CN101787488A - The steel of the tenacity excellent of welding heat affected zone - Google Patents
The steel of the tenacity excellent of welding heat affected zone Download PDFInfo
- Publication number
- CN101787488A CN101787488A CN201010104997A CN201010104997A CN101787488A CN 101787488 A CN101787488 A CN 101787488A CN 201010104997 A CN201010104997 A CN 201010104997A CN 201010104997 A CN201010104997 A CN 201010104997A CN 101787488 A CN101787488 A CN 101787488A
- Authority
- CN
- China
- Prior art keywords
- inclusion
- steel
- cas
- cao
- haz
- 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
Images
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
- C22C38/14—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
- C22C38/002—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
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
Abstract
Steel of the present invention, satisfying specified chemical composition forms, and be dispersed with following inclusion: when the length of width maximum is made as inclusion big or small on the direction of the maximal projection length of the inclusion in the time of will be perpendicular to microscopic examination, its size is more than the 2 μ m, and this inclusion satisfies following formula (1) and formula (2).By formation like this, the generation of thick TiN is inhibited, the HAZ tenacity excellent.0.01≤[Ca]/[Al]≤0.50…(1)，0.08≤([CaO]+[CaS])/([Al
2O
3])≤1.80…(2)。Wherein, [Ca], [Al], [CaO], [CaS] and [Al
2O
3], represent Ca, Al, CaO, CaS and Al in the inclusion respectively
2O
3Content (quality %).
Description
Technical field
The present invention relates to the steel that welded structure was suitable for of bridge, high-rise and boats and ships etc., particularly the tenacity excellent of the heat affected zone (following only be called " HAZ ") after the large-line energy welding steel.
Background technology
In recent years, along with the maximization of above-mentioned various welded structures, the heavy wall of steel are pushed into, from the viewpoint of the reduction of manufacturing cost, the high efficiency of operation etc., weld heat input surpasses the such large-line energy welding of 400kJ/cm and is applied.
But, if carry out the large-line energy welding, then HAZ is kept back Xu Leng for a long time in pyritous austenite (γ) zone, γ when therefore heating grows up, cause this thickization of organizing that is generated as representative with thick ferrite (α) crystal grain in the process of cooling easily, have the problem of the easy deterioration of toughness of this part.From the viewpoint of security,, also can stablize and keep the technology of the toughness (hereinafter referred to as " HAZ " toughness) of HAZ high-levelly even then require a kind ofly in large-line energy welding.
As the method that is used to guarantee that the HAZ flexible is main, proposition has the γ crystal grain-growth pinning (being designated hereinafter simply as " γ pinning ") by the inclusion particle that comes autoxidisable substance, nitride, sulfide etc., generates the miniaturization of carrying out of organizing by the intracrystalline α that with the inclusion particle is starting point.As such technology, for example shown in Japanese Patent Publication 55-26164 number, proposition has following this technology: it is by making the fine TiN of dispersion in the steel as γ pinning particle, thereby be suppressed at thickization of carrying out the austenite crystal that large-line energy when welding produce in HAZ, to suppress HAZ flexible deterioration.But in this technology, except need be that the thick TiN of nuclear generates with the inclusion, so practical situation being that HAZ toughness may not be good carry out also not considering the inclusion morphology in the steel the reheat after the casting with suitable temperature.
On the other hand, also proposing in TOHKEMY 2001-98340 number has a technology, and it is suitably changed by the addition that makes Ti and N, and the dispersion state of TiN is suitably changed, and with thickization of inhibition austenite crystal, thereby suppresses HAZ flexible deterioration.But, only control the addition of Ti and N, in the process of molten steel solidification, the density unevenness one of Ti and N is being difficult to obtain the such problem of sufficient dispersion effect.Particularly finally solidifying portion etc., Ti and N multiviscosisty, thick TiN separates out in molten steel, so HAZ toughness deterioration on the contrary.
Summary of the invention
The present invention is in view of doing under this situation, and its purpose is, provides a kind of generation that suppresses thick TiN, the steel of HAZ tenacity excellent.
Can solve the steel of the present invention of above-mentioned problem, contain the C:0.02～0.15% (meaning of " quality % " respectively.Relate under the chemical ingredients same), Si:0.03～1.0%, Mn:1.0～2.0%, below the P:0.02%, S:0.0002～0.01%, Al:0.005～0.08%, Ti:0.003～0.03%, Ca:0.0003～0.005%, N:0.001～0.01% and below the O:0.004%, surplus is made of iron and inevitable impurity, and disperse following inclusion: when the length of width maximum is made as inclusion big or small on the direction of the maximal projection length of the inclusion in the time of will be perpendicular to microscopic examination, its size is more than the 2 μ m, and this inclusion satisfies following formula (1) and formula (2).
0.01≤[Ca]/[Al]≤0.50?????…(1)
0.08≤([CaO]+[CaS])/([Al
2O
3])≤1.80????…(2)
Wherein, [Ca], [Al], [CaO], [CaS] and [Al
2O
3], represent Ca, Al, CaO, CaS and Al in the inclusion respectively
2O
3Content (quality %).
Also have, the size of above-mentioned so-called inclusion, the meaning be with the vertical direction of maximal projection length of inclusion on, the length of the maximum part of width, its size can be measured at an easy rate by the picture processing of SEM and EPMA etc.In addition, [Ca], [Al], [CaO], [CaS] and [Al in following formula (1) and the formula (2)
2O
3], the meaning is that contained aforementioned size is the composition of the above whole inclusiones of 2 μ m in the mensuration steel, the content when converting as independent inclusion.In addition, the so-called dispersion, the meaning is that size is the above inclusiones of 2 μ m, roughly disperses such state in mother metal equably independently.
In steel of the present invention, as the form of inclusion, preferred described size is that the above Ti that contains of 2 μ m is the number that contains the Ti inclusion more than 10%, is below 7% of number of the whole inclusiones more than the 2 μ m for described size.
In steel of the present invention, also contain as inferior element also useful as required: (a) B:0.005% is following, Nb:0.06% following, V:0.1% is following, Cu:1.5% is following, Ni:3.5% is following, Cr:1.5% is following and at least a kind element of Mo:1.5% among following; (b) Zr:0.05% is following, REM:0.005% following and at least a kind element of Mg:0.005% among following, and by containing these elements, according to its kind, the characteristic of steel will be further improved.
According to the present invention, by being formed, chemical composition of steel includes in the suitable scope, and making the size with specified chemical composition composition is that the above inclusion of 2 μ m suitably disperses, the generation of the TiN that can either realize both having suppressed thick, realized the steel of the tough property improvement of welding heat affected zone (HAZ) again, such steel are extremely useful as the steel that are applied to welded structures such as bridge, high-rise and boats and ships.
Description of drawings
Fig. 1 is expression ([CaO]+[CaS])/([Al
2O
3]) with the graphic representation of the relation of fracture transition temperature vTrs.
Fig. 2 is the graphic representation that expression contains the relation of the ratio of Ti oxide compound and fracture transition temperature vTrs.
Fig. 3 is the explanatory view of form of the inclusion in the steel plate of expression No.25.
Fig. 4 is the explanatory view of form of the inclusion in the steel plate of expression No.27.
Fig. 5 is the explanatory view of form of the inclusion in the steel plate of expression No.35.
Fig. 6 is the explanatory view of form of the inclusion in the steel plate of expression No.37.
Embodiment
Present inventors influence HAZ toughness essential factor when welding for large-line energy, study from various angles.Its result distinguishes that the major cause of HAZ toughness deterioration is the thick existence that contains the Ti inclusion, and such Ti inclusion that contains mainly is TiN or TiO in molten steel solidification stage crystallization
2
For the essential factor that above-mentioned such thick generative process that contains the Ti inclusion and this inclusion make HAZ toughness deterioration, can carry out following consideration.At first, carry out deoxidation by add Al in molten steel, the result is the Al that is dispersed with the shape that is flattening (flat) in molten steel
2O
3Solid, produce solid δ mutually or the γ phase at liquidus temperature (for example below 1535 ℃) by the part of molten steel, Ti, N, S multiviscosisty in remaining liquid phase.Then, if surpass the solubility product of Ti and N, then with solid Al
2O
3For nuclear, TiN is separated out, and do not solidifying the S of portion multiviscosisty, thereby solidus temperature is reduced.Consider finally to grow up at the temperature province between liquidus line and the solidus curve (for example about 1535～1490 ℃) TiN.
Consider such formation mechanism, present inventors just are used for can either suppressing to contain the generation of Ti inclusion, can access the further research repeatedly of good HAZ flexible important document again.It found that, if suitably adjusting the chemical ingredients of steel (mother metal) forms, and satisfy the relation of following formula (1) and formula (2), and be dispersed with size with aforementioned manner definition and be the inclusion more than the 2 μ m, then can either suppress to contain the generation of Ti inclusion, can access good HAZ toughness again, thus the present invention fully.
0.01≤[Ca]/[Al]≤0.50????…(1)
0.08≤([CaO]+[CaS])/([Al
2O
3])≤1.80????…(2)
Wherein, [Ca], [Al], [CaO], [CaS] and [Al
2O
3], represent Ca, Al, CaO, CaS and Al in the inclusion respectively
2O
3Content (quality %).
In steel of the present invention, the dispersive inclusion need satisfy following formula (1) and formula (2), stipulates the reasons are as follows of these conditions.
[[Ca]/[Al]: 0.01～0.50, the relation of following formula (1)]
The promotion of revealing for the eutectic that suppresses inclusion and the eutectic of molten steel are revealed, in addition for the crystallization of the TiN that suppresses to cause because of CaS, and in order to obtain best (CaO) and (Al
2O
3) ratio, need control the interpolation ratio of Ca and Al.In order to obtain these effects, need [Ca]/[Al] is controlled in 0.01～0.50 the scope.If the value of [Ca]/[Al] is lower than 0.01, the inclusion eutectic is revealed, thick TiN crystallization makes HAZ toughness deterioration.On the other hand, if the value of [Ca]/[Al] surpasses 0.50, then except the cleanliness factor that makes steel reduces, be accompanied by the minimizing of the addition of Al, TiO
2Separate out, therefore make HAZ toughness deterioration.Also have, be limited to 0.40 on the value of [Ca]/[Al] preferred.
[([CaO]+[CaS])/([Al
2O
3]): 0.08～1.80, (relation of following formula (2))]
By being become, inclusion contained in the steel (being oxide based inclusion basically) contains CaO, CaS and Al
2O
3Complex inclusion, the inclusion eutectic is revealed, on the other hand because suppress the reduction of the fusing point of molten steel, so also can suppress the crystallization of thick TiN.And, because the separating out of CaS can be reduced the generative capacity from the TiN of the complex inclusion that contains Ca and Al, therefore can suppress the crystallization of thicker TiN.In order to bring into play these effects, need be ([CaO]+[CaS])/([Al of the inclusion more than the 2 μ m with size contained in the steel
2O
3]) value be controlled in 0.08～1.80 the scope.(if [CaO]+[CaS])/([Al
2O
3]) value be lower than 0.08, then inclusion fully eutectic reveal, in addition because the amount of separating out of CaS also is suppressed, so thick TiN crystallization makes HAZ toughness deterioration.On the other hand, if ([CaO]+[CaS])/([Al
2O
3]) value surpass 1.80, the cleanliness factor of steel is reduced, and must reduce Al addition, TiO
2The amount of separating out increase, therefore make HAZ toughness deterioration.Also has ([CaO]+[CaS])/([Al
2O
3]) value preferably be limited to 0.10 down, be limited to 1.1 on preferred.
In steel of the present invention, satisfy the inclusion (complex inclusion) of above-mentioned important document by suitable dispersion, can make HAZ toughness good, but as indicated in the above-mentioned aim, correspondingly, (for example except that TiN, also comprise TiO at the Ti inclusion that contains of TiN representative
2) among, preferably reducing its size as far as possible is the above thick inclusiones of 2 μ m.From this viewpoint, in steel of the present invention, as the form of inclusion, the size that preferably contains Ti and be more than 10% is the above numbers that contain the Ti inclusion of 2 μ m, is that size is below 7% of number of the above whole inclusion of 2 μ m.Also have,,, can not cause what influence HAZ toughness regardless of its number in fine like this containing in the Ti inclusion (particularly below the 0.5 μ m) of big or small less than 2 μ m.
About by making the inclusion that satisfies above-mentioned such important document disperse to make the good mechanism of HAZ toughness of steel, can be to its explanation of all being illustrated, if but also considering the formation mechanism of above-mentioned thick TiN, then can consider as follows.
If in molten steel, add Al, then aluminum oxide (Al
2O
3) form, but, then becoming complex inclusion at this moment if contain Ca simultaneously, fusing point reduces, and becomes liquid state.This state still can continue in the initial stage of solidifying of iron.If be in this state, even the nuclear that does not then also have to separate out during TiN separates out exists, separating out of TiN is suppressed.Thereafter, even TiN separates out, because iron is the state that solidifies, TiN can't thickization.
In addition, Al
2O
3Become solid with CaO and separate out (separating out), make the liquid phase multiviscosisty of S at iron from liquid phase.At this moment, as if the liquid phase multiviscosisty of S at iron, then iron becomes the state that is difficult to solidify.This state promotes thickization of TiN, but because there be (S becomes CaS) in CaS, so think that S does not have multiviscosisty, TiN is difficult to thickization.
In addition as can be known, CaS lattice match with respect to TiN poor (for example in September, 7 distribution is put down in " tissue that steel inclusion forms with the present situation of material control and the research of control mechanism " (society) Japanese iron and steel institute fundamental research meeting), think that CaS is difficult to become the crystallization point of TiN, also be because the existence of CaS, thereby become the reason that thickization of TiN is suppressed.
Want to realize the dispersion state of above-mentioned such inclusion, follow following step and make steel and get final product.At first, make Al concentration in the molten steel become 0.005～0.08% and after adding Al and carrying out deoxidation, implement deoxidation more than 10 minutes with device for deoxidizing (for example RH device).Thereafter, add Ti before finish to deoxidation 5 minutes, circulation is more than 1 minute thereafter.Finish to add Ca after the deoxidation, in each inclusion more than described size is 2 μ m, make Al
2O
3, MnS, MnO, CaO, CaS the quality (100%) of total in shared Al
2O
3, CaO and CaS the standard deviation of quality %, be respectively σ (Al
2O
3Cast behind)≤30 quality %, σ (CaO)≤15 quality % and σ (CaS)≤20 quality % and get final product.At this, described σ (Al
2O
3) looking like is, when investigating the inclusion of the majority in the steel, about the Al in each inclusion
2O
3Contain ratio (with respect to the Al in the inclusion
2O
3, MnS, MnO, CaO, CaS the quality % of total quality) the standard deviation of distribution.σ (CaO), σ (CaS) also are the same meanings.The composition of each inclusion can be investigated with this method that [composition measuring of inclusion] in the explanation of the embodiment of back set forth.Inclusion for majority carries out such mensuration, tries to achieve standard deviation by the data that obtain and gets final product.
Initial Al deoxidation power of adding is strong, combines with oxygen in the molten steel, forms Al
2O
3Then utilize de-gassing vessel to make thick Al
2O
3Float separation Deng impurity.To finishing before 5 minutes of the degassing extraction rate of Ti to be improved, circulation more than 1 minute thereafter, thus Ti is evenly dispersed in the molten steel.
After finishing the degassing, add Ca, make generate CaO and CaS in the molten steel after because Al
2O
3, CaO and CaS the standard deviation of quality % be respectively σ (Al
2O
3)≤30 quality %, σ (CaO)≤15 quality % and σ (CaS)≤20 quality %, CaO and CaS and Al
2O
3Combination equably, above-mentioned such (CaO+CaS) and Al
2O
3Have good equilibrated [relation of following formula (2)], contain Al
2O
3, CaO and Ca complex inclusion be formed.
Also have, when making steel of the present invention, though make with above-mentioned such condition in the stage of molten steel useful, in hot-rolled process, also preferred this condition of suitably control.That is, during the former material of hot-rolled steel (slab), its Heating temperature is preferably about 1000～1250 ℃.When this temperature is lower than 1000 ℃, in hot rolling, causes temperature and reduce, be difficult under suitable temperature, finish rolling, and be difficult to make casting flaw pressing in the slab.On the other hand, if this Heating temperature surpasses 1250 ℃, then thickization of austenite, and TiN be thickization also, so HAZ toughness deterioration.
Be heated to the slab of said temperature scope, then from Ar
3Transformation temperature is to (Ar
3Transformation temperature+100 ℃) temperature province, making the accumulation draft is to implement hot rolling more than 30% to get final product.Carry out hot rolling with above-mentioned such condition,, guarantee on the good base metal tenacity useful making the crystal grain diameter granular of steel.After above-mentioned condition end hot rolling, the speed of cooling of counting more than 3 ℃/second with the surface temperature of steel (steel plate) is cooled to below 500 ℃.The upper limit of rolling end temp is in the scope of above-mentioned Heating temperature.Also has above-mentioned so-called Ar
3Transformation temperature is the value of trying to achieve by following formula (3).
Ar
3Transformation temperature (℃)=868-369[C]+24.6[Si]-68.1[Mn]-36.1[Ni]-20.7[Cu]-24.8[Cr] ... (3)
Wherein, [C], [Si], [Mn], [Ni], [Cu] and [Cr] represent respectively the content (quality %) of C, Si, Mn, Ni, Cu and Cr when not adding alloying element, then not calculate this.
Next, describe with regard to the composition of the chemical ingredients in the Plate Steel of the present invention (mother metal).Steel of the present invention, even the dispersion state of inclusion is suitable, and if chemical composition of steel is formed not in proper range, then can not make the characteristic of mother metal and HAZ good.Therefore, in steel of the present invention, also need to make the amount of each chemical ingredients to be in the proper range as described below.Also have, among these compositions, form the content of the element (for example Al, Ca, Ti etc.) of inclusion, contain and constitute the amount that is mingled with so that its action effect is obvious.
(C：0.02～0.15％)
C is the element that is used to guarantee that the intensity of steel plate (mother metal) and weld part (welding metal) can not be short of.In order to bring into play such effect, the content of C need be for more than 0.02%.Be preferably more than 0.03%.But, therefore need be suppressed at (preferably below 0.13%) below 0.15% if C content surplus then makes HAZ toughness and weldability deterioration.
(Si：0.03～1.0％)
Si has desoxydatoin, and is effective elements on the intensity of mother metal and weld part improves.In order to bring into play such effect, Si is contained more than 0.03%, be preferably more than 0.05%.But if Si contained superfluously, the toughness deterioration of weldability and mother metal then therefore need be below 1.0%.Preferably below 0.7%.
(Mn：1.0～2.0％)
Mn is an effective elements on the intensity of mother metal and weld part improves, and in order to bring into play this effect effectively, need make it to contain more than 1.0%.Preferably contain more than 1.2%.If yet Mn content surplus, HAZ toughness and weldability deterioration therefore need be for below 2.0%.Preferably below 1.8%.
(P:0.02% is following)
P is the impurity element that is unavoidably contained in steel, if its content surpasses 0.02%, then HAZ flexible deterioration is remarkable, therefore need be suppressed at below 0.02%, preferably below 0.0015%.But, be difficult to make the P in the steel to reach 0% industrial.
(S：0.0002～0.01％)
S forms CaS and is bringing into play the effect of the generation that suppresses thick TiN.In order to bring into play this effect, need S content to contain more than 0.0002%.But if S content surplus, then a large amount of MnS that extend that generate, HAZ flexible deterioration is remarkable, therefore need be suppressed at below 0.01%, preferably below 0.008%.
(Al：0.005～0.08％)
Al is strong deoxidant element, and is few as if Al content, then TiO
2The a large amount of generation, so its content need still as if Al content surplus, then can not be guaranteed to form [preceding formula (2)] with (CaO+CaS) corresponding, so need be suppressed at below 0.08% for more than 0.005%.The preferred upper limit of Al content is 0.06%.
(Ti：0.003～0.03％)
Ti separates out as TiN in steel, thereby thickization that Austria of the HAZ that prevents in when welding owes body crystal grain promotes ferrite transformation, therefore is to improve the needed element of HAZ toughness.In order to bring into play such effect effectively, Ti need contain more than 0.003%, is preferably more than 0.005%.But if Ti is contained superfluously, then solid solution Ti amount increases, and separating out of TiC taken place, and make the toughness deterioration of mother metal and HAZ, so its content should be suppressed at below 0.03%.Preferably below 0.02%.
Ca：0.0003～0.005％
Ca is the element that accounts for center-stage in steel of the present invention, as CaOCaS and Al
2O
3Form complex inclusion together,, solid solution S reduced except making the inclusion eutectic reveals, thus the eutectic that suppresses steel reveal, therefore have the approaching effect of fusing point that makes inclusion and steel, can suppress the crystallization of thick TiN.In addition, because the separating out of CaS can be reduced the generative capacity from the TiN of the complex inclusion that contains Ca and Al, therefore can suppress the crystallization of thick TiN.In order to bring into play this this effect, Ca is contained more than 0.0003%.Be preferably more than 0.0005%.But, if Ca content surplus then makes the cleanliness factor of steel reduce, and when casting, produce the melting loss of casting nozzle, therefore need be for below 0.005%.Be preferably below 0.004%.
N：0.001～0.01％
N separates out as TiN in the steel tissue, suppresses thickization of the austenite crystal of HAZ, promotes ferrite transformation in addition, therefore is the element that makes the toughness raising of HAZ.In order to bring into play such effect, need N to contain more than 0.001%.Be preferably more than 0.003%.But if N content surplus, then solid solution N amount increases, and the toughness of HAZ is deterioration on the contrary.Thus, N content need be suppressed at below 0.01%, is preferably below 0.008%.
(O:0.004% is following)
O is the element that constitutes inclusion in the present invention, need manage.Surpass 0.004% superfluous like this O the cleanliness factor of steel is reduced, the thick inclusion that constitutes the destructive starting point is generated in a large number, base metal tenacity, HAZ toughness are reduced.Therefore be below 0.004%.Preferred below 0.003%.On the other hand, O content is few more to be preferred more, does not therefore need to set its lower limit, but has the limit in the reduction of industrial O, can contain more than 0.0005% usually.
The present invention regulation contain element as mentioned above, surplus is iron and unavoidable impurities, as this unavoidable impurities, can allow sneaking into of element (for example Co, Zn, the Pb etc.) that mix because of the situation of raw material, goods and materials, producing apparatus etc.In addition, it is also effective further to contain following element energetically, and according to the kind of the composition that is contained, the characteristic of steel plate is further improved.
(B:0.005% is following, Nb:0.06% following, V:0.1% is following, Cu:1.5% is following, Ni:3.5% is following, Cr:1.5% is following and the element at least a kind or more of Mo:1.5% among following)
B, Nb, V, Cu, Ni, Cr and Mo all are useful elements on the intensity that makes steel improves, and can make it to contain a kind or 2 kinds as required.Wherein, B improves the hardenability of steel, improves the intensity of mother metal and weld part, and when welding in the heated HAZ refrigerative process, combine with N and separates out BN, promote ferrite transformation in austenite crystal, so it is high that HAZ toughness is got.Such effect increases and increases along with its content, but in order to bring into play such effect effectively, preferably makes it to contain (more preferably more than 0.0005%) more than 0.0002%.But if B content surplus, then therefore the toughness of mother metal and HAZ and weldability deterioration are preferably below 0.005%.More preferably below 0.004%.
Nb is useful element improving on intensity and the base metal tenacity, and its effect increases and increases along with its content, but in order to bring into play such effect effectively, preferably makes it to contain more than 0.005%.But if Nb content surplus, then therefore the toughness deterioration of mother metal and HAZ preferably is suppressed at below 0.06%.
V is useful element improving on the intensity, and its effect increases and increases along with its content, but in order to bring into play such effect effectively, preferably makes it to contain more than 0.005%.If but V content surplus, then therefore HAZ toughness and weldability deterioration preferably are suppressed at below 0.1%.
Cu is in the hardenability that improves steel, and improving on the intensity is effective elements.This effect increases and increases along with its content, but in order to bring into play such effect effectively, preferably makes it to contain more than 0.05%.If but Cu content surplus, then therefore the toughness deterioration of mother metal and HAZ is estimated and is elected as below 1.5%.
Ni is useful element on intensity that improves steel and weld part and toughness, and its effect increases and increases along with its content, but in order to bring into play such effect effectively, preferably makes it to contain more than 0.05%.But, therefore, preferably be suppressed at below 3.5% from the viewpoint of economy if Ni content surplus then will become extremely expensive as structural steel.
Cr is an effective elements on the intensity that improves steel.This effect increases and increases along with its content, but in order to bring into play such effect effectively, preferably makes it to contain more than 0.01%.If but Cr content surplus, then therefore HAZ toughness deterioration is preferably below 1.5%.
Mo is an effective elements on intensity that improves steel and toughness.This effect increases and increases along with its content, but in order to bring into play such effect effectively, preferably makes it to contain more than 0.01%.If but Mo content surplus, then therefore HAZ toughness and weldability deterioration are preferably below 1.5%.
(Zr:0.05% is following, REM:0.005% following and at least a kind element of Mg:0.005% among following)
Zr, REM (rare earth element) and Mg are effective elements on the HAZ flexible improves, and can make it as required to contain more than a kind or 2 kinds.Wherein, Zr and REM form oxide compound to be disperseed imperceptibly, thereby HAZ toughness is improved.Such effect increases and increases along with its content, but in order to bring into play such effect effectively, preferably all makes it to contain more than 0.001%.But, if its content surplus then can not be kept (CaO+CaS)/(Al
2O
3) optimum balance, HAZ toughness deterioration.Thus, preferred Zr is below 0.05%, and REM is below 0.005%.Also have, in the present invention, so-called REM (rare earth element) is the meaning that contains lanthanon (15 elements from La to Ln) and Sc (scandium) and Y (yttrium).
Mg improves HAZ toughness by the miniaturization of crystal grain.Such effect increases and increases along with its content, but in order to bring into play such effect effectively, preferably makes it to contain more than 0.001%.But even contain Mg superfluously, its effect also is saturated, therefore is preferably below 0.005%.
Steel of the present invention be set at the former material of Plate Steel basically, but so-called Plate Steel are defined as JIS, and referring generally to thickness of slab is that 3.0mm is above.Steel of the present invention, even for thickness of slab is that Plate Steel such more than the 30mm carries out the heat input large-line energy welding such above 400kJ/cm, still demonstrate good HAZ toughness, therefore the steel plate that is applied to this thickness is preferred mode, but the thickness that is not limited to steel plate is more than the 30mm, does not also get rid of the steel plate that is applied to be lower than this thickness.
The Plate Steel that so obtains can use as the material of for example works of bridge, high-rise and boats and ships etc., and certainly much less little～middle heat input welds, even also can prevent the toughness deterioration of welding heat affected zone in the large-line energy welding.
[embodiment]
Below, illustrate in greater detail the present invention by embodiment, but following embodiment not limiting character of the present invention, the scope of aim described later also can suitably change enforcement before can meeting, and these all are included in the scope of technology of the present invention.
After the molten steel that chemical ingredients shown in the following table 1,2 is formed with continuous casting machine becomes slab, this slab is heated to 1000～1250 ℃, at Ar
3Transformation temperature～(Ar
3Transformation temperature+100 ℃) temperature province, making the accumulation draft is to implement hot rolling more than 30%, obtains the steel plate of thickness of slab 50mm.Also have, in table 1,2, REM is about 30% and to contain Ce be that the form of about 50% norium is added to contain La.Element is not added in "-" expression in the table 1 in addition.
[composition measuring of inclusion]
For each steel plate that obtains in the above described manner, observe its cross section (in the cross section of rolling direction and Surface Vertical) with Shimadzu Seisakusho Ltd.'s system " EPMA-8705 ", be inclusion more than the 2 μ m for the size of definition as described above, quantitative analysis becomes to be grouped into.At this moment viewpoint condition is to observe multiplying power: 100～400 times, and field of view: 10～70mm
2, the one-tenth of the wavelength dispersion quantitative spectrometric analysis inclusion central part by characteristic X-ray is grouped into.
At this moment analytic target element is Al, Mn, Si, Mg, Ca, Ti, Zr, Ni, Cu, V, S, Cr, REM, use known substance, try to achieve the X ray intensity of each element and the relation of concentration of element in advance and measure line, then quantitatively the X ray intensity that obtains by described inclusion and according to the concentration of element of quantitative each inclusion of described inspection amount line as inspection.Based on these measured values, follow following standard, measure CaS, CaO and Al
2O
3Content, and try to achieve [Ca]/[Al], ([CaO]+[CaS])/([Al
2O
3]) value (measuring method as described above).In addition, will contain Ti and be inclusion more than 10% and be defined as and contain the Ti inclusion, with its size be inclusion more than the 2 μ m as object, calculate this and contain Ti inclusion (measuring) shared ratio (%) in whole inclusion numbers by EPMA.
(1) calculating of CaS content: detected S combines with Mn is preferential, forms MnS, with respect to the S formation CaS of Mn surplus.
(2) calculating of CaO content: among the detected Ca, the Ca beyond the CaS exists as CaO.
(3) Al
2O
3The calculating of content: detected Al is all as Al
2O
3Exist.
[evaluation of HAZ flexible]
In order to estimate the toughness that the time is subjected to the HAZ of heat affecting in welding, be the large-line energy welding of 1000kJ/cm or 600kJ/cm for each steel plate simulation weld heat input, carry out the welding shown in following and reproduce test.
(1) weld heat input is 1000kJ/cm: heating keeps cooling off in 30 seconds after making the sample integral body of downcutting from slab become 1400 ℃.At this moment speed of cooling be adjusted into from 800～500 ℃ cooling time be 730 seconds.
(2) weld heat input is 600kJ/cm: heating keeps cooling off in 60 seconds after making the test portion integral body of downcutting from slab become 1400 ℃.At this moment speed of cooling be adjusted into from 800～500 ℃ cooling time be 500 seconds.
From cooled sample, the V nick-break test sheet of JIS Z 2202 that there is the otch of vertical incision on the plate surface that is extracted in the position of HAZ carries out pendulum impact test by the main points of JIS Z 2242, measures the disconnected alternating temperature degree vTrs (1 measured value) of fracture.Then, the disconnected alternating temperature degree vTrs of fracture be 0 ℃ to be evaluated as HAZ toughness good.
These results are presented in the following table 3,4 in the lump.In addition based on these results, ([CaO]+[CaS])/([Al
2O
3]) with being presented among Fig. 1 of the relation of fracture transition temperature vTrs, contain the ratio of Ti oxide compound and the relation of fracture transition temperature vTrs and be presented among Fig. 2.
[table 3]
[table 4]
Can carry out following investigation (also have, following No. represents the steel No. of table 1～4) by these results.The example of the important document of the present invention regulation is satisfied in No.1～34th, and chemical ingredients is formed, the dispersion of inclusion is suitable, can access good HAZ toughness as can be known.With respect to this, No.35～50th, the example of the important document of disengaging the present invention regulation, HAZ toughness deterioration as can be known.
For accessing the good HAZ flexible steel plate (No.2,3,26) and the steel plate (No.47) of HAZ toughness deterioration, each the composition (Al before just casting in the inclusion
2O
3, MnS, MnO, CaS, CaO) standard deviation investigate.Its result is presented in the following table 5, demonstrates good HAZ flexible, and each composition before can confirming to cast in the inclusion is in the interior [σ (Al of scope of regulation
2O
3)≤30 quality %, σ (CaO)≤15 quality % and σ (CaS)≤20 quality %], CaO and CaS and Al
2O
3Combination equably.With respect to this, the HAZ deterioration break away from above-mentioned scope as can be known.
[table 5]
For accessing the good HAZ flexible steel plate (No.2,3,11,13) and the steel plate (No.35,36) of HAZ toughness deterioration, be that the individual number density of the following TiN of 0.5 μ m is investigated with regard to size.Its result is presented in the following table 6, and the individual number density of fine as can be known TiN has no impact to HAZ toughness.
[table 6]
| Steel No. | TiN number density (individual * 10 7) |
| ??2 | ??0.36 |
| ??3 | ??1.30 |
| ??11 | ??0.93 |
| ??13 | ??1.12 |
| ??35 | ??0.58 |
| ??36 | ??0.52 |
Among each above-mentioned steel plate, the form of getting its representational demonstration inclusion.Fig. 3 represents the form [Fig. 3 (a) is for drawing substitutes microphotograph, and Fig. 3 (b) is the explanatory view that medelling ground shows the form of inclusion] of the inclusion in the steel plate of No.25.The part of representing with the reference marks 1 of Fig. 3 (a) is CaO:36%, CaS:29%, Al
2O
3: SiO 63%,
2: 1% part, the part of representing with reference marks 2 is CaO:24%, CaS:6%, MgO:2%, Al
2O
3: 68% part.
Fig. 4 represents the form [Fig. 4 (a) is for drawing substitutes microphotograph, and Fig. 4 (b) is the explanatory view that medelling ground shows the form of inclusion] of the inclusion in the steel plate of No.27.The part of representing with the reference marks 1 of Fig. 4 (a) is MnO:2%, CaS:76%, CaO:19%, Al
2O
3: 3% part, the part of representing with reference marks 2 is CaO:38%, CaS:4%, Al
2O
3: 57% part, the part of representing with reference marks 3 is MnO:1%, CaO:23%, CaS:18%, Al
2O
3: TiO 20%,
2: 38% part.
Fig. 5 represents the form [Fig. 5 (a) is for drawing substitutes microphotograph, and Fig. 5 (b) is the explanatory view that medelling ground shows the form of inclusion] of the inclusion in the steel plate of No.35.The part of representing with the reference marks 1 of Fig. 5 (a) is the part of TiN:100%, and the part of representing with reference marks 2 is MgO:13%, Al
2O
3: the part of TiN:1% 85%.
Fig. 6 represents the form [Fig. 6 (a) is for drawing substitutes microphotograph, and Fig. 6 (b) is the explanatory view that medelling ground shows the form of inclusion] of the inclusion in the steel plate of No.37.The part of representing with the reference marks 1 of Fig. 6 (a) is MnO:10%, CaO:46%, CaS:2%, MgO:2%, Al
2O
3: SiO 26%,
2: TiO 11%,
2: 2% part, the part of representing with reference marks 2 is MnO:4%, CaO:13%, MgO:1%, Al
2O
3: SiO 7%,
2: TiO 4%,
2: 71% part.
Claims (4)
1. steel, it is characterized in that, in quality % contain C:0.02～0.15%, Si:0.03～1.0%, Mn:1.0～2.0%, below the P:0.02%, S:0.0002～0.01%, Al:0.005～0.08%, Ti:0.003～0.03%, Ca:0.0003～0.005%, N:0.001～0.01% and below the O:0.004%, surplus is iron and inevitable impurity
And disperse following inclusion: when the length of width maximum was made as inclusion big or small on the direction of the maximal projection length of the inclusion in the time of will be perpendicular to microscopic examination, its size was more than the 2 μ m, and this inclusion satisfies following formula (1) and formula (2),
0.01≤[Ca]/[Al]≤0.50??…(1)
0.08≤([CaO]+[CaS])/([Al
2O
3])≤1.80??…(2)
Wherein, [Ca], [Al], [CaO], [CaS] and [Al
2O
3], represent Ca, Al, CaO, CaS and Al in the inclusion respectively
2O
3Mass percentage content.
2. steel according to claim 1 is characterized in that, containing Ti in quality % is containing in the Ti inclusion more than 10%, and described size is that the above number of 2 μ m accounts for below 7% of number that described size is the above whole inclusiones of 2 μ m.
3. steel according to claim 1 and 2, it is characterized in that at least a kind of element that also contains below B:0.005%, below the Nb:0.06%, below the V:0.1%, below the Cu:1.5%, below the Ni:3.5%, below the Cr:1.5% and select below the Mo:1.5% in quality %.
4. steel according to claim 1 and 2 is characterized in that, also contain at least a kind of element below the Zr:0.05%, below the REM:0.005% and in below the Mg:0.005% in quality %.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2009017094A JP5432539B2 (en) | 2009-01-28 | 2009-01-28 | Steel with excellent toughness in weld heat affected zone |
| JP2009-017094 | 2009-01-28 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101787488A true CN101787488A (en) | 2010-07-28 |
| CN101787488B CN101787488B (en) | 2012-02-01 |
Family
ID=42530864
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010101049977A Expired - Fee Related CN101787488B (en) | 2009-01-28 | 2010-01-27 | Steel material of a welding heat effect part with excellent toughness |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP5432539B2 (en) |
| KR (1) | KR101164729B1 (en) |
| CN (1) | CN101787488B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102994872A (en) * | 2011-09-13 | 2013-03-27 | 株式会社神户制钢所 | Steel excellent in toughness of base metal and weld-heat affected zone and method for manufacturing the same |
| CN103361549A (en) * | 2012-03-30 | 2013-10-23 | 株式会社神户制钢所 | Steel plate with excellent hydrogen induced cracking resistance, and manufacturing method of the same |
| CN103890209A (en) * | 2011-10-20 | 2014-06-25 | 新日铁住金株式会社 | Bearing steel and method for producing same |
| CN104593641A (en) * | 2014-05-23 | 2015-05-06 | 无锡市乾丰锻造有限公司 | Novel high-strength iron-aluminum alloy forging material |
| CN109321818A (en) * | 2017-07-31 | 2019-02-12 | 东北大学 | It is a kind of easily to weld high temperature hot rolling thick steel plate and preparation method thereof |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5824434B2 (en) * | 2011-11-14 | 2015-11-25 | 株式会社神戸製鋼所 | Thick steel plate with excellent toughness in weld heat affected zone |
| CN105088072B (en) * | 2015-08-27 | 2018-05-25 | 舞阳钢铁有限责任公司 | A kind of high input energy welding steel plate and its production method |
| WO2017135179A1 (en) * | 2016-02-03 | 2017-08-10 | Ｊｆｅスチール株式会社 | Steel for high heat input welding |
| JP7272471B2 (en) * | 2020-09-30 | 2023-05-12 | Ｊｆｅスチール株式会社 | steel plate |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3502822B2 (en) * | 2000-02-10 | 2004-03-02 | 新日本製鐵株式会社 | Steel material excellent in toughness of welded heat-affected zone and method for producing the same |
| JP4821051B2 (en) * | 2001-04-19 | 2011-11-24 | Ｊｆｅスチール株式会社 | High tensile strength steel for low temperature welded structure with excellent weld heat affected zone toughness |
| JP4035990B2 (en) * | 2001-12-13 | 2008-01-23 | Ｊｆｅスチール株式会社 | Super high heat input welding HAZ toughness and low yield ratio steel plate for building structure and method for producing the same |
| JP4379620B2 (en) * | 2005-07-25 | 2009-12-09 | 住友金属工業株式会社 | Steel material for welded structure excellent in toughness of weld heat-affected zone and manufacturing method thereof |
| JP4295315B2 (en) * | 2006-12-28 | 2009-07-15 | 株式会社神戸製鋼所 | Steel sheet with excellent toughness of weld heat affected zone in super large heat input welding |
| JP4969275B2 (en) | 2007-03-12 | 2012-07-04 | 株式会社神戸製鋼所 | High tensile steel plate with excellent toughness of weld heat affected zone |
| JP2009179844A (en) * | 2008-01-30 | 2009-08-13 | Kobe Steel Ltd | High tensile strength thick steel plate having excellent toughness in weld heat affected zone |
-
2009
- 2009-01-28 JP JP2009017094A patent/JP5432539B2/en not_active Expired - Fee Related
-
2010
- 2010-01-27 KR KR1020100007499A patent/KR101164729B1/en active IP Right Grant
- 2010-01-27 CN CN2010101049977A patent/CN101787488B/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102994872A (en) * | 2011-09-13 | 2013-03-27 | 株式会社神户制钢所 | Steel excellent in toughness of base metal and weld-heat affected zone and method for manufacturing the same |
| CN102994872B (en) * | 2011-09-13 | 2016-02-24 | 株式会社神户制钢所 | The steel of the tenacity excellent of mother metal and welding heat affected zone and manufacture method thereof |
| CN103890209A (en) * | 2011-10-20 | 2014-06-25 | 新日铁住金株式会社 | Bearing steel and method for producing same |
| CN103890209B (en) * | 2011-10-20 | 2015-11-25 | 新日铁住金株式会社 | Bearing steel and manufacture method thereof |
| US9732407B2 (en) | 2011-10-20 | 2017-08-15 | Nippon Steel & Sumitomo Metal Corporation | Bearing steel and method for producing same |
| CN103361549A (en) * | 2012-03-30 | 2013-10-23 | 株式会社神户制钢所 | Steel plate with excellent hydrogen induced cracking resistance, and manufacturing method of the same |
| CN104593641A (en) * | 2014-05-23 | 2015-05-06 | 无锡市乾丰锻造有限公司 | Novel high-strength iron-aluminum alloy forging material |
| CN109321818A (en) * | 2017-07-31 | 2019-02-12 | 东北大学 | It is a kind of easily to weld high temperature hot rolling thick steel plate and preparation method thereof |
| CN109321818B (en) * | 2017-07-31 | 2020-08-28 | 东北大学 | Easily-welded high-temperature hot-rolled thick steel plate and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JP5432539B2 (en) | 2014-03-05 |
| JP2010174314A (en) | 2010-08-12 |
| KR20100087677A (en) | 2010-08-05 |
| CN101787488B (en) | 2012-02-01 |
| KR101164729B1 (en) | 2012-07-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101787488B (en) | Steel material of a welding heat effect part with excellent toughness | |
| CN101925685B (en) | High-strength thick steel products excellent in toughness and weldability, high-strength ultra-thick h shape steel and processes for manufacturing both | |
| CN103874777B (en) | The high-tensile steel of the excellent in low temperature toughness of welding heat affected zone and its manufacture method | |
| CN100535165C (en) | Large volume heat inputing in the welding tie-in tenacity excellent thick steel plate | |
| CN101037757B (en) | Low yield ratio and high tension steel material excellent in toughness of weld heat-affected zone, and process for producing the same | |
| CN103361549A (en) | Steel plate with excellent hydrogen induced cracking resistance, and manufacturing method of the same | |
| CN101182618B (en) | Tenacity excellent high intensity steel for welding heat influenced part | |
| JP4035990B2 (en) | Super high heat input welding HAZ toughness and low yield ratio steel plate for building structure and method for producing the same | |
| EP2784168B1 (en) | Steel material for welding | |
| CN103103440A (en) | Steel plate with excellent toughness in heat-affected zone | |
| CN101724780B (en) | Thick steel plate | |
| CN102251175B (en) | Thick steel plate | |
| CN101760695B (en) | Thick steel plate | |
| CN101845590A (en) | The steel of the good-toughness of welding heat affected zone | |
| JP7099653B1 (en) | Steel plate and its manufacturing method | |
| CN101497967B (en) | High tension steel plate with excellent weldability | |
| JP7469714B2 (en) | Steel | |
| US9403242B2 (en) | Steel for welding | |
| KR101260065B1 (en) | Steel for structure and manufacturing method of it | |
| CN101528963B (en) | Ferritic stainless steel having excellent formability of welded zone and corrosion resistance, and method for manufacturing the same | |
| JP4039223B2 (en) | Thick steel plate with excellent super tough heat input weld heat affected zone toughness and method for producing the same | |
| TWI788143B (en) | Precipitation-hardened Asada loose iron-based stainless steel with excellent fatigue resistance | |
| JP3941596B2 (en) | Manufacturing method of steel plate for building structure | |
| JP3736484B2 (en) | A method for producing a steel plate for building structures with a low yield ratio and excellent in heat-affected zone toughness of super large heat input welding. | |
| JP2023148714A (en) | High strength thick steel plate and manufacturing method thereof |
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: 20120201 Termination date: 20210127 |