Detection method for rotor steel weld joint residual austenite

A technology of residual austenite and detection method, which is applied in the direction of measuring device, preparation of test samples, material analysis through optical means, etc., and can solve the problem of insignificant austenite corrosion effect

Inactive Publication Date: 2014-01-29
SHANGHAI UNIV +1
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0006] The applicant of the present invention used residual austenite+rotor steel (residual austenite+rotor steel) as keywords to search the United States Patent Abstracts (USPTO), European Patent Abstracts (EP —PCT), "China Patent Information Network" and "Patent Search of the State Intellectual Property Office of the People's Republic of China", no similar patents were found

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  • Detection method for rotor steel weld joint residual austenite
  • Detection method for rotor steel weld joint residual austenite
  • Detection method for rotor steel weld joint residual austenite

Examples

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Embodiment 1

[0036] The technical process and steps of this implementation example are as follows:

[0037]a Coarse grinding: Put the cut 9Cr–1Mo rotor steel weld metallographic sample on the grinding wheel for grinding, grind off the surface oxide skin and roughly smooth it, put the polished sample in turn on 240 mesh, 400 mesh 600 mesh, 800 mesh and 1000 mesh sandpaper (sandpaper placed on a smooth glass plate) for grinding. During the grinding process, it is necessary to observe frequently to ensure that all scratches are along the grinding direction of the pass and there are no obvious coarse scratches. When grinding the next pass, the sample should be rotated 90° before continuing to grind .

[0038] b Fine grinding-polishing: Place the coarsely ground sample on 1500-mesh and 2000-mesh sandpaper successively for grinding, and the grinding method is the same as that of coarse grinding. The ground sample was cleaned and polished on a polishing cloth, using water as a lubricant, and a ...

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Abstract

The invention relates to a metallographic detection method for rotor steel weld joint residual austenite. The used corrosive agents are divided into two corrosive agents; the formula of the corrosive agent 1# contains 100 ml of distilled water, 4 g of picric acid and 5 ml of diluted hydrochloric acid with volume fraction of 5 percent; the formula of the corrosive agent 2 contains 100 ml of distilled water, 10 g of pyrosulfurous acid and 5-6 drops of hydrochloric acid solution with volume fraction of 5 percent. The used corrosion process is divided into two steps: step one, a polished sample is immersed in the prepared corrosive agent 1# and a face to be corroded is kept vertically downward and is slightly oscillated to etch for 1.5 min; step two, the sample is cleaned, blow-dried and immersed in the prepared corrosive agent 2#, and a face to be corroded is kept vertically downward to etch for 10 min. White spots observed under a metallographic microscope are residual austenite, and the content of the residual austenite can be tested by introducing a metallograph of a proper multiple into Image-ProPlus software. The method can be used for comprehensive analysis of the size, the shape, the distribution and the content of the residual austenite in a rotor steel weld joint, and is simple and feasible in technical implementation.

Description

technical field [0001] The invention belongs to the field of welding quality detection, and in particular relates to a metallographic corrosion method for clearly displaying residual austenite in weld seams of rotor steel and a method for determining its content. Background technique [0002] The rotor is the core component of the steam turbine and has various structural forms, such as integral forged rotors, sleeved rotors, welded rotors and combined rotors. With the development of large capacity, high parameters, and high efficiency of generating sets, the requirements for steam turbine rotors are also increasing. [0003] In the manufacturing process of large steam turbines, the welded rotor has become an ideal rotor structure choice due to its advantages such as being convenient for forging and heat treatment, reducing the weight of the rotor, increasing the critical speed, and meeting the working needs of different parts. In the production research of welded rotors, th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/84G01N1/32
Inventor 刘鹏姬慧君刘霞杨仁杰高玉来
Owner SHANGHAI UNIV
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