CN100441723C - Steel having superior impact absorbency and toughness of parent material - Google Patents
Steel having superior impact absorbency and toughness of parent material Download PDFInfo
- Publication number
- CN100441723C CN100441723C CNB2006101536562A CN200610153656A CN100441723C CN 100441723 C CN100441723 C CN 100441723C CN B2006101536562 A CNB2006101536562 A CN B2006101536562A CN 200610153656 A CN200610153656 A CN 200610153656A CN 100441723 C CN100441723 C CN 100441723C
- Authority
- CN
- China
- Prior art keywords
- contain
- steel plate
- quality
- plate according
- formula
- 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.)
- Expired - Fee Related
Links
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
- C22C38/06—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
- C22C38/002—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
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
-
- 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
- C22C38/04—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
-
- 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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention provides steel having superior impact absorbency and toughness of parent material with tensile strength above 490MPa. The said steel satisfies prescriptive composition, Cep and Di*, and metallic structure satisfies the following condition: the area rate of ferritic of total structure exceeds 90%(area%, same in the structure below); the average diameter of ferritic is: 3-12 mu m; the maximum diameter of ferritic is: less than 40 mu m; the average equivalent circle diameter of the second phase is: less than 0.8 mu m; the preferable retained austenite is: 0.5-10%.
Description
Technical field
The present invention relates to a kind of impact absorbency and base metal tenacity excellence, the steel plate of tensile strength more than 490MPa.
Background technology
In order to prevent the boats and ships impact each other and the immersion in boats and ships that produces when taking place and the outflow of loading, fuel etc. such as hit a submerged reef of boats and ships, as this hull steel, proposition has various steel.For example in patent documentation 1, disclose a kind of steel plate, it is organized as ferrite area occupied rate: the ferrite main body more than 80%, this ferritic hardness is more than Hv160, the average equivalent circular diameter of second phase (phase beyond the ferrite) is below the 5 μ m, and the tissue that has improved the ferrite main body of intensity by formation improves the shock absorption energy.
But in this technology, the average equivalent circular diameter of second phase is more than the 4 μ m, if second be that this size and ferritic phase are hard as described above mutually, then is considered to be difficult to improve base metal tenacity.
Point out that in patent documentation 2 the positive backing layer more than 1/8 of the thickness of slab at least by making steel plate contains counts 1.0～20% residual γ with area occupation ratio, can guarantee that the impact energy of wishing absorbs energy.But,, consider that the characteristic deviation of thickness of slab direction is big, so can fully improve the shock absorption energy of steel plate integral body hardly because residual γ is disperseed in the whole zone of steel plate.In addition, in this patent documentation 2,, can also improve anti-ductile failure performance by making above-mentioned residual γ fine dispersion in ferrite base material (matrix).In addition, rolling effectively in order to form this organizational controls, be exactly to be expressed as in detail, it is direct or be heated to Ac cast sheet
3After the above temperature, carry out hot rolling, and rolling end temp is made as Ar
3+ 100 ℃～Ar
3-50 ℃ temperature range.But in this operation, be difficult to further make residual γ granular, be considered to be difficult to fully improve base metal tenacity.
Regulation makes tissue be made of mutually with hard ferrite in patent documentation 3 in addition, this ferritic phase phase fraction: more than 60%, hardness: below the Hv150, median size: more than the 5 μ m, and the aspect ratio of the rolling direction/thickness of slab direction of hard phase is made as more than 2.By the aspect ratio that so makes the hard phase is more than 2, is intended to improve same extension (homogeneous extension), takes place but be considered to individual anisotropy.The size of hard phase in addition, from Fig. 1 of patent documentation 3 as can be known, because be the size equal, so be difficult to guarantee fully high base metal tenacity with ferritic phase.
[patent documentation 1] spy opens flat 11-193438 communique (table 2)
[patent documentation 2] spy opens flat 11-246934 communique (scope that patent requires, paragraph [0041], paragraph [0044], paragraph [0076])
[patent documentation 3] spy opens the 2001-262272 communique
Summary of the invention
The present invention forms in view of such situation, and its purpose is, the steel plate of a kind of impact absorbency and base metal tenacity excellence is provided.
The steel plate of so-called impact absorbency of the present invention and base metal tenacity excellence has following feature:
In quality % (following all identical), satisfy for composition:
C：0.02～0.10％、
Si：0.05～0.50％、
Mn：1.0～1.6％、
P:0.05% following (not containing 0%),
S:0.05% following (not containing 0%),
Al：0.015～0.06％、
N:0.01% following (not containing 0%), surplus is made up of Fe and inevitable impurity,
Ceq by following formula (1) expression is more than 0.31,
Di* by following formula (2) expression is below 4.0,
Metal structure satisfies:
Account for the ferritic area occupied rate of whole tissues: surpass 90% (meaning of area %, following identical) for tissue,
Average ferrite particle diameter: 3～12 μ m,
Maximum ferrite particle diameter: below the 40 μ m, and
The average equivalent circular diameter of second phase: below the 0.8 μ m,
And tensile strength is more than the 490MPa.
Ceq＝C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4?...(1)
Di*＝C
0.5×(1+0.64Si)×(1+4.10Mn)×(1+2.33Cr)×(1+3.14Mo)×(1+0.27Cu)×(1+0.52Ni)×[1+1.5(0.90-C)×B
2]?...(2)
{ in formula (1), (2), C, Si, Mn, Ni, Cr, Mo, Cu, B represent the content (quality %) of each element }
Steel plate of the present invention in addition is below 490 by the KMs of following formula (3) expression, and if described metal structure contain retained austenite: 0.5～10%, then be preferred because impact absorbency is more excellent.
KMs＝-39Mn-10Cu-17Ni-20Cr-5Mo+550 …(3)
{ in the formula (3), Mn, Cu, Ni, Cr, Mo represent the content (quality %) of each element }
Described steel plate,
(a) in addition as other elements, also can contain more than one that from the group of following composition, select: (do not contain 0%) Cu:0.35% below, (do not contain 0%) below the Ni:0.40%, (do not contain 0%) below the Cr:0.20%, reach and (do not contain 0%) below the Mo:0.08%.
(b) in addition, also comprise Ti:0.1% following (not containing 0%), and if described Ti, N and Al satisfy following formula (4) and (5) because not only can guarantee shock absorption energy and base metal tenacity, so and can guarantee that weldability is preferably.
N≥0.292×Ti …(4)
Al≥1.93×N-0.564×Ti …(5)
{ in the formula (4) (5), N, Ti, Al represent the content (quality %) of each element }
As other element, also can comprise in addition:
(c) B:0.005% following (not containing 0%), and/or Nb:0.05% following (not containing 0%)
(d) mass selection that constitutes from Ca, Mg and REM select more than one: (do not contain 0%) below 0.1%.
Also have, above-mentioned ferritic area occupied rate, average ferrite particle diameter, maximum ferrite particle diameter, the average equivalent circular diameter of second phase, and the area occupied rate of retained austenite are the values of measuring according to the method shown in the embodiment described later.
Steel plate of the present invention, because demonstrate high shock absorption energy, and base metal tenacity is also excellent, so be used under the situation of hull outer wall for example, can prevent boats and ships each other impact and boats and ships hit a submerged reef etc. when taking place the immersion in boats and ships and the outflow of loading, fuel etc.
Embodiment
Present inventors, in order to obtain impact absorbency excellence (demonstrating high shock absorption energy), and the also excellent steel plate of base metal tenacity and studying with keen determination.It found that predetermined component is formed, and the formative tissue form, controls ferritic area occupied rate especially, and median size and maximum particle diameter also have the size of second phase to get final product.Below, the tissue with feature of the present invention is described.
＜average ferrite particle diameter: 3～12 μ m 〉
At first in the present invention, average ferrite particle diameter is made as below the 12 μ m.This is because if it is big for average ferrite particle diameter ratio, then base metal tenacity deterioration, and homogeneous is extended and reduced, and is difficult to guarantee excellent impact absorbency.Average ferrite particle diameter is preferably below the 10 μ m.On the other hand, if average ferrite particle diameter is too small, then the homogeneous extension diminishes, because shock absorption can reduce, so the lower limit of average ferrite particle diameter is made as 3 μ m.
＜maximum ferrite particle diameter: 40 μ m are following 〉
When steel plate being applied distortion, stress concentration is in the crystal grain of maximum.In addition, the big more concentrated stress of the maximum diameter of crystal grain is high more.Its result, homogeneous extends and diminishes, and shock absorption can reduce.Thus in the present invention, the upper limit with maximum ferrite particle diameter is defined as 40 μ m.Be preferably below the 30 μ m.
＜account for the ferritic area occupied rate of whole tissues: surpass 90% 〉
Find in the present invention, make with the ferrite that satisfies above-mentioned prerequisite and organize homogenization, impact absorbency is significantly improved, particularly will make this ferrite surpass 90%.Be preferably more than 95%.
The average equivalent circular diameter of＜the second phase: 0.8 μ m is following 〉
Steel plate of the present invention, the tissue (second phase) as beyond the above-mentioned ferrite comprises MA (Martensite-Austenite constituent) and residual γ, perlite, carbide etc., still, if this is second mutually thick, then when distortion, becomes the destructive starting point and make the base metal tenacity deterioration.Therefore, in the present invention the leveled circular equivalent diameter of second phase is made as below the 0.8 μ m.Below the preferred 0.7 μ m.
＜account for the area occupied rate of the retained austenite (residual γ, γ R) of global tissue: 0.5～10% 〉
By residual γ is existed the TRIP phenomenon is occurred, can further improve ductility, impact absorbency is improved.For such effect is given full play to, can make residual γ exist more than 0.5%.More preferably more than 1.0%.But, if as second the existing in a large number mutually of the hard of residual γ, above-mentioned ferritic area occupied rate relatively reduces, and then can not guarantee excellent impact absorbency, so residual γ is at most 10%.
As mentioned above, exist, recommend to satisfy below 490 by the KMs of following formula (3) expression in order to make residual γ.This KMs is the index of austenite stabilizer element amount, and this value is more little, and residual γ can stably exist more, can expect the appearance of sufficient TRIP effect.KMs is more preferably below 485.
KMs＝-39Mn-10Cu-17Ni-20Cr-5Mo+550 …(3)
{ in the formula (3), Mn, Cu, Ni, Cr, Mo represent the content (quality %) of each element }
As above-mentioned, the present invention is characterised in that and particularly controls the tissue morphology this point, but in order easily to control such tissue morphology, and obtain demonstrating excellent base metal tenacity and high-intensity steel plate, need be grouped into by following being controlled to like this.
<C：0.02～0.10％>
C is a strengthening element, is the element that helps the formation of ferrite area occupied rate and second phase size, residual γ.In order to ensure full intensity, the C amount need be made as more than 0.02%, reach the viewpoint of specified amount from guaranteeing residual γ, the C of above-mentioned amount is contained.It is preferably more than 0.03%.On the other hand, if the C amount is excessive, guarantee that then the ferrite of specified amount is very difficult.In addition, it is big that the diameter of equivalent circle of second phase becomes, and will be difficult to guarantee excellent base metal tenacity and ductility.Therefore C is below 0.10%.Be preferably below 0.08%.
<Si：0.05～0.50％>
Si is the element that works as reductor, in addition as ferritic solution strengthening element, also is the element that helps the raising of intensity.The effect of the decomposition that suppresses γ is also arranged in addition, also help the formation of residual γ.For these effects are given full play to, can allow Si measure is more than 0.05%, to be preferably more than 0.1%.But if Si is excessive, then impact absorbency not only, and base metal tenacity and HAZ toughness also can deteriorations, so the Si amount is below 0.50%.Be preferably below 0.45%.
<Mn：1.0～1.6％>
Mn works as reductor, in addition, also is austenite stabilizer element, helps the formation of residual γ.In addition, transformation temperature is reduced, help the element of ferrite granular.
For these effects are given full play to, the Mn amount is made as more than 1.0%.Be preferably more than 1.2%.On the other hand, excessive if the Mn quantitative change gets, more than then hardenability was brought up to and needed, ferritic maximum particle diameter became greatly on the contrary, causes the reduction of ductility.Therefore the Mn amount is suppressed at below 1.6%.
＜P:0.05% following (not containing 0%), S:0.05% following (not containing 0%) 〉
Because these elements make the steel embrittlement, so preferably do one's utmost to reduce, P is made as below 0.05% in the present invention and (is preferably below 0.03%), S (is preferably below 0.03%) below 0.05%.
<Al：0.015％～0.06％>
Al is the deoxidation effective elements to steel, in addition the solid solution N in the steel is fixed as AlN, plays the deterioration preventing effect of ductility effectively.For this effect is given full play to, the Al amount is made as more than 0.015%, be preferably more than 0.02%.On the other hand, excessive if the Al quantitative change gets, then because the thick non-metallic inclusion (Al of hard
2O
3) generate, the base metal tenacity deterioration is so it is below 0.06%, to be preferably below 0.04%.
＜N:0.01% following (not containing 0%) 〉
N forms TiN and improves HAZ toughness, is the effective elements of guaranteeing to the weldability of excellence.In order to make this effect performance, preferably make N contain (more preferably more than 0.003%) more than 0.001%.On the other hand, if N is excessive to be contained, then above-mentioned thickization of TiN, HAZ toughness is easy to deterioration on the contrary.Therefore, the N amount is below 0.01%.Be preferably below 0.008%.
Also have, contain Ti, when the formation by TiN positively improves HAZ toughness, the relation of above-mentioned N amount and Ti amount, above-mentioned N amount satisfies formula described later (4) and formula (5) with the relation that Ti measures and Al measures.
<Ceq≥0.31>
The represented Ceq of following formula (1) is the index of armor plate strength, has this to be worth the high more tendency of high strength more.In the present invention, for tensile strength reaches more than the 490MPa, and obtain excellent impact absorbency, and above-mentioned Ceq is defined as more than 0.31.Be preferably more than 0.33.Also have, the viewpoint from anti-crackle preferably is made as above-mentioned Ceq below 0.40.
Ceq＝C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4 ...(1)
{ in the formula (1), C, Si, Mn, Ni, Cr, Mo represent the content (quality %) of each element }
<Di*≤4.0>
The Di* of following formula (2) expression is the index of hardenability, and the high more hardenability of this value is high more.In the present invention, if hardenability improves and will need abovely, then have thick bainite to form in the cooling after hot rolling, maximum ferrite particle diameter becomes big and ductility reduces.Therefore, in the present invention, Di* is made as below 4.0.Be preferably below 3.8.
Di*＝C
0.5×(1+0.64Si)×(1+4.10Mn)×(1+2.33Cr)×(1+3.14Mo)×(1+0.27Cu)×(1+0.52Ni)×[1+1.5(0.90-C)×B
2] ...(2)
{ in the formula (2), C, Si, Mn, Cr, Mo, Cu, Ni, B represent the content (quality %) of each element }
That stipulates among the present invention contains element as mentioned above, and surplus is Fe and unavoidable impurities, as this unavoidable impurities, can allow because the sneaking into of the element that the situation of raw material, goods and materials, producing apparatus etc. is brought.In addition, also can further contain following element energetically.
＜from following group, select more than one:
Cu:0.35% following (not containing 0%),
Ni:0.40% following (not containing 0%),
Cr:0.20% following (not containing 0%) and
Mo:0.08% following (not containing 0%) 〉
These elements are the elements that work as negative term in the formula of the KMs that is stipulated by above-mentioned formula (3), are to make residual γ stable, to improving the balance effective elements of intensity and ductility.In order to make above-mentioned effect performance, the situation of preferred Cu is more than 0.1%, and the situation of Ni is more than 0.1%, and the situation of Cr is more than 0.02%, and the situation of Mo is more than 0.02%.On the other hand, if these elements excessively contain, more than then hardenability is brought up to and is needed, thickization of ferrite particle diameter, shock absorption can diminish.Therefore, preferred Cu is below 0.35%, and Ni is below 0.40%, and Cr is below 0.20%, and Mo is below 0.08%.
＜Ti:0.1% following (not containing 0%) 〉
<N≥0.292×Ti>
<Al≥1.93×N-0.564×Ti>
Ti forms TiN and improves HAZ toughness, is to guaranteeing excellent weldability effective elements.In order to make this effect performance, preferably make Ti contain (more preferably more than 0.005%) more than 0.002%.In addition, for the formation by above-mentioned TiN positively improves HAZ toughness, making the relation of Ti amount and N amount satisfy following formula (4), is effective thereby make the TiN granular.
N≥0.292×Ti …(4)
{ in the above-mentioned formula, N, Ti represent the content (quality %) of each element }
Shown in above-mentioned formula (4), by improving atomic ratio, can make TiN trickle with respect to the N of Ti, still, and if excessive solid solution N exists, HAZ toughness deterioration on the contrary then.Therefore in the present invention, for above-mentioned Ti and N, can Al be contained by the mode that satisfies following formula (5), N fixes as AlN with solid solution, and HAZ is further improved.
Al≥1.93×N-0.564×Ti …(5)
{ in the above-mentioned formula, Al, N, Ti represent the content (quality %) of each element }
On the other hand, if Ti is excessive contains, thickization of TiN then, HAZ toughness be deterioration easily on the contrary, and thus, preferred Ti amount is below 0.1%, more preferably below 0.05%, more preferably below 0.03%.
＜B:0.005% following (not containing 0%), and/or
Nb:0.05% following (not containing 0%) 〉
B, Nb are the hardenabilities that improves steel, make organizing of HAZ portion trickle, and HAZ toughness is improved, to guaranteeing excellent weldability effective elements.In order to make this effect performance, the situation of preferred B is more than 0.0003%, and the situation of Nb is more than 0.01%.But if B is excessive to be contained, then hardenability becomes too high, and thick bainite forms, and it is big that maximum ferrite particle diameter becomes.Therefore, B is below 0.005%.In addition,, then in mother metal, separate out, base metal tenacity and homogeneous are extended reduce as NbC if Nb is excessive to be contained.Therefore, Nb is below 0.05%.
＜from the group of Ca, Mg and REM formation, select more than one: (do not contain 0%) below 0.1% 〉
Ca, Mg, REM (rare earth element, La, Ce etc.) are to make the inclusion granular, and to improving HAZ toughness effective elements, if more than one that select from the group of Ca, Mg and REM formation are more than 0.001%, then this effect is given full play to.But because Ca, Mg, REM excessively exist, above-mentioned effect also only can be saturated, so they preferably add up to below 0.1%.
The present invention does not stipulate the manufacture method of above-mentioned steel plate, but obtains above-mentioned tissue in order to ensure ground, recommends with following condition manufacturing.
Final rolling temperature in the＜hot rolling: 700～850 ℃ 〉
Final rolling rate of compression in the＜hot rolling: more than 20% 〉
By making the granular of organizing after the hot rolling, can make the granular positively of organizing of resulting steel plate.If above-mentioned final rolling temperature is low excessively, then because can be rolling, so can not make the granular of organizing after the hot rolling in the ferrite transformation zone.Therefore, final rolling temperature is preferably (more preferably more than 720 ℃) more than 700 ℃.On the other hand, if final rolling temperature is too high, then rolling just intact back austenite restores, and recrystallize produces, so can not make the granular of organizing after the hot rolling.Therefore, final rolling temperature is preferably (more preferably below 800 ℃) below 850 ℃.
In addition, if finally do not implement sufficient processing when rolling, then can not bring austenite sufficient strain, can not make the granular of organizing after the hot rolling, therefore final rate of compression when rolling is made as (more preferably more than 40%) more than 20%.
Cooling after the＜hot rolling: 700 ℃ to 500 ℃ temperature provinces with 3 ℃/more than the s cooling
After the hot rolling, by carry out the 3 ℃/cooling of (more preferably 4.0 ℃/more than the s) more than the s 700 ℃ to 500 ℃ temperature province, can suppress the reduction of ferrite transformation temperature and the ferritic grain of phase transformation grows up, as a result of, can realize tissue, particularly the granular of average ferrite particle diameter.Also have, the upper limit of above-mentioned speed of cooling is not particularly limited, but in steel plate of the present invention, is limited on it about 30 ℃/s.
＜reheat temperature: keep more than three minutes still Tc1=80.67C+14.10Si+43.06Mn+29.73Cr-102.87Mo-21.07Cu-43.2 7Ni+729 at (Tc1-50 ℃)～(Tc1+50 ℃) 〉
By after above-mentioned hot rolling cooling, reheat is to the said temperature zone, perlite, bainite or the MA that can form by an above-mentioned hot-rolled process part, the ferrite of formation specified dimension and trickle second (spheroidite etc.) mutually.In addition, also effective to the formation of residual γ.In order to make the performance of this action effect, special recommendation is made as the reheat temperature more than (Tc1-50 ℃), more preferably more than (Tc1-40 ℃), and keeps (being preferably more than 10 minutes) more than three minutes in this temperature.
On the other hand, if the reheat temperature is too high, thickization of MA then, therefore base metal tenacity reduces is not preferred.Therefore be below (Tc1+50 ℃), more preferably below (Tc1+40 ℃).
Also have, in order to ensure retained austenite is that the TRIP phenomenon is occurred, to realize the further improvement of ductility and shock absorbing capability, be recommended in (Tc1+10 ℃)～temperature range of (Tc1+50 ℃) carries out above-mentioned reheat more than three minutes, cools off from 600 ℃ to 500 ℃ temperature province after this heating with the above speed of cooling of 2 ℃/s.By carrying out reheat, and make carbide or MA can partly become austenite,, can make residual γ remaining with room temperature by with above-mentioned speed cooling in this temperature province.
The present invention particularly is object with the Plate Steel, and more than the about 7mm of thickness of slab, the upper limit is not specially limited, but is generally the following degree of 60mm.
Below, enumerate embodiment and be described more specifically formation of the present invention and action effect, but the present invention is not limited by following embodiment certainly, yet can the scope of aim described later suitably be changed and implement before can be suitable for, and these all are contained in technical scope of the present invention.
[embodiment]
Melting and obtain the steel that the chemical ingredients shown in the table 1 forms (shape: 120mm * 170mm * 200mm).It, is carried out the rolling thickness of slab that makes of multiple tracks and become 60mm after 30 minutes with 1200 ℃ of heating, put afterwards and be chilled to 800 ℃, carry out the rolling thickness of slab of multiple tracks again and become the 30mm postcooling.Final rolling (finally rolling) together is with rate of compression: 50% implements.Final rolling temperature in table 2 expression final rolling (finally rolling) together, from the speed of cooling of this final temperature province of 700 ℃ to 500 ℃ after rolling.In addition, reheat after this hot rolling keeps certain hour (reheat temperature and hold-time are in table 2 expression) in this temperature, thereafter, and from of the speed cooling of 600 ℃ to 500 ℃ temperature provinces with table 2 expression.
Use the steel plate that obtains like this, carry out the observation of metal structure, and measure tensile properties, estimate impact absorbency with following main points.In addition, carry out base metal tenacity and the evaluation of HAZ flexible.
The observation of＜metal structure 〉
Metal structure, with the t/4 that can observe steel plate (after t is plate, below identical) mode of the C direction at position modulates sample, measures average ferrite particle diameter, maximum ferrite particle diameter, ferrite area occupied rate, second phase size with following main points, and the area occupied rate of residual γ.
Average ferrite particle diameter
Behind 3% nital corrosion sample, take multiplying power: 2000 times, the photo in 10 visuals field with scanning electron microscope.Try to achieve average ferrite particle diameter from this microphotograph with segment method (JISG 0552).
Maximum ferrite particle diameter
With ベ ラ Ha reagent (liquid component: Na
2S
2O
35H
2O ... 16g, K
2S
2O ... 3g, H
2O ... 94mL) behind the corrosion sample, with the opticmicroscope multiplying power: 400 times of photochromes of taking 10 visuals field, at the ferrite grain of same correlated area judging with the orientation, traced designs as crystal boundary in this border, (the system Image-pro of microcedia society) analyzes with image analysis software, measures the area of each ferrite grain.Then, therein with the diameter of equivalent circle of the ferrite grain of maximum as maximum ferrite particle diameter.
Ferrite area occupied rate
With 3% nital corrosive sample, with the opticmicroscope multiplying power: 400 times, take the photo in 10 visuals field, with the zone of waiting the axle shape of white as ferrite, trace designs mutually as second in other zone, with above-mentioned image analysis software it is analyzed, try to achieve ferritic area occupied rate (area %).
The average equivalent circular diameter of second phase
Will be with 3% nital corrosive sample, with the scanning electron microscope multiplying power: 2000 times, take the photo in 3 visuals field, with grey or white correlated zone as second phase, calculate diameter of equivalent circle from the area of each particle, with the average equivalent circular diameter of its mean value as second phase.
Retained austenite amount (γ R amount)
The retained austenite amount is tried to achieve by the saturation magnetization of measuring test portion.That is, at first, cut out L30mm * W4mm from the t/4 position of steel plate, the oxide film that it is surperficial grinds with sand paper and removes, and so makes test portion.Adopt direct current magnetometry device (Riken Densi K. K.'s system), make magnetic field positive pole, negative pole counter-rotating, the mean value of each saturation magnetization is tried to achieve it as the saturation magnetization of test portion (for the examination material) with externally-applied magnetic field: 4kOe.Then, the following formula of said determination value substitution (6) is tried to achieve retained austenite amount (γ R amount).
γR＝[(I-Im)/I]×100?...(6)
I: the saturation magnetization of standard test portion (gauss)
Im: the saturation magnetization (gauss) of test portion (for the examination material)
The mensuration of＜tensile properties and the evaluation of impact absorbency 〉
From the t/4 position of each steel plate, take No. 4 test films of JIS Z 2201 with respect to rolling direction in the direction at right angle, carry out tension test with the main points of JISZ 2241, measure yield-point (YP), tensile strength (TS), at the unit elongation (UE) of crest point.Then, estimate impact absorbency with TS * UE.Also have, to satisfying more than the above-mentioned TS:490MPa, and the above test portion of UE:15%, with TS * UE:9000 (MPa%) above be evaluated as the impact absorbency excellence.
The evaluation of＜base metal tenacity 〉
Take the V nick-break test sheet of JIS Z 2202 from the t/4 position of each steel plate, carry out pendulum impact test with the main points of JISZ 2242, measure break transition temperature (vTrs) and test temperature :-60 ℃ absorption can (vE
-60).Then, be below-60 ℃ and vE with vTrs
-60For the average evaluation more than the 150J is the base metal tenacity excellence.
＜HAZ flexible is estimated 〉
In experiment No.1 described later～15, carry out the evaluation of HAZ flexible.At first, near the heat affected zone the bonding wire of simulation when welding, (size: 12.5mm * 55mm * 120mm) is with Heating temperature: after 1350 ℃ of 5 seconds of heating, to cool off from 800 ℃ to 500 ℃ zone for 40 seconds to sample.Then,, downcut the test film of ISZ 2202, implement pendulum impact test, the determination test temperature :-20 ℃ absorption energy (vE-20) with the main points of JISZ 2242 from having implemented above-mentioned heat treated sample.Then vE
-20For the average evaluation more than the 100J is the HAZ tenacity excellent.
In table 3 and table 4, show these results.
[table 1]
※ surplus: iron and unavoidable impurities
[table 2]
[table 3]
[table 4]
Can carry out following investigation (also having the experiment No. during following No. represents) from table 1～4.
Satisfy No.1～11,16,17 of the prerequisite of the present invention's regulation, 25 steel plate, impact absorbency excellence, and base metal tenacity excellence.Particularly, contain No.4～11,25 of the residual γ of specified amount, impact absorbency and base metal tenacity and HAZ toughness are preferred as can be known, also have good weldability.With respect to this, No.12～15,18～21 less than the regulation of unabridged version invention have following defective respectively.
No.12 is because the C amount is excessive, so maximum ferrite particle diameter surpasses the upper limit, impact absorbency and base metal tenacity are all poor.No.13 for Si amount excessive, so become not only impact absorbency, and base metal tenacity and the also poor result of HAZ toughness.No.14 is because Mn quantity not sufficient and undercapacity.No.15 so maximum ferrite particle diameter surpasses the upper limit, consequently can not guarantee excellent impact absorbency because the Mn amount is excessive in addition.
No.18～21 are not condition manufacturings to recommend, thus the example of the tissue that can not get stipulating, and No.18 is because ferrite divides rate little, and second phase size is big, so impact absorbency and base metal tenacity are poor.
No.19,21 is because average ferrite particle diameter, maximum ferrite particle diameter are all big, and second phase size is also big, so impact absorbency and base metal tenacity deterioration.No.20 is because second phase size is excessive, so shock absorption row and base metal tenacity are poor.
No.22 is because maximum ferrite particle diameter is excessive, and No.23 is because average ferrite particle diameter is excessive, and No.24 is because ferrite divides rate little, so the impact absorbency inequality in addition.
Claims (12)
1, the steel plate of a kind of impact absorbency and base metal tenacity excellence is characterized in that,
In quality %, contain:
C：0.02～0.10％；
Si：0.05～0.50％；
Mn：1.0～1.6％；
Below the P:0.05%, but do not contain 0%;
Below the S:0.05%, but do not contain 0%;
Al：0.015～0.06％；
Below the N:0.01%, but do not contain 0%,
Surplus is made of iron and unavoidable impurities,
Ceq by following formula (1) expression is more than 0.31,
Di* by following formula (2) expression is below 4.0,
The metal structure of this steel plate satisfies:
In area %, ferritic occupation rate in metal structure: surpass 90%;
Average ferrite particle diameter: 3～12 μ m;
Maximum ferrite particle diameter: below the 40 μ m; And
The average equivalent circular diameter of second phase: below the 0.8 μ m,
The tensile strength of this steel plate is more than the 490MPa,
Ceq＝C+Si/24+Mn/6+Ni/40+Cr/5+Mo/4 ...(1)
Di*＝C
0.5×(1+0.64?Si)×(1+4.10?Mn)×(1+2.33Cr)×(1+3.14?Mo)×(1+0.27Cu)×(1+0.52Ni)×[1+1.5(0.90-C)×B
2]...(2)
In formula (1), (2), C, Si, Mn, Ni, Cr, Mo, Cu, B represent the content in quality % of each element.
2, steel plate according to claim 1 is characterized in that, is below 490 by the KMs of following formula (3) expression, and described second comprise 0.5～10% retained austenite mutually,
KMs＝-39Mn-10Cu-17Ni-20Cr-5Mo+550 …(3)
In the formula (3), Mn, Cu, Ni, Cr, Mo represent the content in quality % of each element.
3, steel plate according to claim 1 and 2 is characterized in that, in quality %, also contains more than a kind of selection from the group of following formation:
Below the Cu:0.35%, but do not contain 0%;
Below the Ni:0.40%, but do not contain 0%;
Below the Cr:0.20%, but do not contain 0%; And
Below the Mo:0.08%, but do not contain 0%.
4, steel plate according to claim 1 and 2 is characterized in that, in quality %, also contain below the Ti:0.1%, but do not contain 0%, and Ti, N and Al satisfy following formula (4) and (5),
N≥0.292×Ti …(4)
Al≥1.93×N-0.564×Ti …(5)
In formula (4), (5), N, Ti, Al represent the content in quality % of each element.
5, steel plate according to claim 3 is characterized in that, in quality %, also contain below the Ti:0.1%, but do not contain 0%, and Ti, N and Al satisfy following formula (4) and (5),
N≥0.292×Ti …(4)
Al≥1.93×N-0.564×Ti …(5)
In formula (4), (5), N, Ti, Al represent the content in quality % of each element.
6, according to each the described steel plate in the claim 1,2 and 5, it is characterized in that,, also contain in quality %:
Below the B:0.005%, but do not contain 0%; And/or
Below the Nb:0.05%, but do not contain 0%.
7, steel plate according to claim 3 is characterized in that, in quality %, also contains:
Below the B:0.005%, but do not contain 0%; And/or
Below the Nb:0.05%, but do not contain 0%.
8, steel plate according to claim 4 is characterized in that, in quality %, also contains:
Below the B:0.005%, but do not contain 0%; And/or
Below the Nb:0.05%, but do not contain 0%.
9, according to each the described steel plate in the claim 1,2,5,7 and 8, it is characterized in that, in quality %, also contain from the group that Ca, Mg and REM constitute, select more than a kind, and it adds up to below 0.1%, but does not comprise 0%.
10, steel plate according to claim 3 is characterized in that, in quality %, also contain from the group that Ca, Mg and REM constitute, select more than a kind, and it adds up to below 0.1%, but does not comprise 0%.
11, steel plate according to claim 4 is characterized in that, in quality %, also contain from the group that Ca, Mg and REM constitute, select more than a kind, and it adds up to below 0.1%, but does not comprise 0%.
12, steel plate according to claim 6 is characterized in that, in quality %, also contain from the group that Ca, Mg and REM constitute, select more than a kind, and it adds up to below 0.1%, but does not comprise 0%.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005362269 | 2005-12-15 | ||
| JP2005362269A JP4476923B2 (en) | 2005-12-15 | 2005-12-15 | Steel sheet with excellent impact absorption and base metal toughness |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1982490A CN1982490A (en) | 2007-06-20 |
| CN100441723C true CN100441723C (en) | 2008-12-10 |
Family
ID=38165328
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006101536562A Expired - Fee Related CN100441723C (en) | 2005-12-15 | 2006-09-12 | Steel having superior impact absorbency and toughness of parent material |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP4476923B2 (en) |
| KR (1) | KR100914590B1 (en) |
| CN (1) | CN100441723C (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100957907B1 (en) * | 2007-12-24 | 2010-05-13 | 주식회사 포스코 | High Strength Ferritic Steel Sheet having Excellent Yield Strength and Low Temperature Toughness and Manufacturing Method Thereof |
| JP5159296B2 (en) * | 2007-12-26 | 2013-03-06 | 株式会社神戸製鋼所 | Steel wire rod or bar for cold working, method for producing the same, and cold worked steel parts |
| JP5167917B2 (en) * | 2008-04-10 | 2013-03-21 | 新日鐵住金株式会社 | Barbusbau with excellent collision energy absorption capability |
| JP5953952B2 (en) | 2011-11-30 | 2016-07-20 | Ｊｆｅスチール株式会社 | Steel material excellent in impact resistance and method for producing the same |
| JP6160574B2 (en) * | 2014-07-31 | 2017-07-12 | Ｊｆｅスチール株式会社 | High-strength hot-rolled steel sheet excellent in strength-uniform elongation balance and method for producing the same |
| JP6641875B2 (en) * | 2015-10-21 | 2020-02-05 | 日本製鉄株式会社 | Low yield ratio steel sheet and method of manufacturing the same |
| JP6682988B2 (en) * | 2016-04-25 | 2020-04-15 | 日本製鉄株式会社 | High-tensile steel plate with excellent ductility and method of manufacturing the same |
| JP6771429B2 (en) | 2016-08-29 | 2020-10-21 | 株式会社神戸製鋼所 | Thick steel plate and its manufacturing method |
| CN110536973B (en) | 2018-03-16 | 2020-08-18 | 日本制铁株式会社 | Steel plate for cargo hold of coal/ore transport ship |
| KR102164112B1 (en) * | 2018-11-29 | 2020-10-12 | 주식회사 포스코 | High-strength steel sheet having excellent ductility and low-temperature toughness and method for manufacturing thereof |
| JP7056592B2 (en) | 2019-01-17 | 2022-04-19 | Ｊｆｅスチール株式会社 | Manufacturing specification determination method, manufacturing method, and manufacturing specification determination device for metal materials |
| KR102296840B1 (en) | 2019-12-16 | 2021-09-01 | 주식회사 포스코 | High strength steel material having excellent ductility and manufacturing method for the same |
| KR102236853B1 (en) | 2019-12-18 | 2021-04-06 | 주식회사 포스코 | Steel material having excellent strength and ductility and manufacturing method for the same |
| CN113832413B (en) * | 2020-06-23 | 2022-11-18 | 宝山钢铁股份有限公司 | Ultra-thick 800 MPa-grade quenched and tempered steel plate with excellent core low-temperature impact toughness and weldability and manufacturing method thereof |
| KR102484998B1 (en) | 2020-12-11 | 2023-01-05 | 주식회사 포스코 | High strength steel sheet having excellent ductility and method for manufacturing thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1025224C (en) * | 1989-11-16 | 1994-06-29 | 川崎制铁株式会社 | Cold-rolled high tonsion steel strip having excellent stretching and folding properties, and molten zinc coating steel strip, and process for manufacturing same |
| JPH11193438A (en) * | 1997-12-26 | 1999-07-21 | Nippon Steel Corp | Ship steel plate excellent in impact absorption |
| WO2004106571A1 (en) * | 2003-05-27 | 2004-12-09 | Nippon Steel Corporation | High strength thin steel sheet excellent in resistance to delayed fracture after forming and method for preparation thereof, and automobile parts requiring strength manufactured from high strength thin steel sheet |
| CN1648277A (en) * | 2004-01-29 | 2005-08-03 | 杰富意钢铁株式会社 | High strength steel sheet and method for manufacturing same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06287681A (en) * | 1993-02-02 | 1994-10-11 | Nippon Steel Corp | Low yield ratio and high fatigue strength thick steel plate good in toughness |
| JP3525849B2 (en) * | 2000-03-17 | 2004-05-10 | Ｊｆｅスチール株式会社 | Steel material excellent in collision resistance and method for producing the same |
-
2005
- 2005-12-15 JP JP2005362269A patent/JP4476923B2/en not_active Expired - Fee Related
-
2006
- 2006-09-12 CN CNB2006101536562A patent/CN100441723C/en not_active Expired - Fee Related
- 2006-12-14 KR KR1020060127762A patent/KR100914590B1/en active IP Right Grant
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1025224C (en) * | 1989-11-16 | 1994-06-29 | 川崎制铁株式会社 | Cold-rolled high tonsion steel strip having excellent stretching and folding properties, and molten zinc coating steel strip, and process for manufacturing same |
| JPH11193438A (en) * | 1997-12-26 | 1999-07-21 | Nippon Steel Corp | Ship steel plate excellent in impact absorption |
| WO2004106571A1 (en) * | 2003-05-27 | 2004-12-09 | Nippon Steel Corporation | High strength thin steel sheet excellent in resistance to delayed fracture after forming and method for preparation thereof, and automobile parts requiring strength manufactured from high strength thin steel sheet |
| CN1648277A (en) * | 2004-01-29 | 2005-08-03 | 杰富意钢铁株式会社 | High strength steel sheet and method for manufacturing same |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20070064274A (en) | 2007-06-20 |
| JP4476923B2 (en) | 2010-06-09 |
| CN1982490A (en) | 2007-06-20 |
| JP2007162101A (en) | 2007-06-28 |
| KR100914590B1 (en) | 2009-08-31 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100441723C (en) | Steel having superior impact absorbency and toughness of parent material | |
| US9212412B2 (en) | Lean duplex stainless steel excellent in corrosion resistance and toughness of weld heat affected zone | |
| JP4068950B2 (en) | High-strength steel sheet, warm-working method, and warm-worked high-strength member or parts | |
| KR102206319B1 (en) | Austenitic abrasion-resistant steel sheet | |
| JP4529872B2 (en) | High Mn steel material and manufacturing method thereof | |
| CN104854252B (en) | The steel plate of pole excellent in low temperature toughness | |
| CN103108974B (en) | High-strength hot rolled steel sheet having excellent toughness and method for producing same | |
| CN105008574B (en) | The steel plate and its manufacturing method of multi-layer welding connector CTOD characteristic goods | |
| CN101037757B (en) | Low yield ratio and high tension steel material excellent in toughness of weld heat-affected zone, and process for producing the same | |
| CN109136737A (en) | A kind of tensile strength 1100MPa grades of ultra-high strength and toughness steel and its manufacturing method | |
| KR101491228B1 (en) | High-strength thick steel plate with excellent drop weight characteristics | |
| CN101285150B (en) | Heavy plate excellent in haz toughness and mother plate toughness | |
| KR20130125821A (en) | Hot-rolled steel sheet and production method therefor | |
| KR101054601B1 (en) | High tensile steel sheet for high heat input welding with excellent low temperature toughness | |
| JP2008266735A (en) | Low yield ratio high tensile strength steel plate excellent in low temperature toughness of weld heat-affected zone and base material, and its manufacturing method | |
| CN101435050B (en) | Low temperature tenacity excellent low yield ratio high intensity steel plate for welding heat influenced part and mother plate, and manufacturing method thereof | |
| KR102092000B1 (en) | High-strength thick steel plate for structural use and manufacturing method therefor | |
| CN102741442A (en) | High-strength steel plate with excellent warm workability | |
| KR102307145B1 (en) | Low-temperature nickel-containing steel | |
| JP2011202269A (en) | High strength steel sheet having excellent warm workability | |
| KR102309124B1 (en) | Low-temperature nickel-containing steel | |
| JP2012229470A (en) | Steel sheet having excellent low temperature toughness and fracture toughness of welded joint and method for producing the same | |
| KR20070057027A (en) | Thick steel plate having superior toughness and reduced softening in weld heat-affected zone | |
| CN101086054A (en) | HAZ toughness excellent steel plate with less intensity reduce by heat processing after welding | |
| JP2017110249A (en) | Sour resistant steel plate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20081210 Termination date: 20200912 |