Papers by Author: Yong Jin Tang

Abstract: SiCp/Al composite was fabricated by the method of pressureless-infiltration. In atmospheric environment, the atmospheric corrosion behavior of SiCp/Al composites (ZL101+49%SiC+5%Mg) was studied by mass loss, optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FTIR), respectivelhy.The results show that the corrosion rate of the SiCp/Al composites increases with increasing of time in atmospheric environment. Pitting corrosion is the main characteristic of SiCp/Al composite, and corrosion area gradually extends around with time increasing. At last, sheet like corrosion substrates distribute in the surface of n the SiCp/Al composites. Amorphous Al2O3 and amorphous AlxSO4yOHz are the main corrosion products.

Abstract: In this paper, using high tensile strength and yield strength of hot-rolling acid washing thin steel sheet instead of cold-rolling steel sheet as the vehicle frame is investigated. The high pure and finer grain steel can be obtained by deep deoxidation technology, deep desulfurization technology, low nitrogen and microalloy-technology of Boron/Niobium/Titanium. High yield strength (σs>340 MPa) and high specific elongation hot-rolling thin steel sheet have been produced in the EAF-CSP short flow product line. The mechanical property, shape, surface quality and tolerance of steel sheet after hot-rolling can be controlled by optimizing joining-casting-rolling and controlling-rolling-cooling technology. Based on the forming test, cold-bending test, welding test and fatigue test results, it can be seen that cold-bending property, forming ability and fatigue strength of hot-rolling acid washing steel sheet is better and meet the product requirement of vehicle frame. This investigation can resolve the fracture problems of QUANSHUN vehicle, improve the working life, provide reliable automobile and reduce the production cost.

Abstract: The influences of the different Si (0.723%~4.5%) and Cr (2.0%~8.0%) contents on the microstructures and properties of Cr-Si-Mn white cast iron were investigated. It is shown that with increasing of amounts of Si and Cr elements, carbide undergoes an evident change in the morphology from the continuous net to isolated stripe and becomes clearly finer, even forms chrysanthemum-like microstructure which is usually found in high Cr white cast iron. Additionally, the amounts of the carbides increase too. The XRD analysis shows that the carbides are a mixture of Fe3C and Fe7C3 phases. Furthermore, the hardness of carbide and matrix is also found to progressively increase with increasing of amounts of Si and Cr elements. The hardness of the matrix in as-cast white cast iron is over HV400, suggesting that the matrix consists of martensite and bainite phases. The impact toughness of the samples declines evidently when Si content excesses 3.0wt%. It is also revealed that the bainite matrix in the Si-Cr white cast iron has a higher impact abrasive wear resistance than others, which is almost not dependent upon heating temperature and cooling rate. When Cr content approaches 5wt%, the impact wear resistance of the new cast iron is comparable to that of the traditional high Cr cast iron.