscopy (EIS). A combination of AE and CD techniques offers an in-situ non-destructive corrosion monitoring of coating quality before and during delamination development, and useful for can-packaging testing.

Effect of tin on the corrosion behavior of sea-water corrosion-resisting steel

Abstract This paper investigated the effect of tin on the corrosion resistance of tin-containing steel and tin-free steel using electrochemical measurements in seawater. Results showed that tin-containing steel had lower corrosion current and higher impedance than tin-free steel. Surface analyses of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) indicated that tin could form SnO 2 and SnO in rust layer, and both of them could improve impedance and corrosion resistance of rust layer. Besides, the coprecipitation process of tin oxides with iron oxides could make the rust layer more uniform and compact, which could make the tin-containing steel have better corrosion resistance than tin-free steel. Secondary ion mass spectrometer (SIMS) showed that there was no obvious segregation of tin on substrate steel when tin addition was 0.038 wt.%, and tin could improve the oxidation resistance of substrate steel evenly by lowering the steel's Fermi energy from − 9.276 eV to − 14.445 eV.

Effect of thermal processing on the biochemical constituents of green mussel (Perna viridis) in Tin-free-steel cans.

The effect of thermal processing on the biochemical constituents of green mussel (Pernaviridis) in brine was investigated. Depurated mussel samples were thermal processed in tin-free steel cans (TFS) at F0 8.43. The time temperature data was collected during heat processing using EVAL data recorder and heat penetration characteristics were determined using formula method. The total process time was 27.48min and the processed cans were found to be commercially sterile. The mineral composition of processed mussel was significantly higher than raw samples. The instrumental texture analysis indicated that product become soft after thermal processing.The thermal process led to a significant decrease in total amino acid and fatty acid content of the samples. Even though the samples showed a decrease in amino acid and fatty acid composition after thermal processing, the mussel meat was nutritionally well balanced with respect to essential anino acids and fatty acids.Hence the product can be considered as a food source with high quality protein and fat to fulfil consumer's requirements.Based on sensory analysis, the processed products were found acceptable during the study period.

Study on Functions of Chrome and Fluoride Ions in Plating Process of Tin Free Steel by Means of Cyclic Voltammetry

Plating solution of tin free steel (TFS) presents strong corrosion and special chemical action properties of chrome ions and fluoride ions. Electrochemistry behavior of their ions in the plating process of TFS was investigated by means of cyclic voltammetry (CV). The results show that hydrogen and oxygen evolution peaks can only be found in CV curves of the carbon anode in fluoride solution. CV curves of the carbon anode in chromium trioxide solution consist of five anodic peaks and two cathodic peaks. When fluoride ions are added into chrome ions solution, anodic peak disappears at peak potential of 1.18V. For CV curves of lead alloy anode, anodic peak can be found at peak potential of-0.2V in fluoride solution, and oxidation process is in asymmetry with reductive process in chromium trioxide solution or the mixed solution. As to CV curves of lead oxide anode, the current density of all peaks in chrome ions solution is lower compared with that of carbon anode and lead alloy anode. When fluoride ions are added into chrome ions solution, the current density of the oxidation process obviously decreases, while the absolute value of reductive process increase remarkably

Microbial Studies of Prepared Curries Stored in Tin Free Steel Cans

Apart from the nutrient analysis microbial study is very much essential to know the microbial contamination after storage. So in the present study it is aimed to investigate the microbial contamination in the prepared fish and shellfish curries stored in tin free steel cans. The prepared curries of fish, shrimp, crab and mussel were stored in TFS cans at room temperature (30 ± 2°C) for a period of 18 months. During storage the cans were periodically checked in the intervals of 3rd, 6th and12th months especially the visual signs of internal and external rusting like appearance of can walls, adhesion of product to the can walls and internal rusting. About eight cans were selected at random from each batch processed to different Fo values. Four cans from each batch were incubated at 55°C for 4 days and another four were incubated at 37°C for 14 days. The incubated cans were opened under aseptic conditions and the samples were transferred to sterile thioglycollate broth tubes. Then a layer of sterile liquid paraffin was applied in each tube so as to create anaerobic condition. The tubes were then incubated at 37°C for 48 hrs and observed for any development of turbidity, which indicates survival of microorganisms. Tubes not showing any turbidity were incubated for further 48 hrs at 37°C to ascertain the sterility. Besides the above microbiological quality was assessed from the fish, shrimp, crab and mussel curries by standard plate count, t otal coliform count and totalfungal count, according to APHA. The microorganisms are totally absent in the present study for short and longer time storage (3 to 18 months) of fish and shellfish curries stored in TFS cans. Apart from that there is no internal and external rusting, texture during the storage period. So it is conform that TFS cans are suitable to store the fish and shellfish products as evidence by no microbial growth and also not affecting the nutritional quality of the stored food.

Feasibility of Fish and Shellfish Curries Stored in Indigenous Polymer Coated Tin Free Steel Cans

The study indicated that the suitability of indigenous polymer coated TFS cans for processing at high temperature and pressure. The cook value was found to exhibit an inverse relationship with processing temperature (p<0.05) and was maximum at 115°C and minimum at 130°C. The fish products were acceptable even after 24 months of storage at ambient temperature. The initial overall acceptability score of about 8.75 and it was gradually reduced to around 6.78. It can be seen that the initial pH of fish, shrimp, crab and mussel curries are 5.9, 5.7, 5.6 and 6.0 respectively indicating that it is towards the acidic side. The acidic nature of the product can be attributed to the acidity contributed by the curry ingredients like tomato. During storage, the pH of the products was found to exhibit a decreasing trend. On the 6th, month of storage, the pH of fish, shrimp, crab and mussel curries are 5.7,5.6, 5.6 and 5.8 respectively which are significantly lower as compared to initial values. On the 12th month of storage, the pH of fish, shrimp, crab and mussel curries are 5.6, 5.6, 5.5 and 5.7 respectively. The results of the present experiments showed that the polymer coated TFS cans are suitable for processing fish products. Polymer coated TFS cans was found to withstand all the conditions of thermal processing. The TFS cans which are now available in India can be used for thermal processing of various fish products as a substitute to other packs.

Influence of Heat Penetration on the Quality of Canned Ribbon Fish (Trichiurus lepturus )

Influence of heat penetration on the quality changes of ribbon fish canned in different media, oil and curry using tin-free steel cans, was assessed. The total process time for ribbon fish in oil pack was 47 min, and curry pack was 68 min, with a lethality value of 12.84 and 10.8 min for oil and curry pack, respectively. The biochemical and sensory analysis of the products was done during a storage period of 5 months. Total volatile base nitrogen and tri-methylamine nitrogen contents were found to be slightly higher but within the acceptable limit at the end of 5-month storage, while thiobarbituric acid and free fatty acid content increased slightly in curry and oil pack at the end of the storage period. The sensory quality of the processed products was rated as good by the taste panel, and the products were in acceptable condition even after storage of 5 months at room temperature (28 ± 2C). Practical Applications The present work on the development of ready-to-serve ribbon fish canned products will help in meeting the present demand in the market; if commercialized, it may be a better method of utilization of this presently underutilized fish to fetch higher value to both fishermen and processor besides providing a new and low cost raw material base to canning industry as well as it forms a means of diversification. It was found that tin-free steel cans are suitable for processing fish products, so they can be used as an alternative to tin and aluminum cans because of their capacity to withstand all the conditions of thermal processing.