CN-122013061-A - Component-end quenching cooperative process for controlling hardenability bandwidth of 22CrMoH steel

CN122013061ACN 122013061 ACN122013061 ACN 122013061ACN-122013061-A

Abstract

The invention relates to the technical field of metallurgical engineering, and discloses a component-end quenching cooperative process for controlling the hardenability bandwidth of 22CrMoH steel, which comprises an S1 component cooperative design stage, an S2 smelting-continuous casting cooperative process stage, an S3 rolling-slow cooling cooperative process stage, an S4 pretreatment-end quenching cooperative process stage, an S5 hardenability bandwidth control and feedback adjustment stage and an S6 finished product quality verification stage, wherein the process realizes that the hardenability bandwidth is precisely controllable: through the dynamic proportioning mechanism of C, cr and Mo in the component collaborative design and the cooperation of the whole process technology of smelting, continuous casting and rolling, the component segregation (the total section carbon range is less than or equal to 0.0184%) and the tissue defect (the banded structure is less than or equal to 2.5 levels) are effectively controlled, so that J9 hardness fluctuation is less than or equal to 5HRC, J15 hardness fluctuation is less than or equal to 4HRC, the hardenability stability is improved by more than 30 percent compared with the traditional technology, and the requirement of high-end gear processing on the consistency of material performance is completely met.

Inventors

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

Assignees

湖南华菱湘潭钢铁有限公司

Dates

Publication Date: 20260512
Application Date: 20260226

Claims (10)

1. A composition-end quenching cooperative process for controlling the hardenability bandwidth of 22CrMoH steel comprises an S1 composition cooperative design stage, an S2 smelting-continuous casting cooperative process stage, an S3 rolling-slow cooling cooperative process stage, an S4 pretreatment-end quenching cooperative process stage, an S5 hardenability bandwidth control and feedback adjustment stage and an S6 finished product quality verification stage, and is characterized in that the S1 composition cooperative design stage comprises an S101 core element range setting and an S102 composition cooperative principle; wherein, the S2 smelting-continuous casting cooperative process stage comprises an S201 smelting process and an S202 continuous casting process; wherein the S3 rolling-slow cooling cooperative process stage comprises an S301 heating process, an S302 rolling process and an S303 slow cooling post-treatment; Wherein, the S4 pretreatment-end quenching cooperative process stage comprises an S401 pretreatment (normalizing) process and an S402 end quenching process; The S5 hardenability bandwidth control and feedback adjustment stage comprises S501 hardenability control targets and S502 detection and feedback.
2. The composition-end quenching co-process for controlling the hardenability bandwidth of 22CrMoH steel according to claim 1, wherein the S101 core element range is set to be (mass%) Carbon (C) 0.18-0.26; silicon (Si) 0.15-0.40; manganese (Mn) 0.50-0.95; phosphorus (P) is less than or equal to 0.035; Sulfur (S) 0.015-0.038; chromium (Cr) 0.80-1.30; molybdenum (Mo) 0.32-0.48; 0.020-0.045% of aluminum (Al); nitrogen (N) 0.0085-0.0145.
3. The composition-end quenching cooperative process for controlling the hardenability bandwidth of 22CrMoH steel according to claim 1, wherein the composition cooperative principle of S102 is as follows: The proportion of C to Cr and Mo is controlled, the content of C fluctuates by 0.01%, the total content of Cr and Mo is correspondingly regulated by 0.02-0.03%, and the stability of the hardenability foundation is ensured; s content and Mn content are linked, when S is less than or equal to 0.038%, mn is more than or equal to 0.60%, and hot processing defects caused by low-melting-point sulfides are avoided; The Al/N ratio is controlled to be 2.0-4.8, so that the grain refinement effect is ensured.
4. The composition-end quenching cooperative process for controlling the hardenability bandwidth of 22CrMoH steel according to claim 1, wherein the S201 smelting process is characterized in that: Smelting mode, namely electric furnace smelting and vacuum refining (or effective refining process), so as to ensure the purity of molten steel; vacuum treatment, wherein the vacuum degree is less than or equal to 67Pa, the vacuum time is 10-15min, and the degassing and impurity removal are carried out; Soft argon blowing treatment, namely soft blowing for 20-30min after vacuum is finished, and stirring to uniform the components and the temperature; And (3) rechecking the outbound components, namely ensuring that the fluctuation range of core elements is less than or equal to +/-0.015 percent (C, cr and Mo) and other elements are less than or equal to +/-0.02 percent.
5. The composition-end quenching cooperative process for controlling the hardenability bandwidth of 22CrMoH steel according to claim 1, wherein the S202 continuous casting process is characterized in that: The casting blank section is 280X 280-350X 430mm, and the main flow section in the document is covered and moderately expanded Controlling the pulling speed to be 0.45-0.85m/min, and adjusting according to the section; Electromagnetic stirring, wherein the stirring parameters of the crystallizer are 140-160A, 2.0-3.0Hz, and the stirring parameters of the tail end are 240-260A, 7-9Hz; the superheat degree of the tundish is 25-35 ℃ to avoid component segregation; the cooling system is that the water quantity of the crystallizer is 2700-3500L/min and the specific water quantity of the secondary cooling is 0.24-0.28L/kg.
6. The composition-end quenching co-process for controlling the hardenability bandwidth of 22CrMoH steel according to claim 1, wherein the S301 heating process is: The heating temperature is 1180-1220 ℃, the temperature is adjusted according to the section of the casting blank, the heat preservation time is 2.5-4.0h, and the homogenization of the components is ensured; The heating rate is less than or equal to 150 ℃ per hour (low temperature section) and less than or equal to 200 ℃ per hour (high temperature section), and thermal stress cracks are avoided.
7. The composition-end quenching cooperative process for controlling the hardenability bandwidth of 22CrMoH steel according to claim 1, wherein the S302 rolling process is characterized in that: the rolling mode is that high-pressure water is used for dephosphorization and then continuous rolling is carried out, and the dephosphorization pressure is more than or equal to 18MPa; the final rolling temperature is 850-900 ℃ to ensure uniform austenite structure; Cooling after rolling, namely adopting a heat preservation cover slow cooling and pit cooling combined mode, wherein the cooling rate is less than or equal to 3 ℃ per minute (800-500 ℃ interval), and avoiding the exceeding of the band-shaped tissue; s303, slow cooling post-treatment: The slow cooling time is more than or equal to 24 hours, so that the internal stress is released, and the hardness is controlled to be 180-235HB.
8. The composition-end quenching co-process for controlling the hardenability bandwidth of 22CrMoH steel according to claim 1, wherein the S401 pretreatment (normalizing) process is as follows: normalizing at 920-950 deg.c for 30-70min; cooling by air cooling at a cooling rate of 5-10 ℃ per minute, and refining austenite grains to 7-8 grades (meeting the requirement of more than or equal to 6 grades); S402 end quenching process: Preserving heat at 920-930 ℃ before end quenching for 30-40min, wherein the temperature difference in the furnace is less than or equal to +/-5 ℃; the end quenching medium is clear water at 20-30 ℃ and the water flow pressure is 0.15-0.25MPa; end quenching operation, in which the sample is vertically immersed in water, the immersion depth is 60-80mm, and the water flow is kept stable; hardness testing positions are located at positions which are 30mm away from end faces J5, J9, J15, J25 and J30mm (detection points of J5 and J30mm are added), and 3 points are measured at each position to obtain an average value.
9. The composition-end quenching co-process for controlling the hardenability bandwidth of 22CrMoH steel according to claim 1, wherein the hardenability control objective of S501 is: bandwidth requirement, wherein J9 hardness fluctuation is less than or equal to 5HRC, and J15 hardness fluctuation is less than or equal to 4HRC (core control index); hardness range J9 = 35-44HRC, j15 = 30-38HRC; S502 detection and feedback: The detection of the macrostructure, namely, center porosity, general porosity is less than or equal to 2.5 level, center segregation is less than or equal to 2.0 level, and the square frame ratio is less than or equal to 1.18; high-power structure detection, namely, the banded structure is less than or equal to 2.5 grades, and nonmetallic inclusion (A fine is less than or equal to 3.0 grades, A coarse is less than or equal to 2.5 grades and B/C/D class is less than or equal to 2.0 grades); Feedback adjustment, namely adjusting the total content of Cr plus Mo to +/-0.03-0.05% if the J9 bandwidth is more than 5HRC, and improving the content of C by 0.01-0.02% and the content of Mo by 0.01-0.02% if the J15 hardness is lower; batch tracing, namely recording components and smelting-rolling-end quenching parameters in each heat, and establishing a hardenability database to realize parameter optimization among batches.
10. The composition-end quenching cooperative process for controlling the hardenability bandwidth of 22CrMoH steel according to claim 1, wherein the S6 finished product quality verification stage is as follows: Mechanical property verification, namely, the tensile strength Rm=1020-1080 MPa, the yield strength Rp0.2=890-940 MPa, the elongation after break A is more than or equal to 12 percent, and the impact energy Akv2 is more than or equal to 40J; The gas content is required to be less than or equal to 15ppm of total oxygen, less than or equal to 2.0ppm of hydrogen and 85 to 145ppm of nitrogen Ultrasonic flaw detection, namely, according to the B-level detection standard, no defect of not less than 3mm is generated, and surface magnetic powder flaw detection has no crack type defect.

Description

Component-end quenching cooperative process for controlling hardenability bandwidth of 22CrMoH steel Technical Field The invention relates to the technical field of metallurgical engineering, in particular to a component-end quenching cooperative process for controlling the hardenability bandwidth of 22CrMoH steel. Background The 22CrMoH steel is used as a core material of key components such as automobile gears, transmission shafts and the like, the hardenability of the steel directly determines the hardness uniformity, fatigue strength and processing stability of the components, and the steel is a key index for guaranteeing the service life of a terminal product. The core problems of excessive fluctuation of the hardenability bandwidth of 22CrMoH steel production in the current industry are that on one hand, the composition design and the end quenching process lack of coordination, key element proportions of C, cr, mo and the like are only set empirically, a dynamic linkage adjustment mechanism is not established, so that the hardenability is difficult to stabilize when the elements fluctuate, on the other hand, the problems of excessive strip-shaped structure (part of products reach 3.5 level) and the like caused by improper strip-shaped structure segregation (part of steel mill C elements reach 0.0324) and rolling slow cooling process in the smelting continuous casting process are solved, the hardenability dispersion is further aggravated, the J9 hardness fluctuation of part of products exceeds 5HRC, the requirements of high-end gear processing on material performance consistency cannot be met, quality hidden troubles such as inconsistent quenching deformation, insufficient meshing precision and the like of subsequent parts are easily caused, and the application of the materials in the field of high-end equipment is restricted. Disclosure of Invention (One) solving the technical problems Aiming at the defects of the prior art, the invention provides a component-end quenching cooperative process for controlling the hardenability bandwidth of 22CrMoH steel, which has the advantages of precisely controllable hardenability bandwidth and the like, and solves the problem of overlarge hardenability bandwidth fluctuation. (II) technical scheme In order to achieve the aim of precisely controlling the hardenability bandwidth, the invention provides the following technical scheme that the component-end quenching collaborative process for controlling the hardenability bandwidth of 22CrMoH steel comprises an S1 component collaborative design stage, an S2 smelting-continuous casting collaborative process stage, an S3 rolling-slow cooling collaborative process stage, an S4 pretreatment-end quenching collaborative process stage, an S5 hardenability bandwidth control and feedback adjustment stage and an S6 finished product quality verification stage, wherein the S1 component collaborative design stage comprises an S101 core element range setting and an S102 component collaborative principle; wherein, the S2 smelting-continuous casting cooperative process stage comprises an S201 smelting process and an S202 continuous casting process; wherein the S3 rolling-slow cooling cooperative process stage comprises an S301 heating process, an S302 rolling process and an S303 slow cooling post-treatment; Wherein, the S4 pretreatment-end quenching cooperative process stage comprises an S401 pretreatment (normalizing) process and an S402 end quenching process; The S5 hardenability bandwidth control and feedback adjustment stage comprises S501 hardenability control targets and S502 detection and feedback. Preferably, the range of the S101 core element is set as (mass percent) Carbon (C) 0.18-0.26; silicon (Si) 0.15-0.40; manganese (Mn) 0.50-0.95; phosphorus (P) is less than or equal to 0.035; Sulfur (S) 0.015-0.038; chromium (Cr) 0.80-1.30; molybdenum (Mo) 0.32-0.48; 0.020-0.045% of aluminum (Al); nitrogen (N) 0.0085-0.0145. Preferably, the S102 component synergy principle: The proportion of C to Cr and Mo is controlled, the content of C fluctuates by 0.01%, the total content of Cr and Mo is correspondingly regulated by 0.02-0.03%, and the stability of the hardenability foundation is ensured; s content and Mn content are linked, when S is less than or equal to 0.038%, mn is more than or equal to 0.60%, and hot processing defects caused by low-melting-point sulfides are avoided; The Al/N ratio is controlled to be 2.0-4.8, so that the grain refinement effect is ensured. Preferably, the S201 smelting process: Smelting mode, namely electric furnace smelting and vacuum refining (or effective refining process), so as to ensure the purity of molten steel; vacuum treatment, wherein the vacuum degree is less than or equal to 67Pa, the vacuum time is 10-15min, and the degassing and impurity removal are carried out; Soft argon blowing treatment, namely soft blowing for 20-30min after vacuum is finished, and stirring to uniform the components and