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Analysis and detection method of two-phase proportion in as-cast structure of duplex stainless steel

A technology of duplex stainless steel and as-cast structure, which is applied in the analysis of materials, material analysis using wave/particle radiation, and material analysis using measurement of secondary emissions, etc. High-level problems are required to achieve the effect of easy identification, high accuracy and clear boundaries

Inactive Publication Date: 2018-05-01
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The magnetic method has high requirements on the surface of the material, coupled with the low precision of the instrument, resulting in poor accuracy of the measurement results and relatively large application limitations
Metallographic methods are often used in conjunction with image analysis and other related software, and often require corrosion treatment of the sample. However, due to the difficulty in grasping the corrosion effect, the contrast between the phases is often not obvious enough to distinguish them, which is not conducive to accurate quantitative analysis.

Method used

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  • Analysis and detection method of two-phase proportion in as-cast structure of duplex stainless steel
  • Analysis and detection method of two-phase proportion in as-cast structure of duplex stainless steel
  • Analysis and detection method of two-phase proportion in as-cast structure of duplex stainless steel

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Embodiment 1

[0027] The method for analyzing and detecting two phase ratios in the as-cast structure of ferrite / austenite duplex stainless steel according to the present invention includes the following steps:

[0028] Step ①: Carry out cutting, rough grinding, fine grinding and mechanical polishing on the duplex stainless steel sample in sequence. The cutting is: the sample can be processed by wire EDM, and the sample size is a thin slice of 10mm×5mm×3mm; the rough grinding is: the observation surface of the sample is sequentially on 60Cw, 150Cw, 400Cw and 600Cw sandpaper Polished with water as a lubricant; the fine grinding is: wet grinding the rough ground sample on 800Cw, 1000Cw, 1200Cw, 1500Cw and 2000Cw sandpaper in sequence; the mechanical polishing is: the finely ground sample is Wet polish the velvet polishing cloth with 2.5μm diamond polishing paste for 3 to 5 minutes, until the mirror effect is achieved, ensuring that there are no obvious scratches by naked eye observation.

[0029]...

Embodiment 2

[0033] The sample cutting, rough grinding, fine grinding and mechanical polishing process are the same as in Example 1, and the scanning electron microscope and EBSD analysis process after electropolishing are the same as in Example 1. The difference is that the sample is electropolished with a voltage of 10V and a current of 1A. It is observed that the surface of the sample is smoother than that in Example 1. At this time, the effect of the residual stress layer is not obvious, and effective EBSD analysis can still be performed without affecting the final result.

Embodiment 3

[0035] The sample cutting, rough grinding, fine grinding and mechanical polishing process are the same as in Example 1, and the scanning electron microscope and EBSD analysis process after electropolishing are the same as in Example 1. The difference is that the sample is electropolished with a voltage of 20V and a current of 2A. It is observed that the surface of the sample is uneven compared to that in Example 1, but a suitable EBSD analysis area can still be found without affecting the final result.

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Abstract

The invention relates to an analysis and detection method of a two-phase proportion in an as-cast structure of a duplex stainless steel, and belongs to the field of the analysis of metal materials. The analysis and detection method is particularly applied to the accurate measurement of contents of ferrite and austenite phases in the as-cast structure of the duplex stainless steel. According to theanalysis and detection method, the electrolytic polishing is carried out for 20s to 30s in a perchloric acid alcohol solution with a volume fraction of 10 to 20 percent to remove a stress layer, wherein a voltage is 10V to 20V and an electric current is 1A to 2A. The two-phase distribution of a well prepared to-be-detected-and-analyzed product is determined according to a special kikuchi patternof each phase, which is possessed by an EBSD (Electron Backscattered Diffraction) analysis system; the determination is not limited to artificial corrosion dyeing, which is difficultly mastered, any more; the difficult differentiation resulted as a contrast between the phases is not obvious enough, which is caused due to a difference of a corrosion effect, is avoided; the quantitative analysis iscarried out on the content of each phase, and the accuracy is higher.

Description

Technical field [0001] The invention relates to an analysis and detection method of two phase ratios in the as-cast structure of a duplex stainless steel, belonging to the field of metal material analysis, and is specifically applied to the accurate determination of the content of ferrite and austenite phases in the duplex stainless steel. Background technique [0002] Ferritic / austenitic duplex stainless steel has the advantages of high strength and chloride stress corrosion resistance of ferritic stainless steel, and excellent toughness and weldability of austenitic stainless steel. It is widely used in petroleum, chemical, food, Energy, shipbuilding, building materials, military industry and other fields. A large number of research results show that the two phase ratios in duplex stainless steel have an important influence on its mechanical properties, corrosion resistance and processing properties, so it is very important to accurately determine the two phase ratios. [0003] ...

Claims

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Application Information

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IPC IPC(8): G01N23/22G01N23/2202G01N23/203G01N1/28G01N1/32G01N1/34
CPCG01N1/286G01N1/32G01N1/34G01N23/203G01N23/22G01N23/2202G01N2001/2866G01N2001/2873G01N2223/053G01N2223/07G01N2223/624
Inventor 孙彦辉赵勇李晓滨焦帅董健
Owner UNIV OF SCI & TECH BEIJING
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