Heated Mold Continuous Casting Research Articles

Mechanical Properties of Cast Al-Mg5 Alloy Produced by Heated Mold Continuous Casting

To make the high strength and high ductility of the cast aluminum alloys, the Al alloy samples are created by the heated mold continuous casting (HMC) process. Because of the rapid and unidirectional solidification in the HMC process, tiny grains with uniformly orientated crystals are created. In this case, influence of the solidification speed of HMC on the mechanical properties of the Al-Mg-based alloy is studied. The microstructures are altered with the casting speed because of the different solidification rates. The mean secondary dendrite arm spacing (SDAS) for the HMC-Al-Mg alloy made at the high casting speed of 2.7 mm/s is about one-fifth of that for the conventional gravity cast Al-Mg alloy. Nonlinear relationship between the tensile properties (strength and ductility) and the cooling rate are obtained with σ UTS and σ 0.2 increasing and e f decreasing with increasing the cooling rate. The high strength of the HMC samples at the high cooling rate results from the existence of tiny microstructures. The high ductility of the HMC sample at the low cooling rate is affected by the uniform crystal orientation, where shear slips are facilitated by the uniform crystal orientation.

Mechanical Properties of Magnesium Alloys Produced by the Heated Mold Continuous Casting Process

Abstract Investigation of the tensile and fatigue properties of cast magnesium alloys, created by the heated mold continuous casting process (HMC), was conducted. The mechanical properties of the Mg-HMC alloys were overall higher than those for the Mg alloys, made by the conventional gravity casting process (GC), and especially excellent mechanical properties were obtained for the Mg97Y2Zn1-HMC alloy. This was because of the fine-grained structure composed of the α-Mg phases with the interdendritic LPSO phase. Such mechanical properties were similar levels to those for conventional cast aluminum alloy (Al84.7Si10.5Cu2.5Fe1.3Zn1 alloys: ADC12), made by the GC process. Moreover, the tensile properties (σUTS and εf) and fatigue properties of the Mg97Y2Zn1-HMC alloy were about 1.5 times higher than that for the commercial Mg90Al9Zn1-GC alloy (AZ91). The high correlation rate between tensile properties and fatigue strength (endurance limit: σl) was obtained. With newly proposed etching technique, the residual stress in the Mg97Y2Zn1 alloy could be revealed, and it appeared that the high internal stress was severely accumulated in and around the long-period stacking-order phases (LPSO). This was made during the solidification process due to the different shrinkage rate between α-Mg and LPSO. In this etching technique, micro-cracks were observed on the sample surface, and amount of micro-cracks (density) could be a parameter to determine the severity of the internal stress, i.e., a large amount to micro-cracks is caused by the high internal stress.

Effects of Sb, Sr, and Bi on the material properties of cast Al-Si-Cu alloys produced through heated mold continuous casting

Rare earth metals can create a fine eutectic Si structure in cast Al-Si10.6-Cu2.5 (ADC12) alloys produced through heated mold continuous casting. Fine and spherical eutectic Si phases are created in the ADC12 alloys through the addition of Sr0.04, and fine lamellar eutectic Si phases are created through Sb and Bi addition. Crystal orientation on the face perpendicular to the casting direction is formed by [110]; however, this uniform formation is collapsed in the ADC12 alloy with an increasing amount of Sr addition, such as Sr > 0.04%. The shape of the eutectic Si is statically analyzed, and the effects of the eutectic Si characteristics on the mechanical properties are examined experimentally. On the one hand, the mechanical properties of the ADC12-Sr alloy increase with increasing Sr content because of the fine eutectic Si, the randomly orientated crystal formation, and so on. On the other hand, the material ductility increases in the ADC12 alloy with increasing addition of Sb and Bi elements. A high fracture strain of approximately 14% is obtained for the ADC12-Bi1.5 alloy.

OCCプロセスにより作製した99.9%アルミニウム鋳造線の組織と結晶方位に及ぼす鋳造速度の影響

Unidirectional-solidified 99.9% aluminum wires 6 mm in diameter have been produced by a heated-mold continuous casting process (OCC Process) at casting speeds of 0.33–5.0 mm/s. Effect of casting speeds on structures and crystal orientation of the cast wires has been studied by an EBSD technique. It was found that the crystal orientation of all cast wires parallel to the casting direction tended to be [001], the preferred growth orientation of aluminum. At lower casting speed (0.33 mm/s), unidirectional solidified structure wire exhibited single-like crystal morphology with low-angle tilting sub-grain boundaries. In this case, local disorientation angles of the sub-grain boundaries were chiefly distributed near 1 degrees. As the casting speed increased, some of the local disorientation angles of the grain boundaries exceeded 15 degrees. At casting speeds between 0.83–5.0 mm/s, the wires exhibited unidirectional solidified structures containing low-angle and high-angle tilting grain boundaries.

Material Properties of Various Cast Aluminum Alloys Made Using a Heated Mold Continuous Casting Technique with and without Ultrasonic Vibration

This work was carried out to develop high-quality cast aluminum alloys using a new casting technology. For this purpose, commercial Al alloys were created by heated mold continuous casting (HMC) with ultrasonic vibration (UV). With the HMC process, the grain size and the crystal orientation of the Al alloys were controlled, i.e., fine grains with a uniformly organized lattice formation. In addition, an attempt was made to modify the microstructural formation by cavitation. These microstructural characteristics made excellent mechanical properties. Using UV in the continuous casting process, more fine and spherical grains were slightly disordered, which was detected using electron backscattered diffraction. The mechanical properties of the UV HMC Al alloys were slightly higher than those for the related cast Al alloys without UV. Moreover, the severe vibration caused higher mechanical properties. The lattice and dislocation characteristics of the cast samples made with and without UV processes were analyzed systematically using electron backscattered diffraction.

Precise analysis of effects of aging on mechanical properties of cast ADC12 aluminum alloy

To better understand the effects of aging on mechanical properties of cast Al–Si–Cu-based aluminum alloy (ADC12), artificial aging was carried out under a range of conditions after water quenching. Two casting methods were employed: gravity casting (GC) and heated-mold continuous casting (HMC). The Vickers hardness of GC samples was higher overall than that of HMC samples both before and after aging. This was due to the high solubility of the alloy elements in the α-Al matrix and to the presence of complicated dislocation walls in the GC samples. The hardness of GC and HMC samples aged at 433, 448 and 463K increased similarly with increasing aging time, and an aging peak occurred in the age-hardening curve between 10 and 15h. In contrast to the hardness results, the ultimate tensile strength (UTS) for the as-cast GC sample was about 30% lower than that for the as-cast HMC sample, because of large brittle eutectic Si and Fe structures. The highest UTS was obtained for the HMC sample aged at 448K for 13h, and was about 20% and 10% higher, respectively, than those of the as-cast HMC sample and the GC sample aged at 448K for 13h. The high UTS for the HMC sample was due to precipitation of θ′ (Al2Cu) metastable phases as well as the formation of tiny microstructures. With over-aging at 463 and 493K for 100h, the tensile strength decreased for both GC and HMC samples, although the fracture strain increased only for HMC samples (by more than 30%). Such high ductility in ADC12 alloy has not been seen in previous studies. In contrast, no clear improvement in material ductility was detected in GC samples. The tensile strength was directly related to fatigue properties, although no significant effect of ductility on fatigue strength was found.

Mechanical Strength and Failure Characteristics of Cast Mg-9 pctAl-1 pctZn Alloys Produced by a Heated-Mold Continuous Casting Process: Tensile Properties

The mechanical properties and failure characteristics of a cast Mg alloy (AZ91: Mg-Al8.9-Zn0.6-Mn0.2) produced by a heated-mold continuous casting process (HMC) are investigated. In a modification of the original HMC process, the cooling of the liquid alloy by direct water spray is carried out in an atmosphere of high-purity argon gas. The HMC-AZ91 alloy exhibits excellent mechanical properties (high strength and high ductility) that are about twice as high as those for the same alloy produced by conventional gravity casting. The increased material strength and ductility of the HMC sample are attributed to nanoscale and microscale microstructural characteristics. The fine grains and tiny spherical eutectic structures (e.g., Mg17Al12 and Al6Mn) distributed randomly in the matrix of the HMC alloy result in resistance to dislocation movement, leading to high tensile strength. Basal slip on (0001) planes in the relatively organized crystal orientation of the HMC alloy, as well as grain boundary sliding through tiny spherical eutectic structures, results in high ductility. Details of the failure mechanism under static loading in the HMC alloy are also discussed using failure models.

Mechanical strength and failure characteristics of cast Mg–9%Al–1%Zn alloys produced by a heated-mold continuous casting process: Fatigue properties

The fatigue properties and failure characteristics of a cast Mg alloy (AZ91: Mg–Al8.9–Zn0.6–Mn0.2) produced by heated-mold continuous casting (HMC) and conventional gravity casting (GC) are investigated. Excellent fatigue properties are obtained for the HMC alloy compared with the GC alloy. The high fatigue strength of the HMC alloy is a reflection of its improved microstructural characteristics, namely, tiny α-Mg grains and fine spherical eutectic structures (β-Mg17Al12). Fatigue cracks propagate mainly in the α-Mg grains and along high-hardness β-phases in both alloys. The direction of fatigue crack growth is altered as the crack reaches the eutectic phases. Because the tiny eutectic phases are distributed randomly in the HMC alloy, a meandering crack path is formed, which results in high crack growth resistance, leading to the high fatigue strength. For the HMC alloy, a striation-like failure mode can be seen in the crack growth stage, and dimple fracture is the dominant feature in the final failure stage. On the other hand, cleavage-like brittle failure with many microcracks can occur in the GC alloy. Severe lattice strain occurs during the final failure stage, especially for the HMC alloy, resulting in strong work hardening, although this is weak in the crack growth site. Severe strain is distributed uniformly around the entire cracks in the HMC alloy when the sample is fractured by monotonic loading. The lattice strains in the HMC alloy under monotonic and cyclic loading are overall higher than those in the GC alloy, owing to the high material ductility of the HMC alloy.

OS0705 複合的な組織構造を有するアルミニウム合金鋳物の機械的性質に関する研究

The effects of microstructural characteristics (secondary dendrite arm spacing, SDAS) and Si- and Fe-based eutectic structures on the mechanical properties and failure behavior of an Al-Si-Cu alloy are investigated. Cast Al alloy samples are produced by heated mold continuous casting (HMC) process. Dendrite cells appear to grow in the casting direction. SDAS decreased with increasing casting speed .There are linear correlations between casting speeds and tensile properties (ultimate tensile strength crurs and fracture strain ef). These linear correlations, however, break down, especially for ours versus casting speeds and ef versus casting speeds. These results cause a-Al phase and eutectic phase (Si- and Fe-based). These microstructural effects on tensile properties are explained using a proposed model.

Influence of microstructural characteristics on mechanical properties of ADC12 aluminum alloy

The effects of microstructural characteristics on the mechanical properties of an aluminum alloy (ADC12: Al–Si11.3–Cu1.9–Zn0.8–Fe0.8–Mg0.2–Mn0.2) produced by various casting technologies are studied experimentally and numerically. Six different casting processes are employed: gravity casting, cold-chamber die-casting, hot-chamber die-casting, squeeze casting, twin-rolled continuous casting and heated-mold continuous casting. Microstructural characteristics, dislocation density and defect density vary depending on the casting method, owing to differences in solidification rate, casting pressure and injection speed. The material characteristics of the samples affect their mechanical properties. Multiple regression analysis is carried out to find equations to predict tensile strength using five independent factors: secondary dendrite arm spacing, microporosity rate, diameter of eutectic structures, aspect ratio of eutectic structures and dislocation density. All these factors influence the tensile properties, although to different degrees. The estimated values of tensile strength are in good agreement with experimental results.

A New Method of Directional Solidification of Cu-Cr Alloy

In order to meet the need of high-strength and high-electrical conductivity copper alloys in industry. A method of making high-strength and high-electrical conductivity copper alloys is discussed in this paper. This method uses the technology of heated mold continuous casting to make Cu-Cr alloy. Because it utilizes the high electrical conductivity of copper matrix and high strength of the chromium phase, the in-situ composite Cu-Cr alloy with directional solidification structure is got. The in-situ composite Cu-Cr alloy has good properties and will be widely used in industry.

Mechanical and Memory Properties of CuAlNi by Directional Solidification

Abstract Cu-Al-Ni shape memory alloy was fabricated under directional solidification in heated mold continuous casting equipment. The results show that it has distinct textures. Due to these strengthened textures, it has excellent mechanism, fatigue and memory performances. The Ø 1.5 mm wire has a tensile strength of 910 MPa, elongation of 18.76%. Under 4% strain, the repeat tensile fatigue was up to 38560 circles and the recovery rate is 100%.

Process parameters of manufacturing single crystal copper by heated mold continuous casting

The effect of process parameters on the surface quality of single crystal copper ingot was studied through experiment with a self-designed horizontal heated mould continuous casting apparatus, and the mechanism was analyzed. The results show that the process parameters affect the surface quality of pure copper ingot by affecting the position of the liquid-solid interface in the mould. The position of the liquid-solid interface in the mould must be controlled carefully in an appropriate range determined through experiments in order to gain a single crystal copper ingot with a high surface quality.

加熱鋳型式連続鋳造法で作製したＡｌ‐Ａｌ３Ｎｉ一方向凝固材の冷間圧延と機械的性質

Cold rolling and mechanical properties of unidirectionally solidified Al–Al3Ni strip produced by an open type, horizontal, heated mold continuous casting process were investigated. As-cast and heat-treated strips were used as starting materials for cold rolling. Cold rolling was done in two ways in which the rolling direction is parallel and perpendicular to the casting direction, i.e., the longitudinal direction of Al3Ni fiber. Edge cracking during cold rolling was reduced by the heat treatment, and also by cold rolling perpendicular to the fibers. Corresponding to edge cracking, lateral spread of the strip was greater in the case of cold rolling parallel to the fibers than in that perpendicular to the fibers. Heat treatments before cold rolling reduced the tensile strength of rolled sheets, while cold rolling enhanced the strength of cast strips. Although tensile strength of the as-cast strip largely depended on the direction of the fiber alignment, cold rolled strips showed less anisotropic tensile properties.

加熱鋳型式連続鋳造法により製造されたステライト材の性質と応用

Stellite alloy rods produced by the heated mold continuous casting (Ohno Continuous Casting) method exhibit a unidirectional structure. The mechanical and physical properties of these products have been examined. It was found that the OCC stellite materials have superior wear, corrosion and shock resistance properties compared with those of weld-deposited stellite materials. Thus, it was proposed in this work that OCC rods with different cross-sectional shapes can be simply welded onto the objects which require wear resistance by using the existing joining techniques.

上面開放水平加熱鋳型式連続鋳造法によるアルミニウムストリップの冷間圧延性に及ぼす凝固組織の影響

上面開放水平加熱鋳型式連続鋳造法によるアルミニウムストリップの冷間圧延性に及ぼす凝固組織の影響

Strengthening and bending deformability of Al-4.5 mass% Mg alloy billets produced by the heated-mold continuous casting method (OCC): Ohno, A., Motoyasu, G. and Kawai, H. J. Japan Inst. Light Met. Nov. 1990 40, (11), 817–821 (in Japanese)

Strengthening and bending deformability of Al-4.5 mass% Mg alloy billets produced by the heated-mold continuous casting method (OCC): Ohno, A., Motoyasu, G. and Kawai, H. J. Japan Inst. Light Met. Nov. 1990 40, (11), 817–821 (in Japanese)

加熱鋳型式連続鋳造法によって得られたＡｌ‐１ ｍａｓｓ％Ｃｕ合金鋳塊のねじり加工による変形能と強度特性

加熱鋳型式連続鋳造法によって得られたＡｌ‐１ ｍａｓｓ％Ｃｕ合金鋳塊のねじり加工による変形能と強度特性

加熱鋳型式連続鋳造法によって得られたＡｌ‐４．５ｍａｓｓ％Ｍｇ合金鋳塊の曲げ加工による変形能と強度特性

Al-4.5 mass% Mg alloy billets were cast by the heated mold continuous casting (Ohno Continuous Casting) method developed by the authors. The billets were cold worked by 90° bending and cyclic bending. The relationships between the bending workability, crack initiation, mechanical properties and structures of the billets were examined and compared with those of billets produced by the conventional method. The specimens bent from conventional billets tend to exhibit crack initiation at the grain boundary and fracture easily, but the specimens from the OCC billets were free from such defects. The bending fatigue life of the OCC billets was five times that of the conventional billets, and the OCC billets moved through the cyclic bender easily but the conventional billets did not. Mechanical properties of the OCC billets such as hardness, tensile strength, elongation and fatigue strength were superior to those of the conventional billets. Mechanical properties of the OCC billets were improved by cyclic bending.

加熱鋳型式連続鋳造法によって得られたSn-Pb合金半田の組織と加工性

Sn-5 to 50 mass%Pb alloy billets were cast by the heated mold continuous casting (Ohno Continuous Casting) method developed by the authors. The surface quality, macrostructure, microstructure, tensile strength and cold rolling properties of the OCC billets were examined and compared with those of conventionally cast billets.The OCC billets had a smooth and mirror-like surface having high level surface brightness. It is constituted macroscopically of a unidirectionally solidified structure without equiaxed crystals and microscopically of aligned primary and eutectic phases. Wrought products rolled from conventional billets tend to exhibit edge cracking and surface irregularities as rolling progresses, however the products from the OCC billets were free from such defects. In addition, the OCC Sn-Pb alloy billets enable the high-quality productions of fine wires and thin sheets solders for ICs and LSIs.