CN104372243B - 440MPa grade cold rolled strip steel and production method thereof - Google Patents
440MPa grade cold rolled strip steel and production method thereof Download PDFInfo
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- CN104372243B CN104372243B CN201410530391.8A CN201410530391A CN104372243B CN 104372243 B CN104372243 B CN 104372243B CN 201410530391 A CN201410530391 A CN 201410530391A CN 104372243 B CN104372243 B CN 104372243B
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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
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- 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
-
- 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
-
- 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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- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
The invention discloses a 440MPa grade cold rolled strip steel and a production method thereof. The method includes a hot rolling process and a cold rolling continuous annealing process. The strip steel contains the following chemical components: 0.07-0.10% of C, no more than 0.02% of Si, 1.1-1.3% of Mn, no more than 0.015% of P, no more than 0.015% of S, 0.025-0.055% of Als, no more than 0.007% of N, 0.008-0.015% of Ti, 0.045-0.050% of Nb and the balance of Fe. Based on traditional Nb, V and Ti precipitation strengthening, the cold rolled strip steel provided by the invention has the V element with high cost removed, has the content of acid soluble aluminum (Als) increased; and the content of nitrogen (N) in the steel is reasonably control, so as to increase AlN precipitation effect steel based on the original Nb and Ti precipitate strengthening and reduce the original addition amount of Si, Mn, Nb and Ti alloy. The method in ensuring the steel strength improves the ductility of the steel, and produces the cold rolled strip steel with tensile strength of 480-530 MPa, yield strength of 400-440 MPa and elongation rate of 22-27%.
Description
Technical field
The invention belongs to technical field of metallurgical sheet production, especially a kind of 440MPa level cold-strip steel and its producer
Method.
Background technology
With the development of auto industry, environmental protection is increasingly subject to people's attention, in order to reduce motor vehicle exhaust emission,
Automotive energy-saving emission-reducing is imperative.Application on automobile for the high-strength steel, is conducive to automobile to mitigate weight, becomes current auto industry
One of cutting edge technology of development.In order to ensure automobile have after shock protection occupant safety function, need improve vapour
The tensile strength of automobile-used steel.The production method producing the cold-reduced sheet that tensile strength is more than 440MPa at present mainly has dual phase steel to produce
Method, compound augmentation etc..The feature of dual phase steel working system is to improve the tensile strength of steel by phase transformation strengthening.Compound augmentation
Feature is by adding Nb, Ti alloy in steel, improving the precipitating reinforcing effect of steel.
Content of the invention
The technical problem to be solved in the present invention is to provide a kind of 440MPa level cold-strip steel, while retaining hardness of steel,
Improve the ductility of steel；The present invention also provides a kind of production method of 440MPa level cold-strip steel.
For solving above-mentioned technical problem, the weight/mass percentage composition of chemical composition of the present invention is：C 0.07～0.10%, Si≤
0.02%, Mn 1.1～1.3%, P≤0.015%, S≤0.015%, Als 0.025～0.055%, N≤0.007%, Ti 0.008～
0.015%, Nb 0.045～0.050%, balance of Fe.
The inventive method comprises hot-rolled process and cold-rolling continuous annealing operation, the described weight/mass percentage composition with steel chemical composition
For：C 0.07～0.10%, Si≤0.02%, Mn 1.1～1.3%, P≤0.015%, S≤0.015%, Als 0.025～
0.055%, N≤0.007%, Ti 0.008～0.015%, Nb 0.045～0.050%, balance of Fe.
Hot-rolled process described in the inventive method：Hot rolling heating-up temperature is 1200～1240 DEG C；Finishing temperature is 880～910
℃；Coiling temperature is 565～595 DEG C；In course of hot rolling, roughing stay-warm case normally puts into, and roughing is needless to say warm after terminating.
Cold-rolling continuous annealing operation described in the inventive method：Continuous annealing soaking temperature is 790～810 DEG C；Slow cooling final cooling temperature is 670
～690 DEG C；Rapid cooling end temp is 470～490 DEG C；Completion of prescription temperature is 350～380 DEG C；Rapid cooling cooling rate controls 25～
65 DEG C/s, smooth elongation control is 0.7～1.3%.
Have the beneficial effects that using produced by technique scheme：The present invention is in traditional Nb, V, Ti precipitation strength
On the basis of, eliminate relatively costly V element, increased dissolved aluminum（Als）Content, and rationally control nitrogen in steel（N）Content, from
And on the basis of original Nb, Ti precipitate precipitation strength, increased the precipitation effect of AlN in steel, reduce original for Si,
The addition of Mn, Nb, Ti alloy；Ensure hardness of steel of the present invention while, improve steel ductility while, obtain tension
Intensity is 480～530MPa, and yield strength is 400～440MPa, and elongation percentage is 22～27% cold-strip steel.
The inventive method is 440MPa level according to steel grade intensity, with the addition of appropriate Nb, Ti alloy in steel；By controlling
Hot rolling, cold-rolling process, while controlling band structure of steel, control the pattern of Nb, Ti precipitate, class shape and distribution in steel；Reach thin
Change crystal grain and form a certain degree of precipitating reinforcing effect, realize the effect that tensile strength reaches 440MPa.The inventive method is produced
While product intensity reaches 440MPa, elongation percentage reaches more than 22%, makes strip have excellent mouldability.
The cold-strip steel stable performance that the inventive method obtains, the tensile strength amount of being imbued with is big, and yield strength is high, elongation percentage
Height, production cost is relatively low.
Specific embodiment
With reference to specific embodiment, the present invention is further detailed explanation.
Embodiment 1-10：The process conditions of the final chemical composition of this 440MPa level cold-strip steel and production method are such as
Lower described.
（1）The final steel chemical composition of each embodiment see table 1.
Table 1：Each embodiment chemical composition（wt%）
（2）Hot-rolled process：
Described hot-rolled process passes through to control technological temperature, to reduce hot rolling plate strength, reduces the purpose of cold rolling load；
In course of hot rolling, coiling temperature and trimmed size match；Roughing stay-warm case normally puts into；Roughing does not carry out treating temperature after terminating,
Directly carry out finish rolling；The specific technological parameter of each embodiment hot-rolled process is shown in Table 2.
Table 2：Hot-rolled process parameter
（3）Cold-rolling continuous annealing operation：
Described cold-rolling continuous annealing operation is passed through to control soaking, slow cooling, rapid cooling, aging temp and cooling rate, produces 440MPa level
The needed microscopic structure of cold-strip steel is it is ensured that the ferrite crystal grain being formed during soaking has enough refined crystalline strengthening effects；Control slow
Cold temperature, promotes the C in the ferrite crystal grain of equal thermosetting, N element to spread in austenite, reduces impurity element in ferrite
Content it is ensured that the elongation of finished product；Control rapid cooling temperature and aging temp it is ensured that rational timeliness started temperature, control steel
The roughening of middle precipitate；Control rational cooling rate it is ensured that the austenite of steel occurs pearlitic transformation.
The cold rolling trimmed size of each embodiment is 1200 × 1.5mm, and cold rolling reduction ratio is controlled to 62.5%, smooth elongation percentage with
Thickness matches, and concrete annealing process is shown in Table 3.
Table 3：Continuous annealing parameter
In described cold-rolling continuous annealing operation, 790～810 DEG C of insulations contribute to the chill strip after cold rolling and occur to recover to tie again
Crystalline substance, due to microalloy element Nb, Ti, Als in steel etc. with steel in C, N element formed NbCN, TiCN, AlN etc. separate out
Ferrite grain boundaries are had certain anchoring to act on, soaking temperature is too low by thing, will lead to carry crystalline grain of steel meticulous, and lead to finished product to be surrendered
Intensity is higher, and elongation percentage is low.After slow cooling, strip is cooled to 670～690 DEG C, and this is conducive to C, N of solid solution in ferrite
Element converts to austenite, reduces the total constituent content in ferrite, improves ferritic elongation, and the process of slow cooling also promotees
Enter in steel austenite to perlitic transformation；Through being cooled to 470 DEG C～490 DEG C soon, enter Stages of Aging, slow but extremely in aging section
350 DEG C～380 DEG C, this process promotes the precipitates such as NbCN, TiCN, AlN of having been formed in steel to be roughened further, grows up,
Improve precipitating reinforcing effect.Through entirely cold rolled annealed process, the obdurability of steel obtains good coupling.
（4）Each embodiment products obtained therefrom mechanical property is shown in Table 4.
Table 4：Product mechanical property
As shown in Table 4, embodiment products obtained therefrom is fully able to meet the performance requirement of 440MPa level cold-strip steel.
Claims (3)
1. a kind of 440MPa level cold-strip steel is it is characterised in that the weight/mass percentage composition of its chemical composition is：C 0.07～
0.10%, Si≤0.02%, Mn 1.1～1.3%, P≤0.015%, S≤0.015%, Als 0.025～0.055%, N≤0.007%,
Ti 0.008～0.015%, Nb 0.045～0.050%, balance of Fe.
2. a kind of production method of 440MPa level cold-strip steel, comprises hot-rolled process and cold-rolling continuous annealing operation it is characterised in that institute
Stating the weight/mass percentage composition with steel chemical composition is：C 0.07～0.10%, Si≤0.02%, Mn 1.1～1.3%, P≤
0.015%, S≤0.015%, Als 0.025～0.055%, N≤0.007%, Ti 0.008～0.015%, Nb 0.045～
0.050%, balance of Fe；Described hot-rolled process：Hot rolling heating-up temperature is 1200～1240 DEG C；Finishing temperature is 880～910 DEG C；
Coiling temperature is 565～595 DEG C；In course of hot rolling, roughing stay-warm case normally puts into, and roughing is needless to say warm after terminating.
3. the production method of 440MPa level cold-strip steel according to claim 2 is it is characterised in that described cold-rolling continuous annealing work
Sequence：Continuous annealing soaking temperature is 790～810 DEG C；Slow cooling final cooling temperature is 670～690 DEG C；Rapid cooling end temp is 470～490
℃；Completion of prescription temperature is 350～380 DEG C；Rapid cooling cooling rate controls in 25～65 DEG C/s, smooth elongation control 0.7～
1.3%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201410530391.8A CN104372243B (en) | 2014-10-10 | 2014-10-10 | 440MPa grade cold rolled strip steel and production method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410530391.8A CN104372243B (en) | 2014-10-10 | 2014-10-10 | 440MPa grade cold rolled strip steel and production method thereof |
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| Publication Number | Publication Date |
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| CN104372243A CN104372243A (en) | 2015-02-25 |
| CN104372243B true CN104372243B (en) | 2017-02-15 |
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| CN201410530391.8A Expired - Fee Related CN104372243B (en) | 2014-10-10 | 2014-10-10 | 440MPa grade cold rolled strip steel and production method thereof |
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Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103237906A (en) * | 2010-11-15 | 2013-08-07 | Posco公司 | Method for manufacturing high-strength cold-rolled/hot-rolled DP steel having a tensile strength grade of 590 MPa and excellent workability, as well as little deviation in the material properties thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101348883A (en) * | 2008-09-11 | 2009-01-21 | 北京科技大学 | Niobium and titanium composite added ultra-low carbon baking hardening steel plate and manufacturing method thereof |
| CN101348884B (en) * | 2008-09-11 | 2010-05-12 | 北京科技大学 | 440MPa grade niobium-containing high-strength IF steel and manufacturing method thereof |
| CN101684533A (en) * | 2008-09-27 | 2010-03-31 | 鞍钢股份有限公司 | High-strength cold-rolled sheet having excellent formability and method for producing same |
| CN101812637B (en) * | 2009-02-19 | 2012-02-22 | 上海梅山钢铁股份有限公司 | Production method of high-strength high-tenacity steel used for automobile wheels |
| CN102424933A (en) * | 2011-12-02 | 2012-04-25 | 山西太钢不锈钢股份有限公司 | Hot-rolled high-strength strip steel and manufacturing method thereof |
| CN102719740A (en) * | 2012-03-29 | 2012-10-10 | 鞍钢股份有限公司 | Production method of ultra-low carbon high-strength cold-rolled sheet |
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| CN103237906A (en) * | 2010-11-15 | 2013-08-07 | Posco公司 | Method for manufacturing high-strength cold-rolled/hot-rolled DP steel having a tensile strength grade of 590 MPa and excellent workability, as well as little deviation in the material properties thereof |
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