Laser thermal combination remanufacturing method for damaged metal part

Patent metadata

Field	Value
Publication number	US-2017239751-A1
Application number	US-201415307784-A
Country	US
Kind code	A1
Filing date	Dec 17, 2014
Priority date	Nov 12, 2014
Publication date	Aug 24, 2017
Grant date	—

Abstract

A remanufacturing method for a metal part having a damage. The damage groove is divided into a number of levels, and the groove bottom is treated by absorption layer-free laser shock peening to remove surface impurities and to refine surface-layer crystal grains. Then a cladding layer is formed by laser cladding. The process is repeated until the groove is completely filled by the cladding layer to higher than the surface of the metal part and the cladding layer higher than the surface is cut by a mechanical processing and polished, and the upper surface of the laser cladding layer is subjected to large-area overlapped laser shock peening.

First claim

1 - 8 . (canceled)

9 . A method for repairing a scratch in a surface of a metal component, said method comprising the steps of:
dividing the scratch into multiple layers; using laser shock peening (LSP) with laser cladding (wC) LSPwC to treat a bottom of the scratch, remove surface impurities, and refine the surface grains; using laser cladding to form a cladding coating with a given thickness on the scratch; treating each layer by LSPwC first and then laser cladding, until the scratch is completely filled by a cladding coating which extends over a top surface of metallic component; mechanically processing to remove the cladding coating higher than the top surface of metallic component; grinding and polishing the top surface of the cladding coating; and overlapping LSP the top surface of the cladding coating.

10 . The method of claim 9 , wherein the thickness of the laser cladding coating is smaller than the affected depth of LSP on the cladding coating, and the number of cladding coatings formed is based on a depth of the scratch and the thickness of the single laser cladding

11 . The method of claim 9 , wherein LSPwC is used to preprocess the surface layer at the scratch bottom, in which there is no absorbent material applied on the surface of the component, and flowing water is used as transparent confining layer.

12 . The method of claim 9 , including the step of applying a preset cladding powder on the surface of the scratch, and using a fiber laser to complete the first laser cladding coating.

13 . The method of claim 9 , wherein after the cladding coating is solidified, LSPwC is used to treat the top surface of the cladding coating, and
a preset cladding powder is applied to the top surface of cladding coating, and a fiber laser used to complete the second laser cladding coating.

14 . The method of claim 13 , wherein once the scratch is completely filled by the cladding coating to higher than the top surface of metallic component, the N-th laser cladding is completed, and
mechanical processing is used to remove the cladding coating higher than the top surface of metallic component, wherein the top surface of the cladding coating is ground and polished by sandpaper to insure the surface roughness of the cladding coating is less than 0.4 μm.

15 . The method of claim 14 , further comprising using overlapping LSP to treat the surface layer of the polished cladding coating.

16 . The method of claim 15 , wherein absorbing layer material is an aluminum foil with a thickness of 1 mm, the constraining layer is flowing water with a thickness of 1-2 mm, and the overlapping rate between both adjacent spots is 30-50% in both horizontal and vertical directions.

17 . The method according to claim 10 , wherein an affected depth of LSP is a depth of the mechanical properties' improvement in the cladding coating.

18 . The method according to claim 10 , wherein a thickness of the single laser cladding coating is about ⅔ a depth of the scratch.

19 . The method according to claim 10 , wherein a number of cladding coatings “N” applied is determined by the formula

h
b

<
N
≤

h
b

+
1

,

in which the “N” is an integer, “b” is a thickness of the single laser cladding coating, and “h” is a depth of the scratch.

20 . The method according to claim 10 , wherein the laser used has a pulse energy of 3-12 J, a pulse width of 5-20 ns, a spot diameter of 1-3 mm, and an overlapping between adjacent spots of 30-50% in both horizontal and vertical directions.

21 . The method according to claim 10 , wherein the laser used has a power of 400-1800 W, a scanning velocity of 4-9 mm/s, a spot diameter of 1-3 mm, an overlapping of 30-50%, and a flow of protective gas of 3-5 L/min.

22 . The method according to claim 10 , comprising wherein mechanical processing is used to remove the cladding coating higher than the top surface of metallic component, using grinding and polishing is used to insure a surface roughness of the cladding coating of less than 0.4 μm.

Assignees

• Univ Jiangsu

Inventors

• Luo Kaiyu
• Jing Xiang
• Lu Jinzhong
• Liu Bo

Classifications

• B23K26/342 Primary

  Build-up welding · CPC title

• B23K26/0093

  combined with mechanical machining or metal-working covered by other subclasses than B23K · CPC title

• C21D10/005

  by laser shock processing · CPC title

• B23K26/0626

  Energy control of the laser beam (B23K26/0622 takes precedence) · CPC title

• B23K26/144

  the fluid stream containing particles, e.g. powder · CPC title