CN-122012873-A - Ti/Mo residual element regulation and control and heat treatment synergistic process for controlling J9 end quenching value of alloy structural steel

CN122012873ACN 122012873 ACN122012873 ACN 122012873ACN-122012873-A

Abstract

The invention relates to the technical field of ferrous metallurgy, and discloses a Ti/Mo residual element regulation and heat treatment cooperative process for controlling an end quenching value of alloy structural steel J9, which comprises an S1 Ti/Mo residual element regulation step, an S2 continuous casting process cooperative regulation step, an S3 heat treatment cooperative optimization step, an S4 sample processing and detection standard step and an S5 process regulation and feedback step, wherein the process realizes the accurate stable J9 end quenching value, the J9 end quenching value is stably controlled at 36-48HRC through the accurate regulation and control of Ti and Mo residual elements and the cooperative optimization of continuous casting electromagnetic stirring and heat treatment parameters, the two-sided deviation is less than or equal to 3.5HRC, the core pain point caused by large end quenching value fluctuation and over-standard frequency in the prior art is solved, the process realizes the remarkable reduction of quenching cracking risk, namely the element regulation and normalizing pretreatment, the staged quenching cooling process cooperative, the effective elimination of forging and solidification residual stress, the quenching cracking rejection rate is less than or equal to 1.2%, the core structure grading is less than or equal to 4, the quenching permeability and the quality is reduced.

Inventors

YUAN LIN
YANG GENGCHAO
Hou quan
ZHANG JIE
LIU ZHI
LUO JINGXIAN
WU MIN
DU JIANG
Pan Xiquan

Assignees

湖南华菱湘潭钢铁有限公司

Dates

Publication Date: 20260512
Application Date: 20260224

Claims (10)

1. The Ti/Mo residual element regulation and control and heat treatment cooperative process for controlling the J9 end quenching value of the alloy structural steel comprises an S1 Ti/Mo residual element regulation step, an S2 continuous casting process cooperative regulation step, an S3 heat treatment cooperative optimization step, an S4 sample processing and detection standardization step and an S5 process regulation and feedback step, and is characterized in that the S1 Ti/Mo residual element regulation step comprises an S101 element content accurate control step and an S102 element detection and feedback step; the step of S2 continuous casting process cooperative regulation and control comprises the step of S201 continuous casting core parameter optimization and S202 continuous casting process quality control; The step of S3 heat treatment collaborative optimization comprises the steps of S301 pretreatment process, S302 quenching process parameters and S303 tempering process adaptation; the step of S4 sample processing and detection specification comprises S401 end quenching sample processing, S402 detection requirement and S403 detection frequency.
2. The Ti/Mo residual element regulation and control and heat treatment cooperative process for controlling the J9 end quenching value of the alloy structural steel according to claim 1, wherein the content of the S101 element is precisely controlled: Titanium (Ti) with a control range of 0.0020-0.0060 percent (optimized and enlarged material basis of 0.0030-0.0050 percent), a target value of 0.0035-0.0045 percent, and a low Ti alloy raw material, wherein the tapping slag quantity of a converter is less than or equal to 5kg/t, so that recovery and reuse of Ti-containing refining slag are avoided; Molybdenum (Mo) with a control range of 0.0020-0.0180 percent (optimized expansion of 0.0030-0.0100 percent of material base) and a target value of 0.0050-0.0120 percent, selecting low Mo scrap steel ingredients, wherein the adding proportion of the scrap steel is less than or equal to 25 percent, and reducing fluctuation of Mo content; The synergistic control elements are less than or equal to 0.0006 percent of boron (B), less than or equal to 55ppm of nitrogen (N) (material foundation is less than or equal to 60ppm for optimal tightening), less than or equal to 0.020 percent of phosphorus (P), less than or equal to 0.018 percent of sulfur (S), and the influence of the superposition of residual elements on the end quenching value is avoided.
3. The Ti/Mo residual element regulation and control and heat treatment cooperative process for controlling the J9 end quenching value of the alloy structural steel according to claim 1, wherein the S102 element detection and feedback: 3-5 furnaces of molten steel are selected for component detection every casting time, and double verification of spectrum and chemical analysis is adopted, wherein the Ti/Mo content deviation is less than or equal to +/-0.0005%; and (3) establishing a corresponding database of element content-end quenching values, and if the Ti content is more than 0.0055% or the Mo content is more than 0.0150%, immediately adjusting a batching scheme, and stopping rolling key specifications of the Ti/Mo-containing blast furnace heat.
4. The Ti/Mo residual element regulation and control and heat treatment cooperative process for controlling the J9 end quenching value of the alloy structural steel according to claim 1, wherein the S201 continuous casting core parameter optimization: The crystallizer electromagnetic stirring is that the current is 90A-260A (the material foundation is 100A-250A is optimized and enlarged), the frequency is 2.0Hz-3.0Hz, 180A-260A is taken when the section is more than or equal to 120mm, and 90A-180A is taken when the section is less than 120 mm; Terminal electromagnetic stirring, wherein the current is 180A-320A (the material foundation is 200A-300A is optimized and enlarged), the frequency is 7.0Hz-9.0Hz, 180A-250A is taken when the pulling speed is less than or equal to 0.85m/min, and 250A-320A is taken when the pulling speed is more than 0.85 m/min; The continuous casting matching parameters are that the pulling speed is 0.80m/min-0.95m/min, the specific water quantity is 0.18L/kg-0.22L/kg, and the soft reduction process is adopted, the heavy reduction is forbidden, and the component segregation is reduced.
5. The Ti/Mo residual element regulation and control and heat treatment cooperative process for controlling the J9 end quenching value of the alloy structural steel according to claim 1, wherein the S202 continuous casting process quality control: the superheat degree of the molten steel is controlled between 15 ℃ and 30 ℃, the carbon content of the medium inclusion is stabilized between 0.38% and 0.41%, and the abnormal end quenching value of the fluctuation induction of the components is avoided; 2-3 continuous casting blanks are taken every time of casting, and the difference value of the content of Ti/Mo in the detection center part, 1/4R and the edge is less than or equal to 0.0010 percent, and the carbon difference is less than or equal to 0.040 percent.
6. The Ti/Mo residual element regulation and control and heat treatment cooperative process for controlling the J9 end quenching value of the alloy structural steel according to claim 1, wherein the S301 pretreatment process is characterized in that: normalizing temperature is 860-890 ℃ (material foundation 870 ℃ is optimized and enlarged), heat preservation time is 40-70 min, and forging residual stress is eliminated according to blank size adjustment (8 min is added every 10 mm); And the cooling mode is that the furnace is cooled to 320-360 ℃ along with the furnace after normalizing, and the furnace is taken out for air cooling, so that the temperature difference stress between the furnace and a quenching medium is reduced.
7. The Ti/Mo residual element regulation and control and heat treatment cooperative process for controlling the J9 end quenching value of the alloy structural steel according to claim 1, wherein the S302 quenching process parameters are as follows: The quenching temperature is 830-870 ℃, the material base is 840-860 ℃ optimized and enlarged, the quenching value at the J9 end is 850-870 ℃ when the quenching value is lower, and 830-850 ℃ when the quenching value is higher; The heat preservation time is 30-60 min (the material foundation is optimized and enlarged for 30-40 min), and the effective thickness is calculated, and the temperature is increased by 10min every 25mm to ensure complete austenitization of the core; A cooling system comprises adopting 5% -10% PAG polymer quenching liquid (5% -8% optimized expansion of material foundation), stirring at 15Hz-25Hz (18 Hz-22Hz optimized expansion of material foundation), controlling the water outlet temperature at 170-200 ℃ when the diameter of the workpiece is more than 100mm, preserving heat for 10-15min, and transferring to tempering; S303 tempering process adaptation: tempering temperature is 610-650 ℃, heat preservation time is 90-150 min (material foundation is optimized and expanded for 120-140 min), and the material is cooled to below 200 ℃ along with furnace discharging, so that residual stress is released.
8. The Ti/Mo residual element regulation and control and heat treatment cooperative process for controlling the J9 end quenching value of the alloy structural steel according to claim 1 is characterized in that the S401 end quenching sample is processed by fine grinding of a quenching end face with the precision of a cylindrical surface of less than or equal to 0.02mm and thorough burr removal, and the surface finish Ra of less than or equal to 0.7 mu m (optimized tightening of a material base Ra of less than or equal to 0.8 mu m); s402, adopting automatic end quenching detection equipment, calibrating standard samples weekly (covering three grades of 20-30HRC, 30-40HRC and more than 40 HRC), wherein standard sample deviation is less than or equal to +/-0.5 HRC, taking 3 samples in each batch, detecting two sides of each sample, taking an average value of J9 end quenching values, and resampling and detecting when the two sides deviation is more than 3.5 HRC.
9. The Ti/Mo residual element regulation and control and heat treatment cooperative process for controlling the J9 end quenching value of the alloy structural steel according to claim 1, wherein the detection frequency of S403 is that the Ti/Mo content and the J9 end quenching value are detected every time of casting, the correlation between the element content and the end quenching value is counted every month, and a process parameter database is updated.
10. The Ti/Mo residual element regulation and control and heat treatment cooperative process for controlling the J9 end quenching value of the alloy structural steel according to claim 1, wherein the S5 process regulation and feedback step comprises the following steps: if the J9 end quenching value is more than 48HRC, preferentially reducing the Ti content (+ -0.0008%) or the Mo content (+ -0.0030%), and synchronously reducing the quenching temperature by 10-15 ℃; if the J9 end quenching value is less than 36HRC, the Ti content (+0.0005% - +0.0008%) or the Mo content (+0.0020% - +0.0040%) is properly increased, and the quenching heat preservation time is prolonged for 5-10min; If the Ti/Mo content exceeds the standard, immediately stopping the casting rolling, adjusting a batching scheme or a refining process, and improving the non-end quenching requirement application by exceeding the standard furnace number; and analyzing process data every month, optimizing the matching relation between an element control interval and heat treatment parameters, and establishing a linkage model of element content-continuous casting parameters-heat treatment-end quenching values.

Description

Ti/Mo residual element regulation and control and heat treatment synergistic process for controlling J9 end quenching value of alloy structural steel Technical Field The invention relates to the technical field of ferrous metallurgy, in particular to a Ti/Mo residual element regulation and control and heat treatment synergistic process for controlling the J9 end quenching value of alloy structural steel. Background The alloy structural steel is required to meet the requirement of stable J9 end quenching value in the production of key parts (such as steering knuckles) in the mechanical manufacturing process so as to ensure the hardenability and the processing safety. In the prior art, the problems that the regulation and control of residual elements Ti and Mo are lack of coordination with a heat treatment process generally exist, namely, when the content of Ti is higher or the fluctuation of the content of Mo is larger, the hardenability is easy to be abnormally increased, and when the heat treatment process is matched with an irregular heat treatment process (such as insufficient heating and heat preservation time or overlong), the J9 end quenching value exceeds a reasonable range of 36-48HRC, the deviation of the two sides of the end quenching value often exceeds 4HRC, and meanwhile, the synergistic design of element regulation and continuous casting and heat treatment parameters is lacking, the component segregation and residual stress accumulation are further aggravated, the quenching cracking rejection rate is higher, customer complaints and stock blocking risks are caused, the product quality consistency is influenced, and the severe use requirements of downstream key parts are difficult to meet. Disclosure of Invention (One) solving the technical problems Aiming at the defects of the prior art, the invention provides a Ti/Mo residual element regulation and heat treatment synergistic process for controlling the J9 end quenching value of alloy structural steel, has the advantages of precisely stabilizing the J9 end quenching value and the like, and solves the problems that the J9 end quenching value exceeds a reasonable range of 36-48HRC and the deviation of two sides of the end quenching value often exceeds 4 HRC. (II) technical scheme The technical scheme of the invention is that the Ti/Mo residual element regulation and control and heat treatment cooperative process for controlling the J9 end quenching value of the alloy structural steel comprises an S1 Ti/Mo residual element regulation step, an S2 continuous casting process cooperative regulation step, an S3 heat treatment cooperative optimization step, an S4 sample processing and detection standardization step and an S5 process regulation and feedback step, wherein the S1 Ti/Mo residual element regulation step comprises an S101 element content accurate control step and an S102 element detection and feedback step; the step of S2 continuous casting process cooperative regulation and control comprises the step of S201 continuous casting core parameter optimization and S202 continuous casting process quality control; The step of S3 heat treatment collaborative optimization comprises the steps of S301 pretreatment process, S302 quenching process parameters and S303 tempering process adaptation; the step of S4 sample processing and detection specification comprises S401 end quenching sample processing, S402 detection requirement and S403 detection frequency. Preferably, the content of the S101 element is precisely controlled: Titanium (Ti) with a control range of 0.0020-0.0060 percent (optimized and enlarged material basis of 0.0030-0.0050 percent), a target value of 0.0035-0.0045 percent, and a low Ti alloy raw material, wherein the tapping slag quantity of a converter is less than or equal to 5kg/t, so that recovery and reuse of Ti-containing refining slag are avoided; Molybdenum (Mo) with a control range of 0.0020-0.0180 percent (optimized expansion of 0.0030-0.0100 percent of material base) and a target value of 0.0050-0.0120 percent, selecting low Mo scrap steel ingredients, wherein the adding proportion of the scrap steel is less than or equal to 25 percent, and reducing fluctuation of Mo content; The synergistic control elements are less than or equal to 0.0006 percent of boron (B), less than or equal to 55ppm of nitrogen (N) (material foundation is less than or equal to 60ppm for optimal tightening), less than or equal to 0.020 percent of phosphorus (P), less than or equal to 0.018 percent of sulfur (S), and the influence of the superposition of residual elements on the end quenching value is avoided. Preferably, the S102 element detection and feedback: 3-5 furnaces of molten steel are selected for component detection every casting time, and double verification of spectrum and chemical analysis is adopted, wherein the Ti/Mo content deviation is less than or equal to +/-0.0005%; and (3) establishing a corresponding database of element content-end