Method for testing autstenitic grain size of steel bainite structure for nuclear pressure vessel

A technology of austenite grain and pressure vessel, which is applied in the field of testing the bainite structure and austenite grain size of steel for nuclear pressure vessels, can solve the problem that the bainite structure and austenite grain size cannot be displayed, and the operation is complicated. and other problems to achieve the effect of optimizing the heat treatment process

Inactive Publication Date: 2015-03-25
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above methods are either complicated to operate, or cannot display the austenite grain size of the bainite structure. It is increasingly important to invent a suitable and efficient method to display the austenite grain size of the bainite structure of steel for nuclear power pressure vessels.

Method used

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  • Method for testing autstenitic grain size of steel bainite structure for nuclear pressure vessel
  • Method for testing autstenitic grain size of steel bainite structure for nuclear pressure vessel

Examples

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Embodiment 1

[0034] A method for testing the austenite grain size of steel bainite for nuclear electric pressure vessels, including preparation and polishing of metallographic samples, chemical etching of samples, sample observation and statistics of grain size, as follows :

[0035] 1) Preparation and polishing of metallographic samples:

[0036] a. Cutting and inlaying of metallographic samples: From the bulk samples taken from the actual forgings with austenitizing temperature of 1000℃, cut 10mm*10mm*5mm cubes by wire cutting and inlay them with bakelite powder , To prepare for subsequent polishing and polishing;

[0037] b. Coarse grinding of the sample: Grind the sample through 180#→320#→600# silicon carbide water-resistant sandpaper in sequence. The rotation speed of the grinding disc is set to 600rpm. Each time you change the sandpaper, you need to grind the sample along the surface. Rotate 90 degrees so that the new wear scar is perpendicular or nearly perpendicular to the last wear sca...

Embodiment 2

[0049] A method for testing the austenite grain size of steel bainite for nuclear electric pressure vessels, including preparation and polishing of metallographic samples, chemical etching of samples, sample observation and statistics of grain size, as follows :

[0050] 1) Preparation and polishing of metallographic samples:

[0051] a. Cutting and inlaying of metallographic samples: The large samples taken from the actual forgings with austenitizing temperature of 900℃ are used to cut the samples with the size of 10mm*10mm*20mm, because the sample Larger, no inlay is required, samples can be prepared by hand-held grinding and polishing;

[0052] b. Coarse grinding of the sample: Grind the sample through 180#→320#→600# silicon carbide water-resistant sandpaper in sequence. The rotation speed of the grinding disc is set to 500rpm. Each time you change the sandpaper, you need to grind the sample along the surface. Rotate 90 degrees so that the new wear scar is perpendicular or nearl...

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Abstract

The invention relates to a method for testing autstenitic grain size of a steel bainite structure for a nuclear pressure vessel. The method comprises the steps of preparing, grinding and polishing a metallographic phase sample, carrying out chemical etching on a sample and carrying out statistics on the grain size. According to the method, the rational proportions of picric acid, dodecylbenzene sulfonic acid and an additive as well as the etching time are selected, so that the original autstenitic grain size of the low-carbon and low-alloy steel SA508 Gr.3 steel bainite structure for nuclear power can be clearly displayed. After the method is adopted, the problem that the original autstenitic grain boundary is difficult to display in the actual production process of a forge piece of the nuclear pressure vessel can be solved; compared with the traditional method which is used for judging the autstenitic grain size by experience, the method has the advantage that the displayed autstenitic grain boundary is clear and complete; after the method is used for picture processing and statistics, the tested autstenitic grain size is more accurate and the repeatability is good.

Description

Technical field [0001] The invention relates to the technical field of metallographic sample preparation and austenite grain display, in particular to a method for testing the austenite grain size of the bainite structure of steel for nuclear electric pressure vessels. Background technique [0002] Nuclear power is one of the important clean energy sources in modern society. Since the outbreak of the Fukushima nuclear power plant safety accident in Japan in 2010, the importance of nuclear power safety has received more and more attention. Nuclear electric pressure vessels are one of the important guarantees for nuclear power safety. The damage of nuclear electric pressure vessels means nuclear leakage. Therefore, people’s requirements for nuclear electric pressure vessels are becoming more and more stringent. The design strength and toughness continue to increase, and the sensitivity to radiation brittleness and toughness The brittle transition temperature and other requirements ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N15/02G01N1/32
Inventor 顾剑锋李传维韩利战刘庆冬陶新刚潘健生
Owner SHANGHAI JIAO TONG UNIV
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