Advanced Materials Research Vol. 460

Abstract: Based on the FEM code ABAQUS and MSC.Fatigue, the process of LSP before hole-drilling was adopted to study the residual stress field of aluminum alloy7050T7451 with Fastener Holes after Laser shock processing (LSP), and the fatigue life of the specimens by LSP was analyzed in this paper. The results indicate that multiple laser shock processing can improve the residual compressive stress and fatigue life to a certain degree, and with the increasing number of shot, the strengthening effect gradually decreases. The ratio of the fatigue life of specimens treated by LSP to the fatigue life of untreated specimens is gradually decreased as the mean stress σm increases, and when the σm is 67.3MPa, the fatigue life of specimens treated by LSP advances 719%, compared with that of untreated specimens.

Abstract: The difference between inside circumferential defects and outside circumferential defects was proved using the theory of reflection waves, the course of propagation and reflection from inside circumferential defects and outside circumferential defects in steel pipes was simulated with L(0,2) mode by the numerical simulation program ANSYS, and the curves of the reflection waves were obtained. The investigation indicated that the relationship between reflection coefficient of each kind of circumferential defects and the circumference of the defects was linear; in additional, it was found that the reflection coefficient of outside circumferential defects was a little higher than the reflection coefficient of inside circumferential defects; the difference between inside and outside circumferential defect became more obvious as the thickness of the defect increases. So the results provide a basis for detecting and distinguishing circumferential defects of pipes.

Abstract: Local dry welding is an important water welding method with special advantages for good flexibility in nuclear power stations repair where operation spaces are usually very limited, and it can be applied perfectly by simple integration of a lot of welding processes with shielding cup. An underwater welding system chamber was built, which is mainly comprised of an underwater welding test chamber, and a hydraulic driven underwater welding device. Shielding gas is inflated to the small compacted cup to drive water and protect arc and weld pool. At shallow water of 100mm,Pulsed MIG tests were carried out to investigate parameters which are related to welding process of 304 stainless steel cladding layers. Welding tests at different depth indicates that although profiles of welds produced both at pressures of 5 meters water depth and at pressures of 15 meters water depth are perfect, but cladding layer at 15 meters is more narrow and more high

Abstract: The distribution of the compressive residual stresses which caused by laser shock processing is a new surface strengthening technology to improve the quality of material surface. ABAQUS is used to simulate the distribution of residual stress field impacted by the laser power densities and the spot shapes. The consequences indicate that: following the laser power intensities increasing, the reflection waves coming from the spot edges should loaded reversely, inducing the opposite deformation, leading to the “residual stress drops” phenomenon; the spot shapes also influent the converging of the reflection waves toward the center, and the residual stress drops at the center are different. This research provides a basis for a better effect of LSP with the optimization of the technological parameters and the decrease of the residual stress drops at the center of the shocked zones.

Abstract: Preparing composites of broken glass and waste aluminum is one of the effective methods, which are high-added value utilizations of both wastes. It is an original thought which is used to develop circular economy and vein industry in china. The combination of aluminum’s toughness and glass’s hardness is the advantageous factor adding the wastes’ value. The article presents an experimental study on mechanical properties of the waste glass / waste aluminum wearable material. The strength and tough of the material are higher than those of basal material. The abrasive performance of the MMC material is 4.62 ties higher than basal materials, which reach the property standard of strap transport roller.