Industrial Need
The primary need originated from the nuclear power sector. Weld repairs of austenitic weld overlay on ferritic substrates may be required for nuclear power plant components following in-service inspection or during planned maintenance operations. In some instances, the application of preheating and PWHT are impractical, potentially unsafe and/or non-cost-effective. Therefore, a repair solution that does not require any of the above heating operations is required. A similar scenario may also be found in the oil and gas sector, when components with corrosion resistant weld overlays (typically pressure retaining) require weld repair.
In addition, requirements for the qualification of such weld repairs provided by international standards (eg ASME B&PV, Section IX) are only available for original fabrication, and may not be appropriate for service aged components. According to EdF (EdF, 2012), other test applied in industry, such as cold cracking tests (EN ISO 17642) are too severe for ‘cold repairs’ therefore a cold cracking test optimised for temper-bead repair, is required.
Objectives
- Develop and qualify procedures for weld repairs of ferritic components without the need for either preheat or PWHT
- Develop and qualify procedures for weld repairs of austenitic cladding on ferritic components without the need for either preheat or PWHT
- Optimise existing cold cracking test procedures to assess the above weld repair techniques
Project Outline
The project covers one of the current hot topics for the development of specialised repair procedures in the nuclear sector. This project is aimed at providing TWI’s industrial members with repair solutions that do not require preheat nor post-weld heat treatment (PWHT), also referred to as ‘cold’, temper bead or controlled deposition repairs. In addition, ad-hoc test procedures, supplementary to those currently applied for the qualification of standard weld repairs will be evaluated.
Relevant Industry Sectors