(PS11012) Fatigue and SCC Lifetime Enhancement of Steels by Means of Laser Peening

摘要

Laser peening technology has emerged as an important contributor to improved fatigue lifetimes and reduced suspetability to stress corrosion cracking for a broad range of components that can be treated in a factory setting or on site. The process induces deeper levels of plasticity in materials than conventional surface treatments resulting in compressive residual stress to depths of 0.100 inches (2.5 mm) or greater that enable this advanced performance. The technology is being used to enhance the fatigue lifetime and fatigue strength of jet engine fan blades for commercial aircraft such as the B777, the A340 and B787 and military aircraft including the newest jet fighters, for automotive engines and tooling and electrical power gas and steam turbines. Up until now applying the laser peening process was relegated to a shop environment where components are delivered for processing and subsequently returned and installed into systems. This paper discusses development of a transportable laser peening system and advanced beam delivery technology that enables field deployment on large structures such as but not limited to aircraft, ships, pressure vessels, nuclear power plants and bridges. We will discuss the evolution and current capabilities of this field deployable technology as well as provide supporting data showing the generation of deep levels of residual stress and subsequent enhanced fatigue lifetime in test articles and components. Multiple laser peening systems have been built and deployed in field applications; one application involves forming the needed aerodynamic curvature of 105 foot long wing panels for the B747-8 and another the on-wing peening of aircraft structure to enhance fatigue lifetime.