Austenitic stainless steel metallographic etchant, preparing method and use thereof

Abstract

The invention discloses a metallographic-phase aggressive agent of an austenitic stainless steel, a preparation method thereof and application thereof. The metallographic-phase aggressive agent comprises the mixed solution of hydrofluoric acid and nitric acid, calculated by volume ratio, the proportion of each component of the agent is that hydrofluoric acid : nitric acid : water is equal to 2 : 1 : 7. The preparation method thereof is carried out according to the following steps of: taking 70ml of water first, then taking 10ml of analytically pure nitric acid and finally taking 20ml of analytically pure hydrofluoric acid, which are then evenly mixed. The application method thereof comprises the following steps of: putting a simple of the austenitic stainless steel in the metallographic-phase aggressive agent of the austenitic stainless steel and observing the color change of the surface of the sample by time, taking out the sample of the austenitic stainless steel when metallographic-phase surface of the sample is corroded to darker silver gray, washing the sample with water which is then neutralized with alkaline solution and finally washing with water and absolute ethyl alcohol. The technical effects thereof are represented by good corrosion effect, clear austenite grain boundary, slow corrosion speed, easy control, no pollution and other aspects.

Description

technical field [0001] The invention relates to an austenitic stainless steel metallographic etchant, and also relates to a preparation method and application of the austenitic stainless steel metallographic etchant. Background technique [0002] Except for some special structures such as non-metallic inclusions, graphite phase in cast iron, and pores in powder metallurgy materials, the polished surface of the sample must be eroded with an etchant to obtain (or strengthen) the image lining. Only then can it be observed under a microscope. There are many methods to obtain contrast. According to whether the process of obtaining contrast changes the surface of the sample, it can be divided into methods that do not change the surface (such as optical method) and methods that change the surface of the sample (such as electrochemical etching method, physical etching method). category. [0003] In the past, metallographic etchants for austenitic stainless steel mainly included aq...

AI Technical Summary

Problems solved by technology

[0009] One of the technical problems to be solved by the present invention is to provide a new austenitic stainless steel metallographic etchant for the shortcomings of the existing austenitic stainless steel metallographic etchant, such as unclear grain boundaries, too fast erosion speed, and inconvenient control. Phase etchant, can get clear grain boundaries, and can control the erosion speed very well