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Test method of metallographic structure of austenitic stainless steel pipe for nuclear power

A technology of austenitic stainless steel and metallographic structure, which is applied in the inspection field of metallographic structure of austenitic stainless steel tubes for nuclear power, can solve the problems of not being able to obtain clear ferrite, and achieve the effect of avoiding severe corrosion and easy operation

Active Publication Date: 2017-01-11
西安汉唐分析检测有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Austenitic stainless steel tubes used as nuclear power heat exchangers The grain size and ferrite phase inspection of the product are particularly important. With the corrosion method of the conventional metallographic structure inspection of stainless steel, due to the existence of the residual ferrite phase, we cannot obtain clear austenite (γ) equiaxed grains. Grain structure and ferrite (α) phase measured by quantitative metallography

Method used

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  • Test method of metallographic structure of austenitic stainless steel pipe for nuclear power

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Embodiment 1

[0028] In this embodiment, the metallographic structure of 316L stainless steel with an outer diameter of 10.5 mm and a wall thickness of 0.5 mm is inspected. The specific method includes the following steps:

[0029] Step 1. Machining a metallographic observation plane on an austenitic stainless steel tube for nuclear power, then grinding the machined metallographic observation plane on a metallographic grinder, and washing away the sand grains on the metallographic observation plane after grinding; The grinding process is to use 150# and 700# metallographic water sandpaper to grind step by step successively, and the grinding direction is rotated 90° when changing the grain size sandpaper to grind each time, so as to ensure that the last grinding trace is completely eliminated;

[0030] Step 2. Place the metallographic observation plane of the austenitic stainless steel pipe for nuclear power that has been washed out of the sand in step 1 on the polishing machine, and use Cr ...

Embodiment 2

[0037] In this embodiment, the outer diameter is 9.8mm, and the metallographic structure of 304L stainless steel with a wall thickness of 0.4mm is inspected. The specific method includes the following steps:

[0038] Step 1. Machining a metallographic observation plane on an austenitic stainless steel tube for nuclear power, then grinding the machined metallographic observation plane on a metallographic grinder, and washing away the sand grains on the metallographic observation plane after grinding; The grinding process is to use 150# and 700# metallographic water sandpaper to grind step by step successively, and the grinding direction is rotated 90° when changing the grain size sandpaper to grind each time, so as to ensure that the last grinding trace is completely eliminated;

[0039] Step 2. Place the metallographic observation plane of the austenitic stainless steel pipe for nuclear power that has been washed out of the sand in step 1 on the polishing machine, and use Cr 2...

Embodiment 3

[0046] In this embodiment, the outer diameter is 11 mm, and the metallographic structure of 308L stainless steel with a wall thickness of 0.7 mm is inspected. The specific method includes the following steps:

[0047] Step 1. Machining a metallographic observation plane on an austenitic stainless steel tube for nuclear power, then grinding the machined metallographic observation plane on a metallographic grinder, and washing away the sand grains on the metallographic observation plane after grinding; The grinding process is to use 150# and 700# metallographic water sandpaper to grind step by step successively, and the grinding direction is rotated 90° when changing the grain size sandpaper to grind each time, so as to ensure that the last grinding trace is completely eliminated;

[0048] Step 2. Place the metallographic observation plane of the austenitic stainless steel pipe for nuclear power that has been washed out of the sand in step 1 on the polishing machine, and use Cr ...

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Abstract

The invention discloses a test method of metallographic structure of austenitic stainless steel pipe for nuclear power. It is as follows: I. produce the metallographic observation plane by machining on the austenitic stainless steel pipe for nuclear power and grinding; II. conduct mechanical polishing on the plane by a polisher; III. Carry out electrolytic corrosion with the electrolyte the mixture of HNO3 and HCL and H2O [volume ratio, 10:1: (2 - 5)]; IV. Observe and measure the alpha phase of metallographic structure under the microscope; V. Maintain the electrolytic corrosion for another 5s-10s; VI. Observe the austenite grains under the microscope. The invention adopts the mixture of HNO3 and HCL and H2O as the electrolyte in the electrolytic corrosion. Together with the proper voltage, the phase of ferrite would not be affected by heavy corrosion while organization structures of ferrite and austenitic grains with clear levels can be obtained.

Description

technical field [0001] The invention belongs to the technical field of material surface structure measurement, and in particular relates to a method for inspecting the metallographic structure of an austenitic stainless steel tube for nuclear power. Background technique [0002] The field of materials involved in nuclear power plants is very extensive. Due to the mature production technology, wide sources and relatively low prices of steel and nickel-based alloys, they have become the main targets of structural materials for nuclear power plants. [0003] Stainless steel materials mainly involve reactor pressure vessels of nuclear power plants; reactor cores, reactor internals, control rod drive mechanisms; common pipelines and cooling pumps; steam generators and heat exchangers; [0004] Stainless steel materials used in nuclear power have special requirements on composition and performance: 1. Control of thermal neutron absorbing elements, the material requires the content...

Claims

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Application Information

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IPC IPC(8): G01N21/84G01N1/28G01N1/32
CPCG01N1/286G01N1/32G01N21/84G01N2001/2866
Inventor 马红征何伟杨军红石科学
Owner 西安汉唐分析检测有限公司
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