Special micro-nano composite powder for laser repair for micro-cracks on stainless steel surface

A composite powder, micro-crack technology, applied in the field of laser repair, to achieve the effect of improving the density and fracture performance

Active Publication Date: 2017-05-10
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Currently, there are no laser repair-specific metal powders that exhibit a satisfactory degree of densification of the repair layer, nor do they have specific laser-repair metal powders to improve fracture performance, especially for stainless steel parts

Method used

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  • Special micro-nano composite powder for laser repair for micro-cracks on stainless steel surface
  • Special micro-nano composite powder for laser repair for micro-cracks on stainless steel surface
  • Special micro-nano composite powder for laser repair for micro-cracks on stainless steel surface

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Embodiment 1: by weight percent, comprising 5% nanometer WC (50-80nm), 1% nanometer Al 2 o 3 (30-50nm), the balance is micron-sized stainless steel powder (30-50μm). The stainless steel powder contains 0.08% C, 0.5% Si, 1.46% Mn, 0.03% P, 0.005% S, 19% Cr, 9.5% Ni, 0.5% Mo, and the balance is Fe . Using the above formula, various powders are thoroughly mixed through mechanical ball milling, then blended with absolute ethanol and further mixed evenly.

[0020] Before the laser repair process, dry the composite powder at a temperature of 150°C for 2 hours; use 400-2000 sandpaper to polish the area to be repaired in turn, then clean it with absolute ethanol, and then dry it; The composite powder is uniformly pre-placed on the micro-cracks on the surface of the stainless steel substrate to be repaired, and the pre-set thickness is controlled at 0.8-1.2mm to ensure a smooth surface and low porosity; laser technology is used to repair micro-cracks on the surface of the sta...

Embodiment 2

[0022] Embodiment 2: by weight percentage, comprising 3% nanometer WC (50-80nm), 2% nanometer Al 2 o 3 (30-50nm), the balance is micron-sized stainless steel powder (30-50μm). The stainless steel powder contains 0.08% C, 0.5% Si, 1.46% Mn, 0.03% P, 0.005% S, 19% Cr, 9.5% Ni, 0.5% Mo, and the balance is Fe . Using the above formula, various powders are thoroughly mixed through mechanical ball milling, then blended with absolute ethanol and further mixed evenly. The method of repairing cracks by laser is the same as in Example 1. The repaired interface presents metallurgical bonding; the grains in the repaired layer are refined, and the compactness of the structure is improved; under the load of 20kN, the fracture parameter COD of the specimen is reduced by 19.3%, and the fracture performance is improved.

Embodiment 3

[0023] Embodiment 3: by weight percentage, comprising 7% nanometer WC (50-80nm), 0.5% nanometer Al 2 o 3 (30-50nm), the balance is micron-sized stainless steel powder (30-50μm). The stainless steel powder contains 0.08% C, 0.5% Si, 1.46% Mn, 0.03% P, 0.005% S, 19% Cr, 9.5% Ni, 0.5% Mo, and the balance is Fe . Using the above formula, various powders are thoroughly mixed through mechanical ball milling, then blended with absolute ethanol and further mixed evenly. The method of repairing cracks by laser is the same as in Example 1. The repaired interface presents metallurgical bonding; the grains in the repaired layer are refined, and the compactness of the structure is improved; under the load of 20kN, the fracture parameter COD of the specimen is reduced by 18.6%, and the fracture performance is improved.

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Abstract

The invention discloses a special micro-nano composite powder for laser repair for micro-cracks on a stainless steel surface. The special micro-nano composite powder comprises, in percentage by weight, 3-7% of nano-WC, 0.5-2% of nano-Al2O3 and the balance micro-scale stainless steel powder, wherein the micro-nano powders are adequately mixed through mechanical ball milling, then blended by virtue of absolute ethyl alcohol, and then further uniformly mixed; and the stainless steel powder comprises, in percentage by weight, 0.08% of C, 0.5% of Si, 1.46% of Mn, 0.03% of P, 0.005% of S, 19% of Cr, 9.5% of Ni, 0.5% of Mo and the balance Fe. The composite powder provided by the invention is applicable to laser repair with a high-toughness requirement for micro-cracks on the surface of a stainless steel part; and after the laser repair, the composite powder can be adequately fused with a base material, a repair layer is metallurgically bonded with the interface of a base body without cracks and inclusions, and fine crystal grains are contained in the repair layer, thus the compactness and fracture performance of the repair layer are improved.

Description

technical field [0001] The invention belongs to the technical field of laser repair, in particular to a micro-nano composite powder specially used for laser repair of tiny cracks on the surface of stainless steel. Background technique [0002] Due to the characteristics of high strength and excellent mechanical properties of stainless steel, it is widely used in the production of various equipment and components. However, microcracks will inevitably occur in the process of manufacturing or workpiece service, and microcracks are one of the main reasons for the failure of structural components. The initiation and propagation of cracks reduce the service life of workpieces, and may even bring unpredictable catastrophic risks. If the failed workpiece is discarded directly, it will cause huge economic losses and waste of resources. In contrast, repairing is the most economical and environmentally friendly way. [0003] Typically, iron-based, nickel-based and cobalt-based powder...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/44B22F1/00C23C24/10B22F1/052B22F1/0545B22F1/12
CPCC22C38/02C22C38/04C22C38/44C23C24/103B22F1/0545B22F1/052B22F1/12B22F1/09C22C38/40C22C1/1084B22F2007/068B22F2999/00B22F2009/043B23P6/04B22F2304/054B22F2301/40B22F2302/253B22F2301/15B22F2301/35B22F2302/10
Inventor 蒋玮蒋险峰李银银
Owner DALIAN UNIV OF TECH
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