Papers by Keyword: Process Parameter

Abstract: Central damage is the serious defect of horizontal wedge rolling products. The method of combining testing and numerical simulation is used to study the mechanism of central Damage. It represents the evolution process of the start, growth and agglomeration of the GH4169 alloy blades in the horizontal wedge rolling process, and combines the microre porosity shape with the stress-strain state to reveal the mechanism of central Damage. On the basis of analyzing the stress and strain characteristics of the forging center, the effect of mold process parameters on the center damage was studied. Studies have found that the micropores of the center of the forged blank are formed around non-metal miscellaneous objects. Through growth and agglomeration, it becomes a macro-damage in the direction of shear stress and stress, Causes center damage.

Abstract: The orthogonal experiment method is used in optimal design of laser cladding, such as laser power (P), scanning speed (SS), powder feeding rate (PFR) and shielding gas velocity (SGV) etc. Both the dilution rate and the aspect ratio are investigated by comprehensive scoring method, which transforms multi-index into single index. In view of the nonlinear characteristics of laser cladding process parameters, the optimum level of each factor based on interaction effect is obtained by analyzing binary tables. Finally, the relationship between the laser cladding process parameters and the two indexes (the dilution rate and the ratio of width to height of coating) is obtained. This method has potential applications for the further investigating on the laser cladding process rules.

Abstract: In recent years, there is a lot of demand on metal forming processes in which sheet metal forming process has lots of applications in the automotive and aerospace industries. In sheet metal forming operations, incremental forming is an emerging technology in which, single point incremental forming (SPIF) process is die-less in incremental forming process and providing a competitive alternative to economical and effective in fabricating low volume products. The objective of this work is to analyze the forming analysis on truncated pyramid product by avoiding cracking and maintaining the optimum forming conditions. The formability is analyzed by using ABAQUS software and simulation, different process parameters were varied such as sheet thickness, tool diameter, step depth, spindle rotational speed on aluminum AA1050 alloy. From the simulation results, stress stain and stain distribution were evaluated on the deformed sheet. The product produced is truncated pyramid dimension having square base of side and fillet at corner.

Abstract: V-Cr-Ti alloys are promising structural materials for future nuclear systems. In this study, a laser melting deposition process has been applied to the fabrications of V-5Cr-5Ti alloys. Laser powers of 1200W, 1400W and 1600W, scanning speeds of 400 mm/min and 600 mm/min, and scanning strategies of single directional scanning and dual directional scanning have been applied to investigate the effects on the morphologies and microstructures of formed individual deposits and thin walls. The dual directional scanning is favored for fabricating thin walls with regular shape, comparing to the single directional scanning. Microstructures of the deposits and walls consist of columnar grains and equiaxed grains. Due to the effects on temperature gradients, both the laser powers and deposition duration show significant effects on the microstructural evolutions of the thin wall samples. As the laser power and deposition duration increase, columnar to equiaxed transitions have been observed. The regions containing columnar grains and equiaxed grains have a <100> fiber texture and a random texture, respectively.

Abstract: High strength AW-7xxx sheet alloys are promising candidates to manufacture crash relevant parts, but their limited formability at room temperature presents a major challenge. Formability is controlled through heating rate, heat treatment temperature and time, quenching rate, forming temperature and strain rate. In the literature retrogression forming, W-temper forming, warm forming and hot stamping processes have been proposed to improve the formability of AW-7xxx alloys. Of these the greatest improvement in formability comes from W-temper forming and hot stamping. Considering the similarity to the conventional forming processes of cold stamping for aluminium and hot stamping for steel, the W-temper forming and hot stamping of aluminium are promising for AW-7xxx alloys.

Abstract: High Pressure Die Casting (HPDC) is a foundry process particularly suitable for high production rates and applied in several industrial fields, but the amount of scrap, caused by defects or incomplete filling, is sometimes very high. Thus it is important to know which are the main causes of defect formation and their effects on microstructure and mechanical properties. This paper presents, within the European MUSIC project, the qualitative and quantitative results of a study conducted on AlSi9Cu3(Fe) alloy castings, referred to as Horse-shoe Reference Castings, specifically designed to generate different kinds of defects with different severity levels. The work focuses on the correlations obtained between the casting mechanical properties, their defect content in terms of porosity and oxide films and the process parameters adopted, mainly second phase plunger velocity and intensification pressure. The three point bending test was carried out on the four specimens obtained from the two appendixes of the casting. The fracture surfaces were studied by scanning electron microscopy (SEM) and optical microscopy (OM) highlighting that the defect content is clearly correlated to the mechanical properties and the process parameter settings.

Abstract: Effects of polyvinylchloride (PVC) sheet thickness (t), feed speed (υ), spindle speed (ω), Z-axis feed rate (p) and tool head diameter (Φ) as well as their interactions during the single point incremental forming (SPIF) on forming performance of the PVC sheet material were studied through an orthogonal experimental test. In this experiment, the angle-variable cone was used and the maximum forming limiting angle was taken as the experimental index. Results showed that and ω×Φ influence forming performance of PVC sheet material significantly. υ is the main influencing factor of SPIF performance of PVC sheet material. Small υ is good for sheet material forming. p and Φ are proportional to forming performance of sheet material. Over ω will cause material wear-out. Effect of t could be neglected.

Abstract: Experiment was performed to examine the plane polishing of SiC single crystal wafer by using the chemical magnetorheological finishing (CMRF) technique. The influence of some process parameters such as the concentration of diamond abrasive particles, the concentration of carbonyl iron powder and the machining gap in CMRF were studied comparing with the magnetorheological finishing (MRF) method. The results show that the surface roughness of polished SiC single crystal by the CMRF is slightly lower than that by the MRF. Polishing liquid with different components and processing parameters affects the coupling effect of mechanical removal and chemical removal in CMRF, and a better coupling effect can produce a better surface quality in CMRP. In the MRF, the surface roughness of SiC single crystal is lower for a higher concentration of carbonyl iron powder (CIP). However, in the CMRF, the CIP’s concentration may change the contact state between the catalyst and SiC, and the CIP’s concentration of about 20% can produce a better surface roughness of SiC. The machining gap between the polishing disk and the workpiece surface determines the processing effect, and the machining gap of 1.0 mm is suitable for the polishing of SiC in the MRF and CMRF.

Abstract: Front cover is an important part of the car timing system, it is also an important parts of the engine to ensure the smooth flow.The quality of end cap is directly related to the normal and efficient operation of the engine.In this paper, through the research of the fine blanking process of the front cover of the timing system, a new type of fine blanking die is designed to improve the service life of the die and its parts.The influence rules of the process parameters such as the back top force, the counter pressure and the corner radius on punching smooth zone and the life of the mold, are analyzed by using the finite element software and a series of optimized process parameters are obtained after this.

Abstract: During the resistance spot welding quality control process, the traditional quality control methods can’t compensate all the affecting factors effectively. By welding 316LVM stainless steel wire to the surface of sheet of the same material, three kinds of process parameters, including electrode voltage, dynamic resistance and electrode displacement which affected by many affecting factors during the spot welding process were measured and analyzed. The results show that, by comparing with the process parameters during the normal situation, the dynamic change of the these process parameters during different stage appears distinguishable characteristics, these characteristics would supply a research basis for recognizing whether the affecting factors exist.