Strip Production Research Articles

Determination of non-metallic inclusions in a continuous casting slab of ultra-low carbon interstitial free steel by applying of metallographic method, electrolytic method and RTO technique

Metallographic, electrolytic method and RTO(room temperature organic) technique were applied in the present study to more accurately determine non-metallic inclusion in a ultra-low carbon interstitial free(IF) steel and further to confirm their origination in a Compact Strip Production Process (CSP Process) continuous casting (CC) slab. Results show that inclusions detected by metallographic method usually appear relative smaller size and are mainly Al2O3 based or TiN based in composition, whereas those extracted by electrolytic method usually have larger size and are much more calcium-silicate based in composition. In addition, inner structures of extracted inclusions were detected by applying of RTO technique. The large size calcium-silicate based inclusions are confirmed high possibilities originating from mold flux and/or tundish flux entrapment, which are less affected by the liquid steel composition; while the smaller ones are generally endogenous inclusion precipitating during the refining or solidification process that strongly depending on the liquid steel composition and temperature.

Evidence From a Long-Term, Systematic Post-Market Surveillance Program: Clinical Performance of a Hematocrit-Insensitive Blood Glucose Test Strip.

Described is a manufacturer's systematic post-market evaluation of the long-term clinical accuracy of a commercially available blood glucose monitoring (BGM) test strip product. Production batches of test strips were routinely and regularly sampled and evaluated in a clinical setting to assess product accuracy. Evaluations were performed on capillary blood samples from a minimum of 100 subjects with diabetes, by clinical staff according to instructions for use. Readings were compared against capillary blood samples collected at the same time and measured by a standard laboratory reference method. Clinical accuracy was calculated according to EN ISO 15197:2015. A total of 21 115 paired results were obtained, equating to 209 production batches over the >3-year period since test strip launch. Of the results, 97.6% met the accuracy criterion (range: 97.1-98.1% by year), with 98.1% of values presenting zero risk as defined by the surveillance error grid. At the <5th (21.0-33.8%) and >95th (48.3-59.4%) percentile extremes of hematocrit distribution, 97.9% and 96.4% of values were clinically accurate. The product also demonstrated clinical accuracy across all seven glucose ranges ("bins") as defined by the standard. Under conditions of combined hematocrit and glucose (<80 mg/dL and ≥300 mg/dL) extremes, 97.7% of values were clinically accurate. Methodologies and results from a manufacturer's self-imposed clinical accuracy surveillance program of a BGM product is presented. Given the publication of sometimes-conflicting data presented within ad hoc BGM clinical accuracy evaluations, usually of limited size, it is advocated that BGM manufacturers adopt similarly robust and systematic surveillance programs to safeguard patients.

Studies on Technological Features of Obtaining Thin Bimetallic Brass-Aluminum-Brass Strips

Manufacturing of bimetallic brass-aluminum-brass strips is connected with a number of technological features. The features under consideration are cladding (welding) of the primary components, annealing of metal compositions and strain modes assignment. The purpose of the studies upon the development of bimetallic brass-aluminum-brass strips production technologies in SUSU is to analyze the modes, as well as to elaborate recommendations for the primary components thickness selection, strain modes assignment and annealing using bell-type furnace and strand-type furnace. The performed studies resulted in recommendations dealing with annealing cycles. The studies have also delivered the regression ratio between the thickness selection of primary components during the cladding operation, and the supreme total strain. A correct ratio prevents from the surface ruptures on the bimetallic brass-aluminum-brass strips surface while rolling.

Effects of Casting Speed on Thin Gauge Foil Surface Quality of 8079 Aluminum Alloy Produced by Twin Roll Casting Method

In twin roll casting method, casted strips exhibit centerline segregation due to solidification kinetics. Casting parameters have an essential impact on aluminum’s microstructural properties as segregations. Therefore, these parameters have unfavorable effects on strip and foil products. Moreover, in foil products, pinhole surface defects do exist and reveal themselves as undesirable quality problems. In the present study, 8079 aluminum alloys were produced by twin roll casting method at different casting speeds. Diversified homogenization annealing processes were applied in laboratories for indicating optimum temperature leading to microstructural alterations. In order to analyze the influence of casting speed on foil products, microstructural investigations were accomplished on as-cast specimens and homogenized samples with optical microscope and scanning electron microscope. EDS and XRD analysis were conducted to analyze intermetallic structure inside 8079 alloy. In addition, mechanical tests were carried out for indicating the required temper designation for foil product. Scanning electron microscope analysis was performed on the final product surfaces of thin gauge foil in order to characterize the pinhole surface defect.

Development of new alloy systems and innovative processing technologies for the production of magnesium flat products with excellent property profile

Abstract In order to establish magnesium alloys in industrial applications, new alloy systems with an excellent property profile as well as suitable processing technologies are required. Magnesium alloys containing Ca offer a significantly improved formability due to the modification of the rolling texture. Applying innovative processing techniques allows the production of magnesium strips offering good mechanical and technological properties. In the present paper twin roll casting combined with strip rolling was used to produce strips of Ca-containing magnesium alloys (ZAX210, MX20) with a final thickness of 2 mm for comparison. Microstructural characteristics, mechanical properties and formability of the sheets are represented in comparison to commonly used magnesium alloys (AZ31, ZE10).

Characterizing Strip Snap in Cold Rolling Process Using Advanced Data Analytics

Among the undesirable quality incidents in the cold rolling process of strip products, strip snap could result in yield loss and reduced work speed. Therefore, it is necessary to reveal the factors influencing the occurrence of this failure for quality improvement. In this study, a data analytics approach was applied with the aim of determining relevant variables affecting snap occurrence. To validate this approach, a case study was conducted based on real-world data collected from an electrical steel reversing mill. The results suggested a selection of variables to characterize the quality issue of strip snap in the cold rolling process. This quality characterization study was performed as the preliminary stage of a quality improvement task.

Advanced Technology of Combined Thin Slab Continuous Casting and Steel Strip Hot Rolling

On the basis of proceedings of an international symposium on casting and rolling complexes the latest solutions for hot-rolled strip production by a combined process of continuous thin slab casting and rolling are reviewed. Advanced developments in the field of equipment and technologies are presented. The main tendencies and future tasks on this subject are noted.

Achievements of Endless Strip Production in Rizhao Steel

The equipment and technology characteristics of endless strip production line in Rizhao steel were analyzed and the achievements of endless strip production in Rizhao steel were illustrated with detailed productive data in 2017. The achievements of endless continuous casting process was introduced from the aspects of the mold level deviation, the casting speed and the tundish temperature. The achievements of endless continuous rolling process was described from the rolling length, the mechanical properties and the microstructure at different position along the width. The achievements of endless continuous casting and rolling process was discussed from the product qualification rate, the yield rate, the thin strip ratio, the accident rate and the energy consumption. The productive practice of endless strip production (ESP) shows that the longest number of continuous casting furnace reached to 15 heats (4500 tons), the longest rolling length in single casting period was 182 km, the qualified rate of products was up to 99.73%, the yield rate was up to 97.51% and the thin strip ratio had a maximum value of 40.57%. At the same time, its accident rate was below 2.02% and its energy consumption was less than 27.26 kgce·ton-1. These achievements indicated that the ESP line in Rizhao steel had the advantages of low cost, good performance and green manufacturing, so the endless rolling technology will be rapidly promoted and the hot rolled thin products by ESP will further expand the market.

Simulation Experimental Study on Ferrite Rolling Process of Low-Carbon Steels

In this paper, the Steel Plate Heat Commercial (SPHC) that produced by RiZhao Steel’s Endless Strip Production (ESP) line was taken as the research object. The phase transition points under different cooling rates were measured by DIL805A thermal expansion instrument and then the static Continuous Cooling Transformation (CCT) curve was plotted. The rolling process of ferritic zone was simulated by Gleeble-3800 hot compression tester. The microstructure evolution of SPHC under different temperatures and different strain rates were analyzed, and the hot compression deformation behavior was studied. The experimental result has shown that when the cooling rate of low carbon steel is lower than 15 °C·s-1, the microstructure is mainly composed of ferrite and a small amount of pearlite and tertiary cementite. The experimental material showed a mixed crystal phenomenon when the deformation reached 50% at 780 °C. The fitting calculation has shown that the deformation activation energy of the ferrite zone rolling is 112 kJ·mol-1, and the relationship between the deformation energy storage and the temperature compensation strain rate factor was established. Subsequently, the above experimental results were verified in the RiZhao Steel’s ESP line, which laid the experimental foundation for the use of ferrite rolling technology for endless strip production.

Effect of Original Microstructure on Microstructure and Mechanical Properties of High Strength Steel WHF1500H during Hot Forming

The press hardening steel sheets WHF1500H with different original structures produced by compact strip production (CSP) line in Wuhan Iron and Steel Ltd. were austenitized at 950 °C for 5 min, and then hot stamped and quenched by using the flat die. The microstructure and mechanical properties were investigated by optical microscope, transmission electron microscope and universal testing machine. The results show that the microstructure after stamping and quenching is fully composed of lath martensite. The mechanical properties of the steel samples with different original structures are different after hot stamping and quenching, and this difference is smaller than that before hot stamping and quenching. When the original structure consists of ferrite and pearlite, the austenite grains after austenitization are fine and uniform. In addition, the martensite structure obtained after hot stamping and quenching is also uniform and fine, leading to higher mechanical properties. With the increase of the strength of the original steel, when the original structure is martensite, the austenite grains after austenitization are coarse, and the martensite structures obtained after quenching is also coarse, and thereby decreasing the strength.

Supply Chain Quality Management of Magnesium Components: Concept, Examples and Recommendations

Magnesium components offer an enormous potential to achieve considerable weight savings in the automotive industry. As with any innovative construction material, (e.g. carbon-fiber-reinforced polymer, ultra-high-strength steel) a rigid quality management system needs to be established along the supply chain. For this purpose, the concept of the supply chain quality management is to be introduced for the special case of magnesium components, using the example of the magnesium strip production. By the implementation of the widespread ISO 9001 norm, opportunities can be leveraged by both the creation of upstream, downstream linkages and the defined internal processes to achieve the required and stable quality for the automotive industry. The paper suggests procedures and instructions for process control during the magnesium strip production according to the twin-roll casting technology, giving feedback to the respective production system to avoid insufficient quality. The results serve as a basis for the development of all stages up to the assembly of magnesium components. The individual process stages dependent on the manufacturer should be considered during the procedure.

Microstructural evolution and crystallographic texture in the production of aluminium strips for food containers industry. Part 2

Microstructural evolution and crystallographic texture in the production of aluminium strips for food containers industry. Part 2

Selective recovery of cobalt from the secondary streams after NiMH batteries processing using Cyanex 301

Cobalt is considered to be a critical raw material for the European Union. Since it has limited supply, substantial efforts should be made to develop sustainable methods to recover cobalt from alternative sources. Hydrometallurgical processing of spent NiMH batteries generates a concentrated stream containing, preferably, Co (11.8 g/L) and impurities (2.3 g/L Ni, 0.2 g/L Al, 9.3 g/L Mn and 4.6 g/L rare earth elements) in the nitric acid media. In this study, the selective separation of Co from the other ions present was investigated. Co was selectively separated from Al, Mn and REEs using 1 M Cyanex 301 in kerosene. The different kinetic behaviour during extraction with Cyanex 301 was utilized to separate Co and Ni ions selectively. The calculated ΔH for the Co extraction process equals – 11.37 ± 0.5 kJ/mol, which indicates that the extraction of Co in the system tested is an exothermic reaction. The effect of temperature on the Co extraction was used to obtain better selectivity towards Ni. Co was recovered by selective stripping with 4 M HCl at ambient temperature. The final purity of the stripping product was 99.9%.

Thermomechanical Treatment of High-Shear Melt-Conditioned Twin-Roll Cast Strip of Recycled AA5754 Alloy

A continuous high-shear melt conditioning twin-roll casting process has been developed for production of recycled aluminum alloy strip with minimum casting defects. High-shear melt conditioning is applied to increase the impurities tolerance of recycled aluminum. The results of this study showed that solidification during twin-roll casting can be controlled by using intensive melt conditioning prior to casting, which can promote equiaxed growth with minimal defects and result in improved sheet quality. Melt-conditioned twin-roll cast (MC-TRC) AA5754 alloy exhibited fine equiaxed grains and homogenized matrix structure while centerline segregation was eliminated. As-cast melt-conditioned twin-roll cast AA5754 strips showed clear grain recrystallization after thermomechanical treatment at 430°C for 30 min, representing an improvement over conventional twin-roll casting. The MC-TRC strip showed 57.2% higher elongation and 4.1% higher ultimate tensile strength compared with the TRC strip after applying melt conditioning with thermomechanical treatment.

The study of the thermal state of the metal in the production of the hot rolled strips in «Deform 3D»

The mathematical model of the thermal state of the sheet metal has been developed, taking into account radiation heat exchange and convection between the metal surface and the environment, the impact of descaling, heat transfer at the contact of metal with rollers, and also the heating of the metal due to plastic deformation. The model uses the results of mechanical tests obtained on the installation of the Gleeble 3800 under plane strain compression. Simulation of the rolling process is performed in the software complex «Deform 3D». The results of mathematical modeling adequately reflect the study of the thermal state of the metal produced in a sheet rolling shop. The model can be used to study the thermal state of the metal in the hot rolling production of high-quality steel grade.

Microstructural evolution and crystallographic texture in the production of aluminium strips for food containers industry. Part 1

Microstructural evolution and crystallographic texture in the production of aluminium strips for food containers industry. Part 1

Analysis of flatness control capability based on the effect function and roll contour optimization for 6-h CVC cold rolling mill

The 6-high continuously variable crown (6-h CVC) cold rolling mill shows limited capability to control coupled edge and center waves for both narrow strip and ultra-wide strip production. In order to solve this problem, an integrated three-dimensional (3D) elastic-plastic finite element model (FEM) of rolls and strip is built to calculate the effect functions in consideration of work roll bending (WRB), intermediate roll bending (IMRB), and CVC intermediate roll shifting (IMRS) with different strip widths. A set of orthogonal vectors which is defined as eigenvectors is proposed to analyze the similarities and the complementarities of the effect functions. It is applied to study the flatness control characteristics of the cold rolling mill. Based on the analysis of flatness stress characteristics of different strip widths in the production, it is found that the similarities between the flatness stress and the eigenvectors of different strip widths are relative low. The flatness defects are difficult to be eliminated. From the relationship between IMRS and strip widths, a segmented CVC intermediate roll contour is then proposed and experimented in an industrial production. The proportion of coupled edge and center waves is decreased by 15.2%, and the overall flatness is reduced by 0.7 IU.

Design of an one-sided transverse flux induction coil by using a numerical optimization algorithm

The transverse flux heating (TFH) concept offers very high electrical efficiency in combination with unique technological flexibility. Numerous advantages make this method beyond competition to be applied in e.g. continuous strip production and processing lines. However, all potential advantages of TFH can be realized in practice only by optimal design of the inductor shape and optimal control of the heaters, using numerical modelling and optimization techniques. The paper describes a successive approach to optimal design of a single layer induction coil, which will be used for onesided TFH of moving thin steel strip with constant width. The peculiarity of the design refers to the very slow movement speed of the strip and the target temperature, which is set below Curie.

Effect of Microstructure on Post-Rolling Induction Treatment in a Low C Ti-Mo Microalloyed Steel

Cost-effective advanced design concepts are becoming more common in the production of thick plates in order to meet demanding market requirements. Accordingly, precipitation strengthening mechanisms are extensively employed in thin strip products, because they enhance the final properties by using a coiling optimization strategy. Nevertheless, and specifically for thick plate production, the formation of effective precipitation during continuous cooling after hot rolling is more challenging. With the aim of gaining further knowledge about this strengthening mechanism, plate hot rolling conditions were reproduced in low carbon Ti-Mo microalloyed steel through laboratory simulation tests to generate different hot-rolled microstructures. Subsequently, a rapid heating process was applied in order to simulate induction heat treatment conditions. The results indicated that the nature of the matrix microstructure (i.e., ferrite, bainite) affects the achieved precipitation hardening, while the balance between strength and toughness depends on the hot-rolled microstructure.

Formation of Acquired Grain-Growth Inhibitor in the Production of Anisotropic Electrical Steel

The change in structural characteristics during the formation of acquired grain-growth inhibitor in the industrial production of cold-rolled anisotropic electrical steel strip is studied.