Carbon Steel Strip Research Articles

Tribological and mechanical laboratory analysis of DLC as substitutes for hard chromium coating in view of cold rolling of high carbon steel strips

Tribological and mechanical laboratory analysis of DLC as substitutes for hard chromium coating in view of cold rolling of high carbon steel strips

Emulsification and corrosivity study of bio-oil and vacuum gas oil mixtures with a novel surfactant system

Co-processing bio-oil (BO) with petroleum intermediates such as vacuum gas oil (VGO) in existing refining infrastructures provides a promising pathway to transform low-quality BO into value-added biofuels. Nevertheless, the immiscibility between BO and VGO is one of the major obstacles to BO co-processing, especially during the feeding stage of upgrading. To inject BO and VGO as a single-phase fluid and maximize their interactions, emulsification was applied to mix BO and VGO. In this study, a novel surfactant system, based on Span 80 (SP), Tween 80 (TW), and methanol (ME), was developed to suit the remedy to the immiscibility of BO and VGO. Thermogravimetric analysis (TGA), X-ray imaging, and optical microscopy were employed to examine the thermal behavior, phase stability, and microstructure of the as-developed emulsions. Immersion experiments were conducted with carbon steel (CS) strip coupons in BO/VGO emulsions at 50 °C for corrosivity assessment. Results showed that surfactant ST (a mixture of SP and TW) outranked SP and TW in stabilizing BO/VGO emulsions indicating that surfactants with a middle hydrophilic-lipophilic balance value (approximately 8) are more suitable for BO/VGO emulsions. Adding ME notably prolonged the stabilization time of BO/VGO emulsions. The addition of new mixed surfactant STM (e.g., BO:VGO:STM with a weight ratio of 1:4:0.1) resulted in the longest phase separation starting time (100 min, at 50 °C), one order of magnitude longer than that of BO:VGO as 1:4. The BO/VGO emulsion stayed single-phase for 80, 50, and 20 min when reduced the STM ratio to 0.05, 0.03, and 0.02, respectively. TGA results indicated that hydrogen transfers from VGO to BO reduced the coke formation of BO by 55 % at above 400 °C, highlighting the significance of mixing BO and VGO properly before co-processing. Immersion experiments concluded that the addition of studied surfactants did not show prominent effects on CS corrosion in BO/VGO emulsions.

The Atmospheric Corrosion of Trivalent Cr Metal / Cr Oxide Coatings for Packaging Steels

The superior mechanical properties associated with steel mean that it is heavily utilized in many industries including automotive, and construction (1). Although steel offers desirable mechanical properties such as toughness and tensile strength, it is known to corrode, this having cost implications and raising safety concerns, for instance within the food packaging industry. Thus, steel is often used in conjunction with a coating as a preventative measure for corrosion.Within the food packaging industry, steel is often coated with a thin (~20 nm thick) chromium metal-chromium oxide coating, the product being referred to as electro chromium coated steel (ECCS), which is produced during a continuous electrodeposition process whereby a low carbon steel strip passes through baths of chromic acid electrolyte containing hexavalent chromium, Cr(VI). The final coating consists of two distinct layers; a 20-110 mg.m-2 chromium underlayer and a 2-20 mg.m-2 native (hydr)oxide outer layer (2). REACH, a regulation associated with the restriction of chemicals that are harmful to human health and the environment, have made a legislation that has imposed a restriction on the use of Cr(VI) due to its carcinogenic nature (3). This impact has resulted in the drive of the steel packaging industry to find a suitable, non-toxic replacement for ECCS.Coatings made with Trivalent Chromium Coatings Technology (TCCT®) are currently being developed as a potential replacement for ECCS. TCCT® production has developed to consist of a two-electrolyte process involving an aqueous solution of Cr(III) sulphate, sodium sulphate, sodium formate and sulphuric acid leading to the formation/application of a bilayer coating. Various issues including coating inhomogeneity have previously been reported (4).Due to the low coating weights involved, packaging products such as ECCS and TCCT® are also used in conjunction with an organic coating. Thus, they could be susceptible to various modes of organic coating failure including corrosion-driven cathodic delamination, whereby a coating becomes physically separated from the underlying substrate, a key failure process that affects organically coated metal products in high humidity, such as those experienced during storage in the packaging industry. Cathodic delamination occurs when an electrolyte comes into contact with the metallic substrate at a flaw in the organic coating at which anodic metal dissolution occurs. This is coupled to the cathodic oxygen reduction reaction which takes place at the delamination front. The hydroxide ions produced during the cathodic reduction of oxygen, or a reaction intermediate, disturb the bonds between the substrate and coating leading to adhesion failure and delamination of the coating (5).To ensure that new products such as TCCT® are successfully incorporated into the market it is important that they are comparable in performance to existing products. For example, TCCT® must provide sufficient delamination resistance. The scanning kelvin probe (SKP) is a technique which measures corrosion potential under a thin electrolyte film and organic coatings, which can be used to create a surface potential map (6).This study makes use of the SKP to investigate the rate of cathodic delamination as a function of TCCT® Cr(III) oxide (varying from 1.8 mg.m-2 to 23.35 mg.m-2). The results will help to determine the minimum satisfactory chromium oxide coating weight needed for commercial TCCT®.It was found that higher Cr(III) oxide coating weights had a positive effect on inhibiting cathodic delamination, confirming the mechanism. The results were explained using complementary electrochemical data including OCP measurements as well as potentiodynamic polarisation which showed that higher TCCT® Cr(III) oxide coating weights were acting to supress the cathodic reaction.The results also highlighted that a TCCT® Cr(III) oxide coating weight of around 7 mg.m-2 is sufficient with regards to resisting cathodic delamination completely. This work has determined that the Cr(III) oxide coating weight value is very important with regards to improving coating coverage and resisting cathodic delamination.References Singh MK. Application of Steel in Automotive Industry Application of Steel in Automotive Industry. Int J Emerg Technol Adv Eng. 2016;6(7):2250–459.Wijenberg J, Steegh M, Penning JP, Portegies Zwart I. Wo 2014/079909 2014.Petry T, Knowles R, Meads R. An analysis of the proposed REACH regulation. 2007;44(2006):24–32.Allman A, Whiteside J, Jewell E, Griffiths C, McMurray N, de Vooys A. Surface modification of Cr(III) packaging substrates for enhanced adhesion via citric acid processing. Surfaces and Interfaces. 2020 1;20:100545.Øystein O, Knudsen AF. Corrosion Control Through Organic Coatings. Second. Schweitzer PA, editor. New York: Taylor & Francis; 2017.Stratmann M, Streckel H, Feser R. A new technique able to measure directly the delamination of organic polymer films. Corros Sci. 1991;32(4):467–70.

A study on corrosion behaviour of various modes of ATIG welded plain carbon steel

The purpose of this study is to look at the corrosion behaviour of various current modes of Autogenous Tungsten Inert Gas (ATIG) welded powder metallurgy plain carbon steel (Fe-0.5% C). The impacts of different current modes (DC, AC, Mixed, and Pulsed) on ATIG corrosion welded joints are looked at. To get the highest density, the rectangular sintered plain carbon steel strips were subjected to a cold upset. The parent and welded specimens were subjected to aqueous immersion and electrochemical corrosion tests. The corrosion test findings were compared to the microhardness, corroded surface morphology, microstructure, and SEM of the corroded area. It is observed from the test results that as the parent metal contains pores could lead to a high corrosion rate and the ATIG welded specimens exhibit less corrosion rate due to pore free region at the weldment. The DC mode of the welded specimen is observed to exhibit a lesser corrosion rate compared to the other modes of welded specimens due to higher heat generation.

Study of operating properties of aanticorrosion packing papers

Metal products are subjected to atmospheric corrosion during transportation and storing. An important way to prevent this negative phenomenon is application of special packing materials, in particular materials, containing volatile inhibitors of corrosion, which protect metal against various corrosion agents. To protect metal effectively it is necessary to provide a definite level of operating characteristics of packing materials. The purpose of the work was the study of operating properties of inhibited crepe, inhibited and laminated polyethylene film, inhibited crepe and reinforced by polypropylene web papers, manufactured by OJSC “PP TechnoKhim”, Magnitogorsk, used for packing of metals. Structural and dimensional, sorption, deformation and strength characteristics, of the studied anticorrosion papers are presented, the characteristics being calculated based on the results of measurements. To determine their physical-mechanical and anticorrosion properties, standard methods and methodologies were used. To evaluate impact of moisture and transportation conditions, indices of water adsorption and wear of the studied papers were determined. Inhibitor content in these materials was determined by thermogravimetric analysis method. Their protective ability was studied on samples of low carbon steel strip. For accelerated corrosion tests the strip samples were degreased by alcohol, dried in air and packed in the studied anticorrosion papers, after that they were exposed under increased temperatures and moisture conditions. It was determined, that among the materials under the study, the inhibited crepe paper, reinforced by polypropylene web, hhas the best complex of physical-mechanical and anticorrosion properties. It provides a higher level of prevention corrosion of metal l and surpasses other materials in a number of deformation and strength characteristics. Recommendations were proposed to improve qquality of produced anticorrosion papers.

Investigation of Effects of Strip Metals and Relative Sliding Speeds on Friction Coefficients by Reversible Strip Friction Tests

Friction at the interface between strips and dies is an important factor influencing the formability of strip or sheet forming. In this study, the frictional behaviors of strips at variant speeds were investigated using a self-developed strip friction test machine with a dual tension mechanism. This friction test machine, stretching a strip around a cylindrical friction wheel, was used to investigate the effects of various parameters, including sliding speeds, contact angles, strip materials, and lubrication conditions on friction coefficients at the strip–die interface. The friction coefficients at the strip–die interface were calculated from the drawing forces at the strip on both ends and the contact angle between the strip and die. A series of friction tests using carbon steel, aluminum alloy, and brass strips as the test piece were conducted. From the friction test results, it is known that the friction coefficients can be reduced greatly with lubricants on the friction wheel surface and the friction coefficients are influenced by the strip roughness, contact area, relative speeds between the strip and die, etc. The friction coefficients obtained under various friction conditions can be applied to servo deep drawing or servo draw-bending processes with variant speeds and directions.

Multiscale Simulation of the Stress-Strain State of Low Carbon Steel Strip Processed by Asymmetric Rolling

Asymmetric rolling with different work roll circumferential speeds is a process that can be used for improvement of mechanical properties of the processed metals and alloys. Development of the model, which allow to calculate the stress-strain state occurring in the microstructure of the ferritic-pearlitic steels during asymmetric rolling, was the main objective of this paper. Macro level models do not take into account the complicated behavior of the ferritic-pearlitic microstructure in the micro scale. Therefore, development of modelling methods, which allow predicting the properties distribution in the metal volume with the behavioral features of the microstructure under the influence of the deformation, was needed. Representative Volume Element (RVE), representing ferritic-pearlitic steel microstructure, was developed. Simulations of the asymmetric rolling process were performed and local deformation of each structural component was predicted. Selected results, as well as discussion of the effect of microstructure on obtained stress and strain distributions, are presented in the paper. Results of multiscale simulation analysis of the deformation characteristics, presented in this study, can be used for optimization of the asymmetric rolling process.

Optimization of the Induction Process on Light Gauge Steel Profiles Used in Metallic Framed Sustainable Eco-Constructions

Ecological steel framed sustainable and anti-seismic constructions have been highly developed in America, Asia and Europe. Following this trend, Romania has the opportunity to build houses, flats, offices and storage halls using the light gauge steel (LGS) framing system. For reasons of efficient and economic building, sustainable development and requirements from builders of steel framed constructions in Romania, it has been considered an issue to improve some of the steel mechanical characteristics. The metallic profile, which is the basic component of the steel framed system, is manufactured by cold roll forming from laminated low carbon steel strips, galvanized for good corrosion protection. Improving the material’s hardness and tensile strength stands as a challenge caused by the limitations that follow: Reduced material thickness, low carbon content of the material (required for the cold deformation process), estimated profile thermal deformation and customized profile section to harden. This research is focused on the optimization of the induction process (by high frequency current) applied to the LGS material. The advantages and benefits of improving the light gauge steel profile’s hardness are pointed out towards the end of this article.

Effect of hot rolling conditions on the nitride precipitation process in low carbon steel strips

The nitride precipitation process plays an important role in the final mechanical and aging behaviour of low carbon steels in hot rolled state as well as in cold rolled and annealed state. The nitride precipitation process is investigated in an indirect manner: instead of measuring the amount of nitrogen compounds, the free nitrogen content of the samples was measured using a special thermomechanical treatment and a thermoelectric power tester. It was found, that the free nitrogen content in a steel strip strongly depends on three main factors: on the position in strip transverse direction, on the coiling temperature and on the cooling method at the run-out table of the hot rolling mill.

Comparison of Corrosion Rate on Paint Coated and Uncoated SS400 Steel

To prevent corrosion in metal, especially carbon steel, always need efforts which considered expensive one. But, compared with costs and losts when the corrosion attack is not properly managed then the cost of efforts is much lower. The most popular method in preventing corrosion attack is by coating of metal which also has decorative objective. In this research, four coating materials were applied to the surface of low carbon steel strips (SS400) and as control uncoated SS400 steel strips were also employed. The steel strips then were dipped into electrolite solution consisted of 30% of consentration of H2SO4, and NaCl soluted in river water for 15 (fifteen) days. After the presetted time was elapsed, the steel strips then examined for lost of mass. It was found that the highest lost of mass was for unpolished uncoated one dipped in H2SO4 with corrosion rate of 4,566.06 mpy. The lowest lost was for paint coated one dipped in NaCl-river water solution with corroion rate of 0.64 mpy.

Analysis of coil break defects

Abstract Coil breaks are narrow, irregularly changing deformation lines on low carbon steel strips. They can appear in many metallurgical manufacturing processes, such as pickling, galvanizing, cold rolling, processing on slitting or cutting lines, etc. They cause difficulties in many steel plants, since they are considered as serious surface defects leading to esthetical problems on the end product. In this paper, the types, visual appearance and microscopic properties of coil breaks are investigated. The roughness and waviness of the break lines were characterised using a contact-type surface roughness tester, while the microscopic deformation lines were studied using Hirox and Zeiss optical microscopes. The location, arrangement and relation to the microstructure can help to understand the formation mechanism of these surface defects.

Mathematical Modeling and Microstructure Analysis of Low Carbon Steel Strips Produced by Horizontal Single Belt Casting (HSBC)

The horizontal single belt casting (HSBC) process has been proposed as an efficient, economical, and environmentally friendly alternative approach to the production of ferrous alloys. Low carbon steel strips were cast using the HSBC simulator apparatus to study the characteristics and properties of the as-cast steel strips. Three-dimensional computational fluid dynamics simulations using ANSYS FLUENT 14.5 were also performed. Numerical predictions were validated against experimental casting results. Microstructural analyses and as-cast surface texture studies were conducted on low carbon steels.

Grain Refinement and Thermal Stability of AISI1020 Strips Prepared by Large Strain Extrusion Machining

Low carbon steel (AISI1020) strips with grain refinement were successfully produced by large strain extrusion machining (LSEM).A finite element simulation was performed to make comprehensible the deformation behavior of LSEM process. The influence of annealing temperature and annealing time on the microstructure and mechanical properties of strips was investigated by two sets of heat treatments and Vickers hardness test. As a result, strips can maintain high hardness under 400°C but start losing it as the temperature increased to 500°C and above. When annealED at 300°C for 1~9h, hardness of strips can maintain at almost the same level as that before annealing. Obvious hardening was found when annealing at 200~300°C mainly because of the dislocations atresia. Despite of the anneal-hardening behavior, these results indicated that the extruded AISI1020 strip has a good thermal stability at temperature below 400°C.

Numerical and Experimental Investigation of a Modified Twin Roll Strip Casting Process for the Production of Clad Steel Strips

A process for the production of clad steel strips by means of vertical twin-roll strip casting is under investigation at the Institute of Metal Forming (IBF). This production concept is based on the introduction of a solid strip in the casting pool in order to join it with the solidifying melt. The advantages of this concept are a shorter process chain and a higher energy efficiency compared to the existing cladding methods. The contact time and the thickness ratio between solid strip and solidifying melt, their relative position and the alloy combination are fundamental parameters to be considered in the design of this cladding process. A numerical model is used to predict the temperature increase in the solid strip and the solidification of the melt for the material combinations 1.4301/C75 and C75/Cu, and for two process configurations. Carbon steel and copper strips were introduced in the melting pool during casting experiments. Both carbon steel and copper strips could be clad without melting when positioned on the casting roll surface. This indicates that the surface temperature of the copper strip did not rise over 1084°C. Both the copper and the carbon steel strips show partial melting when introduced in a central position.

Making iron aluminides out of scrap

The abundance of iron and aluminum raw materials is often quoted as a strategic advantage of iron aluminides against other competing materials (not only stainless steels, but also nickel and titanium aluminides). These raw materials, however, are not only abundant in the form of ores in earth's crust, but also as scrap produced in the extensive technological activity associated with these base metals. The present work reports results of two prospective experiments designed for obtaining iron aluminides exclusively from readily available scrap (aluminum cans, carbon steel strips and stainless steel sheet metal forming residues, this last as a source of chromium and molybdenum). Two base alloys with nominal composition Fe–30Al–6Cr and different carbon contents were molten in a laboratory induction furnace with no atmosphere protection other than blowing Argon over the melt surface. The produced ingots were characterized concerning their microstructures and final composition, which allows estimating the incorporation efficiency of the alloying elements using this processing route.Oxidation tests at the temperature range of 800–1100°C under air were performed to demonstrate that these alloys show similar behavior as the ones obtained using conventional processing routes. The results are discussed concerning the viability of this low-cost processing route for the industrial production of iron aluminides.

Ultrafast cooling of medium carbon steel strip by air atomised water sprays with dissolved additives

Ultrafast cooling is a newly developing heat treatment technique that can be used for the production of advanced high strength steels. Conventional laminar jet cooling is generally fitted in the runout table; however, it cannot provide the higher cooling rates necessary, and air atomised spray cooling can be the best alternative for ultrafast cooling rates. As water is the commonly used coolant, it is beneficial to know the effect of surface active or volatile additives on the cooling characteristics for high heat flux applications. Thus, this study examines the two aspects of the use of enhancement of air atomised water spray cooling process with a mixture of ethanol and surfactant additives. First, additive based cooling of stainless steel strip was evaluated to optimise the cooling rate, then these optimum parameters were used to study the improvement in mechanical properties and microstructure of medium carbon steel compared to pure water ultrafast cooling. The cooling experiments were carried out at a temperature above the Leidenfrost point of the hot strip. A commercial inverse solver called INTEMP was used for the calculation of surface temperature and heat fluxes. It was observed that the addition of surfactants and alcohol enhanced the cooling rate and critical heat flux of the test strip and has higher impact on martensite phase evolution.

PVD coatings for mill rolls for cold rolling of high carbon steel strips—Laboratory tests

Increasing the productivity of rolling mills requires improving surface properties of roll surface and prolonging roll life. The properties of interest are anti-adhesion to avoid catastrophic adhesive transfer, and wear resistance. Hard Cr coatings provides such properties for Al and carbon steel rolling, but should be replaced in the long run due to health/environmental issues. Physical Vapor Deposition (PVD) and Plasma-Enhanced Chemical Vapor Deposition (PECVD) of ceramic coatings are promising substitutes. In the context of high carbon steel strip rolling, TiN, TiBN, and CrN are tested here in terms of adhesive properties under large sliding conditions (plate-on-ring test) at increasing load. They are compared with a naked High Speed Steel (HSS) surface and a hard chromium coating. A 3-stage evolution is found as load increases, the last stage being characterized by massive adhesive transfer (severe wear) and high, irregular friction. TiN is shown to perform poorly under these conditions and does not bring an alternative solution to HSS steel. On the contrary, TiBN and CrN provide anti-adhesion protection up to the maximum load of the test, like Cr.

Adhesion of Thermal Oxide Scales on Hot-Rolled Conventional and Recycled Steels

The mechanical adhesion of thermally-formed oxide scales formed on industrial hot-rolled low carbon steel strips produced through the blast-furnace route (conventional steel) or the electric-arc-furnace route (recycled steel) was studied. A new macro-tensile test was compared to a micro-tensile test previously used. It was observed that spallation of scales during straining increased with increasing the tensile strain rate. A higher strain rate resulted in a lower strain inducing the first spallation. As a result, the mechanical adhesion energy of scales actually formed on the recycled steel was in the range 300–700 J m−2. Comparison at the same strain rate of the conventional and recycled steels showed higher scale adhesion for the recycled steel due to the presence of high amounts of interfacial silica.

Synthesis, characterization and the effect of the s-triazine ring on physico-mechanical and electrochemical corrosion resistance performance of waterborne castor oil alkyd

The sustainable resource based volatile organic content (VOC) free coatings with superior anticorrosive properties are some of the most in demand in the surface coating industry. In the present investigation, we report the synthesis of butylated melamine formaldehyde (BMF) cured waterborne castor alkyd (WCA-BMF) using environmentally friendly solvent for anticorrosion applications. The cured resin was characterized by spectroscopic techniques, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The molecular weight of the resin was determined by gel permeation chromatography (GPC). The corrosion protection performance of the coatings on carbon steel strips (CS) was investigated by potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and the salt spray test. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) examinations were carried out to study the morphology of bare CS and coated CS before and after exposure to a salt spray chamber. The results showed the prominent role played by the amount of BMF in the performance of the castor alkyd, as reflected by the high thermal stability, good adhesion, bending ability (1/8 inch bend test), impact resistance (>100 cm), scratch hardness (7.50 kg), along with good hydrophobicity and high corrosion protection performance. Thus, this study revealed that the presence of the s-triazine moiety in waterborne castor alkyd can produce a high performance corrosion protection coating material via a green route.

Effect of annealing process on recrystallisation microstructure and texture of low carbon steel strip

The microstructure and texture of cold rolled low carbon steel produced by compact strip production (CSP) after batch and continuous annealing have been investigated. Optical microscopy, bulk X-ray texture analysis and micro-orientation analysis with electron backscattered diffraction were conducted to investigate the general microstructure and texture in correlation with the mechanical properties as well as formability under the two annealing procedures. The results indicate that the microstructure of the cold rolled steel after batch annealing exhibits a special orientation relationship with the matrix in comparison to continuous annealing. As an explanation of the oval shaped grain character, the recrystallisation microstructure and texture evolution are discussed. It is concluded that annealing has a significant effect on the special orientation and texture formation of the CSP strip and thus to the formability and mechanical behaviour of the final products.