Benefits Of Shot Peening For Aircraft
Shot peening is a cold work procedure used to apply compressive residual stresses to a component's surface, changing its mechanical characteristics as a consequence. To increase strength and lower the stress levels of components, shot peening (in German, this is known as kugelstrahlen) is employed. Even components like gears, housings, and camshafts found in aircraft and automobiles can benefit from shot peening by having their fatigue life extended and cracks effectively prevented.
How Does Shot Peening Work?
In order for shot peening to produce plastic deformation, a surface must first be struck with a shot (a spherical metallic, glass, or ceramic particle) with sufficient force. Multiple indentations are created when several shots strike a surface, which in turn encases the component in a compressively strained layer on the metal surface.
What Are the Benefits of Shot Peening?
The main benefit of shot peening is to strengthen a component's resistance to fatigue, including corrosion fatigue, stress corrosion, and cavitation erosion, while also assisting in preventing the emergence and spread of cracks. This increases the component's shelf life. Compression stresses that suppress metal fatigue are produced in order to stop cracks from spreading through the material. Internal plastic deformation brought on by different kinds of shot peening and laser peening helps tensile stressed components from the inside, which also reduces stress corrosion levels and even cracking. Tensile stresses, however, are less harmful since surface cracks are less likely to begin on a material's interior surface.
Applications
Shot peening is utilised in a variety of industries, including the medical, aerospace, and automotive sectors to enhance the surface appearance of components. Shot peening has further uses, such as the removal of sand from foundries, descaling, decoring, and surface polishing of castings used in engine blocks and cylinder heads. The procedure is also frequently employed in aeroplane repairs to relieve tensile stress brought on by work hardening. Shot peening can employ desirable compressive stresses to tackle the tensile stresses that can be produced by techniques like grinding. Moreover, shot peening can extend fatigue life by up to 1000%, depending on the shot quality, intensity, material, and coverage.
Additionally, shot peening can be employed for aesthetic reasons to produce a surface that is rougher than the result of other techniques like sandblasting, which reflects light from the material more effectively. Through the application of an extra powder or liquid with the appropriate surface coating, the technique can also be used to impart material to metal surfaces. In this technique, a shot is fired through the powder or fluid, which in turn coats the workpiece as a result of the peening that's taking place. Due to the chaotic nature of the peening process, this technique has been used to place ceramic coatings and add solid lubricants to surfaces, though the coverage is usually random nevertheless.
Final Thoughts
Internal stress concentrations such as scratches, burns, welds, and other defects may result from the machining and forming of metal parts. Shot peening can prevent these issues from occurring, which may be the cause of early fatigue failure, porosity, material weakening, and corrosion. Otherwise, a compressively stressed peened skin is particularly effective in avoiding crack initiation and growth in some applications since fatigue cracks typically start at surface defects.