Advanced Materials Research Vols. 148-149

Abstract: Semi-ball bottom cylindrical deep drawing is different from the traditional deep drawing, since it is not only characteristics of traditional drawing, but also of bulging. According to the semi-ball bottom cylindrical deep drawing features, the stress conditions of the sheet in different regions have been analyzed by a mathematical modelling. In addition, the effects of processing parameters on the forming limit of the sheet in semi-ball bottom cylindrical deep drawing have been investigated by experimental method and simulation based on dynaform, respectively. It is found that the experimental results are consistent to that in simulation and the results show that the formability of the sheet is influenced greatly by the blank holder force, friction coefficient and thickness. With the blank holder force and friction coefficient decreasing and the thickness increasing, the bulging area can be expanded, which is beneficial to the improvement of the forming limit height of the semi-ball bottom cylindrical deep drawing parts.

Abstract: The main factors that affect properties of solid lubricant coating on high-speed steel surface are the surface roughness and the weight of phosphate coating. The effect of magnetic field on high speed steel phosphate process is significant. It promotes the film and the different appearance and composition of the film. Because the ferric phosphate and dihydric phosphate in phosphate solution may be ordered arrangement by additional magnetic field, they can be deposited on metal surfaces quickly. That is to say that a certain intensity of the magnetic field can reduce the entropy of the phosphate processing system and speed up the formation of phosphate film. During phosphate treatment, the friction performance of high-speed steel coated with solid lubricant coating was significantly improved.

Abstract: Thin walled copper tube is prepared in vacuum melting and argon protecting continuous unidirectional solidification equipment by a short process method. The size of the thin walled copper tube is ф39×1.8 mm. The effect of process parameters on the solidification structure and the surface quality of the thin walled copper tube is investigated. The mechanical properties and electrical properties are tested and analyzed. The results show that the thin walled tube with columnar crystal structure and good quality surface can be obtained continuously and stably under the most appropriate process of the melting temperature is between 1423K and 1453K, the cooling water volume is 0.2～0.5m3•h-1, the cooling distance is 50mm, the drawing speed is not higher 20m•h-1. The elongation can reach 60%, and conductivity can reach 102.6%IACS.

Abstract: Ni ferrites doped with lanthanum with a nominal composition of NiFe2-xLaxO4(x=0.05) were obtained by mechanochemical treatments using NiCO3•2Ni (OH)2•4H2O , La2O3 and Fe2O3 as raw materials. Both series of materials were characterised by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometry (VSM). The results indicated that the mixture became amorphous stage after ball-milled for 30 h, and single phase NiFe1.95La0.05O4 could be obtained after calcined at 700 for 2 h. The addition of lanthanum resulted in a reduction of all the magnetic parameters evaluated.

Abstract: Titanium surface alloyed layer was fabricated on 316L stainless steel substrate at 1000°C by means of the plasma surface alloying technique. The content of element titanium in the surface alloyed layer shows gradually tapering from surface to the inside of the substrate and it means an excellent metallurgical binding between the surface modified layer and 316L stainless steel substrate. The hardness of the titanium surface alloyed Layer is 1305HK0.5, which is much larger than that of the 316L stainless steel substrate. The wear performance of the treated and untreated 316L stainless steel was studied using a ball-on-disc sliding wear machine. Although the titanium surface alloyed layer does not show a friction-reducing effect, it improves the wear resistance of 316L stainless steel significantly and its wear rate is only one-fifteenth of that for untreated 316L stainless steel.

Abstract: This paper investigates the penetration performance of shaped charge against multi-layer target. A titanium alloy liner of shaped charge is proposed in order to obtain large perforated hole. Jet formation and penetrating into multi-layer target was calculated by hydro code AUTODYN. For different liner material include titanium alloy, mild steel and Cu, the explosion energy conversion, jet tip velocity and jet length, also the penetration performance are studied. It is found that the kinetic energy of jet is larger and the shape of jet is podgier when the liner material is titanium alloy, the perforated hole diameter on multi-layer improved 20% compare with the mild steel and Cu liner, the numerical simulation is good agreement to experimental results.

Abstract: Polydichlorophosphazene was synthesized from hexachlorocyclotriphosphazene by high-temperature ring-opening polymerization, and poly(2-(2-methoxyethoxy) ethanol phosphazene)(MEEP) was synthesized by reacting polydichlorophosphazene with alcohol sodium. The optimal synthesis parameters were obtained and the structure of MEEP was analyzed by NMR. Then polyphosphazene electrolyte was prepared by mixing MEEP with LiCF3SO3. The results indicated that the electrolyte prepared in this paper has high decomposition temperature, and its room-temperature conductivity is up to 1.187×10-4 S/cm.

Abstract: Adhesive bonding is a high-speed fastening method which is suitable for joining advanced lightweight sheet materials that are hard to weld. Latest literature relating to finite element analysis (FEA) of fatigue behaviour of adhesively bonded joints is reviewed in this paper. The recent development in FEA of fatigue behaviour of adhesively bonded joints is described with particular reference to three major factors that influence the fatigue behaviour of adhesively bonded joints: failure mechanism, environmental effects and hybrid joining techniques. The main FE methods used in FEA of fatigue behaviour of adhesively bonded joints are discussed and illustrated with brief case studies from the literature.

Abstract: The rigid seals currently being used for the ash unloading device with the impeller under the hopper of the electrostatic precipitator are easy targets of wear and tear. In addition, the airproof capability of these seals is not perfect. In this light, an advanced powder magnetic seal design which installs permanent magnets at the top of the vane and utilizes the magnetism of Fe3O4 in fly ash to seal the space between two vanes is discussed in this paper. In the self-designed device, three categories of permanent magnet parameters and four kinds of powders with respective with respective magnetic powder mass fractions of 7%, 9%, 12%, and 15% were chosen. The airproof capability was also measured. The results show that this device has excellent airproof capability, can withstand wear and tear, and has a low replacement frequency.

Abstract: Two difficulties exist in the finite element analysis of multi-point forming: the complicated modeling process and the difficulty to control the movement pattern of more punches simultaneously. In the present paper, the design process of parametric simulation program for multi-point die forming and force-displacement separated control forming by using ANSYS parametric design language (APDL) is described. The rapid modeling is realized by use of the parameter input dialog box. The calculation program for the original position of each punch is designed, and then the stroke of each punch is determined. The process of model definition, loading and analysis is controlled by customized multi-point forming toolbar. The parametric finite element analysis process for spherical surface forming with the force-displacement separated control forming method is described in the paper. The results indicate that the simulation requirements for different parameters and different forming modes can be satisfied by the designed parametric simulation program.