Methods for preparing prefabricated crack defect and built-in crack defect, and prefabricated member

A method for preparing a prefabricated part with built-in crack defects, based on a technique of laser melting deposition, comprising:

• obtaining a 3D model of the prefabricated part,
• separating the prefabricated part into at least one defect area and one forming area, where the defect area is provided inside the prefabricated part,
• defining a volume percentage of the built-in crack defects in the defect area,
• adjusting a proportion of spherical powder, a proportion of hollow powder and process parameters of defect preparation according to the volume percentage of the crack defects,
• printing the prefabricated part with built-in crack defects layer by layer, where a defect preparation powder comprising the spherical powder and the hollow powder and the process parameters of defect preparation are used to print layers of the defect area,
• wherein a particle size of the defect preparation powder is between 45 μm and 150 μm, wherein the proportion of spherical powder≥93% and the proportion of hollow powder<0.5%,
• the process parameters of defect preparation comprising:
• laser power of 450 W-550 W, scanning rate of 600 mm/min-1200 mm/min, powder feeding rate of 4 g/min-12 g/min, spot diameter of 1 mm-1.2 mm, scanning spacing of 0.5 mm-0.8 mm and layer thickness of 0.08 mm-0.2 mm.

A method for preparing a repaired part with built-in crack defects, based on a technique of laser melting deposition, the repaired part comprises a part body and a repair area, the repair area is used to repair a defect or damage of the part body, the method is comprising:

• obtaining a 3D model of the part body and the repair area respectively,
• obtaining the part body,
• separating the 3D model of the repair area into at least one defect area and one forming area, where the defect area would be provided inside the repaired part after being repaired,
• defining a volume percentage of the built-in crack defects in the defect area,
• adjusting a proportion of spherical powder, a proportion of hollow powder and process parameters of defect preparation according to the volume percentage of the crack defects,
• printing the repair area on the defect of the part body layer by layer, where a defect preparation powder comprising the spherical powder and the hollow powder and the process parameters of defect preparation are used to print layers of the defect area,
• wherein a particle size of the defect preparation powder is between 45 μm and 150 μm, wherein the proportion of spherical powder≥93% and the proportion of hollow powder<0.5%,
• the process parameters of defect preparation comprising:
• laser power of 450 W-550 W, scanning rate of 600 mm/min-1200 mm/min, powder feeding rate of 4 g/min-12 g/min, spot diameter of 1 mm-1.2 mm, scanning spacing of 0.5 mm-0.8 mm and layer thickness of 0.08 mm-0.2 mm.