REPAIR PROCESS USING LASER METAL POWDER DEPOSITION
A laser metal powder deposition method is described which can be utilized for the repair of cast stainless steel components used in nuclear environments. Internal defects found in a component ( 200 ) during routine maintenance and refurbishment are identified and then excavated to form a cavity ( 210 ). The cavity is filled by multiple layers ( 310 1 , 310 2 , . . . , 310 N ) of laser metal powder deposition and then checked for its integrity.
1 . A method of repairing a cast stainless steel component, the method comprising the steps of:
a) identifying the presence of at least one defect in the cast stainless steel component;
b) excavating a region in the cast stainless steel component which includes the at least one identified defect to form a cavity;
c) depositing laser metal powder within the cavity in a predetermined pattern;
d) melting and fusing the deposited powder within the cavity using a laser; and
e) finishing the surface of the filled cavity to match the surface of the cast stainless steel component.
2 . A method according to claim 1 , further comprising the step of cleaning the cavity prior to step c).
3 . A method according to claim 1 or 2 , further comprising repeating steps c) and d) more than once.
4 . A method according to claim 3 , wherein each repetition of steps c) and d) builds a metal layer within the cavity.
5 . A method according to any one of claims 1 to 4 , wherein step b) comprises using non-destructive testing to control the excavation of the region including the defect.
6 . A method according to any one of claims 1 to 5 , wherein step e) comprises a mechanical finishing step.
7 . A method according to any one of claims 1 to 6 , further comprising the step of checking that the repair conforms with the rest of the cast stainless steel component.