Quantitative metallographic analysis method for phase M23C6 of Super 304H steel

Abstract

The invention discloses a quantitative metallographic analysis method for a phase M23C6 of Super 304H steel. The quantitative metallographic analysis method comprises the following steps of (1) cutting, grinding, polishing, corroding and air-drying a test sample, wherein only the M23C6 in the obtained metallographic test sample is corroded, and all the other phases are not corroded; (2) performing photography through a scanning electronic microscope to obtain a clear shape and appearance image of the phase M23C6 in a metallographic grinding surface; (3) extracting and calculating the phase M23C6 in a metallographic structure shape and appearance image through image analysis software Image-Pro-Plus to finally obtain the volume percentage of the phase M23C6 in a material. The quantitative metallographic analysis method disclosed by the invention has the advantages that limitation to the shape and the size of the test sample is small, the sample preparation is simple, the operation is convenient, the observation range is large, and a statistical significance is achieved during calculation of the phase M23C6; furthermore, the quantitative metallographic analysis method is an ideal method for quickly, accurately and quantitatively analyzing the content of the phase M23C6 in the Super 304H steel.

Description

technical field [0001] The invention relates to a Super304H steel M after long-term service or aging test 23 C 6 Quantitative metallographic analysis method for phase volume percentage content. Background technique [0002] my country is a big power consumer and a big power producer. my country's "Twelfth Five-Year Plan" requires my country's comprehensive energy efficiency to increase to 38%, and the standard coal consumption for thermal power supply to drop to 323g / kWh. Therefore, the development of high-efficiency power generation technologies such as supercritical and ultra-supercritical technologies is the current technological development direction of the thermal power industry. Supercritical and ultra-supercritical units will become the main development models after my country's "Tenth Five-Year Plan". [0003] On the basis of TP304H stainless steel in the 1980s, Japan's Sumitomo Metal developed Super304H steel by adding alloy elements such as C, N, Nb, Cu, and B, ...

AI Technical Summary

Problems solved by technology

However, this method has the following disadvantages: 1. The extraction efficiency is low, and the electrolysis process takes a long time; 2. When there are many kinds of precipitated phases, it is very difficult to separate each precipitated phase, and it is also inevitable in the separation process. 3. This method consumes more materials, and it is difficult to extract a sufficient amount of target phases for materials with smaller sizes; 4. This method cannot obtain information about the distribution of precipitated phases in the material

Since there are many types of precipitated phases in Super304H steel, conventional metallographic corrosion methods for austenitic stainless steel (such as corrosion with aqua regia solution or ferric chloride hydrochloric acid aqueous solution) react to each precipitated phase, so it is difficult to detect various precipitated phases. distinguish

Images