Emergency Boiler Repair – Waterwall Tube Replacement at a Power Plant in Germany

Following a boiler failure, the PRO-Welding team was mobilised to carry out the urgent replacement of a damaged waterwall tube section in the furnace roof area.

The key requirement was to complete the repair as quickly as possible and prepare the boiler for return to service. The entire scope of work was completed within 20 hours.

Project information

Location	Germany
Facility	Power plant
Project type	Emergency boiler repair
Scope	Replacement of a damaged waterwall tube section
Material	15Mo3 boiler steel
Tube dimensions	Approx. Ø57.5 × 5 mm
Welding process	TIG 141
Quality control	VT, RT, pressure test
Completion time	20 hours

Scope of work

The repair involved the replacement of a damaged waterwall tube section in the boiler roof.

The scope of work included:

• removal of the damaged tube section,
• edge preparation and bevelling,
• fitting and alignment of the replacement tube section,
• completion of circumferential butt welds,
• longitudinal welding of the new tube to the adjacent membrane fins,
• restoration of the continuity of the boiler membrane wall.

TIG 141 welding

The pressure-part tube joints were welded using the TIG 141 process. TIG welding was used for both the circumferential butt welds and the welds connecting the replacement tube to the membrane fins.

Before welding, all joint areas were carefully prepared, bevelled and mechanically cleaned to bare metal.

Work in a restricted access area

One of the main challenges was restricted access to the repair area. The work was carried out in the boiler roof zone, directly alongside adjacent waterwall tubes.

The limited working space required welding in restricted positions and careful preparation of the work area for welding and material preparation.

Dust, ash and deposits inside the furnace created an additional challenge, making it particularly important to protect the prepared components against contamination.

Quality control and acceptance

Following completion of the repair, the following inspections and tests were carried out:

• VT – 100% visual inspection of the completed welds and repaired membrane wall area,
• RT – radiographic testing of all new pressure-part welds,
• pressure testing of the boiler pressure system.

The inspections and tests were performed in accordance with the applicable acceptance requirements and project technical documentation.

Emergency repair completed in 20 hours

Due to the emergency nature of the project, rapid response, efficient team organisation and coordinated execution of each repair stage were critical.

The entire scope of work was completed within 20 hours from the start of the repair.