CN109321839A - 240 MPa-grade bake-hardening steel and manufacturing method thereof - Google Patents
240 MPa-grade bake-hardening steel and manufacturing method thereof Download PDFInfo
- Publication number
- CN109321839A CN109321839A CN201811246541.7A CN201811246541A CN109321839A CN 109321839 A CN109321839 A CN 109321839A CN 201811246541 A CN201811246541 A CN 201811246541A CN 109321839 A CN109321839 A CN 109321839A
- Authority
- CN
- China
- Prior art keywords
- steel
- 240mpa
- manufacturing
- temperature
- hot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 61
- 239000010959 steel Substances 0.000 title claims abstract description 61
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 26
- 229910000760 Hardened steel Inorganic materials 0.000 claims abstract description 49
- 238000000137 annealing Methods 0.000 claims abstract description 36
- 238000005097 cold rolling Methods 0.000 claims abstract description 29
- 238000005098 hot rolling Methods 0.000 claims abstract description 19
- 239000000126 substance Substances 0.000 claims abstract description 16
- 238000005246 galvanizing Methods 0.000 claims abstract description 10
- 239000012535 impurity Substances 0.000 claims abstract description 9
- 238000001816 cooling Methods 0.000 claims description 13
- 238000010438 heat treatment Methods 0.000 claims description 10
- 230000009467 reduction Effects 0.000 claims description 9
- 239000004615 ingredient Substances 0.000 claims description 8
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 7
- 229910052725 zinc Inorganic materials 0.000 claims description 7
- 239000011701 zinc Substances 0.000 claims description 7
- 229910001335 Galvanized steel Inorganic materials 0.000 claims description 6
- 239000008397 galvanized steel Substances 0.000 claims description 6
- 238000005096 rolling process Methods 0.000 claims description 4
- 238000010583 slow cooling Methods 0.000 claims description 4
- 238000009749 continuous casting Methods 0.000 claims description 3
- 238000005554 pickling Methods 0.000 claims description 3
- 241001417490 Sillaginidae Species 0.000 claims description 2
- 238000013021 overheating Methods 0.000 claims 1
- 238000004321 preservation Methods 0.000 claims 1
- 238000003860 storage Methods 0.000 abstract description 25
- 238000000034 method Methods 0.000 abstract description 22
- 230000035945 sensitivity Effects 0.000 abstract description 6
- 238000003723 Smelting Methods 0.000 abstract description 4
- 230000003712 anti-aging effect Effects 0.000 abstract 1
- 239000000047 product Substances 0.000 description 38
- 239000010955 niobium Substances 0.000 description 25
- 229910052799 carbon Inorganic materials 0.000 description 21
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 15
- 230000008569 process Effects 0.000 description 14
- 238000004080 punching Methods 0.000 description 12
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 229910052758 niobium Inorganic materials 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 230000032683 aging Effects 0.000 description 3
- 238000001953 recrystallisation Methods 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 230000035882 stress Effects 0.000 description 3
- 229910001566 austenite Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000009628 steelmaking Methods 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005282 brightening Methods 0.000 description 1
- 150000001721 carbon Chemical group 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000003749 cleanliness Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 230000036413 temperature sense Effects 0.000 description 1
Classifications
-
- 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
- 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
-
- 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
-
- 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
- C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
-
- 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
-
- 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
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- 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 240 MPa-grade bake-hardening steel and a manufacturing method thereof, wherein the steel comprises the following chemical components in percentage by mass: c: 0.0015-0.0030%; si is less than or equal to 0.03 percent; mn: 0.40-0.6%; p: 0.05-0.065%; s: less than or equal to 0.01 percent; and (3) Alt: 0.02-0.06%; nb: 0.006-0.014%; b: 0.0003 to 0.0008 percent; n: less than or equal to 0.004 percent, and the balance of Fe and inevitable impurities; the manufacturing method comprises the following steps: firstly, smelting a steel billet, and then sequentially carrying out hot rolling, cold rolling, annealing and galvanizing on the steel billet. The finished steel manufactured by the method reduces the temperature sensitivity of the bake-hardened steel, improves the anti-aging time to more than 6 months under the condition of a storage environment ranging from-10 ℃ to 40 ℃, and ensures that the yield point elongation Ae value before stamping is less than or equal to 0.8 percent.
Description
Technical field
The application belongs to cold continuous rolling Hot Galvanizing Technology field in metal material processing, and in particular to a kind of 240MPa grades of baking
Hardened steel and its manufacturing method.
Background technique
Baking hardened steel is a kind of strain-aged steel, it is stamping it is preceding there is lower yield strength, processing performance is excellent
Good, after stamping baking vanish, it is overcoating to be mainly used for automobile exterior panel etc. for the available a degree of raising of yield strength
The production of cover piece.Common outside plate trade mark yield strength domestic at present mainly has two intensity ranks of 180MPa, 220MPa, such as China
Patent application " a kind of the cold rolling baking hardened steel of resistance to timeliness 220BH and its production method " (application number CN201611177925), it is public
A kind of cold rolling baking hardened steel of resistance to timeliness 220BH is opened, yield strength is 220MPa grades, using Ultra-low carbon plus micro Nb, Mo
Element, cooperation high annealing are quickly cooled down technique, acquisition 6 months or more ageing resistance energy.
The country applies the BH steel outside plate that yield strength is 240MPa less at present, since the BH steel timeliness phase becomes temperature
Change more sensitivity, therefore general (>=30 DEG C) storage time under the high temperature conditions is more than easily to occur punching press orange peel after three months to lack
It falls into, seriously affects product quality.
Summary of the invention
In order to solve the above technical problems, the present invention provides one kind can solve existing baking hardened steel due to quick to temperature
Sense, leads to the problem of the 240MPa grade baking hardened steel and its manufacturing method of part punching orange peel caused by timeliness.
Realize that technical solution used by the object of the invention is a kind of 240MPa grades of baking hardened steel, it is 240MPa grades described
Each chemical component and its mass percent of baking hardened steel are as follows: C:0.0015~0.0030%；Si≤0.03%；Mn:0.40
~0.6%；P:0.05~0.065%；S :≤0.01%；Alt:0.02~0.06%；Nb:0.006~0.014%；B:
0.0003~0.0008%；N :≤0.004%, remaining is Fe and inevitable impurity.
Preferably, the ratio of the additional amount of the Nb ingredient and C component content proportion meets 9≤Ceff≤15,
Middle Ceff=C-Nb/7.75.
In 240MPa grades of baking hardened steel provided by the invention, the effect of each chemical component is as follows:
In 240MPa grades of baking hardened steel provided by the invention, Nb element is one of key element, forms chemical combination with C element
Object, the present invention is by being rationally arranged C and Nb constituent content, by the control of the content of C element 0.0015~0.0030%, while Nb
Control of element is 0.006~0.014%, and the common cooperation control section final finished dissolved carbon content Ceff is in 9~15PPm.
In 240MPa grades of baking hardened steel provided by the invention, Si constituent content is lower, Si≤0.03%, and lower Si contains
Amount can guarantee the platability on galvanizing production surface.
The Mn element being dissolved in steel has the intensity for improving material, prevents hot-short ability, to ensure that it is higher that product has
There is good formability again, in 240MPa grades of baking hardened steel provided by the invention, Mn element contains while tensile strength
Amount is designed as 0.40~0.6%.
P element is to replace in a manner of solid solution the effect there are in 240MPa of the invention grade baking hardened steel component system product
For the yield strength for improving final products by solution strengthening mode, yield strength >=240MPa, tensile strength >=340MPa, sheet
It invents in the 240MPa grade baking hardened steel provided, the upper content limit of P element is limited to 0.065%, can reduce the low temperature of product
Brittleness.
S element is impurity element, is controlled as far as possible depending on steelmaking equipment situation by lower limit section.
It is deoxidier that Al element acts in 240MPa grade baking hardened steel of the invention, when purpose mainly removes smelting
The oxygen being dissolved in molten steel improves Molten Steel Cleanliness.In 240MPa grades of baking hardened steel provided by the invention, Holo-Al content 0.02
~0.06%, when hot rolling, a small amount of Al content can refine crystal grain, improve impact flexibility.
B element is used to improve secondary processing brittleness in 240MPa grade baking hardened steel of the invention, because P element is easily in crystalline substance
Boundary's segregation and the intensity for reducing crystal boundary, and B element can play the role of increasing crystal boundary cohesive force, therefore this in grain boundaries precipitation
It invents in the 240MPa grade baking hardened steel provided, the content of B element is 0.0003~0.0008%, can be to avoid due to P member
Secondary cold deformation embrittlement trend caused by element.
N element is the steel-making residual elements in the present invention, is not required to manually increase.But this residual elements can influence finally indirectly
Product dissolved carbon content, therefore in 240MPa grades of baking hardened steel provided by the invention, strict control N element content≤
0.004%.
Based on same inventive concept, the present invention also provides a kind of manufacturing method of 240MPa grades of baking hardened steel, packets
Include following steps:
It smelts and continuous casting, acquisition includes the steel billet of each chemical component of the mass percent；
Hot rolling is carried out to the steel billet, obtains hot rolled coil；
Cold rolling is carried out to the hot rolled coil after hot rolling, obtains chill volume；
It anneals to the chill volume after cold rolling, finally obtains the 240MPa grades of baking hardened steel.
Further, described that hot rolling is carried out to the steel billet, comprising: to heat the steel billet from room temperature, by thick
Roll, finish rolling, after section cooling, low temperature coils into the hot rolled coil.
Further, described to heat the steel billet, heating temperature is 1250 ± 30 DEG C；Finishing temperature be 930 ±
20℃；Coiling temperature is 600 ± 20 DEG C.
When heating temperature is up to 1250 DEG C, the compound N b (C, N) of niobium is decomposed, and obtains a certain amount of solid solution carbon, if plus
Hot temperature is low, and austenite grain size is uneven at this time, and the steel after making processing are also easy to produce mixed crystal, brilliant if heating temperature is high
Grain is excessively grown up, and making steel, crystal grain is difficult to refine after processing.Therefore heating temperature is advisable in the technical program with 1250 DEG C.
Due to the precipitation of Nb (C, N), about from 930 DEG C, it is believed that do not occur substantially to tie again after austenite grain deformation
Crystalline substance, therefore finishing temperature is set to 930 DEG C in the technical program.
The excessively high degree that will increase aggravation hot rolling iron scale of coiling temperature, influences product surface quality, coiling temperature mistake
It is low, the performance of product is influenced, therefore coiling temperature is set as 600 DEG C in the technical program.
Further, the hot rolled coil to after hot rolling carries out cold rolling, comprising: after the hot rolled coil natural cooling
Chill volume is obtained by pickling, cold rolling, cold rolling total reduction is 58~84%.
Certain cold rolling reduction ratio is the driving force of subsequent continuous annealing recrystallization, and determines the more of Recrystallization nucleation point
It is few, therefore in the technical program, according to different steel strip thickness specifications, cold rolling reduction ratio is controlled 58~84%.
Further, the chill volume to after cold rolling is annealed, comprising: is continuously moved back to the chill volume
Fire obtains strip, and strip described after annealing is passed through hot galvanizing, finally obtains the 240MPa grades of baking hardened steel.
Further, that include: the chill volume entered by the preheating section of continuous annealing furnace is described continuous for the continuous annealing
Annealing furnace, and 200 DEG C were heated to continuously across 20~30 seconds in the reducing atmosphere in the continuous annealing furnace；The operation
Purpose is to reduce internal stress before product recrystallizes to the greatest extent, so that product does not occur in subsequent processes due to internal stress mistake
It is big and wooden dipper is bent in producer.
The chill volume was further heated to 760 ± 5 DEG C through 130~200 seconds in the bringing-up section of the continuous annealing furnace,
Keep the temperature 50~70s；Present component system NbC decomposition temperature is within the scope of 800 DEG C~820 DEG C (as shown in Figure 2), it is therefore necessary to
Guarantee 800 DEG C or less anneal, with prevent NbC precipitate be dissolved into carbon, niobium atom and increase product entirety carbon atom solid solution contain
Amount, other temperature height then low strength, temperature is too low, recrystallizes insufficient, and n value, r value are relatively low, therefore general in the technical program
Annealing temperature is set as 760 DEG C, keeps the temperature 50~70s, this process recrystallizes ultra-low carbon baking hardening steel tissue sufficiently.
The chill volume was cooled to 680 ± 5 DEG C through 14~20 seconds in the slow cooling section of the continuous annealing furnace；This process makes
Product it is cooling when internal stress reduce, prevent strip from temperature occur from high temperature re-crystallization temperature cooling procedure and reduce suddenly to cause
Product cobble deformation, so that product is able to maintain good profile.
The chill volume was cooled to 470 ± 5 DEG C through 13~20 seconds in the rapid cooling section of the continuous annealing furnace, is annealed
Strip afterwards.The purpose of the operation is to be rapidly cooled to target temperature, controls the dissolved carbon content of final products, finally controls finished product
Performance.
Further, the medium in the reducing atmosphere in the continuous annealing furnace is H2And N2Mixed gas.In H2With
N2The purpose handled in medium is to guarantee that product belt steel surface does not aoxidize, and can finally obtain the steel base of surface-brightening
Plate.
Further, described to pass through hot galvanizing by the strip after annealing, comprising: the strip is entered into zinc pot zinc-plated, institute
The temperature stated when strip enters zinc pot is 460 ± 10 DEG C, obtains hot-dip galvanized steel strip；
By the hot-dip galvanized steel strip it is flattened after coil into finished product, smooth elongation percentage is 1.4 ± 0.2%, described in acquisition
240MPa grades of baking hardened steels.By appropriate smooth, the initial yield point elongation of annealing product can be eliminated, solves finished product in punching press
There is luders band defect, while but also product obtains certain roughness, improvement surface quality, to meet automobile exterior panel part
Surface quality requirements.
As shown from the above technical solution, 240MPa grades of baking hardened steel provided by the invention and its manufacturing method, by excellent
Meter is set up in chemical conversion separately, in the fluctuation of ingredient existence range, by C, Nb content ratio in control smelting process, cooperates subsequent treatment process
In low temperature curling, low-temperature annealing guarantees that finished product is finally dissolved carbon within the scope of 9~15ppm, and then reduces baking hardened steel
Temperature sensitivity, by adjusting with optimization hot rolling, cold rolled annealed technological parameter, flattening technological parameter, successfully produce a kind of temperature
The low 240MPa grades of baking hardened steels of Ultra-low carbon hot galvanizing of sensibility are spent, the standard yield strength range of the hot-dip galvanizing sheet steel is
240~300MPa reduces baking hardened steel temperature sensitivity, improves storage environment under -10 DEG C to 40 DEG C range of condition
The ageing resistance time to 6 months or more, yield point elongation percentage Ae value≤0.8% before punching press
Detailed description of the invention
Fig. 1 is the flow chart of the manufacturing method of 240MPa grades of baking hardened steels in the embodiment of the present invention；
Fig. 2 is the NbC solubility curve figure of 240MPa grades of baking hardened steels in the embodiment of the present invention.
Specific embodiment
In order to make the application the technical staff in the technical field be more clearly understood that the application, with reference to the accompanying drawing,
Technical scheme is described in detail by specific embodiment.
Embodiment 1:
A kind of 240MPa grades of baking hardened steel, each chemical component and its mass percent of the steel grade are as follows: C:0.0021%；
Si:0.010%；Mn:0.44%；P:0.053%；S:0.004%；Alt:0.036%；Nb:0.009%；B:0.0004%；N:
0.0017%, remaining is Fe and inevitable impurity.The wherein additional amount of Nb ingredient and the ratio satisfaction with C component content proportion
Ceff=C-Nb/7.75=9ppm.
Also correspondence of the embodiment of the present invention provides a kind of manufacturing method of above-mentioned 240MPa grades of baking hardened steels, as shown in Figure 1,
Include the following steps:
Step 1: smelting and continuous casting, acquisition include the steel billet of each chemical component of above-mentioned mass percent.
Step 2: hot rolling being carried out to steel billet, obtains hot rolled coil；
Specifically: steel billet is heated from room temperature, heating temperature is 1270 DEG C；Hot rolled plate is obtained by roughing, finish rolling,
Finishing temperature is 940 DEG C；After hot rolled plate is carried out section cooling, low temperature coils into hot rolled coil, and coiling temperature is 615 DEG C.
Step 3: cold rolling being carried out to the hot rolled coil after hot rolling, obtains chill volume；
Specifically: chill volume will be obtained by pickling, cold rolling after hot rolled coil natural cooling, in the present embodiment, according to the band
Steel thickness specification controls cold rolling reduction ratio 80%.
Step 4: it anneals to the chill volume after cold rolling, continuous annealing specially is carried out to chill volume and obtains strip, it will
Strip passes through hot galvanizing after annealing, finally obtains 240MPa grades of baking hardened steels.Detailed step is as follows:
Step 41: chill volume enters continuous annealing furnace by the preheating section of continuous annealing furnace, and going back in continuous annealing furnace
200 DEG C, in the present embodiment were heated to continuously across 27 seconds in originality atmosphere, the medium in reducing atmosphere in continuous annealing furnace
For H2And N2Mixed gas.
Step 42: chill volume being further heated to 763 DEG C for 159 seconds in the bringing-up section of continuous annealing furnace, keeps the temperature 56s.
Step 43: chill volume being cooled to 682 DEG C through 17 seconds in the slow cooling section of continuous annealing furnace.
Step 44: chill volume being cooled to 469 DEG C through 16 seconds in the rapid cooling section of continuous annealing furnace, strip after being annealed.
Step 45: strip entering to zinc pot is zinc-plated, temperature when strip enters zinc pot is 462 DEG C, obtains hot-dip galvanized steel strip.
Step 46: hot-dip galvanized steel strip is water-cooled to room temperature by cooling section after plating, by hot-dip galvanized steel strip it is flattened after batch
At finished product, smooth elongation percentage is 1.35%, obtains 240MPa grades of baking hardened steels.
Steel grade performance of the test according to the 240MPa grade baking hardened steel obtained after above-mentioned process, results of property such as table
Shown in 1, yield point elongation rate Ae value is as shown in table 2 after storing 6 months under different storage temperature environments.
1 Ultra-low carbon BH Steel Properties of table
Yield point elongation rate Ae value after being stored 6 months under the different storage temperature environments of table 2
| Storage temperature | -10℃ | 20℃ | 40℃ |
| Ae value (after 6 months) | 0.2 | 0.4 | 0.6 |
As seen from the above table, the 240MPa grade baking hardened steel produced through this embodiment is under the conditions of different storage temperature
After saving 6 months, the product quality in user's punching course is effectively guaranteed in yield point elongation rate Ae value≤0.8%.
Embodiment 2:
A kind of 240MPa grades of baking hardened steel, each chemical component and its mass percent of the steel grade are as follows: C:0.0023%；
Si:0.010%；Mn:0.48%；P:0.057%；S:0.006%；Alt:0.039%；Nb:0.010%；B:0.0005%；N:
0.0014%, remaining is Fe and inevitable impurity.The wherein additional amount of Nb ingredient and the ratio satisfaction with C component content proportion
Ceff=C-Nb/7.75=10ppm.
The hot rolling technology control heating temperature of the steel grade is 1260 DEG C；Finishing temperature is 935 DEG C；Coiling temperature is 610 DEG C；
It is 80% that cold-rolling process, which controls cold rolling reduction ratio,.Strip is entered in furnace medium by H by room temperature by preheating section in continuous annealing process2
And N2200 DEG C were heated to continuously across 27 seconds in the reducing atmosphere of composition；Strip was further heated to by bringing-up section through 159 seconds
760 DEG C, keep the temperature 56s；Strip was cooled to 680 DEG C through 17 seconds by slow cooling section；Strip was cooled to 470 DEG C through 16 seconds by rapid cooling section；Most
It is 460 DEG C that whole strip, which enters zinc pot temperature,；Smooth elongation percentage is 1.4%.
Steel grade performance of the test according to the 240MPa grade baking hardened steel obtained after above-mentioned process, results of property such as table
Shown in 3, yield point elongation rate Ae value is as shown in table 4 after storing 6 months under different storage temperature environments.
3 Ultra-low carbon BH Steel Properties of table
Yield point elongation rate Ae value after being stored 6 months under the different storage temperature environments of table 4
| Storage temperature | -10℃ | 20℃ | 40℃ |
| Ae value (after 6 months) | 0.1 | 0.3 | 0.5 |
As seen from the above table, the 240MPa grade baking hardened steel produced through this embodiment is under the conditions of different storage temperature
After saving 6 months, the product quality in user's punching course is effectively guaranteed in yield point elongation rate Ae value≤0.8%.
Embodiment 3:
A kind of 240MPa grades of baking hardened steel, each chemical component and its mass percent of the steel grade are as follows: C:0.0025%；
Si:0.0045%；Mn:0.48%；P:0.052%；S:0.004%；Alt:0.041%；Nb:0.010%；B:0.0005%；
N:0.0019%, remaining is Fe and inevitable impurity.Wherein the additional amount of Nb ingredient and the ratio matched with C component content expire
Sufficient Ceff=C-Nb/7.75=12ppm.
The hot rolling technology control heating temperature of the steel grade is 1250 DEG C；Finishing temperature is 927 DEG C；Coiling temperature is 600 DEG C；
It is 81% that cold-rolling process, which controls cold rolling reduction ratio,.Smooth elongation percentage is 1.4%, remaining technique and corresponding parameter are the same as embodiment 1.
Steel grade performance of the test according to the 240MPa grade baking hardened steel obtained after above-mentioned process, results of property such as table
Shown in 5, yield point elongation rate Ae value is as shown in table 6 after storing 6 months under different storage temperature environments.
5 Ultra-low carbon BH Steel Properties of table
Yield point elongation rate Ae value after being stored 6 months under the different storage temperature environments of table 6
| Storage temperature | -10℃ | 20℃ | 40℃ |
| Ae value (after 6 months) | 0.2 | 0.4 | 0.7 |
As seen from the above table, the 240MPa grade baking hardened steel produced through this embodiment is under the conditions of different storage temperature
After saving 6 months, the product quality in user's punching course is effectively guaranteed in yield point elongation rate Ae value≤0.8%.
Embodiment 4:
A kind of 240MPa grades of baking hardened steel, each chemical component and its mass percent of the steel grade are as follows: C:0.0027%；
Si:0.010%；Mn:0.49%；P:0.055%；S:0.005%；Alt:0.034%；Nb:0.010%；B:0.0004%；N:
0.0022%, remaining is Fe and inevitable impurity.The wherein additional amount of Nb ingredient and the ratio satisfaction with C component content proportion
Ceff=C-Nb/7.75=14ppm.
The hot rolling technology control heating temperature of the steel grade is 1240 DEG C；Finishing temperature is 920 DEG C；Coiling temperature is 590 DEG C；
It is 82% that cold-rolling process, which controls cold rolling reduction ratio,.Smooth elongation percentage is 1.45%, remaining technique and corresponding parameter are the same as embodiment 1.
Steel grade performance of the test according to the 240MPa grade baking hardened steel obtained after above-mentioned process, results of property such as table
Shown in 7, yield point elongation rate Ae value is as shown in table 8 after storing 6 months under different storage temperature environments.
7 Ultra-low carbon BH Steel Properties of table
Yield point elongation rate Ae value after being stored 6 months under the different storage temperature environments of table 8
| Storage temperature | -10℃ | 20℃ | 40℃ |
| Ae value (after 6 months) | 0 | 0.3 | 0.6 |
As seen from the above table, the 240MPa grade baking hardened steel produced through this embodiment is under the conditions of different storage temperature
After saving 6 months, the product quality in user's punching course is effectively guaranteed in yield point elongation rate Ae value≤0.8%.
Embodiment 5:
A kind of 240MPa grades of baking hardened steel, each chemical component and its mass percent of the steel grade are as follows: C:0.0029%；
Si:0.010%；Mn:0.49%；P:0.055%；S:0.005%；Alt:0.047%；Nb:0.011%；B:0.0006%；N:
0.0016%, remaining is Fe and inevitable impurity.The wherein additional amount of Nb ingredient and the ratio satisfaction with C component content proportion
Ceff=C-Nb/7.75=15ppm.
The hot rolling technology control heating temperature of the steel grade is 1230 DEG C；Finishing temperature is 910 DEG C；Coiling temperature is 580 DEG C；
It is 83% that cold-rolling process, which controls cold rolling reduction ratio,.Smooth elongation percentage is 1.5%, remaining technique and corresponding parameter are the same as embodiment 1.
Steel grade performance of the test according to the 240MPa grade baking hardened steel obtained after above-mentioned process, results of property such as table
Shown in 9, yield point elongation rate Ae value is as shown in table 10 after storing 6 months under different storage temperature environments.
9 Ultra-low carbon BH Steel Properties of table
Yield point elongation rate Ae value after being stored 6 months under the different storage temperature environments of table 10
| Storage temperature | -10℃ | 20℃ | 40℃ |
| Ae value (after 6 months) | 0 | 0.4 | 0.6 |
As seen from the above table, the 240MPa grade baking hardened steel produced through this embodiment is under the conditions of different storage temperature
After saving 6 months, the product quality in user's punching course is effectively guaranteed in yield point elongation rate Ae value≤0.8%.
240MPa grade baking hardened steel and its manufacturing method of the invention are come into effect from November, 2016 in certain steel mill, are cut
Only to the end of the year 2017, the production and the supply of material for completing 5951 tons of products are amounted to, properties of product are stablized, and design requirement is met.Economy effect
Benefit: the product in 2017 be averaged simple interest be 1253 yuan/ton, complete 5951 tons of sales volume, realize product profit 1253 yuan/ton * 5951
Ton=7,460,000 yuan.Social benefit: the product and production method solve 240MPa intensity rank product under the high temperature conditions (>=
30 DEG C) storage time be more than after three months punching press easily there is the problem of orange peel, realize automobile exterior panel manufacturing process on the whole
In it is formable with high-intensitive best combination.
Through the foregoing embodiment, the invention has the advantages that advantage:
A kind of 240MPa grades of baking hardened steels provided by the invention and its manufacturing method set up meter separately by being optimized to, adjustment
With optimization hot rolling, cold rolled annealed technological parameter, flattening technological parameter, a kind of Ultra-low carbon that temperature sensitivity is low heat is successfully produced
Zinc-plated baking hardened steel, yield strength >=240MPa；BH steel is reduced to a certain extent to the sensibility of temperature, storage environment
Under -10 DEG C to 40 DEG C range of condition, product timeliness phase >=6 month, yield point elongation percentage Ae value≤0.8% before punching press is realized
The best combination of product strength, deep drawability and low temperature sensibility three.Product strength is being improved, the same of dent resistance is improved
When, that is, it ensure that punching press stability, and reduce the temperature sensitivity of product, improve aging resistance, there is biggish reality to answer
Use meaning.
Although the preferred embodiment of the application has been described, but one of ordinary skilled in the art once knows substantially
Creative concept, then additional changes and modifications may be made to these embodiments.It is wrapped so the following claims are intended to be interpreted as
It includes preferred embodiment and falls into all change and modification of the application range.
Obviously, those skilled in the art can carry out various modification and variations without departing from the essence of the application to the application
Mind and range.In this way, if these modifications and variations of the application belong to the range of the claim of this application and its equivalent technologies
Within, then the application is also intended to include these modifications and variations.
Claims (10)
1. a kind of 240MPa grades of baking hardened steel, it is characterised in that: each chemical component of the 240MPa grades of baking hardened steel and
Its mass percent are as follows: C:0.0015~0.0030%；Si≤0.03%；Mn:0.40~0.6%；P:0.05~0.065%；
S :≤0.01%；Alt:0.02~0.06%；Nb:0.006~0.014%；B:0.0003~0.0008%；N :≤0.004%,
Remaining is Fe and inevitable impurity.
2. 240MPa grades of baking hardened steel as described in claim 1, it is characterised in that: the additional amount of the Nb ingredient with it is described
The ratio of C component content proportion meets 9≤Ceff≤15, wherein Ceff=C-Nb/7.75.
3. a kind of manufacturing method of 240MPa as claimed in claim 1 or 2 grades of baking hardened steels, which is characterized in that including walking as follows
It is rapid:
It smelts and continuous casting, acquisition includes the steel billet of each chemical component of the mass percent；
Hot rolling is carried out to the steel billet, obtains hot rolled coil；
Cold rolling is carried out to the hot rolled coil after hot rolling, obtains chill volume；
It anneals to the chill volume after cold rolling, finally obtains the 240MPa grades of baking hardened steel.
4. manufacturing method as claimed in claim 3, it is characterised in that: described to carry out hot rolling to the steel billet, comprising: will be described
Steel billet is heated from room temperature, and after roughing, finish rolling, section cooling, low temperature coils into the hot rolled coil.
5. manufacturing method as claimed in claim 4, it is characterised in that: described to heat the steel billet, heating temperature is
1250±30℃；Finishing temperature is 930 ± 20 DEG C；Coiling temperature is 600 ± 20 DEG C.
6. manufacturing method as claimed in claim 3, it is characterised in that: the hot rolled coil to after hot rolling carries out cold rolling,
It include: that will pass through pickling, cold rolling acquisition chill volume after the hot rolled coil natural cooling, cold rolling total reduction is 58~84%.
7. manufacturing method as claimed in claim 3, it is characterised in that: the chill volume to after cold rolling is annealed,
Include: to carry out continuous annealing to the chill volume to obtain strip, strip described after annealing is passed through into hot galvanizing, finally described in acquisition
240MPa grades of baking hardened steels.
8. manufacturing method as claimed in claim 7, it is characterised in that: the continuous annealing includes: the chill volume by continuous
The preheating section of annealing furnace enters the continuous annealing furnace, and continuously across 20 in the reducing atmosphere in the continuous annealing furnace
It is heated to 200 DEG C within~30 seconds；
The chill volume is further heated to 760 ± 5 DEG C for 130~200 seconds in the bringing-up section of the continuous annealing furnace, heat preservation
50~70s；
The chill volume was cooled to 680 ± 5 DEG C through 14~20 seconds in the slow cooling section of the continuous annealing furnace；
The chill volume was cooled to 470 ± 5 DEG C through 13~20 seconds in the rapid cooling section of the continuous annealing furnace, band after being annealed
Steel.
9. manufacturing method as claimed in claim 8, it is characterised in that: Jie in reducing atmosphere in the continuous annealing furnace
Matter is H2And N2Mixed gas.
10. the manufacturing method as described in claim 7 or 8 or 9, it is characterised in that: it is described by strip described after annealing through overheating
It is zinc-plated, comprising: the strip to enter to zinc pot is zinc-plated, the temperature when strip enters zinc pot is 460 ± 10 DEG C, obtains hot galvanizing band
Steel；
By the hot-dip galvanized steel strip it is flattened after coil into finished product, smooth elongation percentage is 1.4 ± 0.2%, obtains the 240MPa
Grade baking hardened steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811246541.7A CN109321839B (en) | 2018-10-24 | 2018-10-24 | 240 MPa-grade bake-hardening steel and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811246541.7A CN109321839B (en) | 2018-10-24 | 2018-10-24 | 240 MPa-grade bake-hardening steel and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109321839A true CN109321839A (en) | 2019-02-12 |
| CN109321839B CN109321839B (en) | 2021-01-26 |
Family
ID=65261675
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811246541.7A Active CN109321839B (en) | 2018-10-24 | 2018-10-24 | 240 MPa-grade bake-hardening steel and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109321839B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110499471A (en) * | 2019-08-22 | 2019-11-26 | 唐山钢铁集团有限责任公司 | A kind of zinc-plated baking hardening steel plate and its production method of the timeliness greater than 6 months |
| CN111636031A (en) * | 2020-06-03 | 2020-09-08 | 北京首钢股份有限公司 | Ultra-low carbon bake-hardening steel and production method thereof |
| CN111690874A (en) * | 2020-06-22 | 2020-09-22 | 武汉钢铁有限公司 | Band steel with excellent low-temperature secondary processing performance and tensile strength of 370MPa and production method thereof |
| CN111850263A (en) * | 2020-06-22 | 2020-10-30 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method for improving aging resistance of continuous hot-dip galvanizing baking hardened steel plate |
| CN111850262A (en) * | 2020-06-22 | 2020-10-30 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method of ultra-low carbon baking hardening continuous hot-dip galvanized steel sheet |
| TWI751002B (en) * | 2021-01-20 | 2021-12-21 | 中國鋼鐵股份有限公司 | Hot dip galvanized steel material with high formability and method of manufacturing the same |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100685037B1 (en) * | 2005-09-23 | 2007-02-20 | 주식회사 포스코 | Bake-hardenable cold rolled steel sheet with superior strength and aging resistance, galvannealed steel sheet using the cold rolled steel sheet and method for manufacturing the cold rolled steel sheet |
| JP4258369B2 (en) * | 2003-12-24 | 2009-04-30 | Ｊｆｅスチール株式会社 | Bake-hardening high-strength steel sheet with excellent surface quality after pressing and method for producing the same |
| CN102304665A (en) * | 2011-09-21 | 2012-01-04 | 首钢总公司 | Steel plate for automobile and production method thereof |
| CN103667649A (en) * | 2013-10-08 | 2014-03-26 | 首钢京唐钢铁联合有限责任公司 | Nb-treated hot-galvanized ultra-low carbon bake-hardening steel plate and manufacturing method thereof |
| CN104593674A (en) * | 2015-01-21 | 2015-05-06 | 首钢总公司 | Hot-dip galvanized ultra-low carbon bake-hardening steel and production method thereof |
| CN104946974A (en) * | 2015-05-13 | 2015-09-30 | 首钢京唐钢铁联合有限责任公司 | Ultra-low carbon baking hardened steel slab and method for controlling solid solution carbon content thereof |
-
2018
- 2018-10-24 CN CN201811246541.7A patent/CN109321839B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4258369B2 (en) * | 2003-12-24 | 2009-04-30 | Ｊｆｅスチール株式会社 | Bake-hardening high-strength steel sheet with excellent surface quality after pressing and method for producing the same |
| KR100685037B1 (en) * | 2005-09-23 | 2007-02-20 | 주식회사 포스코 | Bake-hardenable cold rolled steel sheet with superior strength and aging resistance, galvannealed steel sheet using the cold rolled steel sheet and method for manufacturing the cold rolled steel sheet |
| CN102304665A (en) * | 2011-09-21 | 2012-01-04 | 首钢总公司 | Steel plate for automobile and production method thereof |
| CN103667649A (en) * | 2013-10-08 | 2014-03-26 | 首钢京唐钢铁联合有限责任公司 | Nb-treated hot-galvanized ultra-low carbon bake-hardening steel plate and manufacturing method thereof |
| CN104593674A (en) * | 2015-01-21 | 2015-05-06 | 首钢总公司 | Hot-dip galvanized ultra-low carbon bake-hardening steel and production method thereof |
| CN104946974A (en) * | 2015-05-13 | 2015-09-30 | 首钢京唐钢铁联合有限责任公司 | Ultra-low carbon baking hardened steel slab and method for controlling solid solution carbon content thereof |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110499471A (en) * | 2019-08-22 | 2019-11-26 | 唐山钢铁集团有限责任公司 | A kind of zinc-plated baking hardening steel plate and its production method of the timeliness greater than 6 months |
| CN111636031A (en) * | 2020-06-03 | 2020-09-08 | 北京首钢股份有限公司 | Ultra-low carbon bake-hardening steel and production method thereof |
| CN111690874A (en) * | 2020-06-22 | 2020-09-22 | 武汉钢铁有限公司 | Band steel with excellent low-temperature secondary processing performance and tensile strength of 370MPa and production method thereof |
| CN111850263A (en) * | 2020-06-22 | 2020-10-30 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method for improving aging resistance of continuous hot-dip galvanizing baking hardened steel plate |
| CN111850262A (en) * | 2020-06-22 | 2020-10-30 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method of ultra-low carbon baking hardening continuous hot-dip galvanized steel sheet |
| CN111850262B (en) * | 2020-06-22 | 2022-07-26 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method of ultra-low carbon baking hardening continuous hot-dip galvanized steel sheet |
| CN111850263B (en) * | 2020-06-22 | 2022-07-26 | 鞍钢蒂森克虏伯汽车钢有限公司 | Production method for improving aging resistance of continuous hot-dip galvanizing baking hardened steel plate |
| TWI751002B (en) * | 2021-01-20 | 2021-12-21 | 中國鋼鐵股份有限公司 | Hot dip galvanized steel material with high formability and method of manufacturing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109321839B (en) | 2021-01-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104520460B (en) | Cold-rolled steel sheet, its manufacture method and heat stamping and shaping body | |
| CN109321839A (en) | 240 MPa-grade bake-hardening steel and manufacturing method thereof | |
| US7442268B2 (en) | Method of manufacturing cold rolled dual-phase steel sheet | |
| CN104040010B (en) | The manufacture method of cold-rolled steel sheet and cold-rolled steel sheet | |
| EP2169091B1 (en) | High-strength hot-dip galvanized steel sheet with low yield strength and with less material quality fluctuation and process for producing the same | |
| US7959747B2 (en) | Method of making cold rolled dual phase steel sheet | |
| TWI435940B (en) | Bake-hardening cold-rolled steel sheet with high-strength, and manufacturing method thereof | |
| WO2012053637A1 (en) | Steel sheet and steel sheet production process | |
| EP3556896A1 (en) | High strength cold rolled steel plate having excellent yield strength, ductility, and hole expandability, hot dip galvanized steel plate, and method for producing same | |
| JP5272548B2 (en) | Manufacturing method of high strength cold-rolled steel sheet with low yield strength and small material fluctuation | |
| WO2010119971A1 (en) | Cold-rolled steel sheet having excellent slow-aging property and high curability in baking, and method for producing same | |
| CN107739981A (en) | Baking hardening hot-dip galvanizing sheet steel and preparation method thereof | |
| CN109694990A (en) | Light transformation induced plasticity steel with good strong plasticity and production method thereof | |
| CN112159931B (en) | 1000 MPa-grade medium manganese TRIP steel with continuous yield and preparation method thereof | |
| WO2024082755A1 (en) | Tin plate and manufacturing method therefor | |
| JP4818765B2 (en) | Deep drawing steel plate excellent in low-temperature bake hardenability and non-aging at room temperature and method for producing the same | |
| CN109518080A (en) | Strong dual phase steel of cold rolling low cost superelevation and preparation method thereof | |
| CN111534760B (en) | Hot-rolled hot-formed steel and preparation method thereof | |
| CN115505847B (en) | Cold-rolled ultrahigh-strength steel plate with excellent impact property and preparation method thereof | |
| CN108570603A (en) | A kind of aerosol can ferrostan and its production method | |
| JP2013227635A (en) | High strength cold rolled steel sheet, high strength galvanized steel sheet, method for manufacturing high strength cold rolled steel sheet, and method for manufacturing high strength galvanized steel sheet | |
| CN112226674B (en) | Aging-resistant cold-rolled hot-galvanized steel plate for household appliances and production method thereof | |
| JPH05230614A (en) | Manufacture of high strength hot dip calvanized steel sheet for deep drawing | |
| CN109321840A (en) | 280 MPa-level low-alloy high-strength steel and manufacturing method thereof | |
| CN115491583B (en) | Ultra-deep drawing cold-rolled hot-dip aluminum-zinc steel plate and manufacturing method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |