Ti / Mo residual element regulation and heat treatment synergistic process for controlling J9 end quenching value of alloy structural steel

Abstract

The invention relates to the technical field of ferrous metallurgy, and discloses a Ti / Mo residual element regulation and heat treatment synergistic process for controlling the J9 end quenching value of alloy structural steel, which comprises the following steps: S1, Ti / Mo residual element regulation, S2, continuous casting process synergistic regulation, S3, heat treatment synergistic optimization, S4, sample processing and standard detection, and S5, process adjustment and feedback. According to the technology, precise stabilization of the J9 end quenching value is achieved, the J9 end quenching value is stably controlled to be 36-48 HRC through precise regulation and control of residual elements of Ti and Mo in cooperation with continuous casting electromagnetic stirring and heat treatment parameter collaborative optimization, the deviation of the two faces is smaller than or equal to 3.5 HRC, the core pain points that in the prior art, the end quenching value is large in fluctuation and frequently exceeds the standard are solved, and the quality of the J9 end quenching value is improved. According to the process, the quenching cracking risk is remarkably reduced, element regulation and control are coordinated with the normalizing pretreatment and the step quenching cooling process, forging and solidification residual stress is effectively eliminated, the quenching cracking rejection rate is smaller than or equal to 1.2%, the core structure rating is smaller than or equal to the fourth level, the hardenability and the crack resistance are both considered, and the batch quality problem is reduced.

Description

Technical Field

[0001] This invention relates to the field of iron and steel metallurgy technology, specifically to a synergistic process of controlling the Ti / Mo residual element regulation and heat treatment of the J9 end quenching value of alloy structural steel. Background Technology

[0002] Alloy structural steel used in the production of key mechanical components (such as steering knuckles) must meet stable J9 end-quenching values ​​to ensure hardenability and processing safety. Existing technologies commonly suffer from a lack of control over residual elements Ti and Mo, coupled with incoordination in heat treatment processes. High Ti content or large fluctuations in Mo content can lead to abnormally high hardenability. When combined with improper heat treatment processes (such as insufficient or excessive heating and holding time), the J9 end-quenching value can exceed the reasonable range of 36-48 HRC, with deviations between the two sides often exceeding 4 HRC. Furthermore, the lack of coordinated design between element control and continuous casting and heat treatment parameters further exacerbates compositional segregation and residual stress accumulation, resulting in a high scrap rate due to quenching cracking. This not only triggers customer complaints and inventory lock-up risks but also affects product quality consistency, making it difficult to meet the stringent requirements of downstream key components. Summary of the Invention

[0003] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a synergistic process for controlling the Ti / Mo residual element regulation and heat treatment of the J9 end quenching value of alloy structural steel. This process has advantages such as precise and stable J9 end quenching value, and solves the problem that the J9 end quenching value exceeds the reasonable range of 36-48 HRC, and the deviation between the two sides of the end quenching value often exceeds 4 HRC.

[0004] (II) Technical Solution To achieve the aforementioned goal of accurately stabilizing the quenching value at the J9 end, this invention provides the following technical solution: a synergistic process for controlling the Ti / Mo residual element regulation and heat treatment of the quenching value at the J9 end of alloy structural steel, comprising the S1 Ti / Mo residual element regulation step, the S2 continuous casting process synergistic regulation step, the S3 heat treatment synergistic optimization step, the S4 sample processing and testing specification step, and the S5 process adjustment and feedback step. The S1 Ti / Mo residual element regulation step includes S101 precise control of element content and S102 element detection and feedback. Among them, the collaborative control steps of the S2 continuous casting process include optimization of core parameters of S201 continuous casting and quality control of S202 continuous casting process. Among them, the S3 heat treatment co-optimization steps include S301 pretreatment process, S302 quenching process parameters and S303 tempering process adaptation. The S4 sample processing and testing specifications include S401 end-quenched sample processing, S402 testing requirements, and S403 testing frequency.

[0005] Preferably, the content of element S101 is precisely controlled: Titanium (Ti): Control range 0.0020%-0.0060% (material basis 0.0030%-0.0050% optimized and expanded), target value 0.0035%-0.0045%, use low-Ti alloy raw materials, converter tapping slag amount ≤5kg / t, avoid recycling and reuse of Ti-containing refining slag; Molybdenum (Mo): Control range 0.0020%-0.0180% (material basis 0.0030%-0.0100% optimized and expanded), target value 0.0050%-0.0120%, use low-Mo scrap steel as raw material, scrap steel addition ratio ≤25% to reduce Mo content fluctuations; Synergistic control elements: Boron (B) ≤ 0.0006%, Nitrogen (N) ≤ 55ppm (material basis ≤ 60ppm optimized and tightened), Phosphorus (P) ≤ 0.020%, Sulfur (S) ≤ 0.018%, to avoid the cumulative effect of residual elements on end quenching value.

[0006] Preferably, the element detection and feedback in S102: Composition analysis was performed on 3-5 heats of molten steel from each casting, using a combination of spectral and chemical analysis for verification. The Ti / Mo content deviation was ≤ ±0.0005%. Establish a database corresponding to element content and end-quench value. If Ti content > 0.0055% or Mo content > 0.0150%, immediately adjust the batching plan and suspend the rolling of key specifications in furnaces with high Ti / Mo content.

[0007] Preferably, the core parameters of the S201 continuous casting are optimized as follows: Electromagnetic stirring of crystallizer: current 90A-260A (material basis 100A-250A optimized and expanded), frequency 2.0Hz-3.0Hz, 180A-260A when cross-section ≥120mm, 90A-180A when cross-section <120mm; End electromagnetic stirring: current 180A-320A (material basis 200A-300A optimized and expanded), frequency 7.0Hz-9.0Hz, 180A-250A when the pulling speed is ≤0.85m / min, 250A-320A when the pulling speed is >0.85m / min; Continuous casting parameters: casting speed 0.80m / min-0.95m / min, specific water content 0.18L / kg-0.22L / kg, light reduction process is adopted, heavy reduction is prohibited, and component segregation is reduced.

[0008] Preferably, the quality control of the S202 continuous casting process is as follows: The superheat of the molten steel is controlled between 15℃ and 30℃, and the carbon content in the ladle is kept stable at 0.38% to 0.41% to avoid abnormal end-quenching values ​​induced by composition fluctuations. Take 2-3 continuous casting billet samples from each casting run and test the Ti / Mo content difference in the core, 1 / 4R, and edge. The difference in carbon content should be ≤0.0010% and ≤0.040%.

[0009] Preferably, the S301 pretreatment process is as follows: Normalizing temperature: 860℃-890℃ (870℃ is optimized and expanded based on the material), holding time 40min-70min, adjusted according to the billet size (increase by 8min for every 10mm), to eliminate forging residual stress; Cooling method: After normalizing, the furnace is cooled to 320℃-360℃ and then air-cooled to reduce the temperature difference stress with the quenching medium.

[0010] Preferably, the S302 quenching process parameters are as follows: Quenching temperature: 830℃-870℃ (840℃-860℃ for material base, optimized and expanded), 850℃-870℃ when the quenching value of J9 end is too low, and 830℃-850℃ when it is too high; Insulation time: 30min-60min (30min-40min for basic materials, optimized and expanded), calculated based on effective thickness, increase by 10min for every 25mm to ensure complete austenitization of the core; Cooling regime: Use 5%-10% PAG polymer quenching fluid (5%-8% based on material, optimized and expanded), stirring frequency 15Hz-25Hz (18Hz-22Hz based on material, optimized and expanded); when the workpiece diameter is >100mm, the outlet water temperature is controlled at 170℃-200℃, and after holding at this temperature for 10-15 minutes, it is transferred to tempering. S303 tempering process compatibility: Tempering temperature: 610℃-650℃, holding time: 90min-150min (120min-140min for basic materials, optimized and expanded), cool with the furnace to below 200℃ and remove from the furnace to release residual stress.

[0011] Preferably, the S401 end-quenched sample is processed as follows: the cylindrical surface is precision machined to an accuracy of ≤0.02mm, the quenched end face is finely ground, burrs are thoroughly removed, and the surface finish Ra ≤0.7μm (material base Ra ≤0.8μm optimized and tightened). S402 testing requirements: Use automatic end-quench testing equipment, calibrate standard samples weekly (covering three levels: 20-30HRC, 30-40HRC, and above 40HRC), and the standard sample deviation should be ≤ ±0.5HRC; take 3 samples per batch, test both sides of each sample, take the average value of the J9 end-quench value, and resample and test if the deviation between the two sides is > 3.5HRC.

[0012] Preferably, the S403 detection frequency is as follows: the Ti / Mo content and J9 end quench value are detected for each casting, the correlation between element content and end quench value is statistically analyzed monthly, and the process parameter database is updated.

[0013] Preferably, the S5 process adjustment and feedback step is as follows: If the J9 end quenching value is >48HRC: prioritize reducing the Ti content (±0.0008%) or Mo content (±0.0030%), and simultaneously reduce the quenching temperature by 10-15℃; If the quenching value at the J9 end is <36HRC: appropriately increase the Ti content (+0.0005%-+0.0008%) or Mo content (+0.0020%-+0.0040%), and extend the quenching holding time by 5-10 minutes; If the Ti / Mo content exceeds the standard: immediately stop the rolling of that casting, adjust the batching plan or refining process, and reclassify the furnace with the excessive content as an application that does not require end quenching. Monthly analysis of process data optimizes the matching relationship between element control range and heat treatment parameters, and establishes a linkage model of "element content - continuous casting parameters - heat treatment - end quenching value".

[0014] (III) Beneficial Effects Compared with existing technologies, this invention provides a synergistic process for controlling the Ti / Mo residual element regulation and heat treatment of the J9 end quenching value of alloy structural steel, which has the following beneficial effects: 1. This process, which controls the Ti / Mo residual element regulation and heat treatment synergy of the J9 end quenching value of alloy structural steel, achieves precise and stable J9 end quenching value: through precise regulation of residual elements Ti (0.0020%-0.0060%) and Mo (0.0020%-0.0180%), combined with the synergistic optimization of continuous casting electromagnetic stirring and heat treatment parameters, the J9 end quenching value is stably controlled at 36-48 HRC, with a two-sided deviation ≤3.5 HRC. This solves the core pain point of large fluctuations and frequent exceedances of end quenching value in existing technologies.

[0015] 2. The process of controlling the residual Ti / Mo element regulation and heat treatment of the J9 end quenching value of alloy structural steel significantly reduces the risk of quenching cracking: the combination of element regulation and normalizing pretreatment (860℃-890℃) and staged quenching cooling process effectively eliminates residual stress from forging and solidification, resulting in a quenching cracking scrap rate of ≤1.2% and a core microstructure rating of ≤4, balancing hardenability and crack resistance, and reducing batch quality problems.

[0016] 3. The process of controlling the residual Ti / Mo content of the J9 end quenching value of alloy structural steel and the synergistic heat treatment process improves process controllability and detection accuracy: standardizes the sample processing accuracy (precision turning ≤0.02mm, surface finish Ra≤0.7μm) and standard sample calibration process, and adopts dual detection of spectroscopy and chemistry to ensure that the Ti / Mo content deviation is ≤±0.0005%, avoiding misjudgment due to detection deviation and improving the product qualification rate.

[0017] 4. The process of controlling the residual Ti / Mo element of the end quenching value of alloy structural steel J9 and the synergistic heat treatment process enhances the adaptability and stability of the process: a linkage model of "element content - continuous casting - heat treatment - end quenching value" is established. By dynamically adjusting parameters (fine-tuning Ti / Mo content or quenching temperature when the end quenching value exceeds the standard), it can be flexibly adapted to the production of workpieces with different cross sections and specifications. Monthly data optimization further improves the stability and reproducibility of the process. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] This solution provides a technical approach, specifically a synergistic process for controlling the Ti / Mo residual element content at the J9 end of alloy structural steel through heat treatment, including the following steps: S1 Ti / Mo residual element control steps: Precise control of S101 element content: Titanium (Ti): Control range 0.0020%-0.0060% (material basis 0.0030%-0.0050% optimized and expanded), target value 0.0035%-0.0045%, use low-Ti alloy raw materials, converter tapping slag amount ≤5kg / t, avoid recycling and reuse of Ti-containing refining slag; Molybdenum (Mo): Control range 0.0020%-0.0180% (material basis 0.0030%-0.0100% optimized and expanded), target value 0.0050%-0.0120%, use low-Mo scrap steel as raw material, scrap steel addition ratio ≤25% to reduce Mo content fluctuations; Synergistic control elements: Boron (B) ≤ 0.0006%, Nitrogen (N) ≤ 55ppm (material basis ≤ 60ppm optimized and tightened), Phosphorus (P) ≤ 0.020%, Sulfur (S) ≤ 0.018%, to avoid the cumulative effect of residual elements on end quenching value; S102 Element Detection and Feedback: Composition analysis was performed on 3-5 heats of molten steel from each casting, using a combination of spectral and chemical analysis for verification. The Ti / Mo content deviation was ≤ ±0.0005%. Establish a database corresponding to element content and end quench value. If Ti content > 0.0055% or Mo content > 0.0150%, immediately adjust the batching plan and suspend the rolling of key specifications in furnaces with high Ti / Mo content. S2 continuous casting process coordinated control steps: S201 continuous casting core parameter optimization: Electromagnetic stirring of crystallizer: current 90A-260A (material basis 100A-250A optimized and expanded), frequency 2.0Hz-3.0Hz, 180A-260A when cross-section ≥120mm, 90A-180A when cross-section <120mm; End electromagnetic stirring: current 180A-320A (material basis 200A-300A optimized and expanded), frequency 7.0Hz-9.0Hz, 180A-250A when the pulling speed is ≤0.85m / min, 250A-320A when the pulling speed is >0.85m / min; Continuous casting parameters: casting speed 0.80m / min-0.95m / min, specific water 0.18L / kg-0.22L / kg, light reduction process is adopted, heavy reduction is prohibited, and component segregation is reduced; Quality control of S202 continuous casting process: The superheat of the molten steel is controlled between 15℃ and 30℃, and the carbon content in the ladle is kept stable at 0.38% to 0.41% to avoid abnormal end-quenching values ​​induced by composition fluctuations. Take 2-3 continuously cast billet samples from each casting run and test the Ti / Mo content difference in the core, 1 / 4R, and edge areas. The difference in carbon content should be ≤0.0010%, and the difference in carbon content should be ≤0.040%. S3 heat treatment co-optimization steps: S301 Pretreatment Process: Normalizing temperature: 860℃-890℃ (870℃ is optimized and expanded based on the material), holding time 40min-70min, adjusted according to the billet size (increase by 8min for every 10mm), to eliminate forging residual stress; Cooling method: After normalizing, the furnace is cooled to 320℃-360℃ and then air-cooled to reduce the temperature difference stress with the quenching medium; S302 quenching process parameters: Quenching temperature: 830℃-870℃ (840℃-860℃ for material base, optimized and expanded), 850℃-870℃ when the quenching value of J9 end is too low, and 830℃-850℃ when it is too high; Insulation time: 30min-60min (30min-40min for basic materials, optimized and expanded), calculated based on effective thickness, increase by 10min for every 25mm to ensure complete austenitization of the core; Cooling regime: Use 5%-10% PAG polymer quenching fluid (5%-8% based on material, optimized and expanded), stirring frequency 15Hz-25Hz (18Hz-22Hz based on material, optimized and expanded); when the workpiece diameter is >100mm, the outlet water temperature is controlled at 170℃-200℃, and after holding at this temperature for 10-15 minutes, it is transferred to tempering. S303 tempering process compatibility: Tempering temperature: 610℃-650℃, holding time: 90min-150min (120min-140min for basic materials, optimized and expanded), cool in the furnace to below 200℃ and remove from the furnace to release residual stress; S4 Sample Processing and Testing Standard Procedures: S401 end-quenched sample processing: cylindrical surface precision turning accuracy ≤0.02mm, quenched end face fine grinding, burr removal thoroughly, surface finish Ra≤0.7μm (material base Ra≤0.8μm optimized and tightened); S402 testing requirements: Use automatic end-quench testing equipment, calibrate standard samples weekly (covering three levels: 20-30HRC, 30-40HRC, and above 40HRC), and ensure the standard sample deviation is ≤ ±0.5HRC; take 3 samples per batch, test both sides of each sample, take the average value of the J9 end-quench value, and resample and test if the deviation between the two sides is > 3.5HRC; S403 testing frequency: Ti / Mo content and J9 end quench value are tested for each casting, and the correlation between element content and end quench value is statistically analyzed monthly to update the process parameter database; S5 process adjustment and feedback steps: If the J9 end quenching value is >48HRC: prioritize reducing the Ti content (±0.0008%) or Mo content (±0.0030%), and simultaneously reduce the quenching temperature by 10-15℃; If the quenching value at the J9 end is <36HRC: appropriately increase the Ti content (+0.0005%-+0.0008%) or Mo content (+0.0020%-+0.0040%), and extend the quenching holding time by 5-10 minutes; If the Ti / Mo content exceeds the standard: immediately stop the rolling of that casting, adjust the batching plan or refining process, and reclassify the furnace with the excessive content as an application that does not require end quenching. Monthly analysis of process data, optimization of the matching relationship between element control range and heat treatment parameters, and establishment of a linkage model of "element content - continuous casting parameters - heat treatment - end quenching value"; Process objectives: By precisely controlling the residual Ti / Mo elements and coordinating the optimization of heat treatment parameters, the end quenching value of alloy structural steel J9 is stably controlled within 36-48 HRC (covering the core requirements of the material and expanding the range), the deviation of the end quenching value on both sides is ≤3.5 HRC, the scrap rate of quenching cracking is ≤1.2%, and the core structure rating is ≤4, ensuring the consistency of material processing performance; Furthermore, this process achieves precise and stable J9 end quenching value: through precise control of residual elements such as Ti (0.0020%-0.0060%) and Mo (0.0020%-0.0180%), combined with the synergistic optimization of continuous casting electromagnetic stirring and heat treatment parameters, the J9 end quenching value is stably controlled at 36-48 HRC, with a two-sided deviation of ≤3.5 HRC, solving the core pain point of large fluctuations and frequent exceedances of end quenching value in existing technologies; Furthermore, this process significantly reduces the risk of quenching cracks: the synergistic effect of element regulation and normalizing pretreatment (860℃-890℃) and graded quenching cooling process effectively eliminates residual stress from forging and solidification, resulting in a quenching crack scrap rate of ≤1.2% and a core microstructure rating of ≤4, balancing hardenability and crack resistance, and reducing batch quality problems. Furthermore, this process improves process controllability and detection accuracy: it standardizes sample processing precision (precision turning ≤0.02mm, surface finish Ra≤0.7μm) and standard sample calibration procedures, and adopts dual detection of spectroscopy and chemistry to ensure that the Ti / Mo content deviation is ≤±0.0005%, avoiding misjudgment due to detection deviation and improving the product qualification rate. Furthermore, this process enhances process adaptability and stability: a linkage model of "element content - continuous casting - heat treatment - end quenching value" is established. By dynamically adjusting parameters (fine-tuning Ti / Mo content or quenching temperature when end quenching value exceeds the standard), it can flexibly adapt to the production of workpieces with different cross sections and specifications. Monthly data optimization further improves process stability and reproducibility.

[0020] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for controlling the Ti / Mo residual element regulation and heat treatment synergy of the J9 end quenching value of alloy structural steel, comprising the S1 Ti / Mo residual element regulation step, the S2 continuous casting process synergy regulation step, the S3 heat treatment synergy optimization step, the S4 sample processing and testing specification step, and the S5 process adjustment and feedback step, characterized in that: The residual element regulation steps of S1 Ti / Mo include precise control of S101 element content and detection and feedback of S102 element. Among them, the collaborative control steps of the S2 continuous casting process include optimization of core parameters of S201 continuous casting and quality control of S202 continuous casting process. Among them, the S3 heat treatment co-optimization steps include S301 pretreatment process, S302 quenching process parameters and S303 tempering process adaptation. The S4 sample processing and testing specifications include S401 end-quenched sample processing, S402 testing requirements, and S403 testing frequency.

2. The Ti / Mo residual element control and heat treatment synergistic process for controlling the J9 end quenching value of alloy structural steel according to claim 1, characterized in that: The content of the S101 element is precisely controlled: Titanium (Ti): Control range 0.0020%-0.0060% (material basis 0.0030%-0.0050% optimized and expanded), target value 0.0035%-0.0045%, use low-Ti alloy raw materials, converter tapping slag amount ≤5kg / t, avoid recycling and reuse of Ti-containing refining slag; Molybdenum (Mo): Control range 0.0020%-0.0180% (material basis 0.0030%-0.0100% optimized and expanded), target value 0.0050%-0.0120%, use low-Mo scrap steel as raw material, scrap steel addition ratio ≤25% to reduce Mo content fluctuations; Synergistic control elements: Boron (B) ≤ 0.0006%, Nitrogen (N) ≤ 55ppm (material basis ≤ 60ppm optimized and tightened), Phosphorus (P) ≤ 0.020%, Sulfur (S) ≤ 0.018%, to avoid the cumulative effect of residual elements on end quenching value.

3. The Ti / Mo residual element control and heat treatment synergistic process for controlling the J9 end quenching value of alloy structural steel according to claim 1, characterized in that: The S102 element detection and feedback: For each casting, 3-5 heats of molten steel were selected for composition analysis, using both spectral and chemical analysis for verification. The Ti / Mo content deviation was ≤ ±0.0005%. Establish a database corresponding to element content and end-quench value. If Ti content > 0.0055% or Mo content > 0.0150%, immediately adjust the batching plan and suspend the rolling of key specifications in furnaces with high Ti / Mo content.

4. The Ti / Mo residual element regulation and heat treatment synergistic process for controlling the J9 end quenching value of alloy structural steel according to claim 1, characterized in that: The core parameters for S201 continuous casting have been optimized: Electromagnetic stirring of crystallizer: current 90A-260A (material basis 100A-250A optimized and expanded), frequency 2.0Hz-3.0Hz, 180A-260A when cross-section ≥120mm, 90A-180A when cross-section <120mm; End electromagnetic stirring: current 180A-320A (material basis 200A-300A optimized and expanded), frequency 7.0Hz-9.0Hz, 180A-250A when the pulling speed is ≤0.85m / min, 250A-320A when the pulling speed is >0.85m / min; Continuous casting parameters: casting speed 0.80m / min-0.95m / min, specific water content 0.18L / kg-0.22L / kg, light reduction process is adopted, heavy reduction is prohibited, and component segregation is reduced.

5. The Ti / Mo residual element regulation and heat treatment synergistic process for controlling the J9 end quenching value of alloy structural steel according to claim 1, characterized in that: Quality control of the S202 continuous casting process: The superheat of the molten steel is controlled between 15℃ and 30℃, and the carbon content in the ladle is kept stable at 0.38% to 0.41% to avoid abnormal end-quenching values ​​induced by composition fluctuations. Take 2-3 continuous casting billet samples from each casting run and test the Ti / Mo content difference in the core, 1 / 4R, and edge. The difference in carbon content should be ≤0.0010% and ≤0.040%.

6. The Ti / Mo residual element regulation and heat treatment synergistic process for controlling the J9 end quenching value of alloy structural steel according to claim 1, characterized in that: The S301 pretreatment process: Normalizing temperature: 860℃-890℃ (870℃ is optimized and expanded based on the material), holding time 40min-70min, adjusted according to the billet size (increase by 8min for every 10mm), to eliminate forging residual stress; Cooling method: After normalizing, the furnace is cooled to 320℃-360℃ and then air-cooled to reduce the temperature difference stress with the quenching medium.

7. The Ti / Mo residual element control and heat treatment synergistic process for controlling the J9 end quenching value of alloy structural steel according to claim 1, characterized in that: The S302 quenching process parameters are as follows: Quenching temperature: 830℃-870℃ (840℃-860℃ for material base, optimized and expanded), 850℃-870℃ when the quenching value of J9 end is too low, and 830℃-850℃ when it is too high; Insulation time: 30min-60min (30min-40min for basic materials, optimized and expanded), calculated based on effective thickness, increase by 10min for every 25mm to ensure complete austenitization of the core; Cooling regime: Use 5%-10% PAG polymer quenching fluid (5%-8% based on material, optimized and expanded), stirring frequency 15Hz-25Hz (18Hz-22Hz based on material, optimized and expanded); when the workpiece diameter is >100mm, the outlet water temperature is controlled at 170℃-200℃, and after holding at this temperature for 10-15 minutes, it is transferred to tempering. S303 tempering process compatibility: Tempering temperature: 610℃-650℃, holding time: 90min-150min (120min-140min for basic materials, optimized and expanded), cool with the furnace to below 200℃ and remove from the furnace to release residual stress.

8. The Ti / Mo residual element regulation and heat treatment synergistic process for controlling the J9 end quenching value of alloy structural steel according to claim 1, characterized in that: The S401 end-quenched sample processing: cylindrical surface precision turning accuracy ≤0.02mm, quenched end face fine grinding, burr removal thorough, surface finish Ra≤0.7μm (material base Ra≤0.8μm optimized and tightened); S402 testing requirements: Use automatic end-quench testing equipment, calibrate standard samples weekly (covering three levels: 20-30HRC, 30-40HRC, and above 40HRC), and the standard sample deviation should be ≤ ±0.5HRC; take 3 samples per batch, test both sides of each sample, take the average value of the J9 end-quench value, and resample and test if the deviation between the two sides is > 3.5HRC.

9. The synergistic process of controlling the Ti / Mo residual element regulation and heat treatment of the J9 end quenching value of alloy structural steel according to claim 1, characterized in that: The S403 detection frequency is as follows: Ti / Mo content and J9 end quench value are detected for each casting, and the correlation between element content and end quench value is statistically analyzed monthly to update the process parameter database.

10. The Ti / Mo residual element control and heat treatment synergistic process for controlling the J9 end quenching value of alloy structural steel according to claim 1, characterized in that: The S5 process adjustment and feedback steps are as follows: If the J9 end quenching value is >48HRC: prioritize reducing the Ti content (±0.0008%) or Mo content (±0.0030%), and simultaneously reduce the quenching temperature by 10-15℃; If the quenching value at the J9 end is <36HRC: appropriately increase the Ti content (+0.0005%-+0.0008%) or Mo content (+0.0020%-+0.0040%), and extend the quenching holding time by 5-10 minutes; If the Ti / Mo content exceeds the standard: immediately stop the rolling of that casting, adjust the batching plan or refining process, and reclassify the furnace with the excessive content as an application that does not require end quenching. Monthly analysis of process data optimizes the matching relationship between element control range and heat treatment parameters, and establishes a linkage model of "element content - continuous casting parameters - heat treatment - end quenching value".