CN114875313A - Warm forging gear steel and production method thereof - Google Patents
Warm forging gear steel and production method thereof Download PDFInfo
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 46
- 239000010959 steel Substances 0.000 title claims abstract description 46
- 238000005242 forging Methods 0.000 title claims abstract description 45
- 238000004519 manufacturing process Methods 0.000 title claims description 21
- 238000005096 rolling process Methods 0.000 claims abstract description 59
- 238000005266 casting Methods 0.000 claims abstract description 48
- 238000010438 heat treatment Methods 0.000 claims abstract description 43
- 238000001816 cooling Methods 0.000 claims abstract description 26
- 238000000034 method Methods 0.000 claims abstract description 25
- 239000012535 impurity Substances 0.000 claims abstract description 6
- 238000002791 soaking Methods 0.000 claims description 20
- 239000000126 substance Substances 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 10
- 238000004321 preservation Methods 0.000 claims description 9
- 229910052799 carbon Inorganic materials 0.000 claims description 6
- 238000010583 slow cooling Methods 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 5
- 239000000498 cooling water Substances 0.000 claims description 5
- 230000009467 reduction Effects 0.000 claims description 5
- 238000003723 Smelting Methods 0.000 claims description 4
- 238000013461 design Methods 0.000 claims description 3
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- 239000000463 material Substances 0.000 abstract description 6
- 238000005516 engineering process Methods 0.000 abstract description 3
- 238000012545 processing Methods 0.000 abstract description 3
- 230000008569 process Effects 0.000 description 17
- 238000010273 cold forging Methods 0.000 description 12
- 238000009792 diffusion process Methods 0.000 description 11
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- 239000002184 metal Substances 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 230000008901 benefit Effects 0.000 description 4
- 229910052759 nickel Inorganic materials 0.000 description 4
- 229910052717 sulfur Inorganic materials 0.000 description 4
- 229910001566 austenite Inorganic materials 0.000 description 3
- 238000005261 decarburization Methods 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 238000001953 recrystallisation Methods 0.000 description 3
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- 238000007711 solidification Methods 0.000 description 3
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- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- 229910000954 Medium-carbon steel Inorganic materials 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
- B21B45/0203—Cooling
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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Abstract
The warm forging gear steel comprises, by weight, 0.16-0.20% of C, 0.25-0.35% of Si, 0.90-1.10% of Mn, 0.015% or less of P, 0.020-0.040% of S, 1.00-1.20% of Cr, 1.00-1.20% of Ni, 0.030-0.050% of Al, 0.009-0.013% of N, and the balance Fe and inevitable impurities. The key process steps comprise: (1) producing qualified casting blanks; (2) heating the casting blank at high temperature and cogging and rolling; (3) heating at high temperature by two fire, and controlling rolling and cooling. The Brinell hardness of the gear steel material produced by the method can be controlled between 150-190HB, the metallographic structure grade is less than or equal to 3 grade, and the zonal structure grade is less than or equal to 2.5 grade, so that the technical requirements of a warm forging gear processing technology on the gear steel material are completely met, and the isothermal normalizing technology before warm forging of the gear steel is omitted.
Description
Technical Field
The invention belongs to the technical field of metal forming and pressure processing, and relates to warm forging gear steel and a production method thereof.
Technical Field
Generally speaking, for low-carbon and low-alloy steel small-sized precision die forgings with less complex shapes, the cold forging process is adopted to form the die forgings; for small and medium-sized medium-carbon steel precision die forgings with complex shapes, the cold forging method is difficult to solve the forming problem, or the cold forging process is only adopted, so that the cost is high, and warm forging forming can be adopted. Generally, the recrystallization temperature of steel is about 750 ℃, and when forging is performed at 700 ℃ or higher, the deformation energy is dynamically released, and the forming resistance is sharply reduced; when the forging is carried out at 700-850 ℃, the forged piece has less oxide skin, the surface decarburization phenomenon is slight, and the size change of the forged piece is small; when the forging is carried out at the temperature of more than 950 ℃, although the deformation resistance is smaller, the phenomena of oxide skin and surface decarburization of the forging are serious, and the size change of the forging is larger. Therefore, the forged piece with better quality and precision can be obtained by forging within the range of 700-850 ℃.
The warm forging process is adopted to obtain the precision forging, and the warm forging can improve the precision and the quality of the forging and does not have large deformation force like cold forging. The application of the warm forging process has close relation with the forging material, the size of the forging and the complexity of the forging. The warm forging is a less-cutting-free plastic forming process developed on the basis of cold forging. The deformation temperature is generally considered to be in the temperature range of above room temperature and below the recrystallization temperature, the common temperature range of warm forging, the temperature of ferrous metal is generally 200-850 ℃, and the temperature of nonferrous metal is generally above room temperature and below 350 ℃.
Warm forging has the advantages of both cold forging and hot forging to a certain extent. The warm forging is that the deformation of the blank is smaller than that of the cold forging because the metal is heated, the forming is easier than that of the cold forging, and the deformation larger than that of the cold forging can be adopted, so that the number of working procedures is reduced, the cost and the tonnage of the die are reduced, and the service life of the die is longer than that of the cold forging. Compared with hot forging, the method has the advantages of low heating temperature, reduced oxidation and decarburization, higher dimensional tolerance grade of the forged piece and lower surface roughness.
The technical economic comparison of warm forging, cold forging and hot forging is shown in table 1.
TABLE 1 technical-economic comparison of Warm, Cold and Hot forging
Although the gear steel is processed by adopting the warm forging process, compared with hot forging and cold forging, the gear steel has more advantages, the stored energy caused by deformation cannot be released due to the deformation of the gear steel in an austenite non-recrystallization region by adopting the warm forging process, so that the whole free energy is increased, austenite grains are easy to grow in the subsequent carburizing process, and are transformed into a coarse martensite structure after quenching, thereby being unfavorable for the performance of the gear steel. Therefore, customers have specific requirements on the gear steel material, the hardness of the gear steel material is required to be controlled to be 150-190HB, the banded structure is controlled to be within 2.5 grades, and the metallographic structure grade does not exceed 3 grades. These requirements are typically met by isothermal normalizing the hot rolled gear steel feedstock, which can add significantly to the cost of producing the gear steel feedstock.
Disclosure of Invention
The invention aims to provide warm forging gear steel and a production method thereof, which can produce finished products of rolled round steel with the specification of phi 30 mm-phi 80mm, the product has low oxide inclusion and total oxygen content, uniform structure, 8.5-9.0 grade of grain size, less than or equal to 2.5 grade of banded structure and less than or equal to 2.5 grade of metallographic structure, and the product has excellent comprehensive mechanical properties after being processed by customers, better process property stability and can well meet the use requirements of the customers.
The technical scheme of the invention is as follows:
the warm forging gear steel comprises, by weight, 0.16-0.20% of C, 0.25-0.35% of Si, 0.90-1.10% of Mn, 0.015% or less of P, 0.020-0.040% of S, 1.00-1.20% of Cr, 1.00-1.20% of Ni, 0.030-0.050% of Al, 0.009-0.013% of N, and the balance Fe and inevitable impurities. The key process steps comprise:
(1) casting blank production: the qualified casting blank is produced by adopting a normal gear steel smelting production process, the section size of the casting blank is 280 x 280mm, the chemical components of the casting blank are required to meet the design requirements, the macrosegregation carbon range of the section of the casting blank is less than or equal to 0.02%, and the dendritic structure length of the casting blank is not more than 8 mm.
(2) Heating a casting blank at a high temperature and cogging rolling: the temperature of a heating preheating section of the casting blank is less than or equal to 650 ℃, the temperature of a heating section is 1210 +/-20 ℃, the temperature of a soaking section is 1220 +/-20 ℃, the heat preservation time of the soaking section is more than or equal to 80min, and the total heating time is 300-400 min; cogging rolling for 7 times, wherein the primary reduction is more than or equal to 80mm, the cogging size is 150 x 150mm, and concentrated heap cooling is performed after cogging.
(3) Heating at high temperature by using two fires, rolling and cooling: the temperature of a preheating section of the second-fire heating of the rolled blank is less than or equal to 680 ℃, the temperature of a heating section is 1210 +/-20 ℃, the temperature of a soaking section is 1220 +/-20 ℃, the heat preservation time of the soaking section is more than or equal to 60min, and the total heating time is 180-260 min; the second-fire rolling is carried out by adopting a 15-frame horizontal continuous rolling mill and a KOCKS rolling mill.
In the step (3), the temperature in the rolling process is controlled as follows:
for a casting blank with the specification of phi 30-36 mm: the initial rolling temperature is 1100 +/-30 ℃, the two precooling water tanks are respectively opened by 20 percent and 100 percent, the temperature of the initial cooling water tank is 780-810 ℃, the temperature of the final cooling water tank is not opened, the temperature of the upper cooling bed is 750-780 ℃, the cooling bed adopts one-tooth one-steel close-row slow cooling, and the temperature of the final rolling is 850 plus 880 ℃.
For a casting blank with the specification of phi 37-56 mm: the initial rolling temperature is 1100 +/-30 ℃, the two precooling water tanks are respectively opened by 100 percent and 50 percent, the KOCKS temperature is 780-810 ℃, the three final cooling water tanks are respectively opened by 20 percent, the temperature of an upper cooling bed is 750-780 ℃, the cooling bed adopts one-tooth one-steel close-packed slow cooling, and a finishing mill set is vacant.
For a casting blank with the specification of phi 57-80 mm: the initial rolling temperature is 1100 +/-30 ℃, the two precooling water tanks are respectively opened by 100 percent and 70 percent, the temperature of KOCKS is ensured to be 780-810 ℃, the two water tanks before final cooling are respectively opened by 30 percent, the water tank 3 is opened by 20 percent, the temperature of an upper cooling bed is 750-780 ℃, the cooling bed adopts tooth-spaced steel distribution close arrangement slow cooling, and the pre-rolling, the finish rolling and the finish rolling are empty.
The invention principle is as follows:
in the process of casting blank solidification, fine dendritic crystals (chilling layers) are generated on the surface layer due to chilling, the heat transfer capacity of the casting blank from the inside to the outside is reduced along with the increase of the solidification thickness of the surface layer, and the casting blank begins to be directionally solidified to form strip dendritic crystals (columnar crystals) from the outside to the inside. Due to selective crystallization, solute elements accumulate in the molten pool (liquid phase region), and when columnar crystals grow to generate a bridging phenomenon, the molten steel enriched with solute elements is sealed and cannot exchange with other liquids, and positive segregation of elements such as C, S is formed at the position, and at the same time, the upper molten steel cannot supplement solidification shrinkage at the position, and accordingly residual shrinkage cavities are formed. With the development of continuous casting equipment and production technology, although the macrosegregation of a casting blank is greatly improved, the macrosegregation cannot be completely eliminated, and when the control of smelting and continuous casting process parameters is abnormal, the macrosegregation of the casting blank tends to be aggravated, so that necessary measures are required to be taken in later rolling production to reduce the influence of the segregation of the casting blank.
According to thermodynamic analysis, under isothermal and isobaric conditions, the constituent atoms are spontaneously transferred from chemically high to chemically low regardless of the concentration gradient, and dynamic equilibrium is reached only when the points in the chemical position system of each constituent are equal. Since the chemical potential gradient is generally aligned with the direction of the concentration gradient, the effect of the chemical potential gradient is masked when diffusion proceeds from a high concentration to a low concentration. The essential role of the chemical gradient is revealed only when the two are in opposite directions. It can be seen that the driving force for diffusion is not a concentration gradient, but a chemical potential gradient. Can be expressed by F = -M/x, where the minus sign indicates that the diffusion driving force coincides with the chemical potential decreasing direction.
In addition, free energy difference and surface free energy difference caused by temperature gradient and stress gradient and the action of electric field and magnetic field can also promote atoms to diffuse.
The diffusion in the as-formed metal must satisfy the following conditions:
(1) a sufficiently high temperature is required. Since solid state diffusion is performed by thermal activation of atoms, below a certain temperature, as if the diffusion process were "frozen", it can only be performed at a sufficiently high temperature.
(2) For a sufficiently long time. Because the diffused atoms can only move 0.3-0.5 mm distance at most once in transition in the crystal, millions of transitions are needed to realize diffusion for 1mm distance, and the transition process of the atoms is random, each jump has no relation with the previous jump, and the macroscopic directional migration of the substances can be caused only after a long time.
(3) The diffusion atoms must have a certain solid solubility in the matrix metal to be able to dissolve into the matrix lattice to form a solid solution for solid state diffusion.
(4) There is a driving force. The diffusion process is carried out under the action of diffusion driving force, and the driving force comprises chemical potential gradient, temperature gradient, stress gradient and the like.
The invention has the beneficial effects that: the steel produced by the method adopts an alloy component system mainly containing Mn, Cr and Ni, and the product has higher impact toughness and longer fatigue life, and meets the application requirements of gear steel with large load and high rotating speed. The gear steel material produced by adopting the existing gear steel smelting production process and matching with the specially designed controlled rolling and controlled cooling process has excellent performance and completely meets the processing and use requirements of warm forging gear steel. The invention utilizes the existing equipment and process conditions of steel mills, improves the production efficiency for downstream customers by increasing smaller production cost without increasing investment and production organization difficulty, saves energy and reduces consumption, and has higher economic and social benefits.
Drawings
FIG. 1 is a 500 Xphotograph of a metallographic structure of a sample in example 1.
FIG. 2 is a photograph of a band-shaped tissue 100X in example 1.
Detailed Description
The present invention will be further described with reference to the following examples.
Example 1:
the warm forging gear steel and the production method thereof, the chemical composition weight percentage of the steel is C =0.17%, Si =0.28%, Mn =0.98%, P is less than or equal to 0.010%, S =0.025%, Cr =1.13%, Ni =1.11%, Al =0.033%, N =0.012%, and the rest is Fe and inevitable impurity; the process comprises the following steps:
(1) producing qualified casting blanks: the size of the cross section of the casting blank is 280mm multiplied by 280mm, the macrosegregation carbon pole difference of the cross section of the casting blank is 0.017 percent, and the length of the dendritic structure of the casting blank is 7 mm.
(2) Heating a casting blank at a high temperature and cogging rolling: the temperature of a preheating section for heating the casting blank is 633 ℃, the temperature of a heating section is 1225 ℃, the temperature of a soaking section is 1227 ℃, the heat preservation time of the soaking section is 95min, and the total heating time is 353 min; cogging rolling is carried out for 7 times, the primary reduction is 82mm, the cogging size is 150 multiplied by 150mm, and concentrated heap cooling is carried out after cogging.
(3) Heating at high temperature by using two fires, rolling and cooling: heating the rolling blank by two heats at 655 ℃ of the preheating section, 1223 ℃ of the heating section, 1225 ℃ of the soaking section, 71min of the soaking section and 196min of the total heating time; the second-fire rolling is carried out by adopting a 15-frame horizontal continuous rolling mill and a KOCKS rolling mill. The rolling process temperature control was performed as in table 2.
Example 2:
the warm forging gear steel and the production method thereof, the chemical composition weight percentage of the steel is C =0.18%, Si =0.27%, Mn =0.99%, P is less than or equal to 0.011%, S =0.026%, Cr =1.15%, Ni =1.13%, Al =0.035%, N =0.011%, and the rest is Fe and inevitable impurity; the process comprises the following steps:
(1) producing qualified casting blanks: the section size of the casting blank is 280 multiplied by 280mm, the macrosegregation carbon range of the section of the casting blank is 0.018%, and the length of the dendritic structure of the casting blank is 7 mm.
(2) Heating a casting blank at a high temperature and cogging rolling: the temperature of a preheating section for heating the casting blank is 635 ℃, the temperature of a heating section is 1223 ℃, the temperature of a soaking section is 1225 ℃, the heat preservation time of the soaking section is 97min, and the total heating time is 357 min; cogging rolling is carried out for 7 times, the primary reduction is 82mm, the cogging size is 150 multiplied by 150mm, and concentrated heap cooling is carried out after cogging.
(3) Heating at high temperature by using two fires, rolling and cooling: the temperature of a preheating section of the second-fire heating of the rolled blank is 653 ℃, the temperature of a heating section is 1227 ℃, the temperature of a soaking section is 1226 ℃, the heat preservation time of the soaking section is 73min, and the total heating time is 195 min; the second-fire rolling is carried out by adopting a 15-frame horizontal continuous rolling mill and a KOCKS rolling mill. The rolling process temperature control was performed as in table 3.
Example 3:
the forged gear steel comprises the following chemical components, by weight, C =0.17%, Si =0.27%, Mn =0.97%, P ≤ 0.012%, S =0.026%, Cr =1.12%, Ni =1.13%, Al =0.032%, N =0.011%, and the balance of Fe and inevitable impurities; the process comprises the following steps:
(1) producing qualified casting blanks: the section size of the casting blank is 280 multiplied by 280mm, the macrosegregation carbon range of the section of the casting blank is 0.018%, and the length of the dendritic structure of the casting blank is 8 mm.
(2) Heating a casting blank at a high temperature and cogging rolling: the temperature of a preheating section for heating the casting blank is 635 ℃, the temperature of a heating section is 1229 ℃, the temperature of a soaking section is 1225 ℃, the heat preservation time of the soaking section is 99min, and the total heating time is 356 min; cogging rolling is carried out for 7 times, the primary reduction is 82mm, the cogging size is 150 multiplied by 150mm, and concentrated heap cooling is carried out after cogging.
(3) Heating at high temperature by using two fires, rolling and cooling: heating the rolling blank by two heats, wherein the temperature of the preheating section is 652 ℃, the temperature of the heating section is 1225 ℃, the temperature of the soaking section is 1226 ℃, the heat preservation time of the soaking section is 75min, and the total heating time is 192 min; the second-fire rolling is carried out by adopting a 15-frame horizontal continuous rolling mill and a KOCKS rolling mill. The rolling process temperature control was performed as shown in table 4.
Table 2 example 1 rolling process temperature control table
Table 3 example 2 rolling process temperature control table
Table 4 example 3 rolling process temperature control table
TABLE 5 Performance test indexes of the products of the examples
As can be seen from the test results of Table 5 and FIGS. 1 and 2, the rolled round steel produced by the production method of the invention has stable hardness control, uniform metallographic structure and higher level of banded structure and austenite crystal grains, and all meets the requirement of design index, and the product is qualified through the trial detection of customers.
Claims (4)
1. The warm forging gear steel and the production method thereof are characterized in that: the steel comprises, by weight, 0.16-0.20% of C, 0.25-0.35% of Si, 0.90-1.10% of Mn, 0.015% or less of P, 0.020-0.040% of S, 1.00-1.20% of Cr, 1.00-1.20% of Ni, 0.030-0.050% of Al, 0.009-0.013% of N, and the balance of Fe and inevitable impurities; the key process steps comprise:
(1) casting blank production: the qualified casting blank is produced by adopting a normal gear steel smelting production process, the section size of the casting blank is 280 x 280mm, the chemical components of the casting blank are required to meet the design requirements, the macrosegregation carbon range of the section of the casting blank is less than or equal to 0.02 percent, and the dendritic structure length of the casting blank is not more than 8 mm;
(2) heating a casting blank at a high temperature and cogging rolling: the temperature of a heating preheating section of the casting blank is less than or equal to 650 ℃, the temperature of a heating section is 1210 +/-20 ℃, the temperature of a soaking section is 1220 +/-20 ℃, the heat preservation time of the soaking section is more than or equal to 80min, and the total heating time is 300-400 min; cogging rolling for 7 times, wherein the primary reduction is more than or equal to 80mm, the cogging size is 150 x 150mm, and concentrated heap cooling is performed after cogging;
(3) heating at high temperature by using two fires, rolling and cooling: the temperature of a preheating section of the second-fire heating of the rolled blank is less than or equal to 680 ℃, the temperature of a heating section is 1210 +/-20 ℃, the temperature of a soaking section is 1220 +/-20 ℃, the heat preservation time of the soaking section is more than or equal to 60min, and the total heating time is 180-260 min; the second-fire rolling is carried out by adopting a 15-frame horizontal continuous rolling mill and a KOCKS rolling mill.
2. The warm forging gear steel and the production method thereof according to claim 1, wherein the control of the rolling process temperature in the step (3): for a casting blank with the specification of phi 30-36 mm, the rolling temperature is 1100 +/-30 ℃, the two precooling water tanks are respectively opened by 20 percent and 100 percent, the KOCKS temperature is 780-810 ℃, the final cooling water tank is not opened, the temperature of an upper cooling bed is 750 plus 780 ℃, the cooling bed adopts one-tooth-one-steel close-row slow cooling, and the finish rolling temperature is 850 plus 880 ℃.
3. The warm forging gear steel and the production method thereof according to claim 1, wherein the control of the rolling process temperature in the step (3): for a casting blank with the specification of phi 37-56 mm, the initial rolling temperature is 1100 +/-30 ℃, the two precooling water tanks are respectively opened by 100% and 50%, the temperature of the initial KOCKS is 780-810 ℃, the three final cooling water tanks are respectively opened by 20%, the temperature of the upper cooling bed is 750-780 ℃, the cooling bed adopts one-tooth one-steel close-row slow cooling, and the finishing mill set is empty.
4. The warm forging gear steel and the production method thereof according to claim 1, wherein the control of the rolling process temperature in the step (3): for a casting blank with the specification of phi 57-80 mm, the initial rolling temperature is 1100 +/-30 ℃, the two precooling water tanks are respectively opened by 100 percent and 70 percent, the temperature of KOCKS is 780-810 ℃, the two water tanks before final cooling are respectively opened by 30 percent, the water tank 3 is opened by 20 percent, the temperature of an upper cooling bed is 750-780 ℃, the cooling bed adopts tooth-spaced steel distribution close-row slow cooling, and pre-finish rolling and finish rolling are empty.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115354238A (en) * | 2022-08-10 | 2022-11-18 | 中天钢铁集团有限公司 | Manufacturing method of normalizing-free warm forging steel for inner star wheel |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4802918A (en) * | 1985-09-02 | 1989-02-07 | Aichi Steel Works, Limited | Case hardened steel and method of manufacturing the same |
| CN106216391A (en) * | 2016-08-09 | 2016-12-14 | 湖北新冶钢有限公司 | A kind of rolling production method reducing 42CrMo hardness |
-
2022
- 2022-04-26 CN CN202210445670.9A patent/CN114875313A/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4802918A (en) * | 1985-09-02 | 1989-02-07 | Aichi Steel Works, Limited | Case hardened steel and method of manufacturing the same |
| CN106216391A (en) * | 2016-08-09 | 2016-12-14 | 湖北新冶钢有限公司 | A kind of rolling production method reducing 42CrMo hardness |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115354238A (en) * | 2022-08-10 | 2022-11-18 | 中天钢铁集团有限公司 | Manufacturing method of normalizing-free warm forging steel for inner star wheel |
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