Liquid-air alternate quenching method for 13Cr15Ni4Mo3N stainless steel

Abstract

The application relates to a liquid-air alternating quenching method of 13Cr15Ni4Mo3N stainless steel, which comprises the following steps: (1) after austenitizing, the 13Cr15Ni4Mo3N stainless steel workpiece is subjected to cyclic alternating quenching treatment of water cooling and air cooling until the workpiece is cooled to room temperature; (2) the workpiece at room temperature is continuously subjected to cyclic alternating quenching treatment of deep cooling and air cooling until the workpiece is cooled to a set deep cooling temperature; (3) finally, the workpiece cooled to the deep cooling temperature is taken out for air cooling, and the liquid-air alternating quenching is completed. Compared with the prior art, the application can provide any cooling intensity between water quenching and air cooling in the high-temperature-to-room-temperature section, provide the cooling intensity of the fastest liquid nitrogen cooling speed in the low-temperature section, and control the final deep cooling temperature, so that cracking in the deep cooling process is avoided, and the quenching cooling and deep cooling requirements of products of different sizes are met.

Description

Technical Field

[0001] This invention belongs to the field of heat treatment technology for steel materials, and relates to a liquid-air alternating quenching method for 13Cr15Ni4Mo3N stainless steel. Background Technology

[0002] The compressor is one of the most critical components of an aero-engine, determining important performance indicators such as engine intake air volume, air compression ratio, and thrust-to-weight ratio, and is a major factor affecting aircraft maneuverability. Its main function is to compress air and deliver it to the combustion chamber. With the upgrading of engines, the thrust-to-weight ratio is increasing, placing increasingly stringent requirements on 13Cr15Ni4Mo3N stainless steel bladed disks. During the heat treatment process, quenching cracks frequently occur, resulting in poor quality stability and difficulty in meeting production cycle and cost control requirements. Excessive quenching cooling rate leads to increased quenching stress in the workpiece, causing quenching cracks; conversely, insufficient quenching cooling rate, failing to reach the critical cooling rate, negatively impacts performance. Therefore, it is essential to select an appropriate quenching method based on the steel composition and the actual shape of the workpiece, optimizing the bladed disk heat treatment process to improve production efficiency and quality stability.

[0003] 13Cr15Ni4Mo3N stainless steel has an austenitic microstructure after annealing, resulting in good machinability. After quenching and cold treatment, its microstructure becomes martensitic, and subsequent tempering precipitates strengthening phases, giving it high strength, ductility, toughness, and good corrosion resistance. Due to its excellent comprehensive properties, it is widely used in load-bearing components such as bolts and landing gear, and has extensive applications in aerospace, marine engineering, and other fields. 13Cr15Ni4Mo3N stainless steel possesses the dual characteristics of martensite and austenite. By adjusting the heat treatment process, its mechanical properties can be modified. Its emergence compensates for the shortcomings of martensitic precipitation-hardening stainless steel, which has a martensitic microstructure in the solid solution state, high strength, poor cold workability, and is not suitable for manufacturing complex parts. The conventional heat treatment process for 13Cr15Ni4Mo3N stainless steel is as follows: hold at 1040℃±10℃ for 2 hours, then oil quench, deep cryogenics, then hold at 950℃±10℃ for 2 hours, then oil quench, deep cryogenics, and finally tempering. When using this method for quenching, the workpiece ignites upon immersion in oil, generating large amounts of dense smoke, posing a safety hazard and causing severe environmental pollution. The harsh operating environment also poses a significant health risk to workers. Furthermore, water quenching alone results in severe cracking of the impeller, rendering the parts unusable. Therefore, it is necessary to develop a safe, clean, and cost-effective quenching method to address this problem. Summary of the Invention

[0004] The purpose of this invention is to provide a liquid-air alternating quenching method for 13Cr15Ni4Mo3N stainless steel. This method is simple and flexible to operate, safe and pollution-free, and the resulting material is superior to that obtained by conventional quenching processes. It can fully utilize the total mechanical properties of 13Cr15Ni4Mo3N stainless steel workpieces and is suitable for manufacturing core components such as blade disks in the aerospace field.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] In one aspect, the present invention provides a method for alternating liquid-air quenching of 13Cr15Ni4Mo3N stainless steel, comprising the following steps:

[0007] (1) The austenitized 13Cr15Ni4Mo3N stainless steel workpiece is first subjected to alternating water cooling and air cooling quenching treatment until the workpiece is cooled to room temperature.

[0008] (2) Continue to perform alternating deep cryogenic and air cooling quenching on the workpiece at room temperature until the workpiece is cooled to the set deep cryogenic temperature.

[0009] (3) Finally, the workpiece that has been cryogenically cooled to room temperature is taken out and air-cooled to complete the liquid-air alternating quenching.

[0010] Furthermore, in step (1), the temperature of the cooling water used in the water cooling process is 10-30℃, and the water cooling time for each time is 20s-10min, depending on the size of the workpiece.

[0011] Furthermore, in step (1), the air cooling time is 20s-10min each time.

[0012] Furthermore, in step (2), cryogenic treatment is carried out in a cryogenic pool, wherein the cryogenic liquid in the cryogenic pool is liquid nitrogen or a mixture thereof, specifically, the mixture may be liquid nitrogen alcohol.

[0013] Furthermore, in step (2), the deep-cooling time for each step is 4-12 minutes.

[0014] Furthermore, in step (2), the air cooling time is 1-3 minutes each time.

[0015] Furthermore, in step (2), the cryogenic temperature reached by the workpiece cooling is the temperature of the cryogenic liquid in the cryogenic pool.

[0016] Furthermore, in step (3), the air cooling time is until the temperature is cooled to room temperature.

[0017] On the other hand, the present invention also provides a heat treatment method for 13Cr15Ni4Mo3N stainless steel, wherein the 13Cr15Ni4Mo3N stainless steel workpiece is subjected to austenitization treatment, then subjected to quenching treatment by the liquid-air alternating quenching method as described above, and finally subjected to tempering.

[0018] Furthermore, the tempering temperature is 500-540℃, and the tempering holding time is 4-8 hours.

[0019] Furthermore, the composition range of the 13Cr15Ni4Mo3N stainless steel is as follows:

[0020] C: ≤0.13%, Cr: 14.00~15.50%, Ni: 4.00~5.00%, Mo: 2.30~2.80%, Si: ≤0.70%, Mn: 0.50~1.00%, P: ≤0.03%, S: ≤0.015%, N: 0.05~0.10%, with the remainder being Fe and unavoidable impurity elements.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) By adjusting the time the workpiece spends in cooling water and air, the cooling rate of the workpiece core can reach the critical quenching rate of 13Cr15Ni4Mo3N stainless steel, achieving the purpose of quenching through. Simultaneously, it can provide any cooling intensity between water quenching and air cooling, thus meeting the quenching cooling requirements of different products. The final cryogenic rate is any cooling rate between liquid nitrogen cryogenic and air cooling, and the final cryogenic temperature is any temperature between room temperature and liquid nitrogen temperature, avoiding cracking during the cryogenic process, thereby meeting the cryogenic rate and final temperature requirements of different products.

[0023] (2) The quenching of 13Cr15Ni4Mo3N stainless steel by the method of the present invention and the resulting material properties after tempering are superior to those of conventional quenching processes. This method can fully utilize the comprehensive mechanical properties of the material and make it suitable for manufacturing core components such as blade disks in the aerospace field.

[0024] (3) The liquid-air alternating quenching method for 13Cr15Ni4Mo3N stainless steel of the present invention is simple to operate, low in cost, energy-saving and environmentally friendly, safe and pollution-free compared with the conventional oil quenching process, and has good economic benefits and is easy to promote on a large scale. Attached Figure Description

[0025] Figure 1 The image shows the microstructure of the workpiece after processing in Example 1.

[0026] Figure 2 This is a microstructure diagram of the workpiece after processing in Example 2. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0028] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0029] Example 1

[0030] The experiment was conducted using a block-shaped 13Cr15Ni4Mo3N stainless steel sample, and the specific steps included:

[0031] Step 1: Heat an empty quenching furnace to 650°C, place the 13Cr15Ni4Mo3N stainless steel bladed disk sample to be quenched into the furnace, heat it to 1040°C in the furnace, and hold it for 2 hours to allow the bladed disk to be fully austenitized.

[0032] Step 2: Take out the heat-insulated sample and quench it in a water bath containing cooling water at 25°C for 25 seconds.

[0033] Step 3: After 25 seconds, quickly lift it out of the cooling water tank and air cool it for 30 seconds.

[0034] Step 4: After the 30-second air cooling time is up, continue to lower the workpiece into the cooling water tank for 25 seconds of water cooling. Repeat this process until the workpiece is cooled to room temperature.

[0035] Step 5: Cool the workpiece at room temperature in a liquid nitrogen bath at -196°C for 5 minutes.

[0036] Step 6: Remove the workpiece and air-cool it for 1 minute.

[0037] Step 7: After the 1-minute air cooling time is up, continue to lower the workpiece into the liquid nitrogen bath for deep cooling for 5 minutes. Repeat this process until the workpiece is cooled to the liquid nitrogen temperature.

[0038] Step 8: Remove the workpiece after deep cooling and air cool it until the temperature reaches room temperature to complete the liquid air quenching.

[0039] Example 2

[0040] The experiment was conducted using a block-shaped 13Cr15Ni4Mo3N stainless steel sample, and the specific steps included:

[0041] Step 1: Heat the empty quenching furnace to 650°C, place the bladed disk to be quenched in the furnace, heat it to 1040°C in the furnace, and hold it for 2 hours to allow the bladed disk to be fully austenitized.

[0042] Step 2: Take out the heat-insulated sample and quench it in a water bath for 35 seconds.

[0043] Step 3: After 25 seconds, quickly lift it out of the cooling water tank and air cool it for 20 seconds.

[0044] Step 4: After the 20-second air cooling time is up, continue to lower the workpiece into the cooling water tank for 35 seconds of water cooling. Repeat this process until the workpiece is cooled to room temperature.

[0045] Step 5: Cool the workpiece at room temperature to -196°C in a liquid nitrogen bath for 10 minutes.

[0046] Step 6: Remove the workpiece and air-cool it for 3 minutes.

[0047] Step 7: After the 3-minute air cooling time is up, continue to lower the workpiece into the liquid nitrogen bath for deep cooling for 10 minutes. Repeat this process until the workpiece is cooled to the liquid nitrogen temperature.

[0048] Step 8: Remove the workpiece after deep cooling and air cool it until the temperature reaches room temperature to complete the liquid air quenching.

[0049] The mechanical properties of the 13Cr15Ni4Mo3N stainless steel samples obtained by quenching and further tempering (temperature 520℃, time 6h) in the above embodiments and comparative examples were tested, and the results are shown in Table 1 below:

[0050] Table 1

[0051]

[0052] As can be seen from the above embodiments, the quenching method of the present invention has a simple process flow and low material cost. By adjusting parameters such as the residence time in the cooling water tank and the residence time in the air, the cooling rate of the workpiece can be effectively controlled. After deep cooling, the residual austenite content in the material is low, resulting in excellent performance. The residual stress of the workpiece after heat treatment is small, and it is not easy to crack. Moreover, there are no problems such as fire, dense smoke, and harsh operating environment during oil quenching. The whole process is clean and pollution-free, easy to promote, and has good application prospects.

[0053] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for alternating liquid-air quenching of 13Cr15Ni4Mo3N stainless steel, characterized in that, Includes the following steps: (1) The austenitized 13Cr15Ni4Mo3N stainless steel workpiece is first subjected to alternating water cooling and air cooling quenching treatment until the workpiece is cooled to room temperature. (2) Continue to perform alternating deep cryogenic and air cooling quenching on the workpiece at room temperature until the workpiece is cooled to the set deep cryogenic temperature; (3) Finally, the workpiece that has been cryogenically cooled to room temperature is taken out and air-cooled to complete the liquid-air alternating quenching; In step (1), the temperature of the cooling water used in the water cooling process is 10-30℃, and the water cooling time is 20s-10min each time; In step (1), the air cooling time is 20s-10min each time; In step (2), cryogenic treatment is carried out in a cryogenic pool, wherein the cryogenic liquid in the cryogenic pool is liquid nitrogen or a mixture thereof; In step (2), the duration of each deep cryogenic treatment is 4-12 minutes; In step (2), the air cooling time is 1-3 minutes each time; In step (2), the cryogenic temperature reached by the workpiece cooling is the temperature of the cryogenic liquid in the cryogenic pool.

2. The liquid-air alternating quenching method for 13Cr15Ni4Mo3N stainless steel according to claim 1, characterized in that, In step (3), the air is cooled to room temperature.

3. A heat treatment method for 13Cr15Ni4Mo3N stainless steel, characterized in that, After austenitizing the 13Cr15Ni4Mo3N stainless steel workpiece, it is then quenched using the liquid-air alternating quenching method as described in claim 1 or 2, and finally tempered.

4. The heat treatment method for 13Cr15Ni4Mo3N stainless steel according to claim 3, characterized in that, The tempering temperature is 500-540℃, and the tempering holding time is 4-8 hours.

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