Method for displaying original austenitic grain boundary of martensitic heat-resistant steel

A technology of austenitic grain boundaries and heat-resistant steel, which is applied in the field of metallographic sample preparation, can solve problems such as chronic poisoning, contact dermatitis, and low flash point, and achieve the effect of fast etching speed and simple and convenient operation

Inactive Publication Date: 2012-10-10
UNIV OF SCI & TECH BEIJING
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Problems solved by technology

However, because martensitic heat-resistant steel contains high alloying elements and has strong corrosion resistance and oxidation resistance, it is difficult to clearly display the prior austenite grain boundaries by traditional methods.
In addition, the room temperature structure of martensitic heat-resistant steel is mainly martensite structure, so that when the original austenite grain boundary is etched, the martensite structure

Method used

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  • Method for displaying original austenitic grain boundary of martensitic heat-resistant steel
  • Method for displaying original austenitic grain boundary of martensitic heat-resistant steel

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Embodiment Construction

[0015] The technological process and steps of the present embodiment are as follows:

[0016] 1 coarse grinding - fine grinding: the sample taken from the ingot at 400 # →600 # →800 # →1000 # →1200 # →1500 # →2000 # Sanding with silicon carbide metallographic sandpaper. Every time the sand paper is changed during grinding, the sample should be rotated 90o in the same direction, and the surface of the sample should be observed frequently to ensure that there are no large scratches on the surface perpendicular to the grinding direction. Grinding is over when the new sandpaper wear marks completely cover the wear marks of the previous sand paper.

[0017] 2 Mechanical polishing: First, will go through 2000 # Rinse the polished sample with silicon carbide metallographic sandpaper with clean water to avoid sand particles remaining on the surface of the sample and affect the polishing quality. Then place the sample on a polishing cloth for polishing. First use 2.5μ diamond...

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Abstract

The invention relates to a method for displaying an original austenitic grain boundary of martensitic heat-resistant steel, and belongs to the technical field of metallographic sample preparation. The method comprises the process steps of polishing and etching. A polished sample is put into an etching agent, the etching time is 5 to 10 seconds, and the sample is taken out when copper decorating the surface of the sample is observed, washed cleanly by alcohol and dried by blowing; and the clear original austenitic grain boundary can be observed under a metallographic microscope. According to the formula, the etching agent comprises the following components: 5 to 15 g of copper sulfate pentahydrate, 30 to 50 ml of hydrochloric acid and 50 to 70 ml of deionized water. The method has the advantages that the clear original austenitic grain boundary of the martensitic heat-resistant steel can be etched out at normal temperature while a martensitic structure is not displayed, the method is convenient to operate, and the corrosion rate of austenite is higher than that of picric acid solution.

Description

technical field [0001] The invention relates to a method for displaying the original Austrian grain boundary of a martensitic heat-resistant steel at room temperature. The surface of a sample is decorated with copper to reveal the original Austrian grain boundary, which belongs to the technical field of metallographic sample preparation. Background technique [0002] The original austenite grain size of the steel can directly affect the microstructure change in the subsequent processing, thus affecting the strength, toughness and fatigue resistance of the steel and other performance indicators. Therefore, it is of great significance to accurately reflect the austenite grain size. Generally, the size of austenite grains is indirectly reflected by the method of etching austenite grain boundaries. Therefore, a good etching effect is essential for the study and calculation of the austenite grain size. However, since the original austenite is the high-temperature phase of steel...

Claims

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Application Information

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IPC IPC(8): G01N1/32
Inventor 朱博玲杨善武刘国亮杨广善贺信莱尚成嘉王学敏郭晖
Owner UNIV OF SCI & TECH BEIJING
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