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Metallographic corrosion method for clearly displaying 9-12% Cr heat-resistant steel original austenite grain boundary

A clear display and metallographic corrosion technology, which is applied in the field of metallographic corrosion to clearly display the original austenite grain boundaries of 9-12% Cr heat-resistant steel, can solve the difficulty of displaying the original austenite grains of heat-resistant steel, etc. problem, to achieve the effect of increasing the electrochemical reaction intensity, clear display, and clear outline

Inactive Publication Date: 2014-08-13
SHANGHAI ELECTRIC POWER GENERATION EQUIPMENT CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In view of the above-mentioned shortcoming of the prior art, the purpose of the present invention is to provide a metallographic corrosion method that can clearly display the original austenite grains of 9-12% Cr heat-resistant steel, and solve the 9 Difficulty in displaying prior austenite grains of ~12%Cr heat-resistant steel

Method used

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  • Metallographic corrosion method for clearly displaying 9-12% Cr heat-resistant steel original austenite grain boundary
  • Metallographic corrosion method for clearly displaying 9-12% Cr heat-resistant steel original austenite grain boundary
  • Metallographic corrosion method for clearly displaying 9-12% Cr heat-resistant steel original austenite grain boundary

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] (1) Grinding: put the cut 12Cr10Mo1W1VNbN rotor steel metallographic sample on the grinding wheel for grinding, grind off the surface oxide skin and roughly smooth it, put the polished sample in turn on 200 mesh, 400 mesh, 600 mesh Grind on 800-grit, 800-grit, and 1000-grit sandpaper. During the grinding process, it is necessary to observe frequently to ensure that all scratches are along the grinding direction of the pass and there are no obvious coarse scratches. When grinding the next pass, the sample should be rotated 90° before continuing to grind .

[0048] (2) Polishing: clean the ground sample, and polish it on a polishing cloth, using water as a lubricant, and a 2.5 μm diamond polishing paste as the polishing agent. The polished samples were washed with water and ethanol and dried, and observed under a metallographic microscope without obvious scratches.

[0049] (3) Corrosion: Put the polished sample into 60% nitric acid corrosion solution (volume percentage...

Embodiment 2

[0053] (1) Grinding: put the cut 12Cr10Mo1W1VNbN rotor steel metallographic sample on the grinding wheel for grinding, grind off the surface oxide skin and roughly smooth it, put the polished sample in turn on 200 mesh, 400 mesh, 600 mesh Grind on 800-grit, 800-grit, and 1000-grit sandpaper. During the grinding process, it is necessary to observe frequently to ensure that all scratches are along the grinding direction of the pass and there are no obvious coarse scratches. When grinding the next pass, the sample should be rotated 90° before continuing to grind .

[0054] (2) Polishing: clean the ground sample, and polish it on a polishing cloth, using water as a lubricant, and a 2.5 μm diamond polishing paste as the polishing agent. The polished samples were washed with water and ethanol and dried, and observed under a metallographic microscope without obvious scratches.

[0055] (3) Corrosion: Put the polished sample into 55% nitric acid corrosion solution (volume percentage...

Embodiment 3

[0059] (1) Grinding: put the cut 12Cr10Mo1W1VNbN rotor steel metallographic sample on the grinding wheel for grinding, grind off the surface oxide skin and roughly smooth it, put the polished sample in turn on 200 mesh, 400 mesh, 600 mesh Grind on 800-grit, 800-grit, and 1000-grit sandpaper. During the grinding process, it is necessary to observe frequently to ensure that all scratches are along the grinding direction of the pass and there are no obvious coarse scratches. When grinding the next pass, the sample should be rotated 90° before continuing to grind .

[0060] (2) Polishing: clean the ground sample, and polish it on a polishing cloth, using water as a lubricant, and a 2.5 μm diamond polishing paste as the polishing agent. The polished samples were washed with water and ethanol and dried, and observed under a metallographic microscope without obvious scratches.

[0061] (3) Corrosion: Put the polished sample into 65% nitric acid corrosion solution (volume percentage...

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Abstract

The invention provides a metallographic corrosion method for clearly displaying a 9-12% Cr heat-resistant steel original austenite grain boundary, solving the difficult problems that 9-12% Cr heat-resistant steel original austenite crystal grains subjected to quenching and tempering treatment are hardly displayed can be solved by adopting the metallographic corrosion method. By adopting corrosive liquid, on one hand, full acidification effects can be realized, and the electrochemical reaction intensity of a dissolved solution can be improved, and on the other hand, the corrosive liquid can be in chemical reaction with a matrix to generate Fe<3+>, wherein Fe<3+> can be used for inhibiting an intragranular corrosion reaction to a certain extent when heating so as to ensure that the corrosion degree of an intragranular structure is significantly slower than that of a grain boundary. Meanwhile, a certain amount of precipitates exist on the grain boundary to ensure that the corrosion of the grain boundary is relatively strong and can generate a relatively large difference from the intragranular corrosion degree in a certain time, thus obtaining an original austenite grain boundary with a clear outline.

Description

technical field [0001] The invention belongs to the field of metallographic sample preparation, and particularly relates to a metallographic corrosion method for clearly displaying the original austenite grain boundary of 9-12% Cr heat-resistant steel. Background technique [0002] The original austenite grains of the steel directly affect the change of the structure during the subsequent processing. The original austenite grains not only affect the strength of steel, but also have a great influence on the mechanical properties of materials such as cold-brittle transformation and fracture. Therefore, it is of great significance to accurately display the austenite grains of steel. [0003] The microstructure of 9-12% Cr heat-resistant steel after quenching and tempering presents typical martensitic tempered structure characteristics. There are many ways to display the original austenite of 9-12% Cr heat-resistant steel, the most commonly used is picric hydrochloric acid alc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N1/32
Inventor 夏健梅林波吴令萍
Owner SHANGHAI ELECTRIC POWER GENERATION EQUIPMENT CO LTD
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