CN116623104A - A kind of inlet guide vane material for air separation unit and its preparation method - Google Patents

Abstract

The invention provides an inlet guide vane material for an air separation unit and a preparation method thereof, which mainly solves the welding manufacturability, strength and corrosion resistance of the processed guide vane when the existing martensitic stainless steel 2Cr13 is used as the inlet guide vane material Both unsatisfactory technical issues. Based on the requirements of manufacturability and combined with applicable conditions, the present invention accurately limits the dosage of each raw material by weight percentage, and each component includes by weight percentage: 0.05%≤C≤0.12%; 0.1%≤Si≤0.6%; 0.1%≤Mn≤ 0.6%; P≤0.040%; S≤0.030%; 10.0%≤Cr≤12.0%; 0.2%≤Ni≤0.5%; 0.2%≤Mo≤0.5%; 0.01%≤Cu≤0.35%; 0.05%; the rest is Fe. In addition, the C equivalent is <0.8; the Cr equivalent is 6-10; and the Ni equivalent is 2-4. Prepared by smelting, forging, and heat treatment, compared with martensitic stainless steel 2Cr13, the imported guide vane material has better welding processability and improved strength and corrosion resistance.

Description

A kind of inlet guide vane material for air separation unit and its preparation method

technical field

The invention relates to a guide vane material, in particular to an inlet guide vane material for an air separation device and a preparation method thereof.

Background technique

The air separation unit is an industrial equipment that separates the various gas components of the air. It operates within a certain range of conditions and can effectively save energy by improving the adjustment performance of the unit. Guide vane adjustment is an adjustment method that changes the airflow pre-swirl by changing the angle of the inlet guide vane. Compared with other adjustment methods, the guide vane adjustment mechanism has the advantages of simple structure, can be adjusted without stopping the vehicle, and can realize automatic adjustment. Broad application prospects and research value.

When the guide vane adjustment mechanism is used for adjustment, the inlet guide vane is subjected to alternating loads such as bending stress generated by airflow pressure and reflection, as well as torsional stress generated by the interaction between the asymmetrical curve of the blade surface and the airflow pressure, and the force is complex and The change is large, so the material of the inlet guide vane needs to have a certain strength. At the same time, since the working medium is air, which contains impurities such as moisture, carbon dioxide, and hydrocarbons, and the pipes or inlets of the air separation plant are often equipped with spraying devices, the material is required to have certain corrosion resistance.

The outer contour of the existing inlet guide vane is usually shown in Figure 1. It is about 660mm long, 100mm wide, and 100mm high. , the cross-sectional dimensions of each part vary greatly. The material of the existing imported guide vanes is generally martensitic stainless steel 2Cr13, which is commonly used in turbine rotating machinery blades. The yield strength of this material is required to be ≥ 450 MPa, and the forming method is free forging to form a large overall forging. However, this type of material also has the following disadvantages:

(1) The existing martensitic stainless steel 2Cr13 is processed from large forging materials. After heat treatment of large forgings, there are differences in the mechanical properties and structural properties of the material surface and the core. In the process of processing, the material The surface part with better strength is processed and removed, and the remaining part is the core part with slightly weaker strength, which leads to unsatisfactory mechanical properties such as strength of the inlet guide vane.

(2) The welding processability of the existing martensitic stainless steel 2Cr13 is poor.

(3) The unit will spray water from time to time, and the feedback from the on-site operation of the air separation unit shows that the water corrosion resistance of the inlet guide vane is not ideal.

Contents of the invention

The purpose of the present invention is to provide a kind of inlet guide vane material and preparation method thereof for air separation unit, mainly solve the welding manufacturability and strength of the processed guide vane when the existing martensitic stainless steel 2Cr13 is used as the inlet guide vane material And technical problems such as unsatisfactory corrosion resistance.

In order to solve the problems of the technologies described above, the technical solution of the present invention is:

An inlet guide vane material for an air separation unit, which is special in that the composition includes: 0.05%≤C≤0.12%; 0.1%≤Si≤0.6%; 0.1%≤Mn≤0.6%; P≤0.040%; S≤0.030%; 10.0%≤Cr≤12.0%; 0.2%≤Ni≤0.5%; 0.2%≤Mo≤0.5%; 0.01%≤Cu≤0.35%; 0.01%≤V≤0.05%; The rest is Fe;

Among them, the equivalent of C is less than 0.8; the equivalent of Cr is 6-10; the equivalent of Ni is 2-4;

The C equivalent refers to the conversion of the influence of various elements in the composition on the actual carbon content of the eutectic point into the increase or decrease of carbon, C equivalent=C+Si/30+Mn/20+Cu/20+Ni/60+ Cr/20+Mo/15+V/10; said Ni equivalent means the total content of austenite-forming elements, Ni equivalent=Ni+30C+0.5Mn+0.25Cu; said Cr equivalent means the content of martensite-forming elements Total content, Cr equivalent=20-(Cr+1.5Ni+0.7Si+0.75Mn+0.6Mo+1.5V+0.2Cu).

Further, the composition of the inlet guide vane material includes: C: 0.08%; Si: 0.3%; Mn: 0.5%; P: 0.020%; S: 0.005%; Cr: 11.0%; Ni: 0.3%; Mo: 0.3%; Cu: 0.20%; V: 0.01%; the rest is Fe.

In addition, the present invention also provides a preparation method for the inlet guide vane material of the air separation unit, which is special in that it includes the following steps:

Step 1] Smelting

1.1) Weigh raw materials according to the composition and weight percentage of the imported guide vane material;

1.2) Smelting and casting after mixing the weighed raw materials to obtain a steel ingot;

1.3) Carry out secondary smelting and pouring on the primary steel ingot in a vacuum state to obtain the secondary steel ingot;

Step 2] Forging

Forging the secondary steel ingot obtained in step 1.3) in the austenite single-phase region, and cooling it to room temperature to obtain the forging of the inlet guide vane;

Step 3] heat treatment

The forging of the inlet guide vane is sequentially subjected to quenching heat treatment and tempering heat treatment to obtain the inlet guide vane material for the air separation unit.

Further, in step 2], the initial forging temperature of the austenite single-phase region is 1100°C-1150°C, the final forging temperature is 850°C-900°C, and the forging ratio is 4-6.

Further, in step 3], the quenching heat treatment specifically includes putting the forging into the furnace at a temperature lower than 250°C, heating it to 930-980°C, keeping it warm for 3h-6h, and oil cooling to lower than 150°C after being released from the furnace.

Further, in step 3], the tempering heat treatment specifically includes putting the quenched forging into the furnace at a temperature lower than 250°C, heating it to 730-770°C, keeping it warm for 2h-4h, and air-cooling to a low temperature after being released from the furnace. at 150°C.

Compared with the prior art, the present invention has the following beneficial effects:

1. The imported guide vane material of the present invention is based on improving the material utilization rate of guide vane parts, combined with manufacturability requirements and parts application conditions, and limits the content of each raw material component by weight percentage, especially chromium, nickel, molybdenum, copper, vanadium At the same time, the carbon equivalent, chromium equivalent, and nickel equivalent are controlled to ensure the welding processability of materials with large and large cross-section changes, as well as the requirements for the strength of parts during the adjustment of air separation units and the corrosion resistance of materials for water spray settings. performance requirements. In addition, the strength and other mechanical properties of the inlet guide vane material of the present invention are slightly better than those of 2Cr13 material, and its welding processability and corrosion resistance are better than those of 2Cr13 material.

2. On the basis of the existing 2Cr13 material, combined with theoretical research and manufacturability requirements of the guide vane parts, through repeated tests and verifications, the raw material composition and its manufacturing process are optimized, and a new type of welding manufacturability is obtained. The stainless steel material with excellent corrosion resistance is suitable for the inlet guide vane of the air separation unit, which can effectively solve the problems of the current air separation unit inlet guide vane material 2Cr13 free forging, which leads to the deterioration of the mechanical properties of the material and other problems, and has a long service life. long advantage.

3. The preparation method of the imported guide vane material of the present invention has a simple overall process, especially the smelting process, which is different from the conventional electroslag remelting smelting of 2Cr13, which only undergoes vacuum smelting, and then sequentially undergoes forging, quenching heat treatment and tempering heat treatment, reducing It reduces the difficulty of the manufacturing process and is more conducive to popularization and use.

Description of drawings

Fig. 1 is the structure diagram of inlet guide vane;

Fig. 2 is a metallographic structure diagram of the inlet guide vane material prepared by using Embodiment 1 of the present invention;

Fig. 3 is a metallographic structure diagram of the existing martensitic stainless steel 2Cr13.

Detailed ways

The design principle of the present invention is: through the research on the imported guide vane material and its preparation method, a new type imported imported guide vane with better welding processability, improved strength and corrosion resistance and equivalent material cost is obtained compared with martensitic stainless steel 2Cr13. Guide vane material.

The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments and accompanying drawings.

The invention provides an inlet guide vane material for an air separation unit. The main components are calculated by weight percentage and specifically include: 0.05%≤C≤0.12%; 0.1%≤Si≤0.6%; 0.1%≤Mn≤0.6%; P≤0.040%; S≤0.030%; 10.0%≤Cr≤12.0%; 0.2%≤Ni≤0.5%; 0.2%≤Mo≤0.5%; 0.01%≤Cu≤0.35%; 0.01%≤V≤0.05%; The rest is Fe and unavoidable impurities. Wherein, the C equivalent is <0.8; the Cr equivalent is 6-10; and the Ni equivalent is 2-4.

In order to meet the welding processability of the material, the present invention reduces the content of C and Cr. Although the reduction of C content further improves the corrosion resistance, it reduces the strength, and the reduction of Cr content reduces both the corrosion resistance and the strength. Therefore , in order to ensure the strength and corrosion resistance of the material, the present invention increases Ni, Mo, Cu, V elements and content, but the increase of these elements will affect the welding process and can increase the cost to a certain extent, thus further controlling the Ni , Mo content. The present invention comprehensively controls the carbon equivalent, chromium equivalent and nickel equivalent. The composition of each element is not a simple patchwork, and its content range cannot be obtained by a simple single test. It fully considers the welding process requirements of materials and Applicable conditions such as strength and corrosion resistance are determined through repeated tests and actual verification, combined with theoretical research.

In the present invention, the imported guide vane material with better comprehensive performance is obtained by rationally designing the types and proportions of each element. Among them, the C equivalent represents the influence of various alloy elements on the actual carbon content of the eutectic point when the weld pool is formed, including C (main), Si, Cr, Mo, V, etc., and its control is mainly used to ensure the welding process; Cr The equivalent means that the martensite-forming elements include Cr (main), Ni, Mo, and V, and its control is mainly used to ensure the corrosion resistance and strength of the material; the Ni equivalent means that the austenite-forming elements include Ni (main), C, and Mn , Cu, etc., and its control is mainly used to ensure the corrosion resistance of the material and improve the welding process. The above-mentioned C equivalent, Ni equivalent, and Cr equivalent can simultaneously affect the welding processability, strength and corrosion resistance, and through the interaction of various elements, it can meet the manufacturing and use requirements of the imported guide vane.

In the composition of the inlet guide vane material of the present invention, the Cr element is a representative martensite forming element, and its main function is to improve the strength and corrosion resistance. When the Cr content is greater than 10%, the corrosion resistance of the inlet guide vane material In addition, the Cr content can also improve the hardenability of the imported guide vane material, thereby increasing the strength, but the weldability will deteriorate. In summary, combined with the actual application of the imported guide vane material, it is determined that the Cr content should be controlled at 10.0 -12.0%. Ni element is a representative austenite stable element, which can enhance the corrosion resistance of imported guide vane materials. Higher, the strength of the material will be lower. Mo element and V element are the forming elements of ferrite, which can improve the hardenability and refine the grain to improve the strength of the material. A certain amount of Mo can also effectively improve the strength of the passivation film of the material, thereby enhancing the corrosion resistance of the material However, when the content of Mo and V is too high, the amount of ferrite will increase, which seriously affects the welding processability of imported guide vane materials. Cu element is an austenite-forming element, and its prominent role is to improve corrosion resistance, especially when used in conjunction with phosphorus, it can significantly improve the corrosion resistance of imported guide vane materials. However, excessive Cu elements will lead to plasticity of the material. A sharp drop will affect the welding process, and when Cu≤0.5 has little effect on the welding performance. Mn element is an element that expands and stabilizes austenite, and can also improve the hardenability of the imported guide vane material and thereby increase the strength. However, too high a Mn content can promote the precipitation of the б phase, making the imported guide vane material brittle and harmful to the imported guide vane. The weldability of the leaf is disadvantageous. Si is a ferrite forming element, the higher the content, the higher the strength of the inlet guide vane material, and its combination with Mo and Cr improves the corrosion resistance, but the higher the content, the worse the weldability. C element is an element that expands the austenite region, and its content should be controlled below 0.12% in order to ensure corrosion resistance and welding processability.

In summary, the components of the raw materials work together to form the raw materials of the blade material of the present invention, and the ratios of the raw materials are also complementary.

Based on above-mentioned inlet guide vane material, the present invention also provides a kind of preparation method for the inlet guide vane material of air separation unit, specifically as follows:

Step 1] Smelting

1.1) Take the raw material according to the composition and weight percentage of the above-mentioned imported guide vane material;

1.2) Smelting and casting after mixing the weighed raw materials to obtain a steel ingot;

1.3) Perform secondary smelting and pouring on the primary steel ingot in a vacuum state to obtain the secondary steel ingot, ie billet.

The smelting process of the present invention is simple, but the 2Cr13 material usually needs to be smelted by electric furnace + electroslag remelting, and the process is relatively complicated.

Step 2] Forging

The secondary steel ingot obtained in step 1.3) is forged in the austenite single-phase region, and cooled to room temperature to obtain the forging of the inlet guide vane. Among them, the initial forging temperature of the austenite single-phase region is 1100°C-1150°C, the final forging temperature is 850°C-900°C, and the forging ratio is 4-6.

Step 3] heat treatment

The forging of the inlet guide vane is sequentially subjected to quenching heat treatment and tempering heat treatment to obtain the inlet guide vane material for the air separation unit.

The process of quenching heat treatment is that the forging is put into the furnace at a temperature lower than 250°C, heated to 930-980°C, kept for 3h-6h, and oil-cooled to lower than 150°C after being released from the furnace.

The process of tempering heat treatment is that the forging after quenching heat treatment is put into the furnace at a temperature lower than 250°C, heated to 730-770°C, kept for 2h-4h, and air-cooled to below 150°C after being released from the furnace, so as to obtain strength and durability. Imported guide vane materials with superior corrosion resistance.

The imported guide vane material can be used for subsequent welding processing of the imported guide vane, and the material has good welding processability. In turn, imported guide vane finished products with better comprehensive performance can be obtained.

Embodiment one

1. Weigh the following raw materials by weight percentage:

C:0.08%;Si:0.3%;Mn:0.5%;P:0.020%;S:0.005%;Cr:11.0%;Ni:0.3%;Mo:0.3%;Cu:0.20%;V:0.01%; The rest is Fe. Among them, the C equivalent is 0.70, the Cr equivalent is 7.7, and the Ni equivalent is 3.0.

The above raw materials weighed are mixed and then smelted and cast to obtain a primary steel ingot; the primary steel ingot is subjected to secondary smelting and pouring in a vacuum state to obtain a secondary steel ingot. The specific smelting and casting process can be set or adjusted according to the actual situation.

2. Forging

The obtained secondary steel ingot is forged in the austenite single-phase region, the initial forging temperature is set to 1100°C, the final forging temperature is set to 850°C, the forging ratio is 5, and then the stack is cooled to room temperature to obtain the inlet guide vane. Forgings.

3. Heat treatment

The forging of the inlet guide vane is sequentially subjected to quenching heat treatment and tempering heat treatment to obtain the inlet guide vane material for the air separation unit.

The specific process of quenching heat treatment is that the forging of the inlet guide vane is put into the furnace at 220°C for quenching treatment, heated to 950°C, kept for 3 hours, and oil-cooled to 130°C after being released from the furnace.

The specific process of tempering heat treatment is that the forging after quenching heat treatment is put into the furnace at a temperature of 220 ° C, heated to 730 ° C, kept for 2 hours, and air-cooled to 130 ° C after being released from the furnace.

Embodiment two

1. Weigh the following raw materials by weight percentage:

C: 0.10%, Si: 0.5%, Mn: 0.2%, P: 0.010%, S: 0.009%, Cr: 12%, Ni: 0.5%, Mo: 0.2%, Cu: 0.30%, V: 0.05%, The rest is Fe. Among them, the C equivalent is 0.77, the Cr equivalent is 6.5, and the Ni equivalent is 3.7.

The above raw materials weighed are mixed and then smelted and cast to obtain a primary steel ingot; the primary steel ingot is subjected to secondary smelting and pouring in a vacuum state to obtain a secondary steel ingot. The specific smelting and casting process can be set or adjusted according to the actual situation.

2. Forging

The obtained secondary steel ingot is forged in the austenite single-phase region, the initial forging temperature is set to 1150°C, the final forging temperature is set to 900°C, the forging ratio is 4, and then the stack is cooled to room temperature to obtain the inlet guide vane. Forgings.

3. Heat treatment

The forging of the inlet guide vane is sequentially subjected to quenching heat treatment and tempering heat treatment to obtain the inlet guide vane material for the air separation unit.

The specific process of quenching heat treatment is that the forging of the inlet guide vane is put into the furnace at 200°C for quenching treatment, heated to 930°C, kept for 6 hours, and oil-cooled to 100°C after being released from the furnace.

The specific process of tempering heat treatment is that the forging after quenching heat treatment is put into the furnace at a temperature of 200 ° C, heated to 770 ° C, kept for 4 hours, and air-cooled to 100 ° C after being released from the furnace.

Embodiment three

1. Weigh the following raw materials by weight percentage:

C: 0.12%, Si: 0.6%, Mn: 0.1%, P: 0.020%, S: 0.018%, Cr: 10%, Ni: 0.2%, Mo: 0.3%, Cu: 0.10%, V: 0.025%, The rest is Fe. Among them, the C equivalent is 0.68, the Cr equivalent is 9.0, and the Ni equivalent is 3.9.

The above raw materials weighed are mixed and then smelted and cast to obtain a primary steel ingot; the primary steel ingot is subjected to secondary smelting and pouring in a vacuum state to obtain a secondary steel ingot. The specific smelting and casting process can be set or adjusted according to the actual situation.

2. Forging

The obtained secondary steel ingot is forged in the austenite single-phase region, the initial forging temperature is set to 1100°C, the final forging temperature is set to 900°C, the forging ratio is 6, and then the stack is cooled to room temperature to obtain the inlet guide vane. Forgings.

3. Heat treatment

The forging of the inlet guide vane is sequentially subjected to quenching heat treatment and tempering heat treatment to obtain the inlet guide vane material for the air separation unit.

The specific process of quenching heat treatment is that the forging of the inlet guide vane is put into the furnace at a temperature of 180°C for quenching treatment, heated to 950°C, kept for 4 hours, and oil-cooled to 100°C after being released from the furnace.

The specific process of tempering heat treatment is that the forging after quenching heat treatment is put into the furnace at a temperature of 180 ° C, heated to 750 ° C, kept for 3 hours, and air-cooled to 100 ° C after being released from the furnace.

Embodiment four

1. Weigh the following raw materials by weight percentage:

C: 0.05%, Si: 0.2%, Mn: 0.2%, P: 0.010%, S: 0.015%, Cr: 10%, Ni: 0.5%, Mo: 0.5%, Cu: 0.2%, V: 0.03%, The rest is Fe. Among them, the C equivalent is 0.62, the Cr equivalent is 8.6, and the Ni equivalent is 2.2.

The above raw materials weighed are mixed and then smelted and cast to obtain a primary steel ingot; the primary steel ingot is subjected to secondary smelting and pouring in a vacuum state to obtain a secondary steel ingot. The specific smelting and casting process can be set or adjusted according to the actual situation.

2. Forging

The obtained secondary steel ingot is forged in the austenite single-phase region, the initial forging temperature is set to 1150°C, the final forging temperature is set to 870°C, the forging ratio is 6, and then the stack is cooled to room temperature to obtain the inlet guide vane. Forgings.

3. Heat treatment

The forging of the inlet guide vane is sequentially subjected to quenching heat treatment and tempering heat treatment to obtain the inlet guide vane material for the air separation unit.

The specific process of quenching heat treatment is that the forging of the inlet guide vane is put into the furnace at 240°C for quenching treatment, heated to 970°C, kept for 5 hours, and oil-cooled to 120°C after being released from the furnace.

The specific process of tempering heat treatment is that the forging after quenching heat treatment is put into the furnace at a temperature of 240 ° C, heated to 750 ° C, kept for 4 hours, and air-cooled to 120 ° C after being released from the furnace.

After test verification, the method of the present invention is feasible and the comprehensive performance of the imported guide vane material prepared is better. The following combines the imported guide vane material obtained by the present invention with the martensitic stainless steel 2Cr13 for its strength, toughness, metallographic structure and corrosion resistance. sex for comparison.

1. Comparison of strength and toughness indicators (shown in Table 1)

Table 1

It can be seen from Table 1 that, compared with the martensitic stainless steel 2Cr13, the inlet guide vane material prepared by this application has better strength and toughness indicators.

2. Comparison of metallographic structure (control ferrite)

As shown in Fig. 2 and Fig. 3, the structure of the inlet guide vane material obtained in Example 1 is close to or even finer than that of martensitic stainless steel 2Cr13.

3. Corrosion resistance comparison (shown in Table 2)

The electrochemical corrosion performance test of 6% FeCl ₃ salt solution is carried out, that is, the smaller the self-corrosion current density, the smaller the corrosion tendency, and the less prone to corrosion.

Table 2

Material Self-corrosion current density (A) Martensitic stainless steel 2Cr13 0.0013536 The inlet guide vane material that embodiment one obtains 0.0007645

It can be seen from Table 2 that the corrosion resistance of the inlet guide vane material obtained in Example 1 is significantly improved compared with the martensitic stainless steel 2Cr13. Carry out corresponding test to other embodiment, the obtained result is basically similar to embodiment one.

In summary, the present invention controls the content of main components in the material, especially the content of carbon, chromium, nickel, and molybdenum, and then controls the carbon equivalent, so that the prepared inlet guide vane material can obtain good welding processability. At the same time, the metallographic structure is adjusted by controlling the heat treatment system, thereby ensuring the strength and corrosion resistance of the imported guide vane material, and improving its comprehensive performance.

Above, although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, as long as they are within the scope of the spirit of the present invention, changes and modifications to the above embodiments should be regarded as In order to fall within the protection scope of the present invention.

Claims (6)

1. a kind of inlet guide vane material for air separation unit is characterized in that, composition comprises by weight percent: 0.05%≤C≤0.12%; 0.1%≤Si≤0.6%; 0.1%≤Mn≤0.6%; P≤0.040%; S≤0.030%; 10.0%≤Cr≤12.0%; 0.2%≤Ni≤0.5%; 0.2%≤Mo≤0.5%; 0.01%≤Cu≤0.35%; 0.01%≤V≤0.05%; the rest is Fe; Among them, the equivalent of C is less than 0.8; the equivalent of Cr is 6-10; the equivalent of Ni is 2-4; The C equivalent refers to the conversion of the influence of various elements in the composition on the actual carbon content of the eutectic point into the increase or decrease of carbon, C equivalent=C+Si/30+Mn/20+Cu/20+Ni/60+ Cr/20+Mo/15+V/10; said Ni equivalent means the total content of austenite-forming elements, Ni equivalent=Ni+30C+0.5Mn+0.25Cu; said Cr equivalent means the content of martensite-forming elements Total content, Cr equivalent=20-(Cr+1.5Ni+0.7Si+0.75Mn+0.6Mo+1.5V+0.2Cu). 2. the inlet guide vane material for air separation unit according to claim 1, is characterized in that, composition comprises by weight percent: C:0.08%;Si:0.3%;Mn:0.5%;P:0.020%;S:0.005%;Cr:11.0%;Ni:0.3%;Mo:0.3%;Cu:0.20%;V:0.01%; The rest is Fe. 3. a preparation method for the inlet guide vane material of claim 1 or 2, is characterized in that, comprises the following steps: Step 1] Smelting 1.1. Weigh raw materials according to the composition and weight percentage of the imported guide vane material; 1.2. After mixing the weighed raw materials, smelting and casting are carried out to obtain a steel ingot; 1.3. Perform secondary smelting and pouring on the primary steel ingot in a vacuum state to obtain secondary steel ingots; Step 2] Forging Forging the secondary steel ingot obtained in step 1.3) in the austenite single-phase region, and cooling it to room temperature to obtain the forging of the inlet guide vane; Step 3] heat treatment The forging of the inlet guide vane is sequentially subjected to quenching heat treatment and tempering heat treatment to obtain the inlet guide vane material for the air separation unit. 4. the preparation method for the inlet guide vane material of air separation plant according to claim 3, is characterized in that: In step 2], the initial forging temperature of the austenite single-phase region is 1100°C-1150°C, the final forging temperature is 850°C-900°C, and the forging ratio is 4-6. 5. the preparation method for the inlet guide vane material of air separation plant according to claim 4, is characterized in that: In step 3], the quenching heat treatment specifically includes putting the forging into the furnace at a temperature lower than 250°C, heating it to 930-980°C, keeping it warm for 3h-6h, and oil cooling to lower than 150°C after it comes out of the furnace. 6. the preparation method for the inlet guide vane material of air separation plant according to claim 5, is characterized in that: In step 3], the tempering heat treatment specifically includes putting the quenched forging into the furnace at a temperature lower than 250°C, heating it to 730-770°C, keeping it warm for 2h-4h, and air-cooling it to lower than 150°C after being released from the furnace .