Method for embedding sample into oxidation layer on inner wall of heated surface pipe

Abstract

The invention discloses a method for embedding a sample into an oxidation layer on the inner wall of a heated surface pipe. An embedded material in the method comprises the following components in percentage by weight: 50wt%-60wt% of matrix epoxy resin, 5wt%-10wt% of a diluent and 35wt%-45wt% of a curing agent. The method comprises the following steps: sleeving a to-be-detected sample with a PVC pipe segment, pouring the embedded material into the PVC pipe segment until the sample is submerged, and curing at room temperature for 24-36 hours; and after the curing is finished, uncovering weighing paper, carrying out rough grinding and step-by-step accurate grinding on an embedding sample on abrasive paper, polishing, cleaning, carrying out blow-drying, and observing by virtue of a metallographic microscope. By embedding the sample into the oxidation layer on the inner wall of the heated surface pipe, the oxidation layer on the inner wall can be completely preserved, the boundary between the oxidation layer and the embedded material is obvious, and the oxidation layer has a clear structure and complete thickness and does not fall off, so that the accuracies of observation, measurement and analysis of the oxidation layer on the inner wall by virtue of the metallographic microscope and a scanning electron microscope can be guaranteed; furthermore, the sample obtained in the method does not need to be demolded, has a regular appearance and is convenient to hold and easy to polish. The stimulation caused by the curing agent and the diluent utilized in the method to skin is low, and the operation is safe.

Description

technical field [0001] The invention relates to a method for inlaying an oxide layer sample on the inner wall of a heating surface tube, belonging to the technical field of detection and analysis of metal materials. Background technique [0002] Due to the harsh service environment during the operation of thermal power units, under the conditions of high temperature and high pressure, high-temperature steam oxidation will occur on the inner wall surface of the high-temperature heating surface tube (superheater, reheater), forming an oxide layer. As the operating time increases, the thickness of the oxide layer increases accordingly. Moreover, the thermal expansion coefficient difference between the oxide layer and the heating surface tube is relatively large, and the bonding force between the oxide layer and the tube matrix continues to decrease with the start and stop of the boiler. When the thickness of the oxide layer reaches a critical value, the oxide layer is easy to o...

AI Technical Summary

Problems solved by technology

[0007] The oxide layer sample on the inner wall of the heating surface tube prepared by traditional hot mounting will be torn during the hot mounting process due to the weak combination of the inner wall oxide layer and the tube wall, and a large amount of peeling will occur during the polishing process, making the oxidation Layer structure thickness cannot be observed realistically, for failed mosaic samples

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