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Contemporary Machining Processes for New Materials
Published in E. S. Gevorkyan, M. Rucki, V. P. Nerubatskyi, W. Żurowski, Z. Siemiątkowski, D. Morozow, A. G. Kharatyan, Remanufacturing and Advanced Machining Processes for New Materials and Components, 2022
E. S. Gevorkyan, M. Rucki, V. P. Nerubatskyi, W. Żurowski, Z. Siemiątkowski, D. Morozow, A. G. Kharatyan
Laser is also used for supporting other surface engineering techniques, for example, enhanced electroplating. In this method, irradiation of a laser beam on a substrate (cathode) during electrolysis promotes drastic modification of the electrodeposition process in the irradiated region. Other applications of lasers to surface engineering are laser cleaning, paint stripping or laser surface roughening. The latter, executed with pulses from an excimer laser, improves adhesion of glue to a surface. Laser shock hardening or “laser shot peening” has emerged as an industrial process able to create a compressive stress in a surface and thus increase fatigue strength of a component's material (Steen, 2003).
Surface Engineering and Processes
Published in Kenneth C. Ludema, Oyelayo O. Ajayi, Friction, Wear, Lubrication, 2018
Kenneth C. Ludema, Oyelayo O. Ajayi
Some plastic flow processes include the following: 1.Burnishing involves pressing and sliding a hardened sphere or (usually) roller against the surface to be hardened. It is a rather crude process which can leave a severely damaged surface. Lubrication reduces the damage.2.Peening is done either with a heavy tool that strikes and plastically indents a surface, usually repeatedly, or by small particles that are flung against a surface with sufficient momentum to plastically dent the surface. The latter is called shot peening if the particles are metal of the size of ballistic shot. The velocity of shot or other particles may be as high as 35 m/s. It is, therefore, a very noisy and dangerous process.3.Skin pass rolling is done with spheres or (usually) rollers of a diameter and loading such that the surface to be hardened is plastically indented to a small depth. Large rolls will plastically deform thin plate or sheet throughout the thickness, but skin pass rolling can be controlled to plastically deform to shallow depths.
Metal additive manufacturing using lasers
Published in Rupinder Singh, J. Paulo Davim, Additive Manufacturing, 2018
C. P. Paul, A. N. Jinoop, K. S. Bindra
Property enhancements can be done with non-thermal techniques, such as shot peening. Shot peening is a mechanical surface treatment technique in which small balls are impacted on the surface of a component. The repeated impacts of the balls induce compressive residual stress and refine the microstructure. This helps in delaying the crack initiation and hinders the crack propagation [87]. Thus, the mechanical properties and microstructure can be tailored as per the requirement by shot peening. Infiltration is another post-processing technique used in laser-sintered components. Porous LS part is heated in contact with the infiltrant to a temperature at which the infiltrant is molten and will soak into the part through capillary action. The infiltrant solidifies on cooling and produces the final part. The significant attention is on the ability of the infiltrant to wet the solid preform and form the dense solid [88]. The strength of the structure after infiltration is a function of the time period of infiltration as shown in Table 2.5.
The Effect of Shot-Peening Time on Tribological Behavior of AISI5160 Steel
Published in Tribology Transactions, 2022
Xue Han, Zhenpu Zhang, Bo Pang, Gary C. Barber, Jianxin Zhao, Feng Qiu
Shot peening is a type of cold-working process that is a well-known mechanical surface treatment to improve the fatigue strength of metallic components, so it is widely applied in aerospace, automotive, and power generation industries (1–3). Generally, the shot-peening process is accomplished using 0.25-mm to 1-mm diameter cast iron, steel, or glass spherical shots continually bombarding the surface of components at speeds from 20 to 150 m/s (4). During this process, plastic deformation is produced and leads to a hardened surface. When the plastic deformation area expands to other areas, it is constrained by the adjacent deeper material. Then compressive residual stress is produced (5, 6). The shot causes strain hardening and grain deformation, which leads to modified mechanical properties of the components (7). The factors that affect shot peening are that (1) shot peening produces dents, which result in high roughness and stress concentration points; (2) the small balls continuously hit the surface and produce plastic deformation, so a hardened layer with lower ductility is produced on the surface; (3) the grain size may change from micro- to nanometers; (4) the deformation may cause phase transformations, such as the transformation of metastable austenite to martensite; and (5) compressive residual stress is produced (8–13).
Accuracy of X-ray diffraction measurement of residual stresses in shot peened titanium alloy samples
Published in Nondestructive Testing and Evaluation, 2019
Xuesong Fu, Zhiqiang Niu, Ying Deng, Jie Zhang, Chongyuan Liu, Guoqing Chen, Zhiqiang Li, Wenlong Zhou
Ti-6Al-4V(TC4) is widely used in gas-turbine engine as discs and blades because of its excellent specific strength, good corrosion resistance property and outstanding machinability. However, the blade root and disk are subjected to alternating loads during flight, resulting in fatigue and wear. Fatigue can reduce engine life and cause great economic loss. In general, shot peening is the most effective and widely used method to improve fatigue performance. Shot peening uses a high-speed moving small steel ball to impact the surface of the material, causing plastic deformation of the surface, and introducing residual compressive stress on the metal surface [1–3]. It is well known that residual compressive stress can improve the fatigue properties of materials [4]. In many cases, it is important to have the exact value of the residual stress. Residual stress can be measured by X-ray diffraction (XRD), neutron diffraction, wafer curvature, drilling, ultrasonic and electromagnetic methods.
Effect of shot peening coverage on residual stress field and surface roughness
Published in Surface Engineering, 2018
Bin Qiang, Yadong Li, Changrong Yao, Xin Wang
Shot peening is widely used in the fields of aerospace, automotive, turbines, mechanical manufacturing and civil engineering structures as a kind of surface treatment technology. The process involves impacting a component surface using high velocity shots that induce plastic deformation of the component surface layer [1–3]. Shot peening is usually applied as a surface treatment for steel bridges. It introduces residual compressive stress in the surface layer, which can enhance the fatigue resistance of critical load-bearing components. It can also improve the surface roughness to the required level for coating.