Etchant for displaying austenite structure of heat-resistant steel for air valve and using method

Abstract

The invention discloses an etchant for displaying an austenite structure of heat-resistant steel for an air valve and a using method of the etchant. The etchant is divided into an etchant 1 and an etchant 2, the etchant 1 is prepared from ferric trichloride, hydrochloric acid and water, and the etchant 2 is prepared from anhydrous cupric sulfate, sulfuric acid, hydrochloric acid and glycerol. Theusing method comprises the following steps: (1) preparing the etchant; (2) preparing a sample: (3) etching the sample: immersing a metallographic sample prepared in the step (2) into a culture dish filled with the etchant 1 with the observation surface facing downwards, standing for 10-30 seconds, taking out the sample, washing the sample with tap water, washing the sample with absolute ethyl alcohol with the mass fraction of 99.5%, and blow-drying the sample; then, immersing the sample into a culture dish filled with the etchant 2, standing for 10-20 seconds, taking out the sample, washing with tap water, washing with absolute ethyl alcohol with the mass fraction of 99.5%, and blow-drying; and a clear and complete room-temperature austenite structure can be observed under a microscope. Byadopting the etchant and the using method provided by the invention, the metallographic structure quality of the heat-resistant steel for the air valve can be remarkably improved, and the metallographic quantitative analysis accuracy is improved; and the etchant is simple to prepare and easy to popularize.

Description

technical field

[0001] The invention belongs to the technical field of metallographic detection, and in particular relates to an etchant for displaying the austenite structure of heat-resistant steel for gas valves and a use method thereof. Background technique

[0002] The gas valve is an important working part and wearing part of the engine. Its working conditions are extremely harsh. It must withstand frequent reciprocating high-speed motion and friction in high temperature, high pressure, and corrosive gas, and the impact load is large, so it requires high temperature. Performance, corrosion resistance, etc., the quality of its work directly affects the performance of the engine, so the material requirements for preparing the valve are also extremely stringent. At present, the most widely used valve steel material is austenitic heat-resistant steel.

[0003] This kind of steel is based on austenite, and carbon and nitrogen compounds are used as precipitation hardening p...

Examples

Embodiment 1

[0033] In this embodiment, the heat-resistant steel for air valves is taken as an example. The sample is hot-rolled at a temperature of 1150° C. for 15 minutes, air-cooled, and the method for displaying the austenite structure at room temperature includes the following steps:

[0034] 1) Etching agent preparation: Add 5g of ferric chloride and 35ml of hydrochloric acid with a mass fraction of 37% to 100ml of water in sequence, stir evenly, and prepare etchant 1; respectively add 10g of anhydrous copper sulfate, 10ml of sulfuric acid, and 5ml of Slowly add triol into 100ml of hydrochloric acid with a mass fraction of 37%, stir evenly, and prepare etching agent 2;

[0035] 2) Sample preparation: cut out the heat-resistant steel sample for the gas valve, grind and polish the surface of the sample to be inspected, the polished surface is mirror-like, and has no scratches, rinse it with tap water, and then use a mass fraction of 99.5% Rinse with absolute ethanol and blow dry;

[0...

Embodiment 2

[0039] In this embodiment, the heat-resistant steel for air valves is taken as an example. The sample is hot-rolled at a temperature of 1150° C. for 30 minutes, air-cooled, and the method for displaying the austenite structure at room temperature includes the following steps:

[0040] 1) Etching agent preparation: Add 5g of ferric chloride and 35ml of hydrochloric acid with a mass fraction of 37% to 100ml of water in sequence, stir evenly, and prepare etchant 1; respectively add 10g of anhydrous copper sulfate, 10ml of sulfuric acid, and 5ml of Slowly add triol into 100ml of hydrochloric acid with a mass fraction of 37%, stir evenly, and prepare etching agent 2;

[0041] 2) Sample preparation: cut out the heat-resistant steel sample for the gas valve, grind and polish the surface of the sample to be tested. Rinse with water and ethanol and dry;

[0042] 3) Sample erosion: Immerse the metallographic sample prepared in step (2) face down into a petri dish containing etchant 1, ...

Embodiment 3

[0045] In this embodiment, the heat-resistant steel for air valves is taken as an example. The sample is hot-rolled at a temperature of 1150° C. for 45 minutes, air-cooled, and the method for displaying the austenite structure at room temperature includes the following steps:

[0046] 1) Etching agent preparation: Add 5g of ferric chloride and 40ml of hydrochloric acid with a mass fraction of 37% to 100ml of water in turn, stir well, and prepare etchant 1; respectively add 10g of anhydrous copper sulfate, 15ml of sulfuric acid, and 5ml of Slowly add triol into 100ml of hydrochloric acid with a mass fraction of 37%, stir evenly, and prepare etching agent 2;

[0047]2) Sample preparation: cut out the heat-resistant steel sample for the gas valve, grind and polish the surface of the sample to be tested. Rinse with water and ethanol and dry;

[0048] 3) Sample erosion: Immerse the metallographic sample prepared in step (2) face down into a petri dish containing etchant 1, stay fo...

technical field

[0001] The invention belongs to the technical field of metallographic detection, and in particular relates to an etchant for displaying the austenite structure of heat-resistant steel for gas valves and a use method thereof. Background technique

[0002] The gas valve is an important working part and wearing part of the engine. Its working conditions are extremely harsh. It must withstand frequent reciprocating high-speed motion and friction in high temperature, high pressure, and corrosive gas, and the impact load is large, so it requires high temperature. Performance, corrosion resistance, etc., the quality of its work directly affects the performance of the engine, so the material requirements for preparing the valve are also extremely stringent. At present, the most widely used valve steel material is austenitic heat-resistant steel.

[0003] This kind of steel is based on austenite, and carbon and nitrogen compounds are used as precipitation hardening p...

Examples

Embodiment 1

[0033] In this embodiment, the heat-resistant steel for air valves is taken as an example. The sample is hot-rolled at a temperature of 1150° C. for 15 minutes, air-cooled, and the method for displaying the austenite structure at room temperature includes the following steps:

[0034] 1) Etching agent preparation: Add 5g of ferric chloride and 35ml of hydrochloric acid with a mass fraction of 37% to 100ml of water in sequence, stir evenly, and prepare etchant 1; respectively add 10g of anhydrous copper sulfate, 10ml of sulfuric acid, and 5ml of Slowly add triol into 100ml of hydrochloric acid with a mass fraction of 37%, stir evenly, and prepare etching agent 2;

[0035] 2) Sample preparation: cut out the heat-resistant steel sample for the gas valve, grind and polish the surface of the sample to be inspected, the polished surface is mirror-like, and has no scratches, rinse it with tap water, and then use a mass fraction of 99.5% Rinse with absolute ethanol and blow dry;

[0...

Embodiment 2

[0039] In this embodiment, the heat-resistant steel for air valves is taken as an example. The sample is hot-rolled at a temperature of 1150° C. for 30 minutes, air-cooled, and the method for displaying the austenite structure at room temperature includes the following steps:

[0040] 1) Etching agent preparation: Add 5g of ferric chloride and 35ml of hydrochloric acid with a mass fraction of 37% to 100ml of water in sequence, stir evenly, and prepare etchant 1; respectively add 10g of anhydrous copper sulfate, 10ml of sulfuric acid, and 5ml of Slowly add triol into 100ml of hydrochloric acid with a mass fraction of 37%, stir evenly, and prepare etching agent 2;

[0041] 2) Sample preparation: cut out the heat-resistant steel sample for the gas valve, grind and polish the surface of the sample to be tested. Rinse with water and ethanol and dry;

[0042] 3) Sample erosion: Immerse the metallographic sample prepared in step (2) face down into a petri dish containing etchant 1, ...

Embodiment 3

[0045] In this embodiment, the heat-resistant steel for air valves is taken as an example. The sample is hot-rolled at a temperature of 1150° C. for 45 minutes, air-cooled, and the method for displaying the austenite structure at room temperature includes the following steps:

[0046] 1) Etching agent preparation: Add 5g of ferric chloride and 40ml of hydrochloric acid with a mass fraction of 37% to 100ml of water in turn, stir well, and prepare etchant 1; respectively add 10g of anhydrous copper sulfate, 15ml of sulfuric acid, and 5ml of Slowly add triol into 100ml of hydrochloric acid with a mass fraction of 37%, stir evenly, and prepare etching agent 2;

[0047]2) Sample preparation: cut out the heat-resistant steel sample for the gas valve, grind and polish the surface of the sample to be tested. Rinse with water and ethanol and dry;

[0048] 3) Sample erosion: Immerse the metallographic sample prepared in step (2) face down into a petri dish containing etchant 1, stay fo...

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