Advanced Materials Research Vols. 753-755

Abstract: The HOFC (High Order Flatness Control) work roll curve was designed using Matlab. It has great flatness control ability, for the roll diameter in the position of the 1/4 roll length can be altered with the changing of angle and index parameters. Combined with the data from a hot strip factory, the elastic deformation of the HOFC work roll was analyzed following the influence coefficient method. The distribution curves of the exit thickness, roll force, work roll bending, pressure between rolls, roll flatting, and roll gap geometry were given under the conditions of different roll parameters. Results show that the HOFC work roll curve can eliminate the high flatness defects, reduce the edge drop, improve the lateral thickness uniformity, and maximize the available cross section of the strip effectively.

Abstract: This paper is considering the surface quality control of hot-rolled coil. Through analyzing patterns, distributing-regularities and components of surface defect of low-carbon coil of WISCO, got the conclusion that mould powder entrapment was the key factor that lead the defect’s occurrence. Based on discussing the mechanism of powder entrapment in mould, developed a type of high viscosity powder, optimized flow field of mould through modifying the structure of SEN, and improved other relevant process conditions, the incidence rate of this type of defect was under controlled effectively and the degradation rate of the coil caused by the defect dropped from about 4 percent to less than 0.2 percent at the end.

Abstract: Polymer based composites are widely used in the automobile body panels instead of the steel sheet, due to the requirement of reducing automobile weight. Natural fiber composites were proposed to be used for the car bumper beam. In this paper, the mold filling process of the car bumper beam model for VARTM process was simulated by the software of the RTM-worx. The optimization injection scheme was determined based on the simulation results of the different schemes. It was found that the multiple injection ports would reduce the filling times, and the scheme 6 was the best one for the injection. The filling times of the optimization scheme 6 was 742 s, and two vents at the position A and B would expel the bubbles at the intersectional regions of the resin. Moreover, the optimization scheme could be directly used in the practical production.

Abstract: The hot compressive deformation behavior of SWRCH 35K was studied with uniaxial hot compression simulation tests at 923 ~ 1223 K and strain rate of 0.01 ~ 20 /s. The results show that the hot compressive deformation activation energy was 408 kJ/mol and the rang of deformation stored energy was 10 ~ 50 J/mol. The quadratic fitting expression between deformation stored energy and Zener-Hollomon parameter (Z) was established and the deformation stored energy was considered to increased with increasing Z or with lower deformation temperature and increasing deformation rate.

Abstract: Rolling force is critical to realize the industrialized production of the rolled mg alloy sheets especially more than 1500 mm width which affects the mill set-up schedule, the thickness of the rolled metal, and the final product profile. An online calculation model of rolling force with high precision and high speed has also been developed with the finite difference method (FDM) in this paper which can provides a good guidance for the enhancement of product precision and the development of new products.

Abstract: This paper presents a series of injection process simulations for blow molding preforms by using MoldFlow. The injection-blowing system was used and this consists 3 stages on the same machine; (1) preform injection, (2) blowing and (3) ejection. The quality of preform injection process is an important factor that can dominate the whole process efficiency. The injection mold system consists of 10 cavities and a hot runner system. The hot runner system has 10 cavities and temperature of each cavity can be independently controlled. Through several filling analyses, suitable temperature of each gate was determined so that all cavities could be simultaneously filled. Weld lines on the bottom of preforms were predicted. This fact can be an important aspect because preforms will be blown. To improve cooling efficiency, ''Floody Cooling Type" channels were applied. Conventional cooling channels were straight-line types and then distances between cooling channels and cavities cannot be uniformed. Floody cooling type channels were uniformly placed around cavities as far as possible. To compare two different types of cooling channels, cooling tests of MoldFlow were carried out and certain advantages of floody cooling type channels were evaluated.

Abstract: This study applies the finite element method (FEM) to predict maximum forging load and effective strain in helical-bevel gear forging. Maximum forging load and effective strain are determined for different process parameters, such as modules, number of teeth, and die temperature of the helical bevel gear forging, using the FEM. Finally, the prediction of the power requirement for the helical-bevel gear warm forging is determined.

Abstract: The variation of the temperature, stress and deformation of the high strength steel was simulated by using MSC.MARC software. The effect of martensitic transformation on the temperature, stress and deformation filed was discussed. The results shown that, the equivalent stress of the plate along length direction is distributed uneven when considered the phase transition. The maximum deformation and the deformation along length direction of the plate are increased obviously when considered the martensitic transformation.

Abstract: Now there is not engough basic theory to explain the friction mechanism on the shear deformation zone and tool-workpiece deformation zone in the process of metal cutting.But the constant coefficient of friction model is not in accord with the actual cutting tool friction. So Friction law of micro friction process were studied by friction test and simulation, the friction model of micro - cutting are very important which can improve the micro-cutting mechanism, finite element modeling and Simulation of metal cutting process and etc.

Abstract: ZrB₂-SiC ceramic composites with the addition of carbon black were fabricated by hot pressed sintering at 1900 °C for 60 min at a uniaxial pressure of 30 MPa in an argon atmosphere. The mechanical properties of ZrB₂-SiC ceramic composites were improved, adapting to the use requirements of ceramic parts. The precision electromachining technology of complicated structure components was investigated. The processing surface roughness was evaluated.