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Friction stir welding equipment was used to weld 3 mm thick 6082 aluminum alloy and T2 copper, through metallurgical microscopy, hardness testings tensile testing, etc.explore the impacts of rotational speed on the organization and mechanical properties of welded joints. The results show that: Intermittent defects always exist at the interface of the joint, alternating distribution of aluminum and copper, and uniform mixing of the two materials; The microhardness distribution of the joint shows that the highest value appears in the weld core area with hardness of 210 HV, aluminum and copper side heat affected zone hardness have decreased, the lowest value for the aluminum side heat affected zone of about 60 H V; with the increase in speedy the tensile strength increases first and then decreases, when the spindle speed of 1 000 r/min, welding speed of 50 mm/min, the optimal weld forming effect, the tensile strength can reach 255 MPa, the fracture shape becomes more uniform with the increase of rotational speed, and the toughness nest increases, showing a stratified distribution. The fracture location is the aluminum copper bond, and the crack extends along the interface defect, showing mixed brittle ductile fracture at low speed and ductile fracture at high speed. [ABSTRACT FROM AUTHOR]

The mixing and separating process of different-sized particles in a self-designed rotating drum were explored, where the glass beads were taken as particles. The power consumption of rotating drum under different operating parameters were measured. The results show that the particle separation is more evident when the drum is operated at high fill level, where the small particles surrounded by large particles are mostly observed. When the filling rate is low, it is unobvious for the particle separation of the similar size particles at different rotating speeds. The larger difference of the particle size, the more particle separation occurs. With the increasing rotational speed and fill level, the power consumption increases, while the power consumption is relatively less sensitive to the particle size ratio. [ABSTRACT FROM AUTHOR]

Aiming at the problem of bearing characteristics of deep and shallow hydrostatic bearings, the oil film pressure field and temperature field of hydrostatic bearings were simulated and analyzed. Taking the hydraulic and hydrostatic bearings commonly used in the ultra-high speed grinding motorized spindle system as the research object, the three-dimensional finite element model of the oil film of the hydrodynamic and hydrostatic bearings was established and meshed, and then the mesh quality was evaluated. The oil film pressure and temperature distribution of deep and shallow cavity hydrodynamic and hydrostatic bearings under different rotational speed and eccentricity were calculated by using dynamic mesh technology, which can be used to change the eccentricity of the oil film. Distribution of oil film pressure and temperature in shallow chamber hydrodynamic and hydrostatic bearings was analyzed. The influence of rotational speed and eccentricity on bearing capacity and the oil film temperature rise of hydrodynamic bearing was studied. The results indicate that in the operation of deep and shallow chamber hydrodynamic and hydrostatic bearings, with the increase of rotational speed and eccentricity, the bearing capacity and temperature rise of the oil film also increase, and the influence of rotational speed on the temperature rise of the oil film is greater than that of eccentricity. [ABSTRACT FROM AUTHOR]