In present work, two conductive filler (carbon fiber with Nickel (Ni) coatings and carbon fiber with Nickel/Fe3O4 nanoparticle (Ni/Fe3O4-NPs) composite coatings) were prepared by electrodeposition. Microstructure observation indicated that the coatings were deposited uniformly on the surface of fiber. Vibrating sample magnetometer (VSM) and electromagnetic interference (EMI) shielding test showed that the two conductive filler has good saturation magnetization and EMI shielding effectiveness.The conductive filler of carbon fiber with Ni/Fe3O4-NPs composite coatings was more excellent. They are promising for application in electromagnetic shielding materials.

Surface strengthening for H13 steel with powder mixed near dry EDM, research the effect of different discharge parameters on the microstructure and hardness of strengthened layer .The results show that the effect of pulse interval on microstructure and micro hardness is not obvious, the influence of the pulse width less than the peak current. As the increasing of peak current, strengthening layer surface quality get better, when the peak current reach to 14A , preferable microstructure of strengthening layer can be obtained.

In this paper, weld stress field of Non-preheating with t-joint weld process of high strength low alloy steel Q550 is simulated applying the coupling analysis of temperature and stress field in finite element method(FEM) software ANSYS. The research proves that weld joins can achieve equal strength with the base metal using low alloy high strength steel flux-cored welding wire PK-YJ707A of low hydrogen slag type system. Impact absorbing energy comes up with 107J at -20°C and comes up with 80J at -40°C. After the results of bending, the weld joins have no crack or smaller than 3mm. The mechanical property meets the requirements of the HSLA Q550. In addition, the simulation result is able to more accurately predict the welding stress field that can provide theoretical basis for guiding production practices, reducing cost and improving working environment.

YG8 was used as working electrode in the mist medium to reinforce the surface of the H13 steel. Microstructure, thickness, phase composition and hardness of the reinforced surface were studied with the XRD, SEM, micro vickers hardness tester. Experimental results show that the phase are mainly Fe3C、FeCr、α-Fe and Co3Fe7, surface are orange-peel like, the microhardness of surface is 1286HV, 3times better than the body layer.

Multi-point stretch forming is a flexible manufacturing technique for three-dimensional shape forming of craft skin. Its die surface is constructed by many pairs of matrices of elements whose height is controlled by computer. It uses the curved surface of elements instead of the die surface. The element numberis an important parameter because it has great influence on the part quality. This paper simulates the forming process of paraboloid part and saddle-shaped part with different number of elements and studies the influence of element number on the shape accuracy of the part .That will provides guidance for the application of multi-point stretch forming.