Method for displaying two-phase grain boundary of duplex stainless steel

Abstract

The invention relates to a method for displaying two-phase grain boundary of duplex stainless steel. The method comprises the following steps: I, preparation of a metallographic sample, namely, (1) cutting the metallographic sample by adopting a machining saw; (2) roughly grinding the observation surface of the sample; (3) mechanically polishing the observation surface of the sample by adopting a metallographic polishing machine; (4) finely polishing the observation surface by the metallographic polishing machine; (5) cleaning the observation surface of the sample with ethyl alcohol; II, preparation of a corrosive agent, namely, preparing a mixed solution from 10-15g of copper sulfate, 50 mm <3> of nitric acid with the volume percentage being 65-68% and 100-150 mm <3> of hydrochloric acid with the volume percentage being 36-38%; III, corrosion of the metallographic sample, namely, putting the metallographic sample into a metallographic corrosive agent, taking out the duplex stainless steel when the metallographic observation surface is corroded to be deep silver gray, cleaning the sample with water, and wiping the observation surface of the metallographic sample by degreasing cotton dipped with absolute ethyl alcohol. The method for displaying two-phase grain boundary of duplex stainless steel can be used for quickly, simply and conveniently displaying the two-phase grain boundary of the duplex stainless steel.

Description

technical field [0001] The present invention relates to a method of revealing two-phase grain boundaries of duplex stainless steel. Background technique [0002] Duplex stainless steel, also known as ferritic-austenitic stainless steel, has many characteristics of ferritic steel and austenitic steel, and is widely used in sour oil, gas fields, transportation, oil refining, petrochemical and marine engineering. In the production of duplex stainless steel, it is often necessary to check the metallographic structure of the material, and then achieve the desired performance by properly adjusting the composition and production process. During the inspection, methods such as electrolysis of 10% oxalic acid aqueous solution, hot or boiling alkaline potassium ferricyanide solution and 40% sodium hydroxide (potassium) solution are generally used. These methods can show both austenite and ferrite. The phase boundary of the duplex stainless steel is used to measure the phase ratio and...

AI Technical Summary

Problems solved by technology

During the inspection, methods such as electrolysis of 10% oxalic acid aqueous solution, hot or boiling alkaline potassium ferricyanide solution and 40% sodium hydroxide (potassium) solution are generally used. These methods can show both austenite and ferrite. The phase boundary of the duplex stainless steel is used to measure the phase ratio and observe the precipitated phase. The disadvantage is that special instruments are required, time-consuming and electricity is required, especially the two-phase grain boundary of duplex stainless steel cannot be displayed, and the grain size is observed.

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