CN114351055A - 280 MPa-grade cold-rolled welded pipe steel and production method thereof - Google Patents
280 MPa-grade cold-rolled welded pipe steel and production method thereof Download PDFInfo
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- CN114351055A CN114351055A CN202210046357.8A CN202210046357A CN114351055A CN 114351055 A CN114351055 A CN 114351055A CN 202210046357 A CN202210046357 A CN 202210046357A CN 114351055 A CN114351055 A CN 114351055A
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- 229910000831 Steel Inorganic materials 0.000 title description 59
- 239000010959 steel Substances 0.000 title description 59
- 238000004519 manufacturing process Methods 0.000 title description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 22
- 238000000034 method Methods 0.000 description 17
- 238000000137 annealing Methods 0.000 description 12
- 229910052742 iron Inorganic materials 0.000 description 9
- 229910001567 cementite Inorganic materials 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 7
- 239000012535 impurity Substances 0.000 description 7
- 239000011572 manganese Substances 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- 230000003712 anti-aging effect Effects 0.000 description 6
- 238000005097 cold rolling Methods 0.000 description 6
- 238000005098 hot rolling Methods 0.000 description 6
- 229910000859 α-Fe Inorganic materials 0.000 description 6
- 229910001562 pearlite Inorganic materials 0.000 description 5
- 239000006104 solid solution Substances 0.000 description 5
- 238000003723 Smelting Methods 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000004321 preservation Methods 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 239000010960 cold rolled steel Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000010583 slow cooling Methods 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005219 brazing Methods 0.000 description 1
- 229910052729 chemical element Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000010622 cold drawing Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006477 desulfuration reaction Methods 0.000 description 1
- 230000023556 desulfurization Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000009991 scouring Methods 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- CADICXFYUNYKGD-UHFFFAOYSA-N sulfanylidenemanganese Chemical compound [Mn]=S CADICXFYUNYKGD-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention discloses 280 MPa-grade cold-rolled welded pipe steel and a production method thereof, wherein the cold-rolled welded pipe steel comprises the following chemical components in percentage by weight: 0.070-0.120% of C, less than or equal to 0.030% of Si, 0.60-1.0% of Mn, less than or equal to 0.015% of P, less than or equal to 0.012% of S, 0.060-0.10% of Al, 0.0010-0.0020% of B, less than or equal to 0.0040% of N, and the balance of Fe and inevitable impurity elements; through reasonable chemical component design, the product has yield strength of 280-350 MPa, tensile strength of 350-450 MPa and elongation percentage A after fracture50More than or equal to 30 percent and the internal structure is 280MPa grade cold-rolled welded pipe steel of ferrite, pearlite and cementite.
Description
Technical Field
The invention belongs to the technical field of welded pipe steel, and particularly relates to 280 MPa-grade cold-rolled welded pipe steel and a production method thereof.
Background
The welded pipe is a high-precision steel pipe processed by cold drawing, and the precision welded pipe produced by cold-rolled steel sheets is mainly used for a plurality of parts such as automobile brake systems, civil electric box compressor vaporizers, condensers and the like, repeatedly bears various alternating stresses such as stretching, compression, shearing, impact and the like during working, and an inner hole is also subjected to scouring, corrosion and abrasion of high-pressure oil, so that the welded pipe has strict requirements on the material, performance and processing precision of raw materials. The cold-rolled steel coil is processed into the welded pipe through the working procedures of splitting, coiling, brazing and the like, and the cold-rolled welded pipe steel has higher requirements on the surface quality, dimensional tolerance, strength, anti-aging performance and forming performance of the steel plate.
At present, no production method related to welded pipe steel with yield strength of 280MPa is available in the prior art.
Disclosure of Invention
The invention aims to provide 280 MPa-grade cold-rolled welded pipe steel and a production method thereof, and the yield strength of 280-350 MPa, the tensile strength of 350-450 MPa and the elongation percentage A after fracture are produced through reasonable chemical component design50The steel plate is a 280 MPa-grade cold-rolled welded pipe steel with the internal structure of ferrite, pearlite and cementite, and the elongation of the finished steel plate is more than or equal to 25% after the finished steel plate is placed for three months.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the 280 MPa-grade cold-rolled welded pipe steel comprises the following chemical components in percentage by weight: 0.070-0.120% of C, less than or equal to 0.030% of Si, 0.60-1.0% of Mn, less than or equal to 0.015% of P, less than or equal to 0.012% of S, 0.060-0.10% of Al, 0.0010-0.0020% of B, less than or equal to 0.0040% of N, and the balance of Fe and inevitable impurity elements.
The 280 MPa-grade cold-rolled welded pipe steel preferably comprises the following chemical components in percentage by weight: 0.075-0.10% of C, 0.001-0.020% of Si, 0.64-0.85% of Mn, less than or equal to 0.012% of P, less than or equal to 0.010% of S, 0.065-0.085% of Al, 0.0015-0.0020% of B, less than or equal to 0.0040% of N, and the balance of Fe and inevitable impurity elements.
The metallographic structure of the 280MPa grade cold-rolled welded pipe steel is ferrite, pearlite and cementite, and the grain grade is more than or equal to 10 grade.
The thickness of the 280MPa grade cold-rolled welded pipe steel is 0.3-0.5 mm.
The yield strength of the 280 MPa-grade cold-rolled welded pipe steel is 280-350 MPa, the tensile strength is 350-450 MPa, and the elongation percentage A after fracture is50Not less than 30 percent, and the elongation of the finished steel plate is not less than 25 percent after the steel plate is placed for three months.
The production method of the 280 MPa-grade cold-rolled welded pipe steel comprises the following steps: the method comprises the following steps of molten iron pretreatment, converter smelting, alloy fine adjustment station, hot rolling, coiling, cold rolling, cover annealing and leveling.
In the molten iron pretreatment process, impurity removal elements in the molten iron are removed, and the purity of the molten iron is improved, including desiliconization, desulfurization and dephosphorization of the molten iron.
In the converter smelting process, oxygen is blown in, and high-temperature molten iron is subjected to oxidation reaction to remove impurities.
In the alloy fine-tuning station process, argon is blown to the bottom of a steel ladle to accelerate the movement of a molten steel medium, so that the components and the temperature of the molten steel are uniformly distributed, impurities of the molten steel are reduced through a chemical reaction, and the molten steel is cleaned.
In the hot rolling process, the heating temperature of a steel plate before rolling is 1150-1250 ℃, and if the temperature of a casting blank is too low during rolling, mixed crystals can appear in the internal structure of a hot rolled coil; if the temperature of the casting blank is too high, the internal structure of the surface of the steel coil is abnormally large and the defect of surface iron scale is serious; the finishing temperature is controlled between 850 ℃ and 950 ℃, and the finishing temperature is higher than Ar3And mixed crystal structure of the steel coil is avoided, and laminar cooling is performed after hot rolling.
In the coiling process, the coiling temperature is 650-710 ℃, the coiling temperature can control the grain size of the hot-rolled strip steel and the amount and the form of precipitates, and the higher coiling temperature can fully precipitate C, N solid solution atoms in a matrix and improve the anti-aging performance of the steel plate.
In the cold rolling process, the cold rolling reduction is more than or equal to 75%, the larger the reduction is, the smaller the grain size after annealing is, the lower the delta r value is, and the forming performance of the steel plate is facilitated.
In the cover annealing process, the heating temperature of cover annealing is controlled to be 560-700 ℃, and the heating and heat preservation time is controlled to be 10-30 h, preferably 20-30 h; slowly cooling along with the furnace after annealing is finished; the bell-type annealing temperature is lower than Ac1, and a long-time heat preservation heating and furnace cooling slow cooling mode is adopted, so that free solid solution carbon is fully precipitated, and the anti-aging performance of the steel plate is improved.
In the leveling process, the leveling elongation is controlled to be 0.4-1.2%.
In the components of the 280MPa cold-rolled welded pipe steel provided by the invention, the functions and the control of each chemical element are as follows:
c: the content of C is increased, the strength is increased, but the plasticity and the formability of the steel are reduced, so that the control range of the percentage content of C in the invention is 0.070% -0.120% from the comprehensive performance.
Si: the Si content is too high, the iron scale on the surface of the steel plate is not easy to remove, and the percentage content control range of the Si is less than or equal to 0.030 percent.
Mn: mn improves the cold-embrittlement tendency of the steel, and too high Mn content makes the steel brittle and hard. The percentage content of Mn in the invention is controlled within the range of 0.60-1.0%.
P: p increases the cold brittleness of the steel and reduces the plasticity. The percentage content of P in the invention is controlled below 0.015 percent.
S: when the S content is higher, large-size manganese sulfide is easily formed, and the plasticity and the toughness of the steel plate are obviously reduced. The percentage content of S in the invention is controlled below 0.012%.
Al: al is used as a main deoxidizer, can inhibit the generation of other oxides, can be combined with N in steel to form aluminum nitride, and improves the anti-aging performance of the steel plate. The control range of the percentage content of Al is 0.060-0.10%.
B: the B element and the N element form BN, so that the solid solution of the N element is reduced, the anti-aging performance of the steel plate is improved, and the service life of the welded pipe is prolonged. The percentage content control range of B in the invention is 0.0010-0.0020%.
N: it is proved that N is a solid solution element, the anti-aging property of the steel plate is reduced, and N is less than or equal to 0.0040 percent in the invention.
The welded pipe steel with the yield strength of 280MPa is obtained through chemical component design, hot rolling production process design and cover annealing, the tensile strength is 350-450 MPa, and the elongation percentage A after fracture is50Not less than 30 percent. The internal structure of the steel plate mainly comprises ferrite, pearlite and cementite, the cementite is precipitated and refined in the process of cover annealing, the crystal grains are fine, the cementite nucleation mass point is increased, the precipitation of the cementite in the steel is further promoted, the content of free solid solution carbon in the ferrite is reduced, and the elongation of the finished steel plate is more than or equal to 25% after the finished steel plate is placed for three months.
Drawings
FIG. 1 is a metallographic structure chart of a welded pipe steel in example 1, in which the metallographic structure was ferrite + cementite + pearlite.
Detailed Description
The 280 MPa-grade cold-rolled welded pipe steel comprises the following chemical components in percentage by weight: 0.070-0.120% of C, less than or equal to 0.030% of Si, 0.60-1.0% of Mn, less than or equal to 0.015% of P, less than or equal to 0.012% of S, 0.060-0.10% of Al, 0.0010-0.0020% of B, less than or equal to 0.0040% of N, and the balance of Fe and inevitable impurity elements.
The production method of the 280 MPa-grade cold-rolled welded pipe steel comprises the following steps: the method comprises the following steps of molten iron pretreatment, converter smelting, alloy fine adjustment station, hot rolling, coiling, cold rolling, cover annealing and leveling;
in the hot rolling process, the heating temperature of a steel plate before rolling is 1150-1250 ℃, and the finishing temperature is controlled at 850-950 ℃;
in the coiling process, the coiling temperature is 650-710 ℃;
in the cold rolling process, the cold rolling reduction rate is more than or equal to 75 percent;
in the cover annealing process, the lowest heating temperature of cover annealing is more than or equal to 620 ℃, the heating and heat preservation time is controlled to be 20-30 h, and furnace slow cooling is carried out after annealing is finished;
in the leveling process, the leveling elongation is controlled to be 0.4-1.2%;
the present invention will be described in detail with reference to examples.
The chemical compositions and mass percentages of the cold-rolled pipe steels in the examples and comparative examples are shown in table 1, and the balance is Fe and inevitable impurity elements.
Table 1 examples chemical composition, wt.%
| Numbering | C | Si | Mn | P | S | Al | N | B |
| Example 1 | 0.083 | 0.014 | 0.74 | 0.009 | 0.0061 | 0.066 | 0.0036 | 0.0017 |
| Example 2 | 0.075 | 0.008 | 0.64 | 0.010 | 0.0064 | 0.074 | 0.0025 | 0.0018 |
| Example 3 | 0.089 | 0.0014 | 0.85 | 0.012 | 0.0081 | 0.085 | 0.0019 | 0.0015 |
| Comparative example 1 | 0.032 | 0.014 | 0.47 | 0.009 | 0.0061 | 0.046 | 0.0036 | 0.0017 |
| Comparative example 2 | 0.026 | 0.034 | 0.55 | 0.009 | 0.0061 | 0.035 | 0.0025 | 0.0015 |
| Comparative example 3 | 0.089 | 0.0016 | 0.79 | 0.010 | 0.0082 | 0.062 | 0.0019 | - |
The main process parameters of the cold-rolled welded pipe steels in the examples and comparative examples are shown in table 2.
TABLE 2 production Process parameters
The mechanical properties of the cold-rolled welded tube steels in the respective examples and comparative examples are shown in Table 3: the embodiments all meet the requirements; comparative examples 1 and 2 did not meet the strength requirements; comparative example 3 mechanical properties meet the requirements, but the extension does not meet the requirements after the precision welded pipe is manufactured and molded for three months.
TABLE 3 mechanical Properties of the products
As can be seen from the above examples, the present inventionThe microstructure of the steel strip produced by the method is ferrite, cementite and pearlite, and the yield strength, the tensile strength and the elongation percentage A after fracture of the produced steel plate are respectively 280-350 MPa, 350-450 MPa and A50≥30％。
The above detailed description of a 280MPa grade cold-rolled welded tube steel and the method for producing the same with reference to the embodiments is illustrative and not restrictive, and several embodiments can be cited within the limits, so that changes and modifications without departing from the general concept of the present invention shall fall within the protection scope of the present invention.
Claims (10)
1. The 280 MPa-grade cold-rolled welded pipe steel is characterized by comprising the following chemical components in percentage by weight: 0.070-0.120% of C, less than or equal to 0.030% of Si, 0.60-1.0% of Mn, less than or equal to 0.015% of P, less than or equal to 0.012% of S, 0.060-0.10% of Al, 0.0010-0.0020% of B, less than or equal to 0.0040% of N, and the balance of Fe and inevitable impurity elements.
2. The 280MPa grade cold rolled welded pipe steel according to claim 1, comprising the following chemical components in percentage by weight: 0.075-0.10% of C, 0.001-0.020% of Si, 0.64-0.85% of Mn, less than or equal to 0.012% of P, less than or equal to 0.010% of S, 0.065-0.085% of Al, 0.0015-0.0020% of B, less than or equal to 0.0040% of N, and the balance of Fe and inevitable impurity elements.
3. The 280MPa grade cold-rolled welded pipe steel according to claim 1 or 2, wherein the metallographic structure of the 280MPa grade cold-rolled welded pipe steel is ferrite + pearlite + cementite.
4. The 280MPa grade cold-rolled welded pipe steel according to claim 1 or 2, wherein the 280MPa grade cold-rolled welded pipe steel has a yield strength of 280-350 MPa, a tensile strength of 350-450 MPa, and a post-fracture elongation A50Not less than 30 percent, and the elongation of the finished steel plate is not less than 25 percent after the steel plate is placed for three months.
5. The production method of 280MPa grade cold rolled welded tube steel according to any one of claims 1 to 4, characterized in that the production method comprises the following steps: the method comprises the following steps of molten iron pretreatment, converter smelting, alloy fine adjustment station, hot rolling, coiling, cold rolling, cover annealing and leveling.
6. The production method according to claim 5, wherein in the hot rolling process, the heating temperature of the steel plate before rolling is 1150-1250 ℃, the finishing temperature is controlled at 850-950 ℃, and laminar cooling is performed after hot rolling.
7. The production method according to claim 5, wherein in the coiling process, the coiling temperature is 650-710 ℃.
8. The production method according to claim 5, wherein in the cold rolling process, the cold rolling reduction is not less than 75%.
9. The production method according to claim 5, characterized in that in the hood annealing process, the heating temperature of the hood annealing is controlled to be 560-700 ℃, the heating holding time is controlled to be 10-30 h, and furnace slow cooling is carried out after the annealing is finished.
10. The production method according to claim 5, wherein in the flattening process, the flattening elongation is controlled to be 0.4-1.2%.
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