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Abstract:In this article, a geometrical model of different microtextures is established for an axial piston pump valve plate. A finite differential method was used to solve the Reynolds equation for the oil film thickness and pressure, which were simulated under different microtextures. The influence of microtexture shape and structure on performance was studied and optimal parameters sought. Different convergence gaps are formed by different microtexture radii, and they produce different hydrodynamic effects. The lubrication characteristics of the valve plate are better when a microtexture is used and are influenced by the type of microtexture. We reached the following conclusions: (1) The lubrication characteristics of the valve plate are influenced by different microtexture parameters and can be improved by optimizing the microtexture parameters; (2) There is an optimal parameter combination when adding microtexture with three shapes (spherical, cylindrical and square) and the optimal dimensionless oil film pressure lubrication characteristics can be obtained; (3) The degree of improvement in the dimensionless oil film pressure lubrication characteristics was (listed from highest to lowest): micro-hemispherical texture > micro-cylindrical texture > micro-square texture.

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2205 duplex (austenitic-ferritic) stainless steel has a good weldability and an excellent corrosion resistance. The good weldability is achieved when in close to 50-50 ferrite-austenite ratio. In this study, the welding process and properties were investigated by pulsed Nd:YAG laser welding. Tensile test, surface microhardness test, surface topography and microstructures of 2205 duplex stainless steel welds were performed under different welding speeds, input currents, pulse widths, frequencies and defocus distance. The relationship among them was revealed and the optimal welding parameters were obtained. The results showed in the condition of I = 160 A, T = 5 ms, f = 25 Hz, V = 500 mm/min and Z =-1 mm, the amount of ferrite and austenite in welds was roughly same, overlap rate of solder joints was above 78% and the weldability was good.