Corrosive agent for displaying austenite grain boundary of martensitic stainless steel and display method

A technology for martensitic stainless steel and austenite grain boundaries, which is applied in the field of corrosive agents and displays for martensitic stainless steel austenite grain boundaries, and can solve the problems of low-carbon high-alloy steel without corrosive agents and unreasonable corrosion methods. Achieve the effect of high corrosion success rate, good display effect and convenient operation

Inactive Publication Date: 2021-02-02
SHANGHAI JIAO TONG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide an etchant and a display method for displaying the austenite grain boundary of martensitic stainless steel. The corrosion operation is simple and convenient, and the grain boundary display effect is clear. reasonable question

Method used

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  • Corrosive agent for displaying austenite grain boundary of martensitic stainless steel and display method
  • Corrosive agent for displaying austenite grain boundary of martensitic stainless steel and display method
  • Corrosive agent for displaying austenite grain boundary of martensitic stainless steel and display method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] In this example, the grade of low-carbon high-alloy steel is 0Cr16Ni5Mo1, and the specific chemical composition and mass percentage are: C: 0.055%, Cr: 15.32%, Ni: 4.82%, Mo: 0.87%, Si: 0.35%, Mn : 0.88%, P: 0.005%, S: 0.002%, Sn: 0.028%, Cu: 0.04%, and the rest are Fe and unavoidable impurity elements.

[0032] ① Preparation of metallographic samples:

[0033] a. Cut a block sample of 10mm×10mm×5mm by wire cutting method, quench it after austenitizing at 1100℃ for 12 minutes, and prepare for subsequent grinding and polishing;

[0034] b. Coarse grinding of samples: Grind the samples sequentially with 180#→320#→600# silicon carbide water-resistant sandpaper. Rotate 90 degrees so that the new wear marks are vertical or nearly perpendicular to the previous wear marks, and grind until the new wear marks cover the previous wear marks. Use tap water as a lubricant when grinding ;

[0035] c. Fine grinding of the sample: Grind the coarsely ground sample on 1200# silicon ca...

Embodiment 2

[0041] In this example, the grade of low-carbon high-alloy steel is X12CrMoWVNbN10-1-1, and the specific chemical composition and mass percentage are: C: 0.11%, Cr: 10.35%, Ni: 0.80%, Mo: 1.00%, Si: 0.08%, Mn: 0.41%, P: 0.008%, S: 0.004%, W: 1.03%, V: 0.18%, Al: 0.02%, N: 0.05%, Nb: 0.04%, the rest is Fe and unavoidable impurity elements.

[0042] ① Preparation of metallographic samples:

[0043] a. Cut a block sample of 10mm×10mm×5mm by wire cutting method, and quench it after austenitizing at 1150°C for 30 minutes to prepare for subsequent grinding and polishing;

[0044] b. Coarse grinding of samples: Grind the samples sequentially with 180#→320#→600# silicon carbide water-resistant sandpaper. Rotate 90 degrees so that the new wear marks are vertical or nearly perpendicular to the previous wear marks, and grind until the new wear marks cover the previous wear marks. Use tap water as a lubricant when grinding ;

[0045] c. Fine grinding of the sample: Grind the coarsely ...

Embodiment 3

[0051] In this example, the low-carbon high-alloy steel is COST-FB2 rotor steel, the specific chemical composition and mass percentage are: C: 0.14%, Cr: 9.06%, Co: 1.15%, Mo: 1.51%, Ni: 0.17 %, Si: 0.06%, Mn: 0.42%, V: 0.20%, N: 0.06%, Nb: 0.049%, B: 0.008%, and the rest are Fe and unavoidable impurity elements.

[0052] ① Preparation of metallographic samples:

[0053] a. Cut a block sample of 10mm×10mm×5mm by wire cutting method, quench it after austenitizing at 950°C for 5 hours, and prepare for subsequent grinding and polishing;

[0054] b. Coarse grinding of samples: Grind the samples sequentially with 180#→320#→600# silicon carbide water-resistant sandpaper. Rotate 90 degrees so that the new wear marks are vertical or nearly perpendicular to the previous wear marks, and grind until the new wear marks cover the previous wear marks. Use tap water as a lubricant when grinding ;

[0055] c. Fine grinding of the sample: Grind the coarsely ground sample on 1200# silicon ca...

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Abstract

The invention relates to a corrosive agent for displaying the austenite grain boundary of martensitic stainless steel and a display method. The corrosive agent comprises potassium permanganate, concentrated sulfuric acid and water, and the dosage ratio of potassium permanganate to concentrated sulfuric acid to water is (0.5-2) g: (5-15) mL: (85-95) mL; the display method comprises the steps of metallographic sample preparation, sample ultrasonic corrosion, sample observation and grain size statistics. Compared with the prior art, the corrosive agent provided by the invention requires few typesof chemicals, has the advantages of safety, no toxicity, convenience in operation, good display effect and the like, can clearly display the original austenite grains of the martensitic stainless steel sample, solves the problem that the austenite grain boundary of the martensitic stainless steel is difficult to corrode, and is suitable for displaying various low-carbon high-alloy martensitic steel original austenite boundaries which are difficult to corrode, the sample grain boundary corrosion success rate is high, the corrosive agent and the corrosion method are safe and convenient, material grain grading in the actual production process is effectively assisted, and a basis is provided for optimization of the heat treatment process.

Description

technical field [0001] The invention belongs to the technical field of metallographic structure observation of iron and steel materials, and relates to an etchant and a display method for displaying the austenite grain boundary of martensitic stainless steel. Background technique [0002] Low-carbon high-alloy martensitic steel has high strength, hardness and wear resistance, and is widely used in modern industries, especially large castings and forgings in the nuclear power field, such as supercritical rotors, nuclear power steam turbine blades, and aerospace fields Core components, such as engine blades, etc. [0003] Refinement of austenite grains is the only method that can improve both strength and toughness of materials, so the grain size of prior austenite is one of the important indicators for evaluating and testing the performance of low-carbon high-alloy steels. To discuss the refinement of austenite grains, the first thing is to have a suitable method to observe ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N1/32G01N15/02
CPCG01N1/32G01N15/0205G01N15/0227
Inventor 李传维李克宋逸思罗俊鹏仝大明廖瑜张永强顾剑锋
Owner SHANGHAI JIAO TONG UNIV
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