Effect of Processing Parameters On Mechanical Properties of Inconel718 Superalloy Fabricated By Direct Energy Deposit

In this study, Inconel718 specimens with good mechanical properties were prepared by direct energy deposit (DED) with different laser processing parameters. The mechanical properties of Inconel718 samples fabricated by laser direct energy deposit method without heat treatment were measured. The fractures and metallographic structures of prepared Inconel718 were observed, and the mechanism of the effect of diverse machining parameters on mechanical properties of Inconel718 was analyzed from the micro level. The results showed the microstructures of depositions of Inconel 718 specimens prepared by DED were compact with fine grains and anisotropic microstructures, where macroscopic defects were barely seen. The mechanical properties and microstructures of Inconel718 were influenced by processing parameters, among which the forming angle and laser power had the most remarkable effect. According to the experimental data, it could be observed that the Inconel718 specimens prepared by DED had the best performance under the circumstance of 1400W laser power, 1.0mm layer thickness, 600mm/min scanning speed, 1.3mm hatch spacing, and 90° forming angle, whose ultimate tensile strength (UTS) and macro hardness were 1016.10MPa and 36.2HRC respectively. The UTS of Inconel 718 manufactured by DED was close to that of Inconel718 prepared by traditional forging, and even it had higher hardness.

Diffraction and Radiation of Water Waves by a Heaving Absorber in Front of a Bottom-Mounted, V-shaped Breakwater of Infinite Length

In the present study, the problems of diffraction and radiation of water waves by a cylindrical heaving wave energy converter (WEC) placed in front of a reflecting V-shaped vertical breakwater are formulated. The idea conceived is based on the possible exploitation of amplified scattered and reflected wave potentials originating from the presence of V-shaped breakwater, towards increasing the WEC’s wave power absorption due to the wave reflections. An analytical solution based on the method of images is developed in the context of linear water wave theory, taking into account the hydrodynamic interaction phenomena between the converter and the vertical wall. Numerical results are presented and discussed concerning the hydrodynamic forces on the absorber and its wave power efficiency for various examined parameters, namely, the breakwaters’ forming angle, the distance between the converter and the vertical walls and the wave heading angle. The results show that the amount of the harvested wave power by the WEC in front of the walls is amplified compared to the wave power absorbed by the same WEC in the open sea.

Research on Comparison of Simulation and Experiment in Warpage Defects in Roll Forming Process of the Cap-Shaped Part Using a Five-Boundary Condition Forming Angle Distribution Function

Warpage is one of the main defects in multi-pass roll forming. It manifests as the horizontal deviation in the sheet flange part after forming, impacting the final quality of the sheet. In this manuscript, we focus on the cap-shaped part of a small section profile. Considering the lack of previous scientific guidance on the distribution of forming angles—angles that lead to warpage defects and other defects reducing the quality of these products—a five-boundary condition distribution function of forming angle is proposed. We propose a mechanism for warpage defects in roll bending of a cap-shaped part based on this five-boundary condition forming angle distribution function. Furthermore, we examine the effects of forming angle, sheet thickness, and material yield strength on the warpage defects by examining the designed fluctuation of the edge wave, ∆z, and the maximum deviation of the profile curves of the flange edge, z', to test this theory, roll bending experiments are compared to simulation.

Investigation of the influence of incremental sheet forming process parameters using response surface methodology

New methods in metal forming are rapidly developing and several forming processes are used to optimize manufacturing components and to reduce cost production. Single Point Incremental Forming (SPIF) is a metal sheet forming process used for rapid prototyping applications and small batch production. This work is dedicated to the investigation of the profile geometry and thickness evolution of a truncated pyramid. The influence of process parameters during a SPIF process is also studied. A numerical response surface methodology with a Design of Experiments (DOE) is used to improve the thickness reduction and the effects of the springback. A set of 16 tests are performed by varying four parameters: tool diameter, forming angle, sheet thickness, and tool path. The Gurson-Tvergaard-Needleman (GTN) damage model is used to analyze the damage evolution during material deformation. It is found that the model can effectively predict the geometrical profile and thickness with an error of less than 4%. Furthermore, it is noticed that the forming angle is the most influential parameter on the thickness reduction and springback level. Finally, the damage evolution is demonstrated to be sensitive to the forming angle.

A Measure of Optimization of Technological Parameters to Improve the Formability of Aluminum Sheet a 1050 H14 by SPIF Technology

The objective of this paper is to select a set of technological forming parameters including vertical feed Δz, feeding rate of Vxy of the tool (a kind of pestle but no-cutting edges), the diameter of tool D and the revolutions per minute of tool n to achieve the highest forming ability of aluminum sheet A1050 H14 (according to JIS G3101Japanese standard) when forming metal sheet by Single Point Incremental Forming Technology-SPIF. The content of the article consists of 3 processes: Pre-design of experiment (Pre-DOE) to select of a set of reasonable limited parameters when forming aluminum sheet A1050 H14 models when forming on the existent specialized SPIF machine in the National Key Laboratory of Digital Control and System Engineering laboratory (DCSELAB); Performing aluminum sheet A1050 H14 models on the Pre-DOE to obtain the forming angle values; Evaluating the experimental results by analysis of variance; Setting up the regression equation of the angle of deformability with influence parameters; Optimization the regression equation to select an optimal set of forming parameters to gain the highest deformability of aluminum sheet A1050 H14.

A Measure of Optimization of Technological Parameters to Improve the Formability of Stainless Steel Sheet SUS 304 by SPIF Technology

The objective of this paper is to select a set of technological forming parameters including vertical feed Δz, feeding rate of Vxy of the tool (a kind of pestle but no-cutting edges), the diameter of tool D and the revolutions per minute of tool n to achieve the highest forming ability of stainless steel sheet SUS304 (according to JIS Japanese standard) when forming metal sheet by Single Point Incremental Forming Technology-SPIF. The content of the article consists of 3 processes: Pre-design of experiment (Pre-DOE) to select of a set of reasonable limited parameters when forming SUS304 stainless steel models when forming on the existent specialist SPIF machine in the National Key Laboratory of Digital Control and System Engineering laboratory (DCSELAB); Performing SUS304 models on the Pre-DOE to obtain the forming angle values; Evaluating the experimental results by Analyzing of the variance; Setting up the regression equation of the angle of deformability with influence parameters Optimization the regression equation to select an optimal set of forming parameters to gain the highest deformability of stainless steel sheet SUS304.

Effect of rolling parameters on forming quality of flat cross wedge rolling thread shafts

The flat cross wedge rolling is an advanced forming process, which is used to produce thread shafts. In this work, a finite element model of flat cross wedge rolling thread shafts was established by the DEFORM-3D, and the effect of the forming angle, spreading angle, helix angle and flank angle on forming quality are investigated. The research results show that the forming angle, spreading angle, helix angle have a significant influence on the position of the die wedge-in point. The angle designed wrongly makes the die wedge-in point unable to be aligned correctly, causing defects such as slipping in the process, repeated rolling of formed thread, thin or incomplete tooth shapes. The flank angle mainly makes an impact on the axial force. Reducing the right flank angle or increasing the left flank angle can effectively improve the imbalance of axial force to obtain high-quality thread shafts. Through the experiment of flat cross wedge rolling thread shafts, the data comparison demonstrates that the error of the external dimension of formed parts is small, proving the reliability of the rolling parameter selection.