CN113416902A - Low-cost thermal-forming axle housing steel plate with yield strength of 460MPa and preparation method thereof - Google Patents
Low-cost thermal-forming axle housing steel plate with yield strength of 460MPa and preparation method thereof Download PDFInfo
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- CN113416902A CN113416902A CN202110734618.0A CN202110734618A CN113416902A CN 113416902 A CN113416902 A CN 113416902A CN 202110734618 A CN202110734618 A CN 202110734618A CN 113416902 A CN113416902 A CN 113416902A
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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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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0242—Flattening; Dressing; Flexing
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
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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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
Abstract
The invention relates to a low-cost hot-formed axle housing steel plate with yield strength of 460MPa and a manufacturing method thereof, wherein the hot-formed axle housing steel plate consists of the following elements in percentage by mass: c: 0.12 to 0.18%, Si: 0.10 to 0.50%, Mn: 1.8-2.6%, P is less than or equal to 0.015%, S is less than or equal to 0.0030%, and Nb: 0.010-0.030%, V: 0.035-0.050%, B: 0.0008-0.0020%, Al: 0.015-0.035%, N: 0.002-0.008% and the balance of Fe and inevitable impurities; according to the low-cost hot-formed axle housing steel plate with the yield strength of 460MPa, Mn, B and other cheap metals are adopted for alloying, the hot-rolled and hot-formed semi-finished product is bainite, the yield strength of the hot-rolled steel plate and the hot-formed axle housing semi-finished product is more than or equal to 460MPa and the tensile strength is more than or equal to 600MPa through phase change strengthening, the condition that the strength is seriously reduced after ferrite and pearlite axle housing steel is subjected to hot forming is improved, the problem that the manufacturing cost of the axle housing steel is increased due to the addition of a large amount of alloy or precious metal for controlling the reduction of the strength is solved, and the low-cost hot-formed axle housing steel plate has a good application prospect.
Description
Technical Field
The invention relates to the technical field of axle housing steel manufacturing, in particular to a low-cost thermal forming axle housing steel plate with yield strength of 460MPa and a preparation method thereof.
Background
The axle housing of the automobile drive axle is used as a key bearing part of the automobile, and has higher requirements on safety. With the requirements of emission reduction, energy conservation and weight reduction in the automobile industry and the development of axle manufacturing technology, axle housing steel tends to be highly strengthened, and a large amount of hot-rolled axle housing steel with the yield strength of 235MPa and 345MPa and the thickness of 14-20 mm is gradually replaced by special high-strength axle housing steel with the strength level of 460MPa and above. In order to improve the yield, the axle manufacturing industry generally adopts a hot stamping forming mode of heating to 800-920 ℃ to produce the high-strength axle housing, but adopts the hot stamping forming mode, and ferrite grains grow up and recover after heating to easily cause the axle housing strength to be greatly reduced.
In the disclosed hot forming axle housing steel patent technology, CN111074148A discloses an 800 MPa-grade hot stamping axle housing steel and a manufacturing method thereof, a small amount of ferrite and bainite tissues are obtained by controlling the contents of elements such as Mo, Ti, B and the like, and cooling to 360-450 ℃ for coiling or air cooling to room temperature, and the yield strength after hot forming reaches more than 500 MPa.
CN104213019A discloses 600 MPa-grade automobile axle housing steel and a production method thereof, wherein the basic idea of medium-high C, high Si, high V and high N reinforcement is adopted to control the structure and precipitation state of a steel coil, and the 600 MPa-grade automobile axle housing steel is produced, so that the material strength of the 600 MPa-grade automobile axle housing steel can still reach 600MPa after hot forming.
CN103938092A discloses a high fatigue strength hot forming heavy truck axle housing steel and a manufacturing method thereof, wherein the steel is purified at high purity by adding appropriate amount of Nb, V and Ti and 0.18% of Cr element with low C and high Mn content, excellent obdurability matching is achieved, and the yield strength of the steel plate reaches 510-560 MPa.
CN111534758A discloses an axle housing steel for controlling strength reduction after hot forming and a preparation method thereof, wherein high C and high Mn are adopted, and by controlling the curling temperature and the cooling speed, the yield strength is more than 600MPa, the tensile strength is more than 700MPa, the elongation is more than 20%, the yield strength after hot forming is more than 550MPa, the tensile strength is more than 650MPa, and the axle housing steel has excellent surface quality effect.
CN111647805A discloses axle housing steel with yield strength of 600MPa after hot forming and a preparation method thereof, wherein a C-Mn-Nb-V-Ti-Mo microalloy component system is adopted, and the axle housing steel is not easy to grow up in the heating process by precipitating (Nb, V, Ti, Mo) C precipitated phase with good thermal stability, so that the strength of the heated material is ensured.
In the patent technologies, CN111074148A adopts precious metals such as Mo and the like to alloy and controls two-stage cooling after rolling to obtain a ferrite and bainite structure, the yield strength after hot forming reaches more than 500MPa, but the difficulty and the production cost of the axle housing steel are improved; in addition, ferrite and pearlite are adopted in the structure design in other patent technologies, and in order to ensure the strength after hot forming, more alloy or precious metal is added, so that the alloy cost is increased.
Based on the above, the low-cost thermal forming axle housing steel plate with the yield strength of 460MPa is expected to be obtained, through phase change strengthening, the yield strength after thermal forming is higher than 460MPa, the tensile strength is higher than 600MPa, the production difficulty and the manufacturing cost are reduced, and the thermal forming axle housing steel plate is more suitable for manufacturing the thermal forming axle housing.
Disclosure of Invention
The invention aims to provide a low-cost thermal forming axle housing steel plate with yield strength of 460MPa and a preparation method thereof aiming at the defects in the prior art, a proper amount of cheap metals such as Mn, B and the like are adopted for alloying, the structure of the hot-rolled and thermal forming rear axle housing steel is bainite, and through phase change strengthening, the yield strength of a hot-rolled steel plate and a semi-finished product of the thermal forming rear axle housing is more than or equal to 460MPa, and the tensile strength is more than or equal to 600 MPa. The invention improves the condition that the strength of the ferrite and pearlite axle housing steel is seriously reduced after being heated and formed, simultaneously avoids the problem that the manufacturing cost of the axle housing steel is increased by adding a large amount of alloy or noble metal for controlling the reduction of the strength, and has good application prospect.
The invention relates to a low-cost thermal forming axle housing steel plate with 460 MPa-grade yield strength, which consists of the following elements in percentage by mass: c: 0.12 to 0.18%, Si: 0.10 to 0.50%, Mn: 1.8-2.6%, P is less than or equal to 0.015%, S is less than or equal to 0.0030%, and Nb: 0.010-0.030%, V: 0.035-0.050%, B: 0.0008-0.0020%, Al: 0.015-0.035%, N: 0.002-0.008% and the balance of Fe and inevitable impurities.
The thickness of the hot-formed axle housing steel plate is 6-16 mm, the yield strength of a hot-rolled and hot-formed axle housing semi-finished product is more than or equal to 460MPa, and the tensile strength is more than or equal to 600 MPa.
The microstructure of the axle housing steel after hot forming is granular bainite.
The invention discloses a preparation method of a low-cost thermoformed axle housing steel plate with yield strength of 460MPa, which comprises the following steps: smelting, continuous casting, slab heating, rolling, hot straightening, cold bed air cooling and finishing off-line, wherein:
(1) heating the plate blank: heating the slab in a heating furnace to 1150-1250 ℃ for 3.0-4.0 hours, and ensuring that the soaking time of the billet is more than or equal to 45 min;
(2) rolling: the method comprises two stages of rolling in a recrystallization zone and rolling in a non-recrystallization zone; the initial rolling temperature of the rolling stage of the recrystallization zone is 1050-1100 ℃, the final rolling temperature is 920-980 ℃, the single-pass reduction rate is more than or equal to 13%, the cumulative reduction rate is more than or equal to 75%, the intermediate temperature waiting thickness is 30-55 mm, the initial rolling temperature of the non-recrystallization zone is controlled to be 860-900 ℃, the final rolling temperature is 800-840 ℃, and the final reduction amount is more than or equal to 10%;
(3) laminar cooling: after rolling, adopting laminar flow accelerated cooling, controlling the final cooling temperature to be 500-650 ℃, and controlling the cooling speed to be 10-25 ℃/s;
(4) and (3) thermal straightening: straightening the axle housing steel at the temperature of 350-600 ℃;
(5) cooling by a cooling bed: and naturally cooling the steel plate subjected to the hot straightening to room temperature on a cooling bed.
In the component design of the present invention, the design principle is as follows:
c, carbon C: c, the most basic strengthening element, is dissolved in steel to form an interstitial solid solution, and acts as solid solution strengthening, and C acts as precipitation strengthening when forming carbide precipitates with a strong carbide-forming element, and can improve the hardenability of steel. However, too high C is disadvantageous in properties such as ductility and toughness of steel, and reduces solid solution of micro-alloying elements such as Nb and V to affect precipitation strengthening effect and also reduces hardenability effect of B. Therefore, C is controlled to be 0.12-0.18%.
Manganese Mn: mn as an element for expanding the gamma phase region can lower the gamma → alpha transformation temperature of the steel and increase the stability of austenite. When the Mn content is in a certain range, the upper and lower C curves on the supercooling austenite isothermal transformation curve can be obviously separated, and the phase transformation product of bainite can be obtained. However, Mn is likely to cause core segregation in the steel sheet. Therefore, the Mn content of the steel grade is 1.8-2.6%.
Sulfur S, phosphorus P: harmful impurity elements in the steel are inevitable. S is easily combined with Mn to form segregation, inclusion and other defects, and the performance of the steel plate is deteriorated. Therefore, the axle housing steel and the production method thereof adopt the clean steel production technology, and the P is controlled to be less than or equal to 0.015 percent and the S is controlled to be less than or equal to 0.0030 percent.
Niobium Nb: nb increases the recrystallization temperature, and precipitates fine precipitated particles of NbC or Nb (CN), thereby further refining austenite grains during rolling and improving the strength and toughness. However, if the content is too high, the cost increases significantly. Therefore, the content is controlled to be 0.010 to 0.030 percent.
V, V: v can refine the structure and the crystal grains of the steel and improve the coarsening temperature of the crystal grains, thereby reducing the overheating sensitivity of the steel and improving the strength and the toughness of the steel. V can effectively fix C and N in steel, so that the addition of a trace amount of V can play a role in inhibiting aging. For low alloy steel, V can not only refine grains, but also improve the strength, yield ratio and low-temperature toughness of the steel after normalizing, and improve the welding performance of the steel. Therefore, the content is controlled to be 0.035 to 0.050 percent.
B, boron B: b mainly improves the hardenability of steel and reduces the transformation critical cooling rate of bainite and martensite, the premise of the function of B is that the B must be dissolved in the steel, and the best effect is realized when the content of B is less than 0.0020%. Therefore, in order to obtain a good hardenability effect, the content of B is limited to 0.0008 to 0.0020%.
Aluminum Al: al is an important deoxidizer for killed steel, and is usually added in an amount of 0.015% or more, and is present as Al oxide and acid-soluble aluminum. The oxide of Al is easy to form chain-shaped inclusion, which is unfavorable for steel quality. Excessive acid-soluble Al is combined with N to form AlN, so that the growth of crystal grains can be inhibited and the crystal grains can be refined when the axle housing steel is heated. Therefore, the Al content is controlled in a reasonable range, and the mass percentage of the acid-soluble Al in the steel is controlled to be 0.015-0.030%.
N: the trace N element can react with Nb, Al, V and the like to form nitride particles, refine the grain structure and strengthen the matrix. Therefore, the N content is 0.002% -0.008%.
The production process and the process parameter design principle of the invention are as follows:
(1) smelting: smelting a steelmaking raw material into molten steel, wherein the smelting sequentially comprises iron making, molten iron pretreatment, KR desulfurization, converter smelting, LF refining and RH refining; during smelting, the content of elements such as P, S, N in steel is processed to be lower than the corresponding content, so as to ensure that inclusions in molten steel are controlled to generate and purify the steel in the subsequent smelting process.
(2) Continuous casting: continuously casting the molten steel to obtain a plate blank; the slab comprises the following chemical components in percentage by mass: c: 0.12 to 0.18%, Si: 0.10 to 0.50%, Mn: 1.8-2.6%, P is less than or equal to 0.015%, S is less than or equal to 0.0030%, and Nb: 0.010-0.030%, V is 0.035-0.050%, B: 0.0008-0.0020%, Al: 0.015-0.035%, N: 0.002-0.008% and the balance of Fe and inevitable impurities.
(3) Heating the plate blank: in order to fully dissolve micro-alloy elements and ensure a certain austenite grain size, a steel billet is heated to 1150-1250 ℃, the soaking time of the steel billet is ensured to be more than or equal to 45min, and the steel billet is fully heated and the excessive growth of the austenite grain is inhibited.
(4) Rolling: the method comprises two stages of rolling in a recrystallization zone and rolling in a non-recrystallization zone; the initial rolling temperature of the rolling stage of the recrystallization zone is 1050-1100 ℃, the final rolling temperature is 920-980 ℃, the single-pass reduction rate is more than or equal to 13%, the cumulative reduction rate is more than or equal to 75%, the intermediate temperature waiting thickness is 30-55 mm, the initial rolling temperature of the non-recrystallization zone is controlled to be 860-900 ℃, the final rolling temperature is 800-830 ℃, and the final reduction amount is more than or equal to 10%; the rolling in the recrystallization zone adopts a high-temperature and high-pressure process to refine austenite grains, and the rolling in the non-recrystallization zone adopts low-temperature rolling to reduce the tendency of grain recovery and growth, increase the nucleation rate of austenite during hot forming and further refine grains; the grain size of the steel after hot forming has certain inheritance, so that the comprehensive mechanical property of the steel after hot forming can be improved.
(5) Laminar cooling: after rolling, adopting laminar flow accelerated cooling, controlling the final cooling temperature to be 500-650 ℃, and controlling the cooling speed to be 10-25 ℃/s; the accelerated cooling is carried out at the temperature range of more than or equal to 620 ℃, the grain structure of steel plates with different specifications can be further refined, the precipitation phase of V is prevented from being precipitated and grown in a large amount in a high temperature section, and meanwhile, the final cooling temperature is higher so as not to deteriorate the plate shape.
(6) And (3) thermal straightening: straightening the axle housing steel at the temperature of 350-600 ℃; the method can straighten the poor plate shape caused by hot rolling, reduce the internal stress of the steel plate and reduce the unevenness of the steel plate.
(7) Cooling by a cooling bed: and naturally cooling the steel plate subjected to the hot straightening on a cooling bed.
The invention relates to a low-cost thermoforming axle housing steel plate with yield strength of 460MPa and a manufacturing method thereof, and the technical principle is as follows: the stability and hardenability of austenite are improved by using low-price alloy elements such as Mn, B and the like, the transformation of pro-eutectoid ferrite is inhibited, and the rolled over-stable austenite is transformed into a bainite structure in a wider continuous cooling speed range; the grain size is refined and the sizes of Nb and V precipitated phases are controlled through large compression ratio of an austenite complete recrystallization region, low-temperature controlled rolling and controlled cooling of a non-recrystallization region, fine grain tissues are inherited during hot forming, recrystallized grain growth of axle housing steel in the heating process is further inhibited through the Nb and V precipitated phases, and the yield strength of the heated axle housing steel is ensured to be larger than or equal to 460MPa and the tensile strength of the heated axle housing steel is ensured to be larger than or equal to 600MPa by applying main strengthening and toughening mechanisms such as fine grain strengthening, phase transition dislocation strengthening, dispersion strengthening and the like and superposition effects thereof.
Drawings
FIG. 1 is a photograph showing a metallographic structure of a hot rolled steel sheet in example 2;
FIG. 2 is a metallographic structure photograph of a typical portion of a steel sheet formed by heating at 850 ℃ in example 2.
Detailed Description
In order to better explain the technical solution of the present invention, the technical solution of the present invention is further described below with reference to specific examples, which are only exemplary to illustrate the technical solution of the present invention and do not limit the present invention in any way.
The following table 1 is a list of chemical components contained in the steel plates according to the examples of the present invention in percentage by mass;
the following table 2 is a value list of main process parameters of the steel plate according to each embodiment of the invention;
table 3 below shows the mechanical property test results of the examples of the present invention.
The following examples are all smelted and rolled according to the chemical components and production process requirements of the steel.
The preparation method of the low-cost thermoformed axle housing steel plate with the yield strength of 460MPa comprises the following steps: smelting, continuous casting, slab heating, rolling, hot straightening, cold bed air cooling and finishing off-line, wherein:
(1) heating the plate blank: heating the slab in a heating furnace to 1150-1250 ℃ for 3.0-4.0 hours, and ensuring that the soaking time of the billet is more than or equal to 45 min;
(2) rolling: the method comprises two stages of rolling in a recrystallization zone and rolling in a non-recrystallization zone; the initial rolling temperature of the rolling stage of the recrystallization zone is 1050-1100 ℃, the final rolling temperature is 920-980 ℃, the single-pass reduction rate is more than or equal to 13%, the cumulative reduction rate is more than or equal to 75%, the intermediate temperature waiting thickness is 30-55 mm, the initial rolling temperature of the non-recrystallization zone is controlled to be 860-900 ℃, the final rolling temperature is 800-840 ℃, and the final reduction amount is more than or equal to 10%;
(3) laminar cooling: after rolling, adopting laminar flow accelerated cooling, controlling the final cooling temperature to be 500-650 ℃, and controlling the cooling speed to be 10-25 ℃/s;
(4) and (3) thermal straightening: straightening the axle housing steel at the temperature of 350-600 ℃;
(5) cooling by a cooling bed: and naturally cooling the steel plate subjected to the hot straightening to room temperature on a cooling bed.
TABLE 1 tabulation of the mass percentage of chemical components contained in steel sheets of each example of the present invention
Table 2 list of values of main process parameters of steel plates according to various embodiments of the present invention
TABLE 3 mechanical Property test results of the examples of the present invention
As can be seen from the above table 3, the yield strength and the tensile strength of the hot-formed axle housing steel plate with the thickness of 6-16 mm prepared in the embodiments 1-6 of the invention are higher than 460MPa and higher than 600 MPa. After a large number of tests and production tests, and combining the test results in tables 1, 2 and 3, the embodiment 2 is the best embodiment of the invention, and the attached figure 1 is the metallographic structure photograph of the hot rolled steel plate in the embodiment 2; FIG. 2 is a photograph of a metallographic structure of a typical portion of a finished steel sheet obtained in example 2, which was hot formed at 850 ℃. As can be seen from the attached figure 2, the steel plate structure after the heating forming is converted into equiaxial bainite, the crystal grains are fine and uniform, and the reduction of the strength performance after the hot rolling state and the heating forming is less by combining the mechanical properties listed in the embodiment 2, which indicates that the required microstructure is obtained by reasonably optimizing the design of alloy elements and matching the rolling process with controlled rolling and controlled cooling, thereby meeting the required mechanical property requirement and being suitable for the high-strength weight reduction of the hot stamping axle housing with the yield strength of 460 MPa.
The embodiments described above are merely specific examples of the present invention exemplified for explaining the present invention, and do not limit the present invention in any way, and any insubstantial changes from the above-described contents and forms without departing from the scope of the present invention are considered to fall within the scope of the present invention as claimed. The invention is not limited to the specific embodiments described above.
Claims (4)
1. A low-cost thermal forming axle housing steel plate with 460 MPa-level yield strength is characterized by comprising the following elements in percentage by mass: c: 0.12 to 0.18%, Si: 0.10 to 0.50%, Mn: 1.8-2.6%, P is less than or equal to 0.015%, S is less than or equal to 0.0030%, and Nb: 0.010-0.030%, V: 0.035-0.050%, B: 0.0008-0.0020%, Al: 0.015-0.035%, N: 0.002-0.008% and the balance of Fe and inevitable impurities.
2. A low cost 460MPa grade hot formed axle housing steel plate as set forth in claim 1 wherein: the thickness of the hot-formed axle housing steel plate is 6-16 mm, the yield strength of a hot-rolled and hot-formed axle housing semi-finished product is more than or equal to 460MPa, and the tensile strength is more than or equal to 600 MPa.
3. A low cost 460MPa grade hot formed axle housing steel plate as set forth in claim 1 wherein: the microstructure of the axle housing steel after hot forming is granular bainite.
4. A method of making a low cost 460MPa grade hot formed axle housing steel sheet according to claim 1 or 2 or 3 comprising: smelting, continuous casting, slab heating, rolling, hot straightening, cold bed air cooling and finishing off-line, and is characterized in that:
(1) heating the plate blank: heating the slab in a heating furnace to 1150-1250 ℃ for 3.0-4.0 hours, and ensuring that the soaking time of the billet is more than or equal to 45 min;
(2) rolling: the method comprises two stages of rolling in a recrystallization zone and rolling in a non-recrystallization zone; the initial rolling temperature of the rolling stage of the recrystallization zone is 1050-1100 ℃, the final rolling temperature is 920-980 ℃, the single-pass reduction rate is more than or equal to 13%, the cumulative reduction rate is more than or equal to 75%, the intermediate temperature waiting thickness is 30-55 mm, the initial rolling temperature of the non-recrystallization zone is controlled to be 860-900 ℃, the final rolling temperature is 800-840 ℃, and the final reduction amount is more than or equal to 10%;
(3) laminar cooling: after rolling, adopting laminar flow accelerated cooling, controlling the final cooling temperature to be 500-650 ℃, and controlling the cooling speed to be 10-25 ℃/s;
(4) and (3) thermal straightening: straightening the axle housing steel at the temperature of 350-600 ℃;
(5) cooling by a cooling bed: and naturally cooling the steel plate subjected to the hot straightening to room temperature on a cooling bed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110734618.0A CN113416902B (en) | 2021-06-30 | 2021-06-30 | Low-cost thermal-forming axle housing steel plate with yield strength of 460MPa and preparation method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110734618.0A CN113416902B (en) | 2021-06-30 | 2021-06-30 | Low-cost thermal-forming axle housing steel plate with yield strength of 460MPa and preparation method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114836696A (en) * | 2022-04-27 | 2022-08-02 | 鞍钢股份有限公司 | 390 MPa-grade automobile axle housing steel for hot stamping and production method thereof |
| CN115595505A (en) * | 2022-10-28 | 2023-01-13 | 武汉钢铁有限公司（Cn） | 600 MPa-grade axle housing steel with high temperature resistance and high hole expansion rate and production method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102260824A (en) * | 2010-05-25 | 2011-11-30 | 宝山钢铁股份有限公司 | Hot-rolled steel plate with yield strength of 550 MPa for hot forming and manufacturing method thereof |
| CN106244919A (en) * | 2016-08-03 | 2016-12-21 | 唐山钢铁集团有限责任公司 | A kind of low-alloy high-strength punching press axle shell steel and production method thereof |
| CN111074148A (en) * | 2018-10-19 | 2020-04-28 | 宝山钢铁股份有限公司 | 800 MPa-level hot stamping axle housing steel and manufacturing method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102260824A (en) * | 2010-05-25 | 2011-11-30 | 宝山钢铁股份有限公司 | Hot-rolled steel plate with yield strength of 550 MPa for hot forming and manufacturing method thereof |
| CN106244919A (en) * | 2016-08-03 | 2016-12-21 | 唐山钢铁集团有限责任公司 | A kind of low-alloy high-strength punching press axle shell steel and production method thereof |
| CN111074148A (en) * | 2018-10-19 | 2020-04-28 | 宝山钢铁股份有限公司 | 800 MPa-level hot stamping axle housing steel and manufacturing method thereof |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114836696A (en) * | 2022-04-27 | 2022-08-02 | 鞍钢股份有限公司 | 390 MPa-grade automobile axle housing steel for hot stamping and production method thereof |
| CN115595505A (en) * | 2022-10-28 | 2023-01-13 | 武汉钢铁有限公司（Cn） | 600 MPa-grade axle housing steel with high temperature resistance and high hole expansion rate and production method thereof |
| CN115595505B (en) * | 2022-10-28 | 2024-03-19 | 武汉钢铁有限公司 | 600 MPa-level axle housing steel with high-temperature resistance and high-expansion rate and production method thereof |
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| CN113416902B (en) | 2022-06-14 |
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