Establishment of Repair Technology and Assurance of Strength Reliability in Piping Cracks and Holes by Low-Pressure Cold Spray

Abstract

Repair of piping damaged by corrosion or age-related deterioration in power plants and other infrastructure facilities is essential. In general, welding is used to repair cracks and holes in piping, however it involves long repair times and presents a fire risk due to sparks. To address these issues, this study explored the use of cold spray technique as an alternative repair technology. A previous study achieved successful hole repair with a mixed powder of Sn and Zn, however this coating poses a corrosion concern, highlighting the need for more durable solutions. In this study, the feasibility of repairing holes with corrosion-resistant stainless steel using a low-pressure cold spray technique was investigated. Initial repair tests using a mixture of stainless steel/WC powder at various spray angles revealed difficulties in successfully repairing the holes. Subsequently, stainless steel powder was mixed with soft materials such as Zn or Al powder to assist stainless steel particles deposition, leading to successful repairs. In addition, corrosion resistance tests on stainless steel/Zn and Zn deposits were conducted to evaluate the effect of stainless steel addition on corrosion resistance.