A method for displaying the prior austenite grain boundaries of p91, p92 ferritic heat-resistant steel

A technology of austenitic grain boundaries and heat-resistant steel, which is applied in the preparation of test samples, measuring devices, and material analysis through optical means to achieve good reproducibility, easy etching process, and stable display effect

Active Publication Date: 2018-04-06
DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The object of the present invention is to aim at the deficiencies of the above-mentioned prior art, to provide a simple, convenient, fast, safe, easy-to-control etching process and stable display effect, good reproducibility, low cost, non-toxic and pollution-free, easy to observe A new method with simple equipment and no special requirements. It can clearly and completely display the original austenite grain boundary of P91 and P92 ferritic heat-resistant steel, so as to accurately measure the austenite grain size. Research, quality control and quality problem analysis and processing provide accurate and reliable detection basis

Method used

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  • A method for displaying the prior austenite grain boundaries of p91, p92 ferritic heat-resistant steel
  • A method for displaying the prior austenite grain boundaries of p91, p92 ferritic heat-resistant steel
  • A method for displaying the prior austenite grain boundaries of p91, p92 ferritic heat-resistant steel

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Experimental program
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Effect test

Embodiment 1

[0030] (1) Sample: P92 ferritic heat-resistant steel (coarse grain structure)

[0031] (2) Sulfuric acid electrolyte concentration: 5%, sulfuric acid electrolysis voltage 8V, sulfuric acid electrolysis time: 30s;

[0032] (3) Nitric acid electrolyte concentration: 65-68%, nitric acid electrolysis voltage 11V, nitric acid electrolysis time: 8s;

[0033] (4) The complete and clear prior-austenite grain boundaries observed under an optical microscope at a power of 50 times are as follows: image 3 As shown, the measured austenite grain size is 00 grade.

Embodiment 2

[0035] (1) Sample: P92 ferritic heat-resistant steel (coarse grain structure)

[0036] (2) Sulfuric acid electrolyte concentration: 10%, sulfuric acid electrolysis voltage 8V, sulfuric acid electrolysis time: 35s;

[0037] (3) Nitric acid electrolyte concentration: 65-68%, nitric acid electrolysis voltage 10V, nitric acid electrolysis time: 12s;

[0038](4) The complete and clear prior-austenite grain boundaries observed under an optical microscope at a power of 50 times are as follows: Figure 4 As shown, the austenite grain size was determined to be 0.5.

Embodiment 3

[0040] (1) Sample: P92 ferritic heat-resistant steel (fine grain structure)

[0041] (2) Sulfuric acid electrolyte concentration (volume percentage): 15%, sulfuric acid electrolysis voltage 7.5V, sulfuric acid electrolysis time: 40s;

[0042] (3) Nitric acid electrolyte concentration (mass percentage): 60-64%, nitric acid electrolysis voltage 10V, nitric acid electrolysis time: 10s;

[0043] (4) The complete and clear prior-austenite grain boundary diagram observed under the optical microscope at 100 times is as follows Figure 5 As shown, the austenite grain size was determined to be grade 7.

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Abstract

The invention discloses a method for displaying P91 and P92 ferrite heat-resistant steel original austenite crystal boundary. The P91 and P92 ferrite heat-resistant steel original austenite crystal boundary can be clearly and completely displayed through adopting an aqueous sulfuric acid solution electrolytic etching and concentrated nitric acid solution electrolytic etching combination two-step electrolytic etching technology in order to accurately determine the austenite grain size. The method has the advantages of simple, convenient, fast and safe operation, easy control of the etching process, stable display effect and good reappearance.

Description

technical field [0001] The invention relates to a method for displaying the original austenite grain boundary of P91 and P92 ferritic heat-resistant steels, belonging to the technical field of metallographic display. Background technique [0002] P91 and P92 ferritic heat-resistant steels have excellent high-temperature performance and are widely used in super (super) critical boiler production. Since the actual austenite grain size of the steel directly affects the properties of the steel, the coarse austenite grains often lead to the coarse structure of the material after cooling, so that the material has lower plasticity and toughness. For this reason, strengthening the inspection of the actual austenite grain size of P91 and P92 steel has always been an important indicator for boiler manufacturers to evaluate the quality of such materials. It is of great significance to study the effect of grain size on performance. [0003] In view of the great influence of the prior ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N21/84G01N15/02G01N1/28G01N1/32
Inventor 曾辉毛世勇李健张学星
Owner DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
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