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Method for quickly improving corrosion resistance of material surface in situ

A corrosion-resistant, in-situ technology, applied in the field of controlling the surface properties of austenitic stainless steel, to reduce energy consumption, improve grain boundary characteristic distribution, and improve corrosion resistance

Active Publication Date: 2015-04-29
NANJING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Laser shock has been widely used to improve material hardness, fatigue strength and wear resistance. Laser heat treatment is mostly used for surface transformation hardening of medium and high carbon steel materials and surface laser melting of iron-based, nickel-based and cobalt-based alloy materials. However, there is no report at home and abroad that uses the combination of laser shock and laser heat treatment to control the distribution of grain boundary characteristics on the surface of austenitic stainless steel, thereby rapidly improving the corrosion resistance of stainless steel.

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  • Method for quickly improving corrosion resistance of material surface in situ
  • Method for quickly improving corrosion resistance of material surface in situ
  • Method for quickly improving corrosion resistance of material surface in situ

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] The laser shock equipment (YLSS-D25A type) is used to perform laser shock on the austenitic stainless steel plate, and the laser shock energy is selected as 6J, 8J, and 10J. Subsequently, the sample was subjected to laser heat treatment in a laser processing system (YLR-200-AC type), the laser output power was 150W, and the laser scanning speed was 200mm / min. Water quenching was performed immediately after heating. The ratio of low-energy CSL (heavy-site lattice) special grain boundaries inside the treated samples changes with the laser shock energy. The specific test results are shown in Table 3.

[0032] The treated samples were embedded with epoxy resin and curing agent to prepare standard electrochemical corrosion samples. at room temperature in 0.5M H 2 SO 4 Potentiodynamic reactivation (EPR) experiments and polarization curve measurements were performed on samples in +0.01M KSCN solution. The reactivation current ratio and self-corrosion potential varied with la...

Embodiment 2

[0036] The laser shock equipment (YLSS-D25A type) is used to carry out laser shock on the austenitic stainless steel plate, and the laser shock energy is selected as 6J. Subsequently, the sample was subjected to laser heat treatment in the laser processing system (YLR-200-AC type), and the laser scanning speed was 300 mm min -1 、200mm·min -1 、100mm·min -1 , Water quenching immediately after heating. The ratio of low-energy CSL (heavy site lattice) special grain boundaries inside the treated samples varies with the laser scanning speed. The specific test results are shown in Table 4.

[0037]The treated samples were embedded with epoxy resin and curing agent to prepare standard electrochemical corrosion samples. at room temperature in 0.5M H 2 SO 4 Potentiodynamic reactivation (EPR) experiments and polarization curve measurements were performed on the samples in +0.01M KSCN solution. The reactivation current ratio and self-corrosion potential changed with the laser scannin...

Embodiment 3

[0042] The laser shock equipment (YLSS-D25A type) is used to carry out laser shock on the austenitic stainless steel plate, and the laser shock energy is selected as 6J. Subsequently, the sample was subjected to laser heat treatment in the laser processing system (YLR-200-AC type), and the laser scanning times were 200mm / min for one time, 200mm / min for two times, 200mm / min and 300mm / min for two times respectively. times (four times in total), water quenching immediately after heating. The proportion of low-energy CSL (heavy site lattice) special grain boundaries inside the treated samples varies with the number of laser scans. The specific test results are shown in Table 5.

[0043] The treated samples were embedded with epoxy resin and curing agent to prepare standard electrochemical corrosion samples. The samples were subjected to potentiodynamic reactivation (EPR) experiments and polarization curve measurements in 0.5M H2SO4+0.01M KSCN solution at room temperature. The rea...

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Abstract

The invention relates to a method for quickly improving corrosion resistance of a material surface in situ. The method comprises the following steps: firstly selecting suitable laser process parameters, and introducing a pre-stressing force into the material surface by utilizing laser impaction; and then carrying out laser annealing treatment on the material surface by utilizing a laser. Compared with other methods, the method for quickly improving the corrosion resistance of the material surface in situ, disclosed by the invention, has the advantages that the introduction of the pre-stressing force and a subsequent thermal treatment are finished by laser processing so that a complex surface of a workpiece can be subjected to the in-situ treatment, the crystal boundary distribution of an irregular surface can be quickly optimized, and the inter-crystal corrosion resistance of the material surface can be improved.

Description

technical field [0001] The invention belongs to the technique of controlling the surface layer performance of austenitic stainless steel, in particular to a method for rapidly improving the corrosion resistance of the material surface layer in situ. Background technique [0002] The properties of polycrystalline materials are closely related to their microstructure and grain boundary characteristics. Because there are often large distortions, more defects and impurities at the grain boundaries, the surface activity is higher than that of the grain interior, and the grain boundary Various phenomena that are closely related to structure, such as grain boundary diffusion, precipitation, corrosion, etc., are often affected by the grain boundary structure. The selective precipitation of intergranular carbides on grain boundaries is mainly caused by the different energy and structure of different grain boundaries. Aust and Rutter were the first to use experimental methods to obse...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21D1/78
Inventor 杨森顾振宇徐肖冯文
Owner NANJING UNIV OF SCI & TECH