Display method for second phase of austenite heat-resisting steel based on dyeing

Abstract

The invention discloses a display method for a second phase of austenite heat-resisting steel based on dyeing. The display method comprises the following steps: (1) sufficiently mixing sodium hydroxide, potassium permanganate and water in a ratio of (3-6)g to (3-6)g to 100ml to prepare an alkaline potassium permanganate water solution dyeing agent; (2) putting an austenite heat-resisting steel metallographic phase test sample which is cut, ground and polished into the prepared dyeing agent, wherein the dyeing temperature is 70-90 DEG C and the dyeing time is 5-10 minutes; then washing with clean water and spraying with alcohol; blowing to be dried; and (3) observing under a metallographic microscope, wherein the second phase is orange or brown solid particles, and tissue details and crystal boundaries are not displayed. The dyeing agent prepared by the method is used for displaying the second phase in the austenite heat-resisting steel and the second phase is the solid particles, and the tissue details and crystal boundaries are not displayed, so that the quantity and the size of the particles in the second phase are easily observed. Furthermore, the dyeing agent has strong reusability and has slight dangers to inspectors and environments; and the operation is simple and the implementation is easy to realize.

Description

Technical field: [0001] The invention belongs to the technical field of metallographic analysis in iron and steel, and in particular relates to a method for displaying the second phase of austenitic heat-resistant steel based on dyeing. Background technique: [0002] Austenitic heat-resistant steel has high creep strength, good structural stability and excellent resistance to flue gas corrosion and steam oxidation. With the continuous improvement of steam parameters of thermal power units in my country, the amount of austenitic heat-resistant steel used has increased significantly. At present, austenitic heat-resistant steels such as TP304H, TP321H, TP347H, S30432, HR3C and TP347HFG are widely used as boiler tube steels in thermal power units. [0003] The as-supplied microstructure of austenitic heat-resistant steel is austenite + trace second phase. With the extension of service time, the number and size of second phase particles in the microstructure gradually increase. ...

AI Technical Summary

Problems solved by technology

In the past, corrosive agents such as aqua regia, picric hydrochloric acid alcohol solution, or copper sulfate hydrochloric acid aqueous solution could only display structural details (such as twins, slip lines, etc.), grain boundaries, and second phases at the same time, and the second phase with slightly larger particles It is a hollow particle, causing the second phase to be confused with the structure details and grain boundaries, and difficult to distinguish

Studying the changes in the number and size of the second phase particles during service is of great significance for the aging rating and metal monitoring of austenitic heat-resistant steels, but there is currently no good method that only shows the second phase in austenitic heat-resistant steels

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