Crack Arrest and Structural Repair of High Strength Steel Piping by In-Situ Sleeving of Nanostructural Materials

This proposal describes the application of a mature nanotechnology-based crack arrest / structural repair technology as a novel crack arrestor tool for high-strength pipelines. The crack arrestor would comprise a thin layer or sleeve of electrodeposited nanocrystalline material applied to the outside of the pipe either in the coating mill during fabrication or in-field during or following construction. The concept proposed has already been successfully employed for in-situ structural repair / crack bridging of corroded steam generator tubing in nuclear stations across North America and is presently in development for application to the repair of degraded oil and gas heat exchangers in Saudi Arabia. This ASME-approved electroformed nanomaterial provides superior strength and toughness and thus allows for design/operating load conditions to be accomodated with significantly less material build-up and with far superior bonding to the pipe surface than would normally be achievable with a conventional full-encirclement sleeve. The objectives of this proposed program are to carry out a technology review with particular emphasis on the cost of full-scale implementation, to produce sections of nanometal-coated pipe that could be tested for strength, adhesion, etc, and to evaluate the effect of various sleeve configurations on pipeline strength via finite element analysis.