Papers by Author: H.F. Wang

Abstract: The friction and wear properties of the friction stir jointing 7022 aluminum alloy joining region were tested in this paper. The friction coefficients and wearing capacities of the joining regions under different joining process parameters were obtained. The experiment results showed that the friction coefficients and wearing capacities of the joining regions had a certain relationship with the hardness, but not became direct ratio relation. The friction coefficient of the joining region was smaller than that of the base metal. This main reason was base metal was lath-shaped grain, and the joining region was isometric crystal. The wear volume under 400/30 parameters was minimum. The wear volume was greatly influenced by the hardness of the joining region, but was not direct proportion relationship. Due to the random factors influence in friction process, the law of the friction coefficient reflecting friction and wear was not the same with the law of wear volume reflecting friction and wear. The friction form was abrasive wear and adhesive wear.

Abstract: In micro-cutting process, it is very significant to study the variations of cutting forces and the factors affecting the forces for determining the machining parameters and for improving the performance of machining systems. The remarkable characteristic of micro-Cutting is that cutting parameters level closing to the crystal grain msize of material. Though, the prediction formula of micro-cutting forces should reference to strain gradient plasticity theory in formula construction, while cutting edge radius had been regard as a important parameters in the process of micro-cutting. The study show that, strain gradient reaction will be decreased by feed rate’s reducing in process, approximate expression of the strain gradient by the derivative of chip deformation rate, and the micro-cutting forces include hear flow stress, tensile flow stress ,and the friction force of rake surface.