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Orthogonal experiments of ultrasonic deep rolling with Longitudinal-torsional vibration (UDR-LTV) and conventional deep rolling (CDR) Q235 steel were carried out to study the effects of processing parameters on surface roughness. The orthogonal experiments results show that the influence laws of processing parameters on surface roughness are the same, and the values of surface roughness obtained by UDR-LTV are smaller than that of CDR with the same processing parameters. The values of surface roughness obtained by UDR-LTV and CDR increase and then decrease with the increment of the static pressure; and increase with the increment of the feed-rate, and change a little along with the increment of the rolling speed. Meanwhile, the feed-rate has a marked effect on the surface roughness, while the rolling speed has a little effect on the surface roughness. The quadratic regression method is used to construct the mathematic model to predict surface roughness based on the experimental results. The effects of parameter interactions on surface roughness are studied. The research shows that the interaction effects of the rolling speed and the feed-rate, the static pressure and the feed-rate on surface roughness are obvious, but the interaction effect of the static pressure and the rolling speed on surface roughness is not significant. The optimal parameters for the lowest surface roughness are given by the result of orthogonal design and prediction model, which has guiding significance for the application of ultrasonic surface strengthening technology with complex vibration mode.

The mechanism of longitudinal-torsional vibration (LTV) realized by using converter with multiple diagonal slits (MDS) was analyzed based on the acoustic wave propagation when acoustic wave enters obliquely from steel to air. The influences of geometrical parameters of the stepped compound horn with multiple diagonal slits on natural frequencies of LTV were studied with finite element analysis (FEA). The design procedure of stepped compound horn with LTV was provided. The vibration characteristics of actual horn were analyzed with simulation and test. The FEA results show that LTV of the output end of the stepped compound horn may be realized when the input end is excited by longitudinal vibration at certain natural frequency if suitable geometrical dimensions are selected, and the amplitude of the horn is periodical; the trajectory of the particle in the output end is helical curve. The test results indicate that LTV may be realized by stepped compound horn under single acoustic excitation, and the vibration frequency is close to the simulation result, and its vibration properties are good. This method may be applied to design the acoustics system of ultrasonic machining with LTV under single acoustic excitation.

The kinematics model was built based on the principle of ultrasonic deep rolling (UDR) with longitudinal-torsional vibration (LTV), and the trajectory equations of any particles on edge of the roller involved in the process were given; the influences of vibration parameters including phase angle, frequency of LTV, amplitude of longitudinal vibration, amplitude ratio and the rolling process parameters including roller radius, rolling depth, feed rate, the rotation frequency of roller on the trajectory, acoustic system design and processing quality were discussed. The results can provide theoretical basis for the design of acoustic system and optimization of process parameters.

Research on ultrasonic extrusion under different process parameters for 45 steel shaft based on orthogonal test is carried out. The influences of various process parameters on shaft surface roughness and micro hardness are analyzed. The experimental results show that the influences of tool radius, pre-pressure, feed rate and rotating speed in the ultrasonic extrusion on surface roughness and micro hardness are different, but there are optimal values in the given experimental conditions. Compared with conventional extrusion, it can reduce the part surface roughness and improve surface micro hardness significantly in the process of ultrasonic extrusion.

Acoustic system is the core component of power ultrasonic, which is designed by traditional analytic method and modal analysis with finite element analysis method. And component of the step-like horn with rectangular sections and tool head used in two dimension ultrasonic polishing without abrasives are studied, and the calculating results and modal analysis results are consistent on the whole. The harmonic response analysis for the component of horn and tool head is carried out and the three dimensional coordinates of the vibrating node on the tool head with maximal displacement are obtained. The fitting result shows that the moving trajectory of such node is ellipses, which meets the experimental requirement well. So a new way for designing acoustic system of two dimensional ultrasonic vibration through combining theoretical calculation with computer aided design may be applied.

Two-dimensional ultrasonic vibration was introduced into common rolled extrusion, effect of the process parameters including tool head radius, feed speed, preload and spindle speed on the 45 steel shaft surface roughness were analyzed through orthogonal experiments. Experimental results show that lower value of surface roughness may be obtained in the process of two-dimensional ultrasonic rolled extrusion than that of common rolled extrusion, and the influence order of process parameters on surface roughness is feed speed, spindle speed, preload and tool head radius; the influence curves of tool head radius and spindle speed on surface roughness are concave curves, and influence curves of feed speed and preload on surface roughness are convex curves, or optimizing process parameters exist. The empirical formula for surface roughness is given using multiple regression analysis based on the experimental results. This study will provide a new technique for finishing precision parts.

An ultrasonic grinding technology named NC-Contour Evolution Ultrasonic Assisted Creep Feed Grinding that using a simple shaped diamond grinding wheel with small diameter is presented to solve the machining problem of ceramic blade surfaces in integral impeller, which is similar to numerical control profile modeling milling. The grinding parameters of single grit in the grinding wheel are selected as the objective to make clear the grinding properties of creep feed grinding and ultrasonic grinding using grinding wheel with small diameter so as to explore the suitable processing parameters to machine ceramic blade surfaces in integral impeller in theory.

Experiments of ultrasonic polishing the 45# steel shaft without abrasive are carried out by using orthogonal test method to study the polished surface roughness, and experimental results are analyzed with range method. The influence of polishing parameters on the polished surface roughness could be arranged as follows: feed rate, power of generator, preload pressure and radius of the tool head, in which the feed rate brings the most remarkable influence on the polished surface roughness. The surface roughness value reduces at first and then increases when the radius of tool head, preload pressure and power of the generator increase. The surface roughness value increases with the feed rate. Comparative experimental results of ultrasonic polishing without abrasive and the conventional rolling indicate that lower surface roughness value may be obtained by ultrasonic polishing without abrasive.

In order to grind the ceramic blade surface with the Numerical Control contour evolution ultrasonic grinding method using the simple shape grinding wheel, primary comparative experiments of creep feed grinding with and without ultrasonic vibration were carried out to grind Al 2 O 3 ceramics so as to implore the effects of different process parameters on the machined surface quality. It can be concluded that when the direction of ultrasonic vibration is parallel to the direction of creep feed, the value of the surface roughness will be decreased; otherwise the surface quality will become worse. With the ultrasonic grinding method, the slower feed-rate, the smaller grinding depth, the higher grinding speed and the compound feed grinding method should be applied in order to improve the surface quality. The creep feed grinding mechanisms with and without ultrasonic vibration were analyzed theoretically from the experimental results. With the selected grinding parameters resulted from the experiments, the feasibility experiment of ultrasonic grinding ceramic blade surface was carried out.