Advanced Materials Research Vols. 602-604

Abstract: The effect of antimony on the structure, texture and magnetic properties of high efficiency non-oriented electrical steel were investigated. The results showed that antimony played an important role on inhibiting the grain growth and enhancing the fraction of favorable texture in the annealed steels. With the increase of antimony content, core loss of specimens monotonously increased and the magnetic flux density increased firstly and then decreased. The magnetic properties of specimen results showed that the magnetic flux density in the steel with 0.12% antimony reached the maximum value, while the core loss didn’t increase obviously. However, when the antimony content in steel reached 0.22%, the magnetic properties deteriorated significantly. This is maybe that the addition of antimony in steels inhibited the development of {111} texture content and increased the intensity of Goss and {100} texture on the grain boundary.

Abstract: Dynamic recrystallization(DRX) behaviors of 18Ni maraging steel during hot deformation have been investigated by single-pass thermo-mechanical simulative experiment at temperatures of 1173K-1323K and strain rates of 0.001s-1-1s-1. The results show that the true stress-true strain curves type of this alloy is DRX. The DRX in 18Ni maraging steel is easy to occur at low strain rates and high deformation temperatures. Using regression analysis, the activation energy(Q) for DRX of 18Ni maraging steel was calculated to be 413544.96J/mol. The constitutive equation of peak stress for DRX was also obtained. The mathematical models of critical stress and critical strain were finally established.

Abstract: Sintered and forged powder metallurgy (P/M) steels were subjected to tensile, hardness and impact test, in order to understand the influence of the microstructure on the mechanical properties and fracture behavior. Ultimate tensile strength, yield strength, elongation, reduction in area, hardness and impact toughness all increase with a decrease in porosity. With the increase of density, the mode of fracture change from pure ductile in sintered necks of the material to complete brittle from fully dense pearlitic grains.

Abstract: The theoretical prediction of chemical composition, the range of main elements and austenite alteration affected by intercritical annealing temperature were conducted by thermodynamic calculations, which agree with the experimental results. When fixing carbon content at 0.1% and calculating temperature at 1000K, to achieve α+γ phases without cementite or graphite, Al must be less than 1.13%, Mn be 1.25~7.5% and Mo be less than 0.7%. The calculated Ae3 is 54°C higher than the measured Ac3, and calculated Ae1 is 14°C higher than Ac1. The intercritical annealing temperature for DP590 steels with Al as main alloying element can be calculated by setting ratios of α:γ in 70:30, and the calculated value of 807°C was close to the experimental results of 800~840°C.

Abstract: In-situ production of (Fe,Cr)₇C₃ particulate bundles -reinforced iron matrix composite was prepared by infiltration casting between Cr wires and white cast iron at 1200°C plus subsequent heat treatment. The composites under different heat treatment times were comparatively characterized by scanning electron microscopy (SEM) and pin-on-disc wear resistance tests. The results show that the area of the particle bundles gradually increases with the heat treatment time increasing, and the chemical compositions change from eutectic to hypoeutectic, the morphologies of the reinforcements present chrysanthemum-shaped, granular and intercrystalline eutectics. Under 5 N loads, the composites appear excellent wear resistance, which is 36 times for the reference sample.

Abstract: The leaf spring is a key component of heavy vehicle suspension. The stiffness characteristic has an important influence on vehicle ride comfort and road friendliness. Firstly, the structural features and working principle of leaf spring are introduced. Secondly the detail testing scheme of the leaf spring is proposed and the stiffness characteristics are tested through cascaded loading and unloading. The tested results show that the leaf spring has the typical features of non-linearity and hysteresis. In order to satisfy the vehicle dynamics simulation, the Fancher model is chosen to describe leaf spring nonlinear characteristics. Finally, the LSM (Least Squares Method) is utilized to identify five parameters of Fancher model based on experiment results.

Abstract: A measurement method for magnetic property of the non-oriented silicon steels WD23 and WD20 by X-ray diffraction (XRD) has been introduced. The measurement results show that this method is simple and the size(amount) of the required sample is small. Therefore, the method is reasonable.

Abstract: Plasma arc bending of laminated clad metal sheets (LCMS) is a newly developed technique that produces deformation in the LCMS by thermal stress instead of external mechanical force. Since the temperature field leads to the thermal stress, a FEM mode was developed to study the temperature variations in the plasma arc bending of the LCMS which was validated robustness by the experiments. The results show that the temperature variations of the LCMS include the preheating, temperature dramatically changing and cooling stages. The lowest temperature is in the inlet whereas the highest temperature is in the outlet along the heating line. It needs to regulate the energy input of the plasma arc to avoid the possible partial melting of the LCMS.

Abstract: Effects of continuous annealing process on microstructure and properties of Si based cold-rolled TRIP Steel were studied. The results show that the TRIP effect is more obvious on the condition of 800°C with 120s annealing process and 400°C with 520s aging treatment than others progress. The yield strength of the tested steel is 405MPa, tensile strength is 670MPa, elongation is 32% and strain hardening exponent is 0.230. The microstructures are ferrite, bainite and retained austenite and the volume fraction of retained austenite for the tested steel is 9.20%.

Abstract: Cut-to-length bloom can not be controlled at the end of continuous casting process, and the yield of bloom is low. In order to improve the yield of bloom, the CC tail bloom system is proposed according to the bloom continuous casting conditions of equipment and process. Importantly, it is applied in the optimization of tail bloom operation in continuous casting process. Industrial tests show that the yield of bloom is improved obviously, with the quality of bloom is controlled as before.