CN115558845A - High-strength steel for 600 MPa-grade agricultural machinery frame and preparation method thereof - Google Patents
High-strength steel for 600 MPa-grade agricultural machinery frame and preparation method thereof Download PDFInfo
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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
- 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
- C22C38/12—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
- C21D2211/005—Ferrite
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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
Abstract
The invention particularly relates to 600 MPa-grade high-strength steel for an agricultural machine frame and a preparation method thereof, and belongs to the field of steel for agricultural machines. The high-strength steel for the 600 MPa-level agricultural machine frame comprises the following chemical components in percentage by mass: c:0.05 to 0.10%, si: < 0.05%, mn:0.5-1.0%, P: less than or equal to 0.010%, S: less than or equal to 0.003 percent, al:0.03-0.05%, nb:0.03-0.05%, V:0.05-0.10%, N:0.010-0.015% and the balance of Fe and inevitable impurities. The yield strength of the steel prepared by the method is more than or equal to 600MPa, the tensile strength is more than or equal to 700MPa, the elongation after fracture is more than or equal to 25%, the yield ratio is more than or equal to 0.95, the low-temperature impact energy at-20 ℃ is more than or equal to 150J, and the technical problem that the existing steel for agricultural machinery cannot give consideration to both the strength and the yield ratio can be solved.
Description
Technical Field
The invention belongs to the field of steel for agricultural machinery, and particularly relates to high-strength steel for a 600 MPa-grade agricultural machinery frame and a preparation method thereof.
Background
China is the first large producing country of world agricultural machinery equipment, more than 4000 agricultural machinery products can be produced, the annual output is about 500 thousands of agricultural machinery products, and the products are mainly medium-sized, medium-sized and low-sized. As the agricultural machinery equipment has the characteristics of complex service environment, strong application seasonality, high short-time operation intensity, long trial verification period of a new product and the suitability for farmers. The whole agricultural machinery equipment material in China is still at the level of the eighties of the last century, the annual demand of steel is about 500 ten thousand tons, the problems that the lightweight performance, the wear resistance, the corrosion resistance, the consistency and the like are insufficient, a large amount of key materials are still required to be imported and the like exist, and the gap with the foreign advanced level is large. The development of novel agricultural machinery equipment materials has great significance for further promoting the agricultural modernization of China.
The low-alloy high-strength steel is generally adopted for the frame of foreign agricultural machinery, for example, the Russian agricultural machinery uses high-strength steel with yield strength of 490MPa, and the American agricultural machinery uses high-strength steel with yield strength of 680 MPa; the agricultural machine frame in China is made of plain carbon steel with the thickness of 3-10mm, the yield strength of 235MPa and 345MPa, the weight of the agricultural machine frame is increased by 10-20% compared with that of the agricultural machine frame abroad, the average weight of various plows is higher than 20%, the weight of a disc harrow is higher than 30%, and the weight of an agricultural trailer is higher than 30-50%. The agricultural machinery is light in weight, can reduce oil consumption, lightens the compaction degree of soil, improves the soil tiltability, and is one of the main development directions of agricultural machinery equipment in the future. Along with the development requirement of agricultural machinery light weight, the agricultural machinery rack light weight steel in China develops towards the directions of high strength, easy welding and high fatigue, so that a high-strength and high-yield-ratio agricultural machinery steel needs to be developed to meet the forming requirement, welding performance requirement, surface quality and plate shape quality requirement of an agricultural machinery cold-bending section product.
Disclosure of Invention
The application aims to provide high-strength steel for a 600 MPa-grade agricultural machine frame and a preparation method thereof, and aims to solve the technical problem that the existing agricultural machine steel cannot give consideration to both strength and yield ratio.
The embodiment of the invention provides high-strength steel for a 600 MPa-grade agricultural machinery frame, which comprises the following chemical components in percentage by mass:
c:0.05 to 0.10%, si: < 0.05%, mn:0.5-1.0%, P: less than or equal to 0.010%, S: less than or equal to 0.003 percent, al:0.03 to 0.05%, nb:0.03-0.05%, V:0.05-0.10%, N:0.010-0.015% and the balance of Fe and inevitable impurities.
Optionally, the metallographic structure of the steel comprises: ferrite and nano precipitated phase.
Optionally, in the metallographic structure of the steel, the volume percentage of ferrite is more than or equal to 95%, and the average grain size of the ferrite is 1.5-3.5 μm.
Optionally, in the metallographic structure of the steel, the volume ratio of the total amount of the nano precipitated phase with the size of 1-50nm to the total amount of the nano precipitated phase is not less than 90%.
Based on the same invention concept, the embodiment of the invention also provides a preparation method of the high-strength steel for the 600 MPa-grade agricultural machinery frame, which comprises the following steps:
smelting and refining in sequence to obtain molten steel according with the chemical components;
continuously casting the molten steel to obtain a steel billet;
and heating, rough rolling, finish rolling, laminar cooling, coiling, slow cooling and air cooling the steel billet to obtain the 600MPa grade high-strength steel for the agricultural machine frame.
Optionally, the heating temperature is 1100-1150 ℃, and the heating heat preservation time is 1.5-2.0h.
Optionally, the number of rough rolling passes is 6, and the final temperature of the rough rolling is 950-1000 ℃.
Optionally, the starting temperature of the finish rolling is 930-980 ℃, and the finishing temperature of the finish rolling is 780-820 ℃.
Optionally, the cooling speed of the laminar cooling is not less than 50 ℃/s, and the coiling temperature is 550-600 ℃.
Optionally, the slow cooling is performed by using a slow cooling pit, and the heat preservation time of the slow cooling is 24-48h.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
the high-strength steel for the 600 MPa-level agricultural machine frame provided by the embodiment of the invention effectively balances the strength and the yield ratio of the steel by designing the chemical components of the steel, and particularly, because the improvement effect of the C element on the tensile strength is greater than that on the yield strength, the yield ratio is effectively improved while considering the wall thickness by reducing the C content on the premise of ensuring the strength; on the premise of ensuring solid solution strengthening, the formation rate of a ferrite structure is improved by controlling the contents of Si and Mn to be lower levels, so that the yield ratio of the steel is improved; a precipitation phase is formed by adding Nb element, and the precipitation strengthening action is exerted, and the recovery of austenite and the grain growth of recrystallization in the hot rolling process are suppressed, so that the ferrite phase has a target grain size; by adding the element V, a precipitation strengthening effect is exerted, precipitates are fine and low in solubility, the strength of steel can be obviously improved, and the strength, the welding performance and the plasticity and toughness can be considered at the same time by controlling the content of the precipitates; n element is added to form a nano precipitated phase with Nb, al and V, and the size of the precipitated phase can be reduced by controlling the content of the N element, so that the plasticity and toughness are improved; through the matching of the elements and the contents, the technical problem that the existing steel for agricultural machinery cannot give consideration to both strength and yield ratio is effectively solved.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a flow chart of a method provided by an embodiment of the present invention;
FIG. 2 is a metallographic structure diagram of high-strength steel for a 600 MPa-grade agricultural machinery frame provided by an embodiment of the invention;
FIG. 3 shows a nano precipitated phase of 600MPa grade high strength steel for agricultural machinery frames provided by the embodiment of the invention.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are illustrative of the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention. For example, room temperature may refer to a temperature in the interval of 10 to 35 ℃.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
In order to solve the technical problems, the general idea of the embodiment of the application is as follows:
according to a typical embodiment of the invention, the high-strength steel for the 600 MPa-grade agricultural machine frame is provided, and the chemical components of the steel comprise the following components in percentage by mass:
c:0.05 to 0.10%, si: < 0.05%, mn:0.5-1.0%, P: less than or equal to 0.010 percent, S: less than or equal to 0.003 percent, al:0.03-0.05%, nb:0.03-0.05%, V:0.05-0.10%, N:0.010-0.015% and the balance of Fe and inevitable impurities.
The actions and the limited ranges of the main alloy elements are explained in detail as follows:
c: c is one of the most economical strengthening elements in steel. However, since the C element has a greater effect of increasing the tensile strength than the yield strength, if the C content is too high, a desired high yield ratio cannot be secured, and the welding performance is also adversely affected. If the carbon content is too low, the matrix strength is affected, and other alloying elements need to be added, resulting in increased cost. Therefore, the content of C in the steel is controlled to be 0.05-0.10% by comprehensively considering the strength, weldability and yield ratio of the material.
Si: si is a solid solution strengthening element. Si is a solid solution strengthening element, but an fayalite phase can be formed during heating, the removing difficulty in a descaling stage is increased, the surface quality of the strip steel is not facilitated, and the toughness and weldability of the strip steel are also not facilitated. In order to obtain higher surface quality, the Si element in the steel is controlled as low as possible. Therefore, the Si content in the steel of the present invention is controlled to 0.05% or less.
Mn: mn is a solid-solution strengthening element. When the Mn content is too high, a severe band structure is formed, the transverse elongation is reduced, and cold formability is affected, and in addition, the contribution of the Mn content to the tensile strength is greater than the yield strength, which is not favorable for controlling the high yield ratio. Therefore, the invention designs the content of Mn to be 0.5-1.0% by comprehensively considering the toughness of the material.
P and S: p and S are impurity elements in steel, and the P element easily causes center segregation of the steel and deteriorates the weldability and the ductility and toughness of the steel; the S element is likely to form MnS inclusions with the Mn element, and deteriorates weldability and formability of the steel. Therefore, the content of P in the steel is controlled to be less than or equal to 0.010 percent and the content of S in the steel is controlled to be less than or equal to 0.003 percent by comprehensively considering the weldability and the ductility and toughness of the material.
Al: al acts as a deoxidizer in steel making. While insufficient deoxidation leads to a decrease in cold formability of the material, an excessively high Al content leads to an excessive amount of AlN inclusions in the steel, and a decrease in elongation of the material. Therefore, the Al content of the present invention is controlled to 0.03 to 0.05% in consideration of the combination of deoxidation and cold formability.
Nb: nb serves as a second phase-forming element, exerts a precipitation strengthening effect, and has an effect of suppressing austenite recovery and recrystallization grain growth in the hot rolling step, thereby making the ferrite phase have a desired grain size. However, if the Nb content is too high, the difficulty of rolling in the hot rolling process is significantly increased. Therefore, the Nb content in the steel is controlled to be 0.03-0.05 percent by comprehensively considering the rolling difficulty and the strengthening effect.
V: v exerts a strong precipitation strengthening action as a precipitation strengthening element, and since the solubility of precipitates is low, the precipitates are fine and contribute greatly to the strength. However, the addition amount of V element is high, which causes an increase in cost and is disadvantageous in welding performance. The content of V in the steel is controlled to be 0.05-0.10 percent by comprehensively considering the economy, the weldability and the ductility and toughness.
N: the N element belongs to solid solution strengthening elements, the N element in the steel can form a second phase with Nb, al and V in a high-temperature austenite region to be precipitated, and in order to promote the precipitation of V and exert the precipitation strengthening effect of V to the maximum extent, the precipitation thermodynamics and kinetics of V can be improved by adding the N element; however, when the N content is too high, a coarse second phase is formed with Al, which deteriorates the ductility and toughness of the steel. Therefore, the content of the N element in the steel is not easy to be too high, and the content of the N element in the steel is controlled to be 0.010-0.015%.
As an alternative embodiment, the metallographic structure of the steel comprises: ferrite and nano precipitated phase.
By controlling the metallographic structure, the prepared steel has high strength and high rigidity, and excellent weldability is ensured.
Preferably, in the metallographic structure of the steel, the volume percentage of ferrite is more than or equal to 95%, and the average grain size of the ferrite is 1.5-3.5 μm.
Preferably, in the metallographic structure of the steel, the volume ratio of the total amount of the nano precipitated phase and the nano precipitated phase with the size of 1-50nm is more than or equal to 90%.
According to another exemplary embodiment of the invention, a manufacturing method of the high-strength steel for the 600 MPa-grade agricultural machine frame is provided, which comprises the following steps:
s1, sequentially smelting and refining to obtain molten steel according with the chemical components.
And S2, continuously casting the molten steel to obtain a steel billet.
And S3, heating, rough rolling, finish rolling, laminar cooling, coiling, slow cooling and air cooling the steel billet to obtain the 600MPa grade high-strength steel for the agricultural machine frame.
It should be noted that rough dephosphorization is required before rough rolling, and fine dephosphorization is required before fine rolling.
As an optional embodiment, the heating temperature is 1100-1150 ℃, and the heating holding time is 1.5-2.0h.
The reason for controlling the heating temperature and the holding time is that: the control can promote the tissue to be fully austenitized, ensure the remelting of micro-alloy elements, ensure the uniformity and fineness of original austenite grains and create conditions for obtaining good strong plasticity matching of the final product.
In an alternative embodiment, the number of the rough rolling passes is 6, and the final temperature of the rough rolling is 950-1000 ℃.
The reason for controlling the rough rolling pass is as follows: and (3) fully performing rough phosphorus removal and fine scale removal, ensuring that primary iron scales generated on the surface of the furnace are completely removed by utilizing the rough phosphorus removal, and further perfecting the removal of secondary iron scales in the rough rolling stage by utilizing the fine scale removal.
The reason why the rough rolling end point temperature is controlled is that: ensuring the sufficient recrystallization and refining structure of the original austenite in the rough rolling stage.
As an alternative embodiment, the starting temperature of the finish rolling is 930-980 ℃, and the finishing temperature of the finish rolling is 780-820 ℃.
The reason why the finish rolling start temperature and the finish rolling temperature are controlled is that: realizes rolling in a non-recrystallization area, avoids mixed crystal tissues, and ensures higher steel throwing speed so as to obtain uniform and fine ferrite tissues and thinner iron scales.
As an alternative embodiment, the cooling speed of laminar cooling is more than or equal to 50 ℃/s, and the coiling temperature is 550-600 ℃.
The rapid cooling is carried out through laminar cooling, the tissue uniformity and the cooling uniformity in the thickness direction of the strip steel are ensured, and good performance uniformity and plate shape quality are ensured; by controlling the coiling temperature, uniform and fine ferrite and pearlite structures are obtained, and meanwhile, the iron scale on the surface of the strip steel has high adhesion and is not easy to fall off.
As an optional embodiment, the slow cooling is carried out by using a slow cooling pit, and the holding time of the slow cooling is 24-48h.
The present application will be described in detail below with reference to examples, comparative examples, and experimental data.
Example 1
The chemical components of the high-strength steel for the 600 MPa-grade agricultural machine frame are shown in the table 1 in percentage by mass.
The metallographic structure includes: ferrite and nano precipitates (see fig. 2 and 3).
The preparation method of the high-strength steel for the 600 MPa-level agricultural machine frame comprises the following steps:
s1, smelting and refining in sequence to obtain molten steel according with chemical components.
And S2, continuously casting the molten steel to obtain a billet.
And S3, heating, rough rolling, finish rolling, laminar cooling, coiling, slow cooling and air cooling the steel billet to obtain the 600MPa grade high-strength steel for the agricultural machine frame.
The preparation process parameters are shown in Table 2.
Example 2
The chemical components of the high-strength steel for the 600 MPa-grade agricultural machinery frame are shown in the table 1 in percentage by mass.
The preparation method of the high-strength steel for the 600 MPa-level agricultural machine frame is different from the preparation method of the embodiment 1 only in parameters, and the parameters are shown in a table 2.
Example 3
The chemical components of the high-strength steel for the 600 MPa-grade agricultural machinery frame are shown in the table 1 in percentage by mass.
The preparation method of the high-strength steel for the 600 MPa-grade agricultural machine frame is different from the preparation method of the example 1 only in parameters, and the parameters are shown in a table 2.
Comparative example
The chemical components of the high-strength steel for the agricultural machine frame are shown in the table 1 in percentage by mass.
The preparation method of the high-strength steel for the agricultural machine frame is different from the preparation method of the embodiment 1 only in parameters, and the parameters are shown in a table 2.
TABLE 1 chemical composition of the steels
| C | Si | Mn | P | S | Alt | Nb | V | Ti | N | |
| Example 1 | 0.05 | 0.03 | 0.8 | 0.008 | 0.002 | 0.035 | 0.050 | 0.06 | 0.010 | |
| Example 2 | 0.07 | 0.02 | 0.6 | 0.007 | 0.002 | 0.035 | 0.035 | 0.07 | 0.012 | |
| Example 3 | 0.09 | 0.02 | 0.5 | 0.009 | 0.001 | 0.030 | 0.030 | 0.90 | 0.015 | |
| Comparative example | 0.08 | 0.10 | 1.5 | 0.009 | 0.005 | 0.040 | 0.03 | 0.10 | 0.005 |
TABLE 2 parameters of the preparation method
Examples of the experiments
The performance of the high-strength steel for the agricultural machinery frame provided by the embodiments 1 to 3 and the comparative example is tested, and the specific results are shown in the following table.
As can be seen from the above table, the yield strength of the steels provided in examples 1-3 is more than or equal to 675MPa, and reaches 690MPa at most; the tensile strength is more than or equal to 710MPa and reaches 725MPa to the maximum; the elongation is more than or equal to 25.0 percent and can reach 29.5 percent at most; the yield ratio is more than or equal to 0.95; meanwhile, all the cold bending tests with 180 degrees d =0a are qualified; the impact energy is more than or equal to 190J at the temperature of minus 20 ℃. In the comparative example, the yield ratio is only 0.913, and the-20 impact energy is less than 150J although the mechanical properties meet the conditions that the yield strength is more than or equal to 600MPa, the tensile strength is more than or equal to 700MPa, and the elongation reaches 22.5%.
In addition, the steel is stable in rolling in production and has no apparent wave shape; edge warping and red iron scales do not exist on the surface of the strip steel, and the iron scales in the pipe making process do not fall off; meanwhile, the cold forming property and the weldability are excellent, and the processing performance requirement of rolling forming production of the agricultural machine frame section is met.
Finally, it should be further noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (10)
1. The high-strength steel for the 600 MPa-grade agricultural machine frame is characterized by comprising the following chemical components in percentage by mass:
c:0.05-0.10%, si: < 0.05%, mn:0.5-1.0%, P: less than or equal to 0.010 percent, S: less than or equal to 0.003 percent, al:0.03 to 0.05%, nb:0.03-0.05%, V:0.05-0.10%, N:0.010-0.015% and the balance of Fe and inevitable impurities.
2. The 600MPa grade high strength steel for agricultural machinery frame according to claim 1, wherein the metallographic structure of the steel comprises: ferrite and nano precipitated phase.
3. The 600MPa grade high-strength steel for agricultural machinery frames according to claim 2, wherein the volume percentage of ferrite in the metallographic structure of the steel is not less than 95%, and the average grain size of the ferrite is 1.5-3.5 μm.
4. The 600 MPa-grade high-strength steel for agricultural machinery frames as claimed in claim 2, wherein the volume ratio of the total amount of the nano precipitated phase and the nano precipitated phase with the size of 1-50nm in the metallographic structure of the steel is not less than 90%.
5. The preparation method of the high-strength steel for the 600 MPa-level agricultural machine frame as claimed in any one of claims 1 to 4, is characterized by comprising the following steps:
smelting and refining in sequence to obtain molten steel according with the chemical components;
continuously casting the molten steel to obtain a steel billet;
and heating, rough rolling, finish rolling, laminar cooling, coiling, slow cooling and air cooling the billet to obtain the 600MPa grade high-strength steel for the agricultural machine frame.
6. The method for preparing the 600MPa grade high-strength steel for the agricultural machinery frame according to claim 5, wherein the heating temperature is 1100-1150 ℃, and the heating heat preservation time is 1.5-2.0h.
7. The method for preparing the high-strength steel for the 600 MPa-level agricultural machinery frame according to claim 5, wherein the number of rough rolling passes is 6, and the final temperature of the rough rolling is 950-1000 ℃.
8. The method for preparing the high-strength steel for the 600 MPa-level agricultural machine frame according to claim 5, wherein the starting temperature of the finish rolling is 930-980 ℃, and the finishing temperature of the finish rolling is 780-820 ℃.
9. The method for preparing the 600 MPa-grade high-strength steel for the agricultural machinery frame according to claim 5, wherein the cooling speed of laminar cooling is more than or equal to 50 ℃/s, and the coiling temperature is 550-600 ℃.
10. The method for preparing the 600MPa grade high-strength steel for the agricultural machinery frame according to claim 5, wherein slow cooling is performed by using a slow cooling pit, and the heat preservation time of the slow cooling is 24-48h.
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Citations (9)
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| CN112522618A (en) * | 2020-11-24 | 2021-03-19 | 首钢集团有限公司 | Full-ferrite high-strength steel and preparation method thereof |
| CN113802054A (en) * | 2020-06-16 | 2021-12-17 | 上海梅山钢铁股份有限公司 | Hot rolled steel plate with yield strength of 420MPa and manufacturing method thereof |
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| JP2010222614A (en) * | 2009-03-23 | 2010-10-07 | Jfe Steel Corp | High-tensile-strength thick steel plate superior in balance between strength and ductility, and method for manufacturing the same |
| CN106119699A (en) * | 2016-06-21 | 2016-11-16 | 宝山钢铁股份有限公司 | A kind of 590MPa level hot-rolled high-strength height reaming steel and manufacture method thereof |
| CN107557673A (en) * | 2016-06-30 | 2018-01-09 | 鞍钢股份有限公司 | A kind of high-strength hot rolling acid-cleaning steel plate of high-elongation and its manufacture method |
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| CN113802054A (en) * | 2020-06-16 | 2021-12-17 | 上海梅山钢铁股份有限公司 | Hot rolled steel plate with yield strength of 420MPa and manufacturing method thereof |
| CN112522618A (en) * | 2020-11-24 | 2021-03-19 | 首钢集团有限公司 | Full-ferrite high-strength steel and preparation method thereof |
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