Horizontal Continuous Casting Research Articles

Preparation and properties of copper-aluminum composite strips and foils by horizontal continuous composite casting and rolling

Cu-Al composite strips and foils show broad application prospects in electric power, new energy and other fields. However, they are difficult to prepare because of brittle interfacial intermetallic compounds and deformation ability difference between two matrix metals. In this study, Cu-Al composite strips and foils with the thickness of 350 µm and 50 µm are successfully prepared by horizontal continuous composite casting and rolling. Moreover, the effects of as-cast interfacial layer thickness on the properties of Cu-Al composite strips are studied. In the rolling, the as-cast interfacial layer is broken into fragments, so as to promote the Cu-Al matrix bonding at atomic scale. The local solid-state amorphous transformation is also observed at the newly formed Cu-Al interface. Therefore, with the as-cast interfacial layer thickness decreasing from 400 µm to 25 µm, the peeling strength of Cu-Al composite strips increasing from 15.1 N/mm to 17.5 N/mm. With the as-cast interfacial layer thickness decreasing from 400 µm to 65 µm, the conductivity of Cu-Al composite strips increases from 62.36%IACS to 72.58%IACS because the size of interfacial layer fragments is reduced. However, with the as-cast interfacial layer thickness decreasing from 65 µm to 25 µm, the conductivity decreases from 72.58%IACS to 68.65%IACS because the copper layer thickness after rolling is reduced. Large interfacial layer fragments hinder current conduction, but a suitable interfacial layer thickness can inhibit the coordinated deformation of Cu and Al, so as to increase the proportion of copper layer thickness in the entire composite strip.

Fabrication of carbon fiber reinforced aluminum matrix composites by inorganic binders

Infiltration is an important issue for unidirectional carbon fiber-reinforced aluminum matrix (CF/Al) composites. In the present study, aluminum dihydrogen phosphate (ADP) and silica sol were used to prepare CF preforms, then CF/Al composites were prepared by simulated horizontal continuous casting. The results showed that silica sol significantly affects the curing process of ADP. When the content of silica sol is 50 % and heated at 500 °C, the product transformed from Al(PO3)3 (cubic system) to an amorphous phase with good thermostability. The mixture binder can fully fill the gaps between CFs, leading to a dense CF preform. The obtained CF/Al composite has a good bonding interface between Al and CFs, without pores or crack defects, and thus shows an obvious enhancement in tensile strength of 64.9 MPa, which is 34.6 % improved compared with that of CPAl. The CF/Al composites also maintained a good electrical conductivity of 56.9 % IACS, similar to that of CPAl.

Adjustment of the Coarse Grain Problem of the Horizontal Continuous Casting Slab by Optimizing the Crystallizer Structure

This paper mainly focuses on the problem of coarse grain on the bottom surface of the red copper horizontal continuous casting billet, and tries to thicken the bottom end of the crystallizer by combining numerical simulation and industrial experiment, and indirectly improves the cooling strength of the bottom surface of the casting billet to solve the problem of grain coarseness. The results show that the optimum diameter of the lower inlet of the copper sleeve was 14.2 mm, when the diameter of the inlet increased from 11 mm to 14.2 mm, the cooling intensity of the lower part of the casting billet gradually increased, and the grain on the lower surface was significantly refined; and with the increase of the diameter of the water inlet, the average width of the columnar grain decreased from 1.94 mm to 1.64 mm, the grain size decreased, and the number of grains increased.

Texture evolution and its influence mechanism on properties of single crystal copper and polycrystalline copper during cumulative deformation

The φ16 mm single crystal copper rod was prepared by heated-mold horizontal continuous casting, and the φ16 mm polycrystalline copper rod was prepared by up-casting technology. Both of them were drawn to φ0.2 mm, the conductivity, strength, elongation, and microstructure evolution of single-crystal copper wire and polycrystal copper wire were compared and analyzed. The results show that the plasticity of as-cast single-crystal copper rod is 13.94% higher than that of as-cast polycrystalline copper rod. When drawing to φ0.2 mm, a single crystal copper wire with high strength (506 MPa) and high conductivity (98.01% IACS). At the same deformation amount, the single crystal copper wire obviously deforms more slowly and has a higher plastic deformation capacity; the texture transformation of single crystal copper wire is from soft → hard orientation, selective orientation to discrete distribution, while the weave transformation of polycrystalline copper wire is from soft → hard orientation, then from hard → soft orientation, and finally stabilizes to selective orientation. The microstructural evolution of single-crystal copper wire and polycrystalline copper wire during continuous deformation was observed: dislocation entanglement into dislocation cells by slip → microstrip structure → lamellar organization → twinning organization, single-crystal copper wire appears twinning later, single-crystal copper deformation coordination ability is better than polycrystalline copper. It is found that the increase of dislocation density, the decrease of grain width and the increase of <111> texture are the main factors for the strength improvement of micro-nano pure copper wires.

Simultaneously enhanced strength-ductility synergy and corrosion resistance in liquid-solid bonded stainless steel cladding carbon steel plate by hot rolling and annealing treatment

Liquid-solid (L-S) bonded stainless steel/carbon steel (SS/CS) laminated composites have strong metallurgical bonding interface, while the solidification structure of SS deteriorates the mechanical properties and corrosion resistance. In this study, hot rolling and annealing were proposed to regulate the microstructures and balance the performance of L-S bonded SS/CS clad plates. SS cladding CS plates were prepared by horizontal continuous liquid-solid composite casting and hot rolled at 1200 °C with a reduction rate of 90%, and annealed at 1000 and 1050 °C for 30 min. The microstructural evolution was studied by scanning electron microscope and electron back-scatter diffraction, elemental distribution was investigated by electron probe microanalysis. Microhardness, tensile test and anodic-cathodic polarization test in a 3.5% NaCl solution were carried out on hot-rolled and annealed SS cladding CS plates, and the mechanism for the simultaneous enhancement of strength-ductility synergy and corrosion resistance by hot rolling and annealing was analyzed. Annealing at 1050 °C resulted in excellent properties with tensile strength of 550 MPa and elongation of 50%, corrosion potential of −0.21 V and corrosion current density of 0.13 μA cm−2. The strength and ductility of the SS cladding CS plate were synergistically improved by a strong metallurgical bonding cladding interface, high frequency of low-Σ CSLs and refinement of grains in 304 SS. The low-Σ CSLs in 304 SS restricted the formation of carbides in the carburized layer and broke down the connectivity of random boundaries, improving the corrosion resistance.

Microstructure, properties and deformation mechanism of HCCM horizontal continuous casting Cu–Ni–Co–Si alloy strip during cold rolling

Cu-1.3 wt%Ni-1.0 wt%Co-0.9 wt%Si-0.1 wt%Mg alloy strip with 10 mm in thickness produced by heating-cooling combined mold (HCCM) horizontal continuous casting was cold rolled. Microstructure evolution and mechanical properties of the cold-rolled alloy strips with different reduction were studied, and the deformation mechanism was clarified. The results showed that the continuous casting strips had axial columnar grain with main <001> orientations and straight small angle grain boundaries, the elongation after fracture was up to 25.0%, which can be directly processed by large deformation cold rolling, and the maximum cumulative cold deformation was up to 99%.When the reduction was 40% and 60%, the dislocation bands crossed each other and shear bands formed, and the alternating distribution of soft/hard oriented grains were conducive to improve the deformation coordination ability of micro-region under high strain. When the deformation exceeded 80%, deformation twins formed and the twins had strong interaction with the shear band and grain boundaries, resulting in strong shear and rotation of the local grains. The tensile strength and hardness increased from 464 MPa to 137HV of the as-cast strip to 629 MPa and 208HV with reduction 90%, respectively, while the elongation decreased from 25.0% to 4.1%. These results can lay a foundation for the development of compact method for producing high performance Cu–Ni–Co–Si alloy strips.

Mechanisms for high strength and ultra-high electrical conductivity of Cu-3.5wt.%Ag alloy prepared by thermomechanical treatment

Copper-based wire is the key conductor material in integrated circuit bonding wire, high-end audio and video transmission line, medical wire harness and other fields. It is of significant interests to improving the strength and retaining their good electrical conductivity of copper-based wires for broad applications. The combination of heat treatment and deformation to control the microstructure is a promising method for this objective. In this paper, the Cu-3.5 wt.%Ag alloy rod with diameter of 16 mm was prepared by the hot mold horizontal continuous casting. We discussed the effects of solution + aging (S.A), solution + aging + cold drawing (S.A.C), solution + cold drawing + aging (S.C.A) on the distribution of Ag phase, dislocation morphology, strength and electrical conductivity of Cu-3.5 wt.%Ag alloy. The results show that continuing cold deformation after aging makes the strength of Cu-3.5 wt.%Ag alloy is up to 417.2 MPa, which is 84.6% higher than that by S.A process. After S.A.C treatment, the dislocation density sharply increases, and the dislocation is arranged in a network structure. The dispersed nano-spherical Ag phase with an average size of 12 nm precipitation after aging strongly prevents dislocation slip. Moreover, the chain-like Ag phase effectively "intercepts" or "lock" the dislocations in the local area. The S.A.C process fully exerts the synergistic strengthening effect of aging precipitation strengthening and deformation strengthening induced by the interaction between nano-Ag phase and dislocation. This process is suitable for medical wiring harness, bonding wire and other application scenarios with higher strength requirements. On the other hand, if cold deformation is applied before aging, that is, S.C.A process. The electrical conductivity of Cu-3.5 wt.% Ag alloy reaches 95.5% IACS, which is close to 100% IACS of pure copper. The achievement of ultra-high conductivity is mainly attributed to the formation of a large number of band-shaped nano-Ag phase with an average length of 450 nm and width of 25 nm, and the arrangement direction remain consistent. In addition, the uniform distribution of dislocations is also beneficial to greatly improve the electrical conductivity. The S.C.A process is suitable for high-end audio and video transmission lines and other application scenarios that require higher electrical conductivity. • The strength of Cu-3.5 wt.% Ag alloy prepared by S.A.C process reaches 417.2 MPa, which is 84.6% higher than that by S.A process. • The electrical conductivity of Cu-3.5 wt.% Ag alloy prepared by S.C.A process reaches 95.5% IACS, which is close to 100% IACS of pure copper. • The strengthening mechanism of Cu-3.5 wt.%Ag alloy prepared by cold deformation after aging (S.A.C) is the synergistic effect of dispersed nano-spherical Ag phase precipitation and local chain-like Ag phase locking dislocation. • The achievement of ultra-high conductivity of Cu-3.5 wt.%Ag alloy prepared by cold deformation before aging (S.C.A) is mainly attributed to the formation of a large number of band-shaped nano-Ag phases with large aspect ratio and consistent alignment direction, and the uniform distribution of dislocations.

Enhanced superelasticity of Cu-Al-Ni shape memory alloys with strong orientation prepared by horizontal continuous casting

Enhanced superelasticity of Cu-Al-Ni shape memory alloys with strong orientation prepared by horizontal continuous casting

Regulation of primary phase in Cu-Cr-Zr alloy and its effect on nano-structure and properties

In this study, Cu-0.8Cr-0.1Zr alloy was prepared by vacuum horizontal continuous casting method. The effect of different thermo-mechanical treatment processes on the properties was studied, and the microstructure evolution at different stages of thermo-mechanical treatment were observed by SEM, EBSD and (HR)TEM. The results showed that the optimal comprehensive performance of tensile strength (803 MPa) and conductivity (76% IACS) was obtained by three-stage drawing and thermal treatment (primary 43.75% drawing and solution treatment at 950 °C for 60 min + secondary 97.2% drawing and aging at 500 °C for 30 min + tertiary 75% drawing). Through the microstructure characterization, it was found that the morphology and distribution of the Cr-rich primary phase can be regulated by solution treatment, and inherited during the thermo-mechanical treatment. It acts as a nucleation point and hard point, thereby refining the grain and improving the strength of the alloy. Additionally, it reduces the number of solid solution atoms in the matrix and prevents the loss of conductivity. Furthermore, drawing with a large amount of deformation can produce a nano-lamellar structure with high temperature stability, and drawing after high temperature aging can induce substructure formation. The combination of nano-lamellar structure and substructure further improves the strength.

Hot compressive deformation of eutectic Al-17at% Cu alloy on the interface of the Cu-Al composite plate produced by horizontal continuous casting

Hot compressive deformation of eutectic Al-17at% Cu alloy on the interface of the Cu-Al composite plate produced by horizontal continuous casting

Rolling deformation behaviour and interface evaluation of Cu-Al bimetallic composite plates fabricated by horizontal continuous composite casting

Cu-Al bimetallic composite plates with a thickness of 2 mm were prepared by a horizontal continuous composite casting-rolling process. The effects of rolling parameters on the forming performance of Cu-Al composite plates and the interface evolution mechanisms were investigated. The results reveal that a suitable deformation temperature and an increase in first-pass deformation are both conducive to enhancing bimetallic deformation coordination. For cold rolling, the first-pass reduction should exceed 60 % to avoid delamination cracking. When the rolling temperature rises to 200–300 °C, the first-pass reduction can be decreased to 55 % due to the better deformation coordination of bimetallic. However, an excessive rolling temperature results in the formation of a continuous layer of intermetallic compounds at the new interface, and the formability of the plates is decreased significantly. In the rolling process of Cu-Al composite plates, the original Cu-Al interface is first shattered, and then the matrix metal flows into the gaps of the broken interface. Finally, a new oxidation-free interface at the atomic scale is developed, which is beneficial to the bonding strength of the composite plates. The Cu-Al composite sheets prepared by the above reasonable parameters exhibit a tensile strength of 180–191 MPa, an elongation of 8%–12 %, and an excellent interfacial bonding strength of 66–89 MPa.

Microstructure and mechanical properties of Cu-Ni-Si alloy plate produced by HCCM horizontal continuous casting

C70250 (Cu-2.6 wt%Ni-0.5 wt%Si) alloy plates with straight columnar grains, inclined columnar grains and equiaxed grains were produced by a heating-cooling combined mold (HCCM) horizontal continuous casting, respectively, and the influences of microstructure on the mechanical properties of the alloy were studied. The results showed that, when the casting speed was 30 mm/min, the straight columnar grains along the casting direction formed in the C70250 alloy plate and the precipitate content was relatively high, ～ 10%. When the casting speed was 50 mm/min and 80 mm/min, inclined columnar grains and equiaxed grains formed, respectively, with a low precipitate content of 6%. The high casting speed made the solid-liquid interface at the entrance of the cold mold and the solidified plate was cooled rapidly due to strong cooling effect, which suppressed formation of precipitated phase. The yield strength of the alloy plate with equiaxed grains were 219 MPa and the elongation to failure was 36%. For the plate with inclined columnar grains, its yield strength (76 MPa) were obviously lower than that of the other two plates and the elongation reached 45%. Compared with the equiaxed grain plate, the columnar grain plate had smaller grain orientation difference, better intergranular deformation compatibility and intergranular deformation uniformity, which was mainly responsible for its better plasticity.

Numerical Calculation About Influence of Crystallizer Structure on the Stress Evolution Process of Horizontal Continuous Casting of Copper Tubes

Abstract The horizontal continuous casting plays a key role in the production of inner grooved copper tubes. In order to improve the accuracy of the temperature field model of the copper tubes' horizontal continuous casting process, the model heat transfer coefficient was validated through temperature measurement experiment of graphite crystallizer. The finite element model of stress field evolution was established, based on considering the temperature and microstructure changes. It was found that tensile stress was generated in the outer layer of the casting billet and compressive stress was generated in the inner layer, when the casting billet entered the primary cooling zone. The paper investigated the mechanism of the liquid inlet number and shape on the microstructure and stress distribution after the casting billet was solidified. When the number of liquid inlets was 6, the ratio of the semimajor axis of ellipsoid to the short semiaxis was 3:2, and the backward tilt angle was 10 deg, the equivalent stress value of the casting billet was smaller, and the grains were dense and uniform. This paper promotes the research of horizontal continuous casting process and provides measurable reference for improving the quality of casting billet in the further.

Copper Based Alloys Hardenable by Precipitation

The paper presents the experimental research conducted with the purpose of accomplishing long products out of special copper-based alloys, from Cu-Cr-Zr systems, hardenable by precipitation, appropriate for large domains of utilization within top industries realized by modern casting – deforming procedures. Therefore, one of the modern technologic alternatives meeting these requirements is horizontal continuous casting which ensures the realization of long semi-fabricated materials out of special alloys that can be used in cast state and/or plastically deformed, in warmth and/or cold, for the accomplishment of certain products required on the market. The effect of precipitation function of hardening degree applied to the samples put in solution is quantified on consecrated compositions of the Cu-Cr-Zr alloys, containing ˜ 1% Cr and ˜ 0.12% Zr respectively, after the solubility treatment. The macroscopic resistance determinations as well as the electronic microscope and X-ray investigations shall furthermore lead to the accomplishment of a concluding image on the mechanism of precipitation within the analysed systems.Key words: Copper based alloys, horizontal continuous casting.

Evolution of microstructure and properties of Cu-4.5 wt.% Ag alloy prepared by vacuum horizontal continuous casting in solid solution and aging treatment

The vacuum horizontal continuous casting method was used for preparing Cu-4.5 wt.% Ag alloy rod containing few oxygen. The evolution of microstructure was observed by metallographic microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the hardness and electrical conductivity of Cu-4.5 wt.% Ag alloy aged at 450 °C for 12 h were increased by 60 HV and 12 %IACS than solution treated alloy. TEM observation showed that the continuous precipitates of Ag are uniformly distributed in matrix with the form of particles and strips. Through calculation, the strength increment of peak aged Cu-4.5 wt.%Ag alloy from solid solution hardening and precipitation hardening are 86 MPa and 136 MPa, respectively.

Study on the horizontal continuous casting of Cu-based bulk metallic glass slab

To improve the fabrication efficiency of bulk metallic glasses (BMGs) with high mechanical properties and low costs, Cu47Zr45Al8 and (Cu47Zr45Al8)98.5Y1.5slabs with the cross-section of 50 ×6 mm were produced by horizontal continuous casting method (HCC). It is proved that by adding Y to Cu47Zr45Al8, the crystallization behavior could be significantly decreased, and an amorphous structure was obtained when it was casted at DT=80 K. The obtained amorphous structure was proved by XRD, TEM, DSC analysis. The glass transition behavior and crystallization were identified with Tgof 671 K, Txof 771 K, ΔTxof 80 K, andΔH0of 46.2 J/g, respectively. In terms of mechanical properties, the compressive strength and Vickers hardness reached 1803 MPa and 493 HV, respectively. Fracture morphology revealed that the fracture is characterized by limited rheological deformation and high localization of shear band expansion, which results in a mixed fracture mode of ductile and brittle.

Effects of Ultrasonic Bending Vibration Introduced by an L-Shaped Ultrasonic Rod on the Microstructure and Properties of a 1060 Aluminum Alloy Strip Formed by Twin-Roll Casting.

In order to achieve the industrial application of ultrasonic energy in the continuous casting and rolling production of aluminum alloy, a new type of L-shaped ultrasonic rod was used to introduce an ultrasonic bending vibration into the aluminum melt in the launder during the horizontal twin-roll continuous casting and rolling process of a 1060 aluminum alloy. The effects of the ultrasonic bending vibration on the microstructure and properties of the 1060 aluminum alloy cast rolling strip and its subsequent cold rolling strip were studied experimentally, and the effect of the ultrasonic-assisted refining with different amounts of Al-Ti-B refiner was explored. The results show that under the same addition amount of Al-Ti-B refiner, the ultrasonic bending vibration can refine the grains of the cast rolling strip, make the distribution of precipitates more uniform, reduce the slag inclusion defects, and improve the mechanical properties to a certain extent. The microstructure and properties of the ultrasonic cast rolling strip with 0.18 wt% Al-Ti-B refiner or 0.12 wt% Al-Ti-B refiner are better than those of the conventional cast rolling strip, but the microstructure and properties of the ultrasonic cast rolling strip with 0.09 wt% Al-Ti-B refiner are slightly worse than those of the conventional cast rolling strip. Moreover, after cold rolling, the effect of the ultrasonic bending vibration on the improvement of the microstructure and properties of the aluminum alloy strip is inherited. A comprehensive analysis shows that the use of ultrasonic energy in this paper cannot completely replace the effect of the Al-Ti-B refiner, but it can reduce the addition amount of the Al-Ti-B refiner by 1/3.

Microstructure evolution and mechanical properties of Cu-0.36Be-0.46Co alloy fabricated by heating-cooling combined mold horizontal continuous casting during cold rolling

Cu-0.36wt.%Be-0.46wt.%Co alloy plate with 300 mm in width and 10 mm in thickness prepared by heating-cooling combined mold (HCCM) horizontal continuous casting was cold rolled. Microstructure evolution and mechanical properties of the alloy as well as its deformation mechanism were investigated. The results showed that the as-cast alloy plate had columnar grains along the length direction, good surface quality and elongation of 35%, which was directly large-reduction cold rolled without surface treatment, and the accumulative cold rolling reduction reached 98%. When the reduction was small (20%), numerous dislocations and dislocation cells formed, and the deformation mechanism was dislocation slip. When the reduction was 40%, deformation twins appeared, and interactions between twins and dislocation cells induced strip-like dislocation cells. When the reduction exceeded 60%, shear bands formed and apparent crystal rotation in the micro-region happened. Further increasing the reduction, the amount of the shear bands rose and they interacted with each other, which refined the grains apparently. The tensile strength and hardness increased from 353 MPa and HV 119 of the as-cast alloy to 625 MPa and HV 208 with 95% reduction, respectively, and the elongation reduced from 35% to 7.6%. A process of HCCM horizontal continuous casting-cold rolling can work as a novel compact method to fabricate Cu-Be alloy sheet.

Effect of aging on properties and nanoscale precipitates of Cu-Ag-Cr alloy

Abstract In this paper, the Cu-0.52Ag-0.22Cr alloy was prepared by hot horizontal continuous casting. The effects of aging process on micro-hardness, electrical conductivity, and nanoscale precipitates of Cu-0.52Ag-0.22Cr alloy were studied. The electrical conductivity and micro-hardness increase significantly in the early aging time. With the extension of aging time, the electrical conductivity is basically unchanged and remains at a high level. While, the micro-hardness increases slowly, the change trend is different at 623 K, 723 K, and 773 K. The optimisation of process parameters occurs in 723 K for 2 h. At this time, the electric conductivity is 95.8% IACS and the hardness is 104.1 HV0.1. The XRD result shows that the Ag and Cr are precipitated in elemental form copper matrix. Further TEM shows that, Cr exists at the sub-boundary in the form of larger nanoscale precipitates (100-200 nm). While a large number of Ag nanoscale precipitates (8-10 nm) is dispersed on the copper matrix. The synergistic effect of Ag and Cr nanoscale precipitates significantly improved the properties of the alloy.

Evolutions of the Micro- and Macrostructure and Tensile Property of Cu-15Ni-8Sn Alloy During Electromagnetic Stirring-Assisted Horizontal Continuous Casting

The present study investigates the evolution of the micro- and macrostructure and tensile property of the Cu-15Ni-8Sn (weight percent) alloy prepared by horizontal continuous casting and electromagnetic stirring (EMS). The results show that the application of EMS is beneficial for grain refinement and for microstructure transformation from the dendrite to the rosette structure and that it leads to a significant improvement in the tensile property. The forced flow induced by EMS homogenizes the temperature field ahead of the solid-liquid interface, disturbing the heat flow direction and resulting in the columnar to equiaxed transition. The grain refinement under different electromagnetic stirring frequencies is mainly derived from the homogenization of the temperature and the remelting of dendritic arms. In addition, the evolution of the tensile property with and without EMS is discussed from the perspective of fracture mode and fine-grain strengthening.