Etching agent for displaying solidification dendritic structures of middle-high grade non-oriented silicon steel as well as etching method

Abstract

The invention discloses an etching agent for displaying solidification dendritic structures of middle-high grade non-oriented silicon steel as well as an etching method, and belongs to the technical field of metallographic examination analysis. The etching agent comprises the following components according to ratio: 1.5-2.0 g of picric acid, 35-50 ml of distilled water, 0.4-0.6 ml of hydrochloric acid, 0.3-0.5 g of anhydrous cupric chloride and 0.5-1 g of sodium dodecyl benzene sulfonate. The etching method of the etching agent comprises the following steps: heating the prepared etching agent to be in the boiling state, and then suspending a processed sample in the etching agent for 8-15 s, wherein the polished surface of the processed sample faces downwards; after the etching is finished, conducting clean water washing and cotton ball wiping treatment on the etched surface; then polishing the sample at the 1/2 radius part of a polishing machine for 5-10 s. The etching time is short, and the operation procedures are simple; the clear primary and secondary solidification dendritic structures of the middle-high grade non-oriented silicon steel can be quickly observed, so that technical bases can be provided for optimization of the continuous casting process and increase of the axis crystal proportions of a casting blank and the like.

Description

technical field [0001] The invention belongs to the technical field of metallographic inspection and analysis, and in particular relates to an etchant and a display method for displaying the solidified dendrite structure of non-oriented silicon steel of medium and high grades. Background technique [0002] Due to the high content of silicon and aluminum in medium and high-grade non-oriented silicon steel, the cast slab mainly grows in the form of dendrites during the solidification process, so coarse columnar crystals will be formed. This kind of columnar crystals is not easy to undergo α-γ phase transformation during hot rolling, and the dynamic recovery and recrystallization are very slow, so it is difficult to break completely, resulting in the formation of coarse and elongated deformed grains in the hot-rolled sheet, especially near the center of the sheet thickness. , and it is difficult to recrystallize in the subsequent cold rolling and annealing process, so it appear...

AI Technical Summary

Problems solved by technology

The etchant containing picric acid has weak corrosion ability and long corrosion time. It is often necessary to add ferric chloride at the same time to improve its corrosion ability. Due to the strong corrosion ability of ferric chloride, it often causes serious damage to the secondary dendrites; Copper etchant, always forms a layer of copper deposits on the eroded surface to cover the dendrites after erosion, and needs to be removed with ammonia solution. After removing the film, it will not only destroy the dendrites, but also reduce The surface cleanliness of the dendrite structure affects the display effect

Using the above four dendrite etchants and corresponding methods to etch the structure of medium and high grade non-oriented silicon steel slabs, either the primary or secondary dendrite structure cannot be corroded, or the display effect is very poor.

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