Abstract: Scaling of minor hysteresis loops in the amorphous alloy Co66Fe3Cr3Si15B13 with a very high initial permeability (more than 150000) and low coercivity (about 0.1 А/m) has been studied. In weak magnetic fields and in the region of maximal growth of permeability a similarity of minor loops was detected. Analytical expressions for hysteresis losses are derived which provide a good accordance of calculations with the results of measurements.
Abstract: The effect of the base strip temperature on the bonding between base strip and overlay strips in a three-layer clad strip cast by a vertical-type tandem twin roll caster was investigated. The base strip was 3003 aluminum alloy and the overlay strip was 4045 aluminum alloy. The bonding was investigated for base strip temperatures ranging from 200 °C to 550 °C. The bonding condition was investigated by cold-rolling, bending-to-failure test and tensile shear test. The shear stress increased with the base strip temperature. Sound bonding was achieved at base strip temperatures higher than 450 °C. The results of this study indicated that the second caster is not required to be set below the first roll caster.
Abstract: In manufacturing process of rocket components, quenching and tempering process can be used to achieve suitable hardness, ultimate tensile strength and yield strength of raw material. The trial and error of quenching and tempering process to succeed suitable properties of raw material will waste of budget and time. In this study, numerical analysis of quenching and tempering process on AISI 4130 steel was investigated comparative to actual heat treatment process to evaluate the agreement between them. The numerical analysis technique was used to seek suitable tempering temperature with specify quenching temperature at 870°C and soaking time for an hour. The result showed that suitable tempering temperature was 450°C to achieve as-required mechanical properties. The actual quenching and tempering process was performed by furnace heating to 860°C and soaking for 60 minutes, followed by 450°C tempering for 2 hours. The results will be comparatively concluded that they slightly differed from numerical analysis around 5%-12% and showed a good agreement between numerical analysis and experimental result.
Abstract: The objective of this study was to investigate the influence of specimen radius on the hardness of AISI 4130 steel in water-quenching process. The paper demonstrates how these parameters can affect the hardness from the surface to center of round samples. The experiment was performed and constructed relationship between hardness and geometry parameters to estimate hardness distribution for shaft diameter 55 mm and 80 mm. The relationship between hardness and radius was also constructed to predict hardness at center and corner for shaft radius 7.5-40 mm.
Abstract: Heat treatment is very important factor for improving material strength. In our previous work, we combined a furnace heating and induction heating to develop a new method (furnace-induction heating, FIH). We observed the microstructure in JIS SUJ2 bearing steel and found that FIH process refined the prior austenite grains. In this work, we further investigated the relation between hardness distribution and retained austenite in furnace-induction heated JIS SUJ2 steel.
Abstract: A single wheel caster equipped with rotating side dam plates was proposed and assessed in conjunction with a pool-less pouring method as a compact and economical system for producing metal rods. The diameter and width of the single wheel were 600 and 10 mm, respectively, while those of the rotating side dam plates were 200 and 15 mm. Both were made from mild steel and rotated at the same speed. This system was tested using 5182 aluminum alloy at a casting speed of 5 m/min, and it was determined that rods with convex cross-sections could be formed with cross-sectional areas ranging from 75 to 135 mm2.
Abstract: This paper is concerned with the effects of process parameters on the shape changes of a micro cementite band in wire drawing of pearlitic steel. Two process parameters, an initial orientation of cementite band and its location, are chosen. In this study, a macro deformation behavior at a material point in macro wire drawing of pearlitic steel is represented by an averaged behavior of a unit model. This unit model is simulated by a micro finite element analysis, while a macro wire drawing of pearlitic steel is simulated by finite element method at a continuum scale. The shape changes of a cementite band would be traced, by solving the unit problem with the changes of boundary conditions corresponding to the macro deformation behaviors of material points along a particle path. The predicted shapes of cementite bands are compared to those by the experiments reported in the literature. Qualitative comparisons between the current predictions and experiments verify the proposed method. Effects of an initial orientation of cementite band and its location on its shpae changes are presented. It was also noted that the most micro deformation in a unit model occurs in the deformation zone.
Abstract: As a result of more requirements for improving natural environment and economic environment, the manufacturing of light weight components is becoming increasingly vital in industrial development. Variable thickness rolling (VTR)-a new process for rolled profile strips (RPS) is proposed in this paper. This so-called “variable thickness rolling” is based on the utilization of a special roll system that causes the material to flow in latitudinal direction. The rolled profile strips with defined cross-sections are obtained by this process. The elastic-plastic finite element model is established to analyze the forming principle. The simulation results agree with experimental data on the whole.
Abstract: Casting of a convex rod from 5182 aluminum alloy was attempted using a single wheel caster with a V-shape groove. The diameter of the mild steel wheel was 600 mm, the angle of the vortex was 90 degrees, and the width of the groove was 20 mm. Important factors to cast a rod with a convex shape are the speed of the molten metal ejected from a hole-nozzle and the collapse angle between the molten metal stream and the wheel. Important factors that affected the cross sectional shape of cast-bar were the speed of molten metal ejected from the hole-nozzle and the collapse angle of the molten metal against the wheel. A collapse angle close to 90° was better than an angle less than 90°. Casting speeds of 5 m/min and 15 m/min were employed, which resulted in convex cross sectional rod areas of 30 mm2 to 190 mm2.