In-line Rolling Research Articles

Direct Strip Casting of Magnesium

AbstractA new interest in magnesium alloys has arisen since lightweight constructions have become more and more attractive. Products that are currently available are mostly cast, forged, and extruded. A cost-effective production of sheet metals will render new perspectives in the design of lightweight constructions [1, 2].The development of new casting technologies like thin slab casting or strip casting with an in-line rolling process is expected to result in a shorter processing time featuring a high potential of saving energy, time, and cost [3, 4, 5, 6, 7, 8, 9]. Particular attention is paid to the casting process parameters such as casting speed and solidification speed. This article deals with some aspects of a magnesium-adapted singlebelt caster. Results of casting experiments and material examination are shown as well as some advices given concerning safety and handling of liquid magnesium [10].

Inline Rolling Shear Alignment: Deposition and Long-Range Order of Block Polymer Templates in a Fast, Single-Step Process

We report the first demonstration of a rapid, single-step technique to align block polymer, thin-film nanostructures, which is amenable to continuous speeds of ≥10 mm/s. This method, termed inline rolling shear alignment (IRSA), uses an elastomeric roller coupled with an electric hysteresis brake to shear films before the casting solvent fully evaporates, and it can enable high-throughput, large-area manufacturing of patterns such as nanowire templates. IRSA is adaptable to various polymer systems including diblock and triblock polymers, and a post-shear annealing step can yield high-quality nanostructures with orientation parameters >0.99 and defect densities as low as 5 defect-pairs/μm2. To demonstrate the effectiveness of IRSA, platinum nanowires were produced from this rapid deposition and alignment approach using poly(styrene-b-2-vinylpyridine), followed by open-air, atmospheric-pressure plasma etching. This integrated concept, with 50× faster operation than existing processes, could be leveraged for cost-effective manufacturing of macroscopically aligned nanostructures in roll-to-roll systems.

The effect of inline rolling on Al-Mg alloy strip cast by the unequal diameter twin roll caster

The effect of inline rolling on Al-Mg alloy strip cast by the unequal diameter twin roll caster

Feasibility Study of Continuous Casting of Steel Billets in Twin-Belt Caster

Integrated casting and rolling in a series production line is well established for the non-ferrous metals through the use of twin-belt casting technology. However, this twin-belt casting with high mass flow is not yet commercialized in the continuous production of steel alloys. A novel steel casting for the in-line rolling (named LUUP method) is presented and one main focus of this work is to design a casting machine: twin-belt caster. Influence of mass flow rate and dimensional ratio on the solidification, compensation, and total process length is addressed. A gap-dependent belt and dam block side heat transfer is modeled. The admissible casting speed due to the limitations of caster length and shell strength is addressed. The total process length only depends on the mass flow rate. A 2D traveling slice numerical model is presented with realistic boundary conditions for the entire process starting from the meniscus to roll mill entry.

The Study of Heat Transfer Coefficient during Cooling Plates of High Strength

Nowadays methods of hot-rolled sheets should ensure high mechanical and plastic properties of sheets, in-line rolling. Such technologies require application of devices for accelerated cooling of a band after last deformation. The essential thing in this process is selection of an appropriate positioning of the cooling intensity. The paper presents results of the cooling intensity for the selected air-water nozzle. On the basis of the results, the map of distribution of heat transfer coefficient for the nozzle to the surface of the cooling was performed. These tests were carried out for different settings of water and air. The research was carried out for high-strength steel. The obtained results allow executing of computer simulation of the impact of cooling intensity on the final product’s structure.

Hot rolling of AISI 304 tailored strips produced by twin roll strip casting

A process for the production of steel strips with an optimized cross section by means of twin-roll strip casting has recently been developed at the Institute of Metal Forming and offers considerable technical and commercial potentials. This production concept is based on the use of profiled casting rolls which continuously transfer the profile geometry to the solidified strip. In order to reduce the internal porosity and improve the surface finish the cast strip was hot rolled using profiled rolls. Offline and inline rolling experiments were performed to prove the effectiveness of this combined forming process. This paper describes the design of a proper rolling tool and the effect of this forming step on the final profile geometry, surface quality, internal porosity and mechanical properties of the strip. The experiments showed that a rolling step with 15 % thickness reduction already allows the global internal porosity to be reduced by 48 % and the strip surface roughness to reach a minimum value of Ra = 2.3 µm. The tensile strength is improved after the hot rolling operation and the obtained values are within the 500–700 MPa range specified by the norm EN 10088-3 for the stainless steel AISI 304. The prescribed ultimate elongation of 45 % is also reached.

503 Al合金用縦型高速双ロールキャスターにおけるインライン圧延(GS-4 軽合金)

503 Al合金用縦型高速双ロールキャスターにおけるインライン圧延(GS-4 軽合金)

Fabrication of Al/Mg Clad Material Using a Horizontal Tandem Twin Roll Caster

This study was aimed that Fabrication of Al/Mg clad material using a horizontal tandem twin roll caster. Magnesium is the lightest of structural metals combining high mechanical strength and low density. However, magnesium is low corrosion resistance. Aluminum alloys and magnesium alloys were fabricated as an Al/Mg composite using aluminum alloys as protective layers, improvement of the corrosion resistance of the magnesium alloys can be expected. In this study using twin roll casting process and downward melt drag process. And also in-line rolling process was used. A horizontal tandem twin roll caster consists of three kind of twin roll. AZ121 was cast by first twin roll, this is first strip. Downward melt drag process was used for casting of A1050, this is second strip. In case of narrow roll gap, AZ121 was melted by A1050 due to increased heat transfer coefficient. In this study, bonding could be better that cladding of aluminum on third twin roll would rather than cladding of aluminum on second twin roll. Thickness of clad strip was 5.5 mm, aluminum layer was 1.1 mm, magnesium layer was 4.3 mm. cladding ratio was 1.1 : 4.3. Mixed layer was 70-90μm in bonding region. Each diffuse layer of Al layer and Mg layer was 10 μm. Primary crystal size of Mg layer was 77μm at mixed layer region, 19μm at center region, 83μm at surface region.

702 高速双ロール法により作製したAl合金薄板のインライン圧延

702 高速双ロール法により作製したAl合金薄板のインライン圧延

Inline Rolling of 5182 Aluminum Alloy Strip Cast by a Vertical Type High Speed Twin Roll Caster

An inline hot rolling was operated on 5182 aluminum alloy strip cast using a vertical type high speed caster (VHSTRC) at the speed of 60 m/min. A porosity existing at center line of the thickness and a ripple mark on the surface, these are typical defects of the strip cast by the VHSTRC, could be improved by the inline rolling. The rolling speed was as same as the roll-casting-speed of 60m/min. The temperature of the strip, when the inline rolling was operated, was 450oC. The reduction of the strip of the inline rolling was 35%.

In-Line Rolling of Aluminum Alloy Strip Cast by a High Speed Twin Roll Caster

In-line rolling was operated on the as-cast strip cast by a vertical type high speed twin roll caster. The AA6022 and AA6111 strip was tested. The casting and rolling speed was 60m/min. Reduction was from 20% to 55%. The temperature of the rolling was within from 400oC to 450oC. The porosity and crack in the strip were improved by the in-line rolling. The in-line as rolled strip was cold rolled down to 1mm, and T4 heat treatment was operated. The microstructure of the strip, on which in-line rolling was operated, became uniform at thickness direction than the microstructure of the strip on which only the cold rolling was operated. The surface defects like the ripple mark and trace line of the nozzle were improved.

Mathematical Modeling of Draft Schedule for In-line Rolling of Ultra Thin Strip in the Combined Single-belt Casting/Hot Rolling Process

The single-belt process is a new route to produce steel strips, in which the single-belt caster is directly connected with hot mills. This process should be able to roll strip with thickness 1 mm or below. In hot rolling of the ultra thin strip there are many limitations which are represented by the finishing rolling temperature of the strip, the oxidation of the strip, the overheat of the roll and the maximum rolling speed. In the present paper the possibility of hot rolling ultra thin strip in the single-belt process was investigated. On the basis of mechanical/thermal/metallurgical behavior of the strip a mathematical model of draft schedule was proposed. In terms of different criteria the draft schedule was optimized. The results show that austenitic hot rolling of ultra thin strip in the single-belt process can be carried out like the conventional hot rolling for low carbon steels. With consideration of roll life the maximal roll surface temperature has a large influence on the establishment of the draft schedule for hot rolling of ultra thin strips.

Direct Strip Casting of Magnesium

Abstract A new interest in magnesium alloys has arisen since lightweight constructions have become more and more attractive. Products that are currently available are mostly cast, forged, and extruded. A cost-effective production of sheet metals will render new perspectives in the design of lightweight constructions [1, 2]. The development of new casting technologies like thin slab casting or strip casting with an in-line rolling process is expected to result in a shorter processing time featuring a high potential of saving energy, time, and cost [3–9]. Particular attention is paid to the casting process parameters such as casting speed and solidification speed. This article deals with some aspects of a magnesium-adapted single-belt caster. Results of casting experiments and material examination are shown as well as some advices given concerning safety and handling of liquid magnesium [10].

Strip casting experiences at MEFOS

Continuous casting of flat products today is a mature technique for production of steel semis with an as-cast thickness of 200 mm. At present, the thin slab casting is developed to the extent of casting and in-line rolling of strips with a thickness of 1–2 mm. Up to now, it is reported that 27 thin slab production lines are under construction or in operation. The strip-casting technique is the next generation of production lines for steel to be developed for production of flat products. There are 2 main directions in the development of strip casting. The 1st is the twin roll casting technique, which so far has concentrated its efforts on production of stainless steel strips. The 2nd is the single-belt casting technique (DSC – Direct Strip Casting) which is aiming for high production volumes of flat products with the necessary hot reduction possibility to receive good material properties.The development of strip casting at MEFOS started in the late 80s with the joint efforts of a Nordic group of steel companies. The aim of the project was to built up know-how in the field of strip casting by the erection and operation of a strip caster at MEFOS. After a 1-year prestudy, the single-belt casting technique was chosen. The German machine-building company, Mannesmann Demag Metallurgy, and the Nordic consortium had complementary interests, and in 1991, a co-operation agreement was signed in the field of strip casting. At MEFOS, the emphasis is focused on the industrial application of casting 870 mm wide strips, while the focus of the development at Technical University of Clausthal (TUC) is devoted to casting and in-line rolling. Based on the potential of the process and the promising results obtained in the research facilities, the industrial partners are now in the position to decide on building a demonstration caster in a steel plant.

Recent advances in near-net shape flat steel manufacturing

Near-Net Shape Casting (NNSC) has been one of the major paradigms of process development in the steel industry in the last ten years. It has also made possible the development of flat product mini-mills, in conjunction with electric arc furnace steelmaking and in-line rolling on compact hot-strip mills. More development is still to come, with the adoption of NNSC casting in integrated mills and the emergence of strip casting.

Cold-rolled, high-strength sheet steels for auto applications

Several groups of cold-rolled, high-strength sheet steels have been developed to optimize the required strength and formability levels for automotive applications. Multiphase steels offer new opportunities where high-strength levels are demanded. The future in steel development will be determined by the physical modeling of properties and by adapting new process routes such as thin slab casting and in-line rolling. In this article, developments in traditional strengthening concepts (e.g., microalloying and substitutional hardening with phosphorus) and more recently developed concepts (e.g., bake hardening and strengthening of interstitial-free steels) are reviewed.