"Plate thickness should suit the depth of the prepared surface, however, should
not be less than 3/8 inch (10 mm). The edges of the plates should be beveled,
and welding between plates should be full penetration (
not be less than 3/8 inch (10 mm). The edges of the plates should be beveled,
and welding between plates should be full penetration (
"Grinding to Contour. The surface finish and profile should be as discussed
previously for weld repair.
previously for weld repair.
"Inspection. The weld repair should be fully inspected by dye penetrant testing.
"Remove Damage Section and Replace with New Plates Welded in Place.
"General. The removal of a severely damaged section of a runner blade and
replacement with a new plate is relatively common in both shop and field repair
of turbine runners. When welded with full penetration welds and properly
shaped to match the contour of the blade, this can be a very effective repair
technique. For a carbon steel runner the new plate should be 304 stainless with
309 filler metal.
replacement with a new plate is relatively common in both shop and field repair
of turbine runners. When welded with full penetration welds and properly
shaped to match the contour of the blade, this can be a very effective repair
technique. For a carbon steel runner the new plate should be 304 stainless with
309 filler metal.
"The basic considerations and procedures as discussed previously for repair by
welding will also apply to this method of repair. The weld is more structural in
nature, therefore, increased inspection is warranted.
welding will also apply to this method of repair. The weld is more structural in
nature, therefore, increased inspection is warranted.
"Process. Either shielded metal arc or gas metal arc processes are suitable.
"Surface Preparation. Damaged blade sections should be burned away and the
edges prepared for welding in the new plate. The new plate should be shaped
as close as possible to the required final contour.
edges prepared for welding in the new plate. The new plate should be shaped
as close as possible to the required final contour.
"Preheat. Preheat requirements will be as discussed for repairs by welding.
"Application. The weld should be fully penetrated and applied in multiple
passes. Each pass should be peened, except for the root pass and final pass.
Care must be taken in preventing blade distortion. One method is to preset the
item for the expected distortion and allow the welding to bring the component
into correct shape.
passes. Each pass should be peened, except for the root pass and final pass.
Care must be taken in preventing blade distortion. One method is to preset the
item for the expected distortion and allow the welding to bring the component
into correct shape.
"Each weld pass should be visually inspected and a dye penetrant check made
after the final weld is ground to contour.
after the final weld is ground to contour.
"Grinding to Contour. The surface finish and profile should be as discussed
previously for weld repairs.
previously for weld repairs.
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