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A method for displaying the grain boundaries of prior austenite in steel for ultra-supercritical units containing CO

An ultra-supercritical unit, austenite grain boundary technology, applied in the preparation of test samples, etc., can solve the problem of difficult to accurately evaluate the thickness and uniformity of steel grains, and achieve the effect of effective display and simple operation.

Active Publication Date: 2018-10-26
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a method for displaying the original austenite grain boundary of steel used in Co-containing ultra-supercritical units, so as to solve the problem of accurately evaluating the grain size and uniformity of a Co-containing ultra-supercritical unit steel The problem

Method used

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  • A method for displaying the grain boundaries of prior austenite in steel for ultra-supercritical units containing CO
  • A method for displaying the grain boundaries of prior austenite in steel for ultra-supercritical units containing CO
  • A method for displaying the grain boundaries of prior austenite in steel for ultra-supercritical units containing CO

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] 1. Grinding - polishing

[0031] Take a steel sample for a Co-containing ultra-supercritical unit, grind the original austenite grain interface of the sample to be displayed, and then polish it. After polishing to no scratches, rinse and dry with alcohol;

[0032] 2. Pre-chemical etching

[0033] Cover the surface of the polished sample with saturated picric acid solution, let it stand for 60s, rinse it with clean water, and then dry it with alcohol;

[0034] 3. Electrolytic etching

[0035] A DC voltage controllable device equipped with a DC ammeter and a sliding resistor is used, the sample is used as an anode, and a stainless steel sheet is selected as a cathode, which is placed in an 8% dilute sulfuric acid aqueous solution; the sample has been chemically corroded in advance. Cathode stainless steel sheet, adjust the output voltage to 20V, move the sliding rheostat to make the current density reach 1.6A / cm 2 , keep the power-on time for 120s, so that the original...

Embodiment 2

[0039] 1. Grinding and polishing

[0040]Take a steel sample for a Co-containing ultra-supercritical unit, grind the original austenite grain interface of the sample to be displayed, and then polish it. After polishing to no scratches, rinse and dry with alcohol;

[0041] 2. Pre-chemical etching

[0042] Cover the surface of the polished sample with saturated picric acid solution, let it stand for 120s, rinse it with clean water, and then dry it with alcohol;

[0043] 3. Electrolytic etching

[0044] A DC voltage controllable device equipped with a DC ammeter and a sliding resistor is used, the sample is used as an anode, and a stainless steel sheet is selected as a cathode, and put into a dilute sulfuric acid aqueous solution with a mass fraction of 4% at the same time; the sample has been chemically etched in advance. Cathode stainless steel sheet, adjust the output voltage to 10V, move the sliding rheostat to make the current density reach 0.8A / cm 2 , keep the power-on t...

Embodiment 3

[0048] 1. Grinding and polishing

[0049] Take a steel sample for a Co-containing ultra-supercritical unit, grind the original austenite grain interface of the sample to be displayed, and then polish it. After polishing to no scratches, rinse and dry with alcohol;

[0050] 2. Pre-chemical etching

[0051] Cover the surface of the polished sample with saturated picric acid solution, let it stand for 80s, rinse it with clean water, and then dry it with alcohol;

[0052] 3. Electrolytic etching

[0053] A DC voltage controllable device equipped with a DC ammeter and a sliding resistor is used, the sample is used as the anode, and a stainless steel sheet is selected as the cathode, and it is placed in a dilute sulfuric acid aqueous solution with a mass fraction of 7%. Cathode stainless steel sheet, adjust the output voltage to 18V, move the sliding rheostat to make the current density reach 1.4A / cm 2 , keep the power-on time for 150s, so that the original austenite grain interf...

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Abstract

The invention relates to the technical field of observing the original austenite grain boundaries of metallographic samples. Specifically, it is a method of observing the original austenite grain boundaries of Co-containing steel for ultra-supercritical units with high alloy content, strong corrosion resistance and good oxidation resistance. Display method, the specific process steps are: first grind and polish the Co-containing ultra-supercritical unit steel sample, then use the method of pre-chemical corrosion + electrolytic corrosion, and finally combine the mechanical polishing method to finally display the original clearly. Austenite grain boundaries. The present invention can clearly and completely display the original austenite grain boundaries of the Co-containing type ultra-supercritical unit steel, thereby comprehensively reflecting the size and distribution of the original austenite grains and solving the problem of difficulty in accurately solving the problem. The problem of grain size and uniformity of the evaluated Co-containing steel for ultra-supercritical units.

Description

technical field [0001] The invention relates to the technical field of metallographic sample preparation and prior austenite grain boundary observation, in particular to a steel former austenite for a Co-containing ultra-supercritical unit with high alloy content, strong corrosion resistance and good oxidation resistance The grain boundary display method can obtain the complete prior austenite size and distribution in the process of evaluating the grain thickness and uniformity of the Co-containing ultra-supercritical unit steel, and finally obtain accurate inspection results. Background technique [0002] As we all know, the microstructure thickness and uniformity of steel have a great influence on various performance indicators of steel, and the evaluation of steel microstructure thickness and uniformity has important index significance in actual production. Co-containing ferritic heat-resistant steel is the fourth-generation casting steel for ultra-supercritical thermal p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N1/32
CPCG01N1/32
Inventor 刘越马煜林刘春明古金涛屈光倪楠周玲
Owner NORTHEASTERN UNIV LIAONING