Study on Microstructure, Mechanical Properties and Erosion Characteristics of Al-Si Alloy Manufactured by Continuous Casting Direct Rolling Process

Al-Si alloys exhibit promising wear resistance, thus being mainly employed to weld Al alloy parts and processed into components of equipment. During the new continuous casting direct rolling (CCDR) process, the raw material gradually cools and solidifies, simultaneously plastically deformed. Hence, the materials manufactured through the CCDR process presented an unparalleled microstructure. The experimental results indicated that the strength of the CCDR Al-Si alloy can be increased through cold rolling. A two-stage heat treatment (solid solution and aging treatment) was introduced to improve the ductility and satisfy the industrial application. Furthermore, the erosion wear characteristics and fracture mechanism of the CCDR Al-Si alloy dominated by the ductility were confirmed. Both cold rolling specimens (FR) and those with heat treatment (FRH) showed greater wear resistance than as-manufactured (F). The FR specimens exhibited greater wear resistance owing to a higher Al matrix strength at a lower impact angle; on the other hand, at a higher impact angle, the FRH specimens with a softer Al matrix presented better wear resistance due to the formation of a lip structure to reduce material removal. The TEM results confirmed that the nanoscale grains formation was induced in the erosion-affected region and affected the Si concentration. Conclusively, the heat-treated CCDR Al-Si alloy possessed excellent erosion resistance and workability, which can serve as a reference processed as wear-resistant mechanical parts.

Specific Features of The Structure Formation of Aluminum Alloys During Rapid Crystallization-Deformation

The results of studies of the structure and properties of semi-finished products from aluminum and its alloys, obtained with the use of cast-free rolling-extruding are presented. It has been found that the rods obtained by the high-speed crystallization-deformation technology by the direct rolling-extrusion method have a stable ultrafine subgrain structure, which makes it possible to use them as modifiers. Experimental studies have been carried out, which confirmed the assumption that the initial structure of the modifying rod affects the melt. It was revealed that the size and density of distribution of additional crystallization centers formed in the volume of the melt based on clusters are inherited from the original subgrain structure of the modifying rod made of aluminum or its alloys. Metallographic studies have also shown that the subsequent severe plastic deformation by equal-channel angular extruding of rods obtained by direct rolling-extruding from an experimental alloy of the composition Al-0.2Zr-0.2Fe-0.4Mg makes it possible to achieve additional strengthening of the metal, since even more refines its structure, while the average grain size is 647 μm.

Injection-rolling nozzle in an imprint system with continuous injection direct rolling for ultra-thin microstructure guide light plate

A novel Injection-rolling Nozzle (IRN) in an imprint system with continuous injection direct rolling (CIDR) for ultra-thin microstructure polymer guide light plates was developed to achieve uniform flow velocity and temperature at the width direction of the cavity exit. A novel IRN cavity was designed. There are eight of feature parameters of cavity were optimized by orthogonal experiments and numerical simulation. Results show that the flow velocity at the width direction of the IRN outlet can reach uniformity, which is far better than that of traditional cavity. The smallest flow velocity difference and temperature difference was 0.6 mm/s and 0.24 K, respectively. The superior performance of the IRN was verified through a CIDR experiment. Several 0.35-mm thick, 340-mm wide, and 10-m long microstructural Polymethyl Methacrylate (PMMA) guide light plates were manufactured. The average filling rates of the microgrooves with the aspect ratio 1:3 reached above 93%. The average light transmittance is 88%.

Application of Queuing Theory in Production Efficiency of Direct Rolling Process of Long Product

Based on the mathematical method of queuing theory, the queuing model of billets in the direct rolling process of the long product was established, which represented the conveying process of billets at the casting and rolling interface. Using the billets queuing model, the influence of different steel quantity, length, speed and other factors on the average waiting time of a single billet in the direct rolling production process was analyzed. Combined with the temperature drop of billets, the optimal average waiting time for a single billet was determined. The method improved the conveying connection efficiency of the casting-rolling interface and the direct rolling rate of billets.

Development, modeling and research of technology for producing longish deformed semi-finished products from aluminum-magnesium alloys with low scandium contents

The paper provides the results of studying the technology for producing longish deformed semi-finished products by sheet rolling and direct rolling-extruding of aluminum-magnesium alloys with different scandium contents. Computer and physical modeling methods were used for the research and the results were verified by pilot tests. These alloys were selected for the research due to the fact that Al–Mg aluminum alloys doped with scandium have increased corrosion resistance along with their high strength. In this regard, this research was aimed to obtain longish deformed semi-finished products in the form of sheet metal, rods and welding wire from economically alloyed Al–Mg alloys. Computer simulation was performed using the DEFORM-3D software package to determine rational conditions of hot rolling of large-sized ingots and deformation modes of the combined processing using the method of direct rolling-extruding of rods made of the investigated alloys. At the same time, the technological and force parameters of these processes were justified with the laws of their change presented. Experimental results obtained made it possible to determine the limit values of force parameters and to study the structure and properties of deformed, annealed and welded semi-finished products made of the investigated alloys during the physical modeling of processes studied. In addition, metal properties were determined in a fairly wide range of changes in temperature, speed, and deformation parameters. Based on the results of experimental studies and modeling, recommendations were given for the industrial development of the technology for hot rolling of thick ingots from the investigated alloys. At the same time, technological solutions, regulations and conditions for deformed semi-finished products made of the investigated alloys were developed and batches of sheet metal with the required level of mechanical and corrosion properties were obtained.