PROCEDURE FOR FIN WELDING
- Select the correct fin material IS 2062 Gr. A for water wall, cyclone, CIC, COC and steam cooled wall. Fit up of the fin plate must be done after proper grinding with water
wall tubes with a minimum gap of 1 mm at both sides. Provide the fin plate flats with width 2 mm less than the tube pitch. Deploy professional gas cutter for fin cutting.
- Welding can be done by arc welding with E 7018 welding electrode.
- Fillet size must not exceed 4mm.Visual inspection mainly for any deep undercut. Deep undercut may lead to tube failure in future. Other defects like porosity; cracks etc may be lead to flue leakages in future. After welding grind the surface smoothly for doing the DP test. DP test percentage can be decided based on the visual inspection. Pre heating post heating not required for carbon steel. Welding electrode storage and handling must be done as per above procedure.
- The fin material for Secondary Super heater & Final super heater is SA 387 Gr.22 which is alloy steel material E-8018 is the welding electrode for this material.