An elongated air valve alloy bar and a method for preventing deformation thereof

Abstract

The present application relates to a kind of elongated valve alloy bar and its anti-deformation method, belong to valve alloy manufacturing technical field.Anti-deformation method obtains ingot by vacuum induction smelting and electroslag remelting;Obtain rolling blank by forging and rolling;Then solid solution, cold straightening and tempering treatment;Again, twice cold straightening and twice low-temperature aging treatment;Finally, rough machining, low-temperature aging and finishing, obtain valve alloy bar.Utilize the method of three low-temperature aging and three straightening combination, simultaneously control parameter in processing process, can prepare the valve alloy bar of diameter less than 30mm, length greater than 2m, its straightness is below 0.045mm / m, after one year storage, straightness still satisfies the requirement of less than 0.1mm / m.

Description

Technical Field

[0001] This invention relates to the field of valve alloy manufacturing technology, and in particular to a slender valve alloy bar and a method for preventing deformation therefrom. Background Technology

[0002] Valve, also known as air valve, is an important component in fuel and gas engines. Its function is specifically to introduce air into the engine and expel exhaust gases after combustion.

[0003] Based on their material composition, valves can be divided into valve steel and valve alloy. In the manufacturing process of valve alloys, to save material, the manufacturing length is usually over 2 meters. However, due to space limitations in internal combustion engines and the weight requirements of the engine itself, the diameter of the valve cannot be too large, so the diameter of valve alloys is usually around 20mm. Therefore, valve alloy bars are typical slender parts, and deformation can occur during processing or manufacturing.

[0004] Furthermore, after forming, valve alloy bars may be stored in the warehouse for a certain period of time depending on production needs. If these slender valve alloy bars are not subjected to anti-deformation treatment, deformation will occur after long-term storage, making subsequent processing difficult. On the other hand, deformation will also appear in the finished products, seriously affecting product quality. Therefore, anti-deformation processes during the machining of slender parts are crucial for the final quality and dimensional stability of the parts. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a slender valve alloy rod and a method for preventing deformation therefrom. This method not only reduces deformation during the processing of the valve alloy rod and ensures the dimensional accuracy of the valve alloy during use, but also effectively prevents deformation during long-term storage and extends the service life of the valve alloy rod.

[0006] On one hand, the present invention provides a method for preventing deformation of slender valve alloy rods, comprising the following steps:

[0007] S1: Smelting, obtaining ingots through vacuum induction smelting and electroslag remelting;

[0008] S2: Hot deformation, obtaining a rolled billet through forging and rolling;

[0009] S3: Then perform solution treatment, cold straightening and tempering;

[0010] S4: Perform two more cold straightening processes and two more low-temperature aging processes;

[0011] S5: Finally, rough machining, low-temperature aging and finish machining are performed to obtain valve alloy bars.

[0012] Furthermore, the straightness of the obtained valve alloy rod is below 0.045 mm / m, and after one year of storage, the straightness is less than 0.1 mm / m.

[0013] Furthermore, the temperature for the low-temperature aging is 40–80°C, and the duration of the low-temperature aging is 15–20 days.

[0014] Furthermore, the low-temperature aging process uses casting sand.

[0015] Furthermore, during the roughing process, the depth of cut is 4.00–5.50 mm, the feed rate is 0.10–0.30 mm / r, and the cutting speed is 25–35 m / min;

[0016] After rough machining, leave a margin of 0.30 to 0.80 mm on the surface of the bar.

[0017] Furthermore, during the finishing process, the depth of cut is 1.00–1.50 mm, the feed rate is 0.02–0.08 mm / r, and the cutting speed is 120–190 m / min.

[0018] Furthermore, during the roughing and finishing processes, the cutting tools are titanium carbonitride-based cemented carbide tools with the following composition: Ti(C,N): 46% + Ta: C 5.5% + WC: 10.5% + Co: 8% + Ni: 30%.

[0019] Furthermore, the diameter of the valve alloy rod is less than 30 mm and the length is greater than 2 m.

[0020] Furthermore, the valve alloy rod is an austenitic valve alloy with the following chemical composition by weight percentage: 0.01–0.08%, Si: 0.1–0.4%, Mn: 0.50–1.00%, P: ≤0.020%, S: ≤0.020%, Cr: 16.00–19.00%, Ni: 23.0–27.0%, Al: 1.00–2.50%, Ti: 2.10–3.20%, Nb: 0.50–1.50%, V: 0.10–0.40%, Zr: 0.005–0.025%, Ce: 0.001–0.05%, with the remainder being Fe and unavoidable impurities.

[0021] On the other hand, the present invention provides a slender valve alloy rod, which is prepared by the anti-deformation method described in the present invention.

[0022] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0023] 1. This invention, by employing a combination of three low-temperature aging processes and three straightening processes, minimizes the combined thermal stress, structural stress, and deformation stress generated during heat treatment and straightening, thus solving the problem of excessive deformation in slender parts or bars after long-term storage and increasing the dimensional stability of valve alloy bars. Simultaneously, by using a combination of roughing and finishing machining methods and controlling the machining parameters, deformation of slender valve alloys during machining is avoided, improving the product qualification rate.

[0024] 2. The low-temperature aging temperature of this invention is 40-80℃, and the low-temperature aging time is 15-20 days. The low-temperature aging process is completed in the casting sand, that is, the residual heat of the casting sand is used for low-temperature aging. On the one hand, it can save energy and reduce production costs; on the other hand, during the long-term low-temperature aging process, there will be no obvious changes in the structure and properties, only the segregation of individual atoms inside, but it can eliminate the stress accumulated in the previous process and prevent deformation during processing and long-term storage.

[0025] 3. By using the anti-deformation method provided by this invention to prepare valve alloy rods, and by combining three low-temperature aging and three straightening processes, while controlling the parameters during the processing, valve alloy rods with a diameter of less than 30 mm and a length of more than 2 m can be prepared, with a straightness of 0.045 mm / m.

[0026] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0027] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0028] Figure 1 This is a metallographic diagram of the valve alloy rod of Embodiment 1 of the present invention. Detailed Implementation

[0029] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0030] Valve, also known as air valve, is an important component in fuel and gas engines. Its function is specifically to introduce air into the engine and expel exhaust gases after combustion.

[0031] Based on their material composition, valves can be divided into valve steel and valve alloy. In the manufacturing process of valve alloys, to save material, the manufacturing length is usually over 2 meters. However, due to space limitations in internal combustion engines and the weight requirements of the engine itself, the diameter of the valve cannot be too large, so the diameter of valve alloys is usually around 20mm. Therefore, valve alloy bars are typical slender parts, and deformation can occur during processing or manufacturing.

[0032] Furthermore, the valve alloy rods generate stress during manufacturing, and in actual production, they often need to be stored for a period of time. However, after a period of time, the valve alloy rods may undergo severe deformation, making subsequent processing difficult and compromising the final quality and dimensional stability of the rods.

[0033] Therefore, the present invention provides a method for preventing deformation of slender valve alloy rods, comprising the following steps:

[0034] S1: Smelting, obtaining ingots through vacuum induction smelting and electroslag remelting;

[0035] S2: Hot deformation, obtaining a rolled billet through forging and rolling;

[0036] S3: Then perform solution treatment, cold straightening and tempering;

[0037] S4: Perform two more cold straightening processes and two more low-temperature aging processes;

[0038] S5: Finally, rough machining, low-temperature aging and finish machining are performed to obtain valve alloy bars.

[0039] Compared with existing technologies, this invention, by employing a combination of three low-temperature aging processes and three straightening processes, minimizes the combined thermal stress, structural stress, and deformation stress generated during heat treatment and straightening, thus solving the problem of excessive deformation of slender parts or bars after long-term storage and increasing the dimensional stability of valve alloy bars. Simultaneously, by using a combination of roughing and finishing machining methods and controlling the machining parameters, deformation of slender valve alloys during machining is avoided, improving the product qualification rate.

[0040] This invention utilizes a combination of three low-temperature aging processes and three straightening processes, while simultaneously controlling parameters during processing, to produce valve alloy bars with a diameter less than 30 mm and a length greater than 2 m, exhibiting a straightness below 0.045 mm / m. Furthermore, the straightness remains below 0.1 mm / m even after one year of storage.

[0041] Specifically, ingots are obtained through vacuum induction smelting and electroslag remelting.

[0042] It should be noted that in this invention, the smelting can be carried out using existing vacuum induction smelting and electroslag remelting to prepare ingots, which will not be elaborated here.

[0043] Specifically, in the hot deformation process, a rolled billet is obtained through forging and rolling;

[0044] It should be noted that the microstructure and properties of the valve alloy bars can be guaranteed during the forging and rolling processes. However, thermal stress will be generated within the valve alloy bars after forging and rolling, causing deformation of the valve alloy bars and thus failing to meet the straightness requirements. Therefore, subsequent steps are needed to remove the thermal stress.

[0045] In this invention, the control parameters during the forging process are: initial forging temperature of 1150-1170℃, final forging temperature of 930-950℃, and air cooling after forging.

[0046] In this invention, the control parameters during the rolling process are: initial rolling temperature of 1130-1150℃, final rolling temperature of 930-950℃, and air cooling after rolling.

[0047] In this invention, after rolling, the rolled billet undergoes solution treatment, cold straightening treatment, and tempering treatment. The solution treatment temperature is 980–1000℃, and the billet is held at this temperature for 1.0–1.5 hours before water cooling. The tempering treatment temperature is 740–760℃, and the tempering time is 4.5–5.0 hours.

[0048] It should be noted that metallic materials inevitably experience thermal stress and structural stress during heating and cooling. Due to the effects of thermal stress and structural stress, parts develop varying residual stresses after heat treatment. When the stress exceeds the material's yield strength, deformation will occur, which is particularly pronounced in thin-walled or slender parts.

[0049] Thermal stress and structural stress are generated during forging, rolling, and heat treatment (i.e., solution treatment). These stresses accumulate and accumulate in the parts. Current methods only reduce internal stress through tempering, but this cannot effectively remove it. The internal stress still exists during the part's processing or after a period of storage. This internal stress slowly releases, leading to deformation of the part and a decrease in its precision.

[0050] Therefore, the present invention adopts a method combining three cold straightening and three low-temperature aging to ensure that the internal stress of the material is released while ensuring that no significant structural transformation occurs inside the material.

[0051] The entire process is as follows: after solution treatment, the first cold straightening is performed, followed by tempering, then the second cold straightening, the first low-temperature aging, the third cold straightening, and the second low-temperature aging; finally, rough machining, the third low-temperature aging, and finish machining are performed.

[0052] It should be noted that in this invention, a combination of three low-temperature aging processes and three straightening processes is used to maximize stress removal. The purpose or function of each stage is not entirely the same. The purpose of the first cold straightening is to correct the deformation caused by solution cooling; the purpose of the second cold straightening is to correct the residual deformation after tempering; and the purpose of the third cold straightening is to correct the residual deformation after low-temperature aging. The first low-temperature aging process relieves the internal stress present after tempering; the second low-temperature tempering process relieves the internal stress generated during the third cold straightening process; and the third aging process relieves the internal stress generated during rough machining.

[0053] Specifically, the low-temperature aging temperature is 40–80°C, and the low-temperature aging time is 15–20 days.

[0054] The low-temperature aging process uses casting sand.

[0055] It should be noted that the temperature of low-temperature aging is crucial in this invention, as it must ensure that the internal stress of the material is released while preventing significant structural transformation. This invention employs a low-temperature, long-time aging method, where the aging temperature can be 40°C, 50°C, 60°C, 70°C, or 80°C, and the aging time can be 15, 16, 17, 18, 19, or 20 days.

[0056] During the low-temperature aging process, the residual internal stress inside the part gradually decreases as the low-temperature aging time increases. Three low-temperature aging cycles can eliminate this internal stress to the maximum extent. With further extension of the low-temperature aging time, the internal stress can be further eliminated to meet higher dimensional accuracy requirements, but the extended time will lead to a decrease in work efficiency.

[0057] In this invention, low-temperature aging, due to its low temperature, only causes the segregation of individual atoms within the material, without significant changes in its microstructure and properties, but it can eliminate previously accumulated stress. If the low-temperature aging temperature exceeds 80°C, the internal microstructure of the material will change, affecting its properties. For example, the segregation of individual atoms can cause uneven material properties.

[0058] In this invention, the low-temperature aging process uses casting sand, that is, the residual heat generated by the casting sand is used for low-temperature aging. On the one hand, from the perspective of production cost, no additional heating is required for the parts, which can save resources and costs. At the same time, the residual heat of the casting sand can be effectively reused. On the other hand, from the perspective of aging effect, it can better or to the maximum extent reduce the internal stress in the parts and ensure the dimensional accuracy during processing or storage.

[0059] Specifically, during the roughing process, the depth of cut is 4.00–5.50 mm, the feed rate is 0.10–0.30 mm / r, and the cutting speed is 25–35 m / min;

[0060] After rough machining, leave a margin of 0.30 to 0.80 mm on the surface of the bar.

[0061] Specifically, during the finishing process, the depth of cut is 1.00–1.50 mm, the feed rate is 0.02–0.08 mm / r, and the cutting speed is 120–190 m / min.

[0062] It should be noted that deformation of the part can also occur during the machining process, mainly in two stages: one is during part clamping, and the other is during the machining process itself. During part clamping, deformation primarily arises from the misalignment between the clamping point and the support point.

[0063] During machining, parts undergo elastic deformation in the direction of the cutting force. Simultaneously, to ensure a good surface finish, high cutting speeds are often used. The frictional heat generated between the tool and the part has a greater impact on deformation, especially for thin-walled parts. To prevent deformation, symmetrical machining is typically employed to balance the stress on opposite sides, achieving a stable state and resulting in a smooth surface on the machined part.

[0064] In this invention, a clamping method with one clamp and one support is used for clamping before turning. A center support is placed in the middle of the valve alloy bar to increase support, thereby increasing the rigidity of the valve alloy bar in the machining area and avoiding machining errors caused by elastic deformation of the valve alloy. At the same time, the clamping point should be as close as possible to the machining surface to increase the contact area between the valve alloy bar and the fixture, which can effectively reduce the deformation of the valve alloy bar.

[0065] In this invention, the machining process uses a relatively fast cutting speed. In high-speed cutting, since the chips are removed in a short time, most of the cutting heat is carried away by the chips, reducing the thermal deformation of the parts.

[0066] For deformation caused by frictional heat, a faster cutting speed can be selected because in high-speed machining, the chips are removed in a shorter time, and most of the cutting heat is carried away by the chips, reducing thermal deformation of the part. Secondly, in high-speed machining, the reduction of the softened portion of the cutting material can also reduce machining deformation of the part, which helps to ensure the dimensional and shape accuracy of the part.

[0067] Therefore, this invention employs a smaller feed rate and a faster cutting speed. The roughing feed rate is 0.1–0.3 mm / r, and the cutting speed is 25–35 m / min (which can be 25 m / min, 26 m / min, 27 m / min, 28 m / min, 29 m / min, 30 m / min, 31 m / min, 32 m / min, 33 m / min, 34 m / min, or 35 m / min). The finishing feed rate is 0.05–0.1 mm / r, and the cutting speed is 120–190 m / min (which can be 120 m / min, 130 m / min, 140 m / min, 150 m / min, 160 m / min, 170 m / min, 180 m / min, or 190 m / min). The smaller feed rate ensures that the part is subjected to less tool pressure, and the faster cutting speed ensures less frictional heat, thereby ensuring the straightness of the slender valve alloy.

[0068] In finishing, excessive feed rate will result in unsatisfactory surface roughness, while insufficient feed rate will affect production efficiency. Excessive cutting speed will cause severe tool wear, leading to frequent tool changes. Conversely, insufficient cutting speed will also negatively impact machining efficiency.

[0069] Preferably, during the roughing and finishing processes, the cutting tool is a titanium carbonitride-based cemented carbide tool with the following composition: Ti(C,N): 46% + Ta: C 5.5% + WC: 10.5% + Co: 8% + Ni: 30%.

[0070] It should be noted that this invention uses titanium carbonitride-based carbide cutting tools instead of high-speed steel or ceramic tools for machining. High-speed steel tools wear out quickly and require frequent tool changes, while ceramic tools are expensive. Using titanium carbonitride-based carbide tools results in smooth machining and is better suited to both high-speed and low-speed turning operations.

[0071] Specifically, the valve alloy rod is a precipitation-hardening austenitic valve alloy with the following chemical composition by weight percentage: 0.01–0.08%, Si: 0.1–0.4%, Mn: 0.50–1.00%, P: ≤0.020%, S: ≤0.020%, Cr: 16.00–19.00%, Ni: 23.0–27.0%, Al: 1.00–2.50%, Ti: 2.10–3.20%, Nb: 0.50–1.50%, V: 0.10–0.40%, Zr: 0.005–0.025%, Ce: 0.001–0.05%, with the remainder being Fe and unavoidable impurities.

[0072] It should be noted that in this invention, the valve alloy rod is a precipitation-hardening austenitic valve alloy, and its internal matrix is ​​austenitic. During solution cooling, carbides and intermetallic compounds (γ') precipitate in the valve alloy, inevitably causing an increase in the volume of the alloy matrix. For the valve alloy, during solution cooling, the surface cools first, and the surface volume increases first, while the core volume remains unchanged. Since the core hinders the increase in surface volume, compressive stress is generated on the surface, and tensile stress is generated in the core. Therefore, due to the difference in specific heat between the austenitic matrix and the precipitates generated during solution cooling, structural stress will be generated.

[0073] The valve alloy rods are relatively long, and the time difference of this phase transformation is more obvious along the length. In particular, valve alloy rods with a length of more than 2m and a diameter of less than 30mm are more prone to deformation along their length.

[0074] The structural stress, thermal stress, and deformation stress generated by solution treatment and straightening can be partially eliminated by tempering, but some remain inside the valve alloy bar. After this valve alloy bar is processed into parts, the residual stress will gradually act on the parts during use, causing deformation after long-term storage or use, resulting in decreased dimensional stability and affecting the continued use of the parts.

[0075] Therefore, this invention employs a combination of three cold straightening processes and three low-temperature aging processes. The residual internal stress inside the part gradually decreases as the low-temperature aging time increases. Three low-temperature aging processes can eliminate this internal stress to the maximum extent, ensuring that the internal stress is released and that no significant structural transformation occurs inside.

[0076] To more clearly describe the present invention, the following embodiments and comparative examples are provided for further illustration.

[0077] Example 1

[0078] A method for preventing deformation of a slender, elongated valve alloy rod includes the following steps:

[0079] S1: Smelting, ingots were obtained by vacuum induction smelting and electroslag remelting; 6 furnaces of ingots with different compositions were prepared, as shown in Table 1.

[0080] S2: Hot deformation, obtaining Φ25×2500mm round bars through forging and rolling;

[0081] S3: Then perform solution treatment, first cold straightening and tempering;

[0082] The solution treatment temperature was 990℃, and the solution was kept at that temperature for 1.5 hours before water cooling.

[0083] The tempering process involves 750℃ and holding for 5.0 hours.

[0084] The parameter for cold straightening is that it remains in place for 8 minutes under the action of 180 kg force.

[0085] S4: Perform two more cold straightening processes and two more low-temperature aging processes;

[0086] The process or sequence is as follows: second straightening, first low-temperature aging treatment, third straightening and second low-temperature aging treatment; the molding sand temperature is maintained at 40℃ and the aging time is 20 days.

[0087] S5: Finally, after roughing, low-temperature aging and finishing, the valve alloy bar is obtained. The parameters for roughing and finishing are shown in Table 3. During the roughing and finishing processes, titanium carbonitride-based cemented carbide tools are used. The tool composition is Ti(C,N): 46% + Ta: C 5.5% + WC: 10.5% + Co: 8% + Ni: 30%.

[0088] Table 1 Chemical composition (wt%) of embodiments of the present invention

[0089]

[0090] In this invention, each batch of ingots is prepared into two bars of the same specifications, which are numbered sequentially. Table 2 shows the test results of the bar straightness at different stages, mainly including the unstraightened stage after tempering, the straightened stage after tempering, and the stage of low-temperature aging + straightening + low-temperature aging (i.e., before rough machining, i.e., step S4), as shown in Table 2.

[0091] Table 2 Straightness results at different stages

[0092]

[0093] Straightness was tested at different stages before rough machining. Table 2 shows that the straightness was relatively high before straightening, ranging from 0.85 to 1.85 mm / m, indicating significant deformation. After straightening, the straightness decreased to 0.22-0.57 mm / m. However, after applying low-temperature aging followed by straightening and then low-temperature aging again, the straightness further decreased, falling below 0.27 mm / m.

[0094] Table 3 Process Parameter Control

[0095]

[0096]

[0097] As can be seen from Table 3, by using the machining method provided by this invention, controlling the depth of cut, feed rate and cutting speed in roughing and finishing, the straightness is further reduced under their interaction, and the straightness is kept below 0.045 mm / m, which meets the requirements.

[0098] Table 4. Straightness of the bars after one year of storage (unit: mm / m)

[0099]

[0100] Table 4 compares the straightness of valve alloy bars prepared using the conventional process after one year of storage with that prepared using the method of this invention after one year of storage. The conventional process involves straightening the valve alloy bars after solution treatment and tempering, followed by direct machining into bars using ordinary machining techniques. The straightness of the machined bars meets the requirement of less than 0.1 mm / m.

[0101] As can be seen from the table, valve alloy bars manufactured using traditional methods, after one year of storage without undergoing low-temperature aging treatment, did not effectively release internal stress, resulting in a significant increase in straightness that no longer meets the requirement of greater than 0.1 mm / m. However, the method of this invention, through three low-temperature aging processes and appropriate machining techniques, can effectively reduce stress in the valve alloy bars, increase their dimensional stability, and prevent excessive deformation of such slender parts.

[0102] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preventing deformation of a slender, elongated valve alloy rod, characterized in that, Includes the following steps: S1: Smelting, obtaining ingots through vacuum induction smelting and electroslag remelting; S2: Hot deformation, obtaining a rolled billet through forging and rolling; S3: Then perform solution treatment, cold straightening and tempering; the solution treatment temperature is 980~1000℃, and the holding time is 1.0~1.5h followed by water cooling; the tempering temperature is 740~760℃, and the holding time is 4.5~5.0h. S4: Perform two more cold straightening processes and two more low-temperature aging processes; The process is as follows: second alignment, first low-temperature aging treatment, third alignment, and second low-temperature aging treatment; S5: Finally, roughing, low-temperature aging, and finishing are performed to obtain the valve alloy bar. During the roughing process, the depth of cut is 4.00~5.50mm, the feed rate is 0.10~0.30mm / r, and the cutting speed is 25~35m / min. During the finishing process, the depth of cut is 1.00~1.50mm, the feed rate is 0.02~0.08mm / r, and the cutting speed is 120~190m / min. The low-temperature aging temperature is 40~80℃, and the low-temperature aging time is 15~20 days; the diameter of the valve alloy rod is less than 30mm and the length is greater than 2m; the straightness of the obtained valve alloy rod is less than 0.045mm / m, and the straightness is less than 0.1mm / m after one year of storage; The valve alloy rods mentioned therein are austenitic valve alloys with the following chemical composition by weight percentage: 0.01~0.08%, Si: 0.1~0.4%, Mn: 0.50~1.00%, P: ≤0.020%, S: ≤0.020%, Cr: 16.00~19.00%, Ni: 23.0~27.0%, Al: 1.00~2.50%, Ti: 2.10~3.20%, Nb: 0.50~1.50%, V: 0.10~0.40%, Zr: 0.005~0.025%, Ce: 0.001~0.05%, with the remainder being Fe and unavoidable impurities.

2. The method for preventing deformation of a slender gas valve alloy rod according to claim 1, characterized in that, The low-temperature aging temperature is 50~80℃, and the low-temperature aging time is 16~20 days.

3. The method for preventing deformation of a slender gas valve alloy rod according to claim 1, characterized in that, The low-temperature aging process uses casting sand.

4. The method for preventing deformation of a slender gas valve alloy rod according to claim 1, characterized in that, During the roughing process, the depth of cut is 4.00~5.50mm, the feed rate is 0.10~0.30mm / r, and the cutting speed is 26~35m / min; After rough machining, leave a margin of 0.30~0.80mm on the surface of the bar.

5. The method for preventing deformation of a slender gas valve alloy rod according to claim 1, characterized in that, During the finishing process, the depth of cut is 1.00~1.50mm, the feed rate is 0.02~0.08mm / r, and the cutting speed is 140~190m / min.

6. The method for preventing deformation of a slender gas valve alloy rod according to claim 1, characterized in that, During the roughing and finishing processes, the cutting tools are titanium carbonitride-based cemented carbide tools with the following composition: Ti(C,N): 46% + Ta: C 5.5% + WC: 10.5% + Co: 8% + Ni: 30%.

7. A slender, elongated alloy rod for a valve, characterized in that, It is prepared by the anti-deformation method according to any one of claims 1-6.

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