CN101210300A - Toughness excellent steel plate of welding heat influence part in ultra-high heat input welding - Google Patents

Toughness excellent steel plate of welding heat influence part in ultra-high heat input welding Download PDF

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CN101210300A
CN101210300A CNA2007101693017A CN200710169301A CN101210300A CN 101210300 A CN101210300 A CN 101210300A CN A2007101693017 A CNA2007101693017 A CN A2007101693017A CN 200710169301 A CN200710169301 A CN 200710169301A CN 101210300 A CN101210300 A CN 101210300A
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steel plate
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welding
haz toughness
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CN100494455C (en
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高冈宏行
冈崎喜臣
武田裕之
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Kobe Steel Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • 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
    • 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
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium

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  • 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

Provided is a steel plate capable of full playing excellent HAZ toughness when implementing superrelevation hot input soldering with above 60 kJ/mm of welding heat energy, moreover even though implementing soldering with larger heat energy such as above 15kJ/mm of welding heat energy. The steel plate of the present invention controls chemical constituent composition suitably and meets the relations as follows: 1.0 <= [Ti]/[N] <= 2.5......(1) wherein [Ti] and [N] represent content of Ti and N (by weight) separately; 2.0 <= 1000 * ([Ca] + 2 * [S] + 3 * [O]) <= 10.0...... (2) wherein [Ca], [S] and [O] represent the content of Ca, S and O (by weight) separately, 0.1 <= [1000 * ([Ca] + 2 * [S] + 3 * [O])/(solidification cooling speed) <= 100.0...... (3), wherein the solidification cooling speed represents average cooling speed (DEG C/s) when the steel plate solidifying.

Description

The steel plate of the tenacity excellent of the welding heat affected zone in the excessive heat input welding
Technical field
The present invention relates to the steel plate that welded structure was suitable for of boats and ships, building, marine structure etc., relate in particular to the steel plate of the tenacity excellent at the position (hereinafter referred to as " HAZ ") that when carrying out excessive heat input welding, is subjected to heat affecting.
Background technology
The works in each field such as boats and ships, building, marine structure, by welding steel are engaged to construct to form, but in the employed steel of this works the viewpoint of guaranteeing from security, certainly much less steel strength but also requires the toughness of weldability also good.
In recent years, along with the maximization of welded structure, the viewpoint from the reduction of the raising of the operating efficiency of works and construction cost just requires the raising of welding procedure efficient, and this has pointed to the increase of welding heat energy.It is the tendency that the above such excessive heat input of 60kJ/mm is welded that enforcement welding heat energy is particularly arranged.
When implementing above-mentioned this excessive heat input welding, the HAZ[that is subjected to heat affecting of welding base metal (as the steel plate of soldered material) is compared with the interface (fusion portion) of welding metal and mother metal, and the mother metal side is counted the position of mm] toughness become problem.This HAZ is in when welding, and mother metal is exposed under the high temperature under the fluxing point, and the easy chap of the austenite crystal in the metal structure is big, and because the increase of welding heat energy causes speed of cooling also to slow down, therefore easily forms thick tissue.This point becomes reason, thereby has HAZ toughness to reduce such problem easily.
The steel plate that is suppressed as the HAZ toughness deterioration when adopting high heat energy welding process, up to now also proposed multiple, for example in the patent documentation 1,2, proposition has a kind of HAZ of improvement flexible technology, it is to make that TiN is fine to be dispersed with in the steel plate, and make that MnS is compound to separate out, suppress thickization of austenite crystal.In patent documentation 3,4, the Ti oxide compound is fine separates out by making in proposition in addition, its karyogenesis point as ferrite transformation is used, thereby improves near the flexible technology of welding fusion portion.
In patent documentation 5, proposing has a kind of HAZ of improvement flexible technology, and it is in the process of cooling when welding, the BN that separates out on the TiN etc. is used as the karyogenesis point of ferrite transformation, to improve HAZ toughness.
We also know, if solid solution N crosses HAZ toughness deterioration at most, for the improvement of HAZ generally will realize low Nization (for example, non-patent literature 1).In addition in patent documentation 6, also propose to have a kind of technology that HAZ toughness in the excessive heat input welding is improved, it is from thorough this viewpoint of reduction solid solution N, by the Al that contains Ti and fully measure, again the Ca oxide compound is applied flexibly as fine oxide, thus the HAZ toughness in the raising excessive heat input welding.
On the other hand, in patent documentation 7, also propose to have by applying flexibly CaS, thereby realize that the HAZ flexible in the high heat energy welding improves.
[patent documentation 1] spy opens flat 2-250917 communique
[patent documentation 2] spy opens flat 2-254118 communique
[patent documentation 3] spy opens clear 60-245768 communique
[patent documentation 4] spy opens clear 61-79745 communique
[patent documentation 5] spy opens clear 61-253344 communique
[patent documentation 6] spy opens the 2001-107177 communique
[patent documentation 7] spy opens the 2001-356379 communique
[non-patent literature 1] Institute of Welding's collection of thesis, vol.13, No.4, P758-766, (in November, 1985 distribution)
Yet any one technology that is proposed is up to now improved HAZ toughness with all failing essence, and there is following problems respectively in it.
In making the fine technology that is dispersed in the steel of TiN (described patent documentation 1,2,5), when carrying out the welding of high heat energy, because will be near the welding fusion portion by the high temperature long-time heating, so the TiN fusion, thickization that can not suppress crystal grain, practical situation are to obtain good HAZ toughness.
In making the fine dispersive technology of Ti oxide compound (described patent documentation 3,4) in addition because it is difficult especially that oxide compound is dispersed in the steel equably, can not make the good such problem of HAZ toughness so exist.In the technology that reduces solid solution N (described patent documentation 6, non-patent literature 1), if contain superfluous ground Ti, then cause solid solution N amount to increase, there is the embrittlement tissue to generate such problem on the contrary.
In addition, in applying flexibly the technology of CaS (described patent documentation 7), CaS is thicker, and HAZ toughness is improved.Also have, in this technology,, the synergy of its ferrite generation energy that brings with TiN fully can not be applied flexibly, still have the HAZ tough property improvement effect insufficient such problem of high heat energy in welding though also consider and use TiN.
Summary of the invention
The present invention forms in order to solve these problems of the prior art, it is a kind of not only when to weld heat energy be excessive heat input welding more than the 60kJ/mm that its purpose is to provide, even when for example welding heat energy and be the bigger welding of heat energy more than the 15kJ/mm, all can bring into play excellent HAZ flexible steel plate.
The so-called steel plate of the present invention that can reach above-mentioned purpose has following some main idea: contain the C:0.03～0.10% (meaning of quality % respectively, down with), Si:0.50% following (containing 0%), Mn:1.0～2.0%, P:0.015% following (not containing 0%), S:0.0010% following (not containing 0%), Al:0.005～0.060%, Ti:0.008～0.030%, N:0.0050～0.010%, Ca:0.0015～0.0035% and O:0.0015% following (not containing 0%), and satisfy relation respectively by following (1)～(3) defined.
1.0≤[Ti]/[N]≤2.5 …(1)
Wherein, [Ti] and [N] represents the content (quality %) of Ti and N respectively.
2.0≤1000×([Ca]+2×[S]+3×[O])≤10.0 …(2)
Wherein, [Ca], [S] and [O] represent the content (quality %) of Ca, S and O respectively.
0.1≤[1000 * ([Ca]+2 * [S]+3 * [O])]/(solidification cooling)
≤100.0 …(3)
Wherein, solidification cooling: the average cooling rate (℃/second) when steel plate solidifies during the expression casting.
In steel plate of the present invention, contain as inferior element also effective as required: (a) B:0.0035% following (not containing 0%); (b) below Cu:2%, (do not contain 0%), (do not contain 0%) below the Ni:2% and (do not contain 0%) below the Cr:1.5% more than a kind of selection the group who is constituted; (c) Mo:0.5% following (not containing 0%); (d) Nb:0.035% following (not containing 0%) and/or V:0.1% following (not containing 0%); (e) Mg:0.005% following (not containing 0%); (f) Zr:0.1% following (not containing 0%) and/or Hf:0.05% following (not containing 0%); (g) Co:2.5% following (not containing 0%) and/or W:2.5% following (not containing 0%); (h) REM:0.010% following (not containing 0%) can further improve the characteristic of steel plate according to the composition that these contained.
In steel plate of the present invention, about the element that HAZ toughness is impacted, by making it to satisfy the relational expression of regulation, tight simultaneously regulation chemical ingredients is formed and suitableization of realization, then can realize having given play to good HAZ flexible steel plate, this steel plate is extremely useful as the former material of various building structures etc.
Description of drawings
Fig. 1 is the extracting position of pendulum impact test sheet is extracted in expression from weld part diagrammatic illustration figure.
Embodiment
Present inventors study from various angles for carrying out influencing HAZ flexible essential factor when the excessive heat input is welded repeatedly in order to reach above-mentioned problem.Its result obtains as drawing a conclusion: the HAZ toughness of steel plate is subjected to the influence whether the embrittlement tissue generates to a great extent, and the generation of this embrittlement tissue can prevent by suppressing austenitic thickization in the heat zone and make the phase transformation that promotes ferrite transformation examine fine dispersion when the cooling.In the past, thought, so can not make HAZ toughness stable good because these factors are insufficient.
Therefore, present inventors examine fine dispersion in order to make ferrite transformation, CaS, the TiN of the solidification stages of applying flexibly when casting effectively and with its as this imagination of caryogenic MnS under further research repeatedly.CaS, TiN can Individual existences, also can exist with compound the separating out of MnS, but in order to make their fine dispersions the ferrite product nucleus is disperseed in a large number, then as can be known on the basis that the chemical ingredients of suitably adjusting steel plate is formed, the relation that satisfies following formula (1) and (2) is effective.In addition, because CaS can crystallization under higher temperature, so the speed of cooling during for casting takes in also very important.If this solidification cooling is slow, then thickization of CaS can not make the ferrite product nucleus increase, and therefore needed MIN speed of cooling is stipulated by following formula (3).
In the past, because solid solution N can cause toughness to reduce, therefore generally can realize low Nization (described non-patent literature 1), but in the present invention, by also using CaS, can reduce [Ti]/influence of the solid solution N that [N] change when reducing (energetically high Nization) is Duoed, and TiN self being also by fine dispersion, is emphasis for the point of the tough property improvement of HAZ.Stipulate following (1)～(3) formula from this viewpoint, stipulate the reasons are as follows of these formula.
1.0≤[Ti]/[N]≤2.5 …(1)
Wherein, [Ti] and [N] represents the content (quality %) of Ti and N respectively.
In order to disperse TiN imperceptibly,, need make the interpolation balance of Ti and N be in this scope so that the ferrite core product nucleus generates in a large number.By adjusting balance for this reason, the ferrite product nucleus of CaS, MnS etc. is increased, can guarantee HAZ toughness good under the superelevation heat energy.If the value (hereinafter referred to as " P value ") of [Ti]/[N] is above 2.5, thickization of TiN then, if be lower than 1.0, then TiN self growing amount tails off.From this viewpoint and regulation following formula (1).Also have, the value preferred lower limit of [Ti]/[N] is 1.5, and preferred upper limit is 2.0.
2.0≤1000×([Ca]+2×[S]+3×[O])≤10.0 …(2)
Wherein, [Ca], [S] and [O] represent the content (quality %) of Ca, S and O respectively.
0.1≤[1000 * ([Ca]+2 * [S]+3 * [O])]/(solidification cooling)
≤100.0 …(3)
Wherein, solidification cooling: the average cooling rate (℃/second) when steel plate solidifies during the expression casting.
After the solidification stages CaO of steel plate generates, be used to make the fine dispersion conditions needed of CaO by above-mentioned formula (2) and formula (3) expression.With respect to " coefficient " of each composition, represent that each unit have and in the use level of CaS miniaturization, tries to achieve according to experiment.
In the scope of specified chemical composition of the present invention, it is strong to represent that by the order of Ca, S and O high-density makes it the dispersive tendency.Be set in 2.0～10.0 scope by value (hereinafter referred to as " Q " value), can import in a large number guaranteeing the effective ferrite product nucleus of HAZ toughness under the superelevation heat energy, thereby obtain good HAZ toughness [1000 * ([Ca]+2 * [S]+3 * [O])].
In addition, because dispersion state also can be subjected to the influence of speed of cooling, so also need to consider.If the value of [1000 * ([Ca]+2 * [S]+3 * [O])]/(solidification cooling) (hereinafter referred to as " R " value) surpasses 100.0, thickization of CaS then, thus can not get the dispersion state that needs.Therefore the R value need be below 100.0.On the other hand, if the R value is lower than 0.1, then speed of cooling is too fast, will make CaO and CaS crystalline time hard up.The preferred lower limit of R value is 5 (more preferably 10), and preferred upper limit is 90 (more preferably 80).
In steel plate of the present invention, in order to bring into play its characteristic, it also is important prerequisite that its chemical ingredients composition is controlled in the proper range.This also comprises the element (Ti, N, Ca, S and O) that relates to above-mentioned (1)～(3) formula, and its scope limits and the reasons are as follows.
[C：0.03～0.10％]
C is the needed element of intensity that is used to guarantee steel plate (welding base metal), need make it to contain more than 0.03% in order to ensure desired intensity.Yet,, HAZ toughness is reduced if contain C superfluously.Thus, its upper limit need be 0.10%.Also have, the preferred lower limit of C content is 0.05%, and preferred upper limit is 0.08%.
[Si:0.50% following (containing 0%)]
Si is being used to guarantee effective elements on the intensity of steel plate, is being contained as required.Yet,, make and separate out island martensite body phase (M-A phase) in the steel (mother metal) in a large number and make the toughness deterioration if make and contain more superfluously.Thus, be limited to 0.50% on it.Also have, the preferred lower limit of Si content is 0.1%, and preferred upper limit is 0.4%.
[Mn：1.0～2.0％]
Mn improves hardenability, is guaranteeing on the armor plate strength it is effective elements, and in order to bring into play this effect, need contain Mn is more than 1.0%.Yet if contain Mn superfluously, the HAZ toughness deterioration of steel plate, therefore with the upper limit as 2.0%.The preferred lower limit of Mn content is 1.3%, and preferred upper limit is 1.8%.
[P:0.015% following (not containing 0%)]
P is the impurity of unavoidably sneaking into, because bring disadvantageous effect can for the toughness of steel plate and the toughness of HAZ, so preferably the least possible.From this viewpoint, P is suppressed at below 0.015% and is advisable.The preferred upper limit of P content is 0.01%.
[S:0.0010% following (not containing 0%)]
S forms CaS in steel plate when the steel plate in when casting solidifies, form MnS on the CaS making after the welding thus, is to form the element that effectively plays a role at the ferrite of HAZ portion.This effect increase along with the increase of its content, but if superfluous being contained surpass 0.0010%, the toughness deterioration of mother metal and HAZ then.Also have,, preferably make it to contain more than 0.0005%, be limited to 0.0007% on preferred in addition in order to bring into play the above-mentioned effect that S brings.In order to make this S be reduced to specialized range, make desulfurization time grow (for example more than 25 minutes) and get final product.
[Al：0.005～0.060％]
Al is an effective elements as reductor, and is bringing into play the base metal tenacity that the microstructure miniaturization of steel plate brings and improving effect.In order to bring into play this effect, needing Al content is more than 0.005%.Yet,, make and separate out island martensite body phase (M-A phase) in the steel plate (mother metal) in a large number and make HAZ toughness deterioration if it superfluously is contained.Therefore, be limited to 0.060% on it.Also have, the preferred lower limit of Al content is 0.01% (more preferably more than 0.02%), and preferred upper limit is 0.04%.
[Ti：0.008～0.030％]
Ti forms nitride, suppresses thickization of old austenite crystal when high heat energy welds, and is improving effective elements on the HAZ toughness.In order to bring into play this effect, needing Ti content is more than 0.008%.Yet, if Ti is contained superfluously, thick inclusion is separated out, make HAZ toughness deterioration on the contrary, so be limited to 0.030% on it.Also have, the preferred lower limit of Ti content is 0.01%, and preferred upper limit is 0.025%.
[N：0.0050～0.010％]
In high heat energy welded H AZ, guarantee that for high level ground toughness, effective means are to make the fine TiN of separating out of old austenite crystal intragranular, thereby prevent thickization of old austenite crystal.In order to bring into play this effect, needing N content is more than 0.0050%.Yet, surpassing 0.010% if N content is superfluous, thick TiN separates out, and HAZ toughness reduces.Also have, the preferred lower limit of N content is 0.006%, and preferred upper limit is 0.009% (more preferably 0.008%).
[Ca：0.0015～0.0035％]
The form of Ca control sulfide is the element that helps HAZ toughness to improve.In order to bring into play this effect, need make it to contain more than 0.0015%, still, contain above 0.0035% superfluously, then also can make HAZ toughness deterioration on the contrary.Also have, the preferred lower limit of Ca content is 0.002%, and preferred upper limit is 0.003%.
[O:0.0015% following (not containing 0%)]
O is contained as unavoidable impurities, but exists as oxide compound in steel.Yet if its content surpasses 0.0015%, thick CaO generates, HAZ toughness deterioration.Thus, O content on be limited to 0.0015%.The preferred upper limit of O content is 0.0013%.
In steel plate of the present invention, be to constitute beyond the mentioned component by Fe and unavoidable impurities (for example Sb, Se, Te etc.), but also can comprise the trace ingredients (permission composition) that can not hinder the degree of its characteristic, such steel plate is also contained in the scope of the present invention.In addition, as required, contain as inferior element also effective: (a) B:0.0035% following (not containing 0%); (b) below Cu:2%, (do not contain 0%), (do not contain 0%) below the Ni:2% and (do not contain 0%) below the Cr:1.5% more than a kind of selection the group who is constituted; (c) Mo:0.5% following (not containing 0%); (d) Nb:0.035% following (not containing 0%) and/or V:0.1% following (not containing 0%); (e) Mg:0.005% following (not containing 0%); (f) Zr:0.1% following (not containing 0%) and/or Hf:0.05% following (not containing 0%); (g) Co:2.5% following (not containing 0%) and/or W:2.5% following (not containing 0%); (h) REM:0.010% following (not containing 0%).The scope qualification that these compositions are contained sometimes be the reasons are as follows.
[B:0.0035% following (not containing 0%)]
B is near the fusion portion of superelevation heat energy HAZ, and making with BN is the intracrystalline ferrite generation of nuclear, and contains the fixed action of solid solution N, is to improve effective elements on the HAZ toughness, contained as required.Yet superfluous if the content of B becomes, the tissue of fusion portion becomes thick bainite structure, therefore makes HAZ toughness deterioration on the contrary.Thus, B is contained sometimes, can be with its upper limit as 0.0035%.Preferred range is 0.0010～0.0025%.
[below Cu:2%, (not containing 0%), (do not contain 0%) below the Ni:2% and (do not contain 0%) below the Cr:1.5% more than a kind of selection the group who is constituted]
The intensity that Cu, Ni and Cr all makes improving hardenability is effective elements on improving, and is contained as required.Yet if the content surplus of these elements, HAZ toughness reduces on the contrary, therefore for Cu and Ni preferably at (more preferably below 1%) below 2%, for Cr preferably at (more preferably below 1%) below 1.50%.The preferred lower limit that is used to bring into play above-mentioned effect is 0.20% (more preferably 0.40%).
[Mo:0.5% following (not containing 0%)]
Mo improves hardenability, is guaranteeing on the intensity that effectively, appropriateness is used in order to prevent temper brittleness.This effect increases and increases along with its content, but if Mo content surplus, then therefore HAZ toughness deterioration is preferably below 0.5%.More preferably below 0.30%.
[Nb:0.035% following (not containing 0%) and/or V:0.1% following (not containing 0%)]
Nb and V improve hardenability, are bringing into play the effect that strength of parent is improved.In addition, V improves the effect of temper softening in addition.Yet, if it is contained in a large number, HAZ toughness deterioration, so Nb is (more preferably below 0.030%) below 0.035%, V is (more preferably below 0.05%) below 0.1%.Also have, be used for bringing into play effectively the content of their effects, Nb is more than 0.005%, and V is more than 0.01%.
[Mg:0.005% following (not containing 0%)]
Mg forms MgO, and thickization of the austenite crystal by suppressing HAZ has the effect that HAZ toughness is improved, and therefore contained as required.Yet, if the content surplus of Mg, thickization of inclusion, therefore HAZ toughness deterioration makes it at (more preferably below 0.0035%) below 0.0050%.
[Zr:0.1% following (not containing 0%) and/or Hf:0.05% following (not containing 0%)]
Zr is the same with Ti with Hf, forms nitride with N, and the austenite crystal miniaturization of the HAZ when making welding is an effective elements improving aspect the HAZ toughness.But,, HAZ toughness is reduced if it is contained superfluously.Therefore, when containing these elements, Zr is below 0.1%, and Hf is below 0.05%.
[Co:2.5% following (not containing 0%) and/or W:2.5% following (not containing 0%)]
Co and W improve hardenability, have the effect that improves strength of parent, are therefore contained as required.But if contain superfluously, HAZ toughness deterioration then, so its upper limit is below 2.5%.
[REM:0.010% following (not containing 0%)]
REM (rare earth element) is the element that helps HAZ toughness to improve therefore owing to make the shape miniaturization balling of the inclusion (oxide compound and sulfide etc.) of unavoidably sneaking in the steel, is contained as required.This effect increases along with the increase of its content, but superfluous if the content of REM becomes, thickization of inclusion then, and therefore HAZ toughness deterioration preferably is suppressed at it below 0.010%.Also have, in the present invention, so-called REM is the meaning that comprises lanthanon (15 elements from La to ln) and Sc (scandium) and Y (yttrium).
Also have, as the steel plate of object, being assumed to thickness of slab basically is the above Plate Steel of 60mm among the present invention, even but also have equal characteristic under the thickness of slab hereunder, include in object of the present invention.In addition, heat energy when welding steel plate of the present invention is assumed to more than the 60kJ/mm, it demonstrates good HAZ toughness when welding under this superelevation heat energy, but be not limited to this heat energy, for example also can demonstrate good HAZ toughness under the heat energy more than the 15kJ/mm.
Below, illustrate in greater detail the present invention according to embodiment, but following embodiment does not limit character of the present invention, follow the front/rear aim of stating and carry out all being included in the technical scope of the present invention of design variations.
[embodiment]
According to common melting method, the steel that chemical ingredients shown in following table 1～3 is formed carries out melting, (casting sheet surface temperature: average cooling rate 1300～1000 ℃ temperature range) (solidification cooling) when limit control is cast, cool off this molten steel and after becoming steel billet on the limit, be heated to 950～1300 ℃ and carry out hot rolling, become thickness of slab: the hot-rolled sheet of 80mm, quench as required, become various high-tensile steels (test board).Also have, in table 1, REM is about 50% and to contain Ce be that the form of about 25% norium is added to contain La.In addition, element is not added in the expression of "-" in table 1～3.Also have, in table 1～3, also P value ([Ti]/[N]), the Q value [1000 * ([Ca]+2 * [S]+3 * [O])] for the present invention's regulation shows.In addition, solidification cooling is controlled by cooling water inflow, and is measured by the radiation thermometer.
[table 1]
Test No. Chemical ingredients is formed * (quality %) The P value The Q value
C Si Mn P S .Al Cu Ni Cr Mo V Nb Ti B N Ca o Other
1 0.068 0.15 1.55 0.007 0.0007 0.035 0.30 0.30 0 0 0 0 0.013 0.0015 0.0065 0.0025 0.0008 - 2.0 6.3
2 0.066 0.15 1.53 0.007 0.0001 0.035 0.30 0.30 0 0 0 0 0.013 0.0015 0.0065 0.0035 0.0015 - 2.0 8.2
3 0.071 0.15 1.55 0.007 0.0001 0.035 0.30 0.30 0 0 0 0 0.013 0.0015 0.0065 0.0035 0.0001 - 2.0 4.0
4 0.063 0.15 1.52 0.007 0.001 0.035 0.30 0.30 0 0 0 0 0.013 0.0015 0.0065 0.0034 0.0015 - 2.0 9.9
5 0.066 0.15 1.55 0.007 0.001 0.035 0.30 0.30 0 0 0 0 0.013 0.0015 0.0065 0.0035 0.0001 - 2.0 5.8
6 0.070 0.15 1.54 0.007 0.0001 0.035 0.30 0.30 0 0 0 0 0.013 0.0015 0.0065 0.0015 0.0015 - 2.0 6.2
7 0.065 0.15 1.55 0.007 0.0001 0.035 0.30 0.30 0 0 0 0 0.013 0.0015 0.0065 0.0015 0.0001 - 2.0 2.0
8 0.071 0.15 1.55 0.007 0.0010 0.035 0.30 0.30 0 0 0 0 0.013 0.0015 0.0065 0.0015 0.0015 - 2.0 8.0
9 0.070 0.15 1.55 0.007 0.0010 0.035 0.30 0.30 0 0 0 0 0.013 0.0015 0.0065 0.0015 0.0001 - 2.0 3.8
10 0 068 0.15 1.55 0.007 0.0003 0.035 0.30 0.30 0 0 0 0 0.008 0.0015 0.0065 0.0025 0.0008 - 1.2 5.5
11 0.066 0.15 1.53 0.007 0.0003 0.035 0.30 0.30 0 0 0 0 0.008 0.0015 0.0080 0.0025 0.0009 - 1.0 5.8
12 0.071 0.15 1.55 0.007 0.0003 0.035 0.30 0.30 0 0 0 0 0.013 0.0015 0.0065 0.0023 0.0008 - 2.0 5.3
13 0.071 0.15 1.52 0.007 0.0003 0.035 0.30 0.30 0 0 0 0 0.013 0.0015 0.0085 0.0028 0.0008 - 1.5 5.8
14 0.066 0.15 1.55 0.007 0.0003 0.035 0.30 0.30 0 0 0 0 0.015 0.0015 0.0065 0.0025 0.0008 - 2.3 5.5
15 0.070 0.15 1.54 0.007 0.0003 0.035 0.30 0.30 0 0 0 0 0.015 0.0015 0.0085 0.0025 0.0007 - 1.8 5.2
16 0.065 0.15 1.55 0.007 0.0003 0.035 0.30 0.30 0 0 0 0 0.017 0.0015 0.0070 0.0025 0.0008 - 2.4 5.5
17 0.071 0.15 1.55 0.007 0.0003 0.035 0.30 0.30 0 0 0 0 0.025 0.0015 0.0100 0.0022 0.0008 - 2.5 5.2
18 0.070 0.15 1.55 0.007 0.0003 0.035 0.30 0.30 0 0 0 0 0.030 0.0015 0.0120 0.0025 0.0008 - 2.5 5.5
19 0.05 0.15 1.55 0.007 0.0003 0.035 0.25 0.35 0 0 0 0.008 0.015 0.0018 0.0065 0.0025 0.0008 - 2.3 5.5
20 0.05 0.15 1.55 0.007 0.0003 0.035 0.25 0.35 0 0 0 0.008 0.015 0.0025 0.0065 0.0025 0.0009 - 2.3 5.8
21 0.05 0.15 1.55 0.007 0.0003 0.035 0.25 0.35 0 0 0 0.008 0.018 0.0022 0.0075 0.0023 0.0008 - 2.4 5.3
22 0.08 0.15 1.55 0.007 0.0003 0.035 0.0 0.0 0 0 0 0.018 0.012 0.0010 0.0050 0.0028 0.0008 - 2.4 5.8
23 0.08 0.15 1.55 0.007 0.0003 0.035 0.0 0.0 0.30 0 0 0.010 0.015 0.0017 0.0065 0.0025 0.0008 - 2.3 5.5
24 0.06 0.15 1.55 0.007 0.0003 0.035 0.25 0.35 0 0 0 0 0.015 0.0015 0.0075 0.0025 0.0007 - 2.0 5.2
25 0.06 0.15 1.55 0.007 0.0003 0.035 0.25 0.35 0 0 0 0 0.013 0.0015 0.0065 0.0025 0.0008 - 2.0 5.5
* surplus: iron, and P, O beyond unavoidable impurities
[table 2]
Figure S2007101693017D00111
* surplus: iron, and P, O beyond unavoidable impurities
[table 3]
* surplus: iron, and P, O beyond unavoidable impurities
For the various steel plates that obtain, measure its tensile properties with following method, and under following condition, weld, make weld part.
(tensile properties of steel plate)
Extract 2201 No. 4 test films of JIS Z from the t/4 (t is a thickness of slab) of steel plate, carry out tension test, measure tensile strength (TS) by the main points of JIS Z 2241.Among the present invention, tensile strength TS:440MPa is above to be qualified.
(welding conditions)
Welding process: electro-gas welding (electrogas arc welding)
Welding current: 400A
Weldingvoltage: 40V
Welding speed: 0.58mm/ second
Heat energy: 60kJ/mm
Welding wire: DWS-50GTR, DWS-50GTF
Groove shape: 18 ° of groove angles (anti-V groove), root opening: 10mm
At resulting weld part, as shown in Figure 1, extract pendulum impact test sheet (JIS Z2202: high 10mm * wide 10mm * long 55mm), open recess at+0.5mm mother metal side position, the V pendulum impact value (vE under measuring-55 ℃ from fusion portion from the position of the t/4 (t is a thickness of slab) of steel plate -55), estimate HAZ toughness.At this moment V pendulum impact value (vE -55) be that 100J is above for qualified.
The solidification cooling of these results when making is presented in following table 4～6.Also have, in table 4～6, also be presented under the heat energy 15kJ/mm, when welding, with the V pendulum impact value (vE of above-mentioned same mensuration with following welding conditions -55).
(welding conditions)
Thickness of slab: 25mm
Groove angle: 40 °
Root width: 11mm
Welding material (welding wire): DWS-50G (1.6mm )
[table 4]
Test No. Manufacture method The mother metal characteristic HAZ toughness
Solidification cooling (℃/second) The R value Tensile strength TS (MPa) The vE of fusion+0.5mm portion -55(J) [input heat: 15kJ/mm] The vE of fusion+0.5mm portion -55(J) [input heat: 60kJ/mm]
1 0.50 12.6 534 328 345
2 0.50 16.4 528 319 334
3 0.50 8.0 540 342 359
4 0.50 19.8 520 309 324
5 0.50 11.6 530 331 348
6 0.50 12.4 537 331 346
7 0.50 4.0 528 354 371
8 0.50 16.0 540 320 335
9 0.50 7.6 538 343 360
10 0.50 11.0 534 359 373
11 0.50 11.6 528 361 378
12 0.50 10.6 540 336 351
13 0.50 11.6 537 345 362
14 0.50 11.0 530 326 341
15 0.50 10.4 537 342 359
16 0.50 11.0 528 322 337
17 0.50 10.4 540 320 337
18 0.50 11.0 538 320 335
19 0.50 11.0 497 324 341
20 0.50 11.6 505 324 339
21 0.50 10.6 502 322 339
22 0.50 11.6 516 321 336
23 0.50 11.0 553 324 341
24 0.50 10.4 514 337 352
25 0.50 11.0 514 333 350
[table 5]
Test No. Manufacture method The mother metal characteristic HAZ toughness
Solidification cooling (℃/second) The R value Tensile strength TS (MPa) The vE of fusion+0.5mm portion -55(J) [input heat: 15kJ/mm] The vE of fusion+0.5mm portion -55(J) [input heat: 60kJ/mm]
26 0.5 11.0 524 335 350
27 0.5 11.6 504 331 348
28 0.5 10.6 5187 336 351
29 0.5 11.6 518 331 348
30 0.5 11.0 518 335 350
31 0.5 10.4 496 335 352
32 0.5 11.0 496 335 350
33 0.5 11.0 517 333 350
34 0.1 63.0 538 179 194
35 0.07 90.0 538 106 113
36 0.50 12.6 530 306 323
37 0.50 12.6 463 328 345
38 0.2 51.5 433 203 210
39 0.2 49.5 640 29 35
40 0.2 52.5 524 37 44
41 0.2 49.0 426 210 216
42 0.2 50.0 528 35 42
43 0.2 50.5 500 30 36
44 0.2 51.5 697 46 53
45 0.2 51.5 556 39 45
46 0.2 49.5 628 25 32
47 0.2 51.0 549 26 32
[table 6]
Test No. Manufacture method The mother metal characteristic HAZ toughness
Solidification cooling (℃/second) The R value Tensile strength TS (MPa) The vE of fusion+0.5mm portion -55(J) [input heat: 15kJ/mm] The vE of fusion+0.5mm portion -55(J) [input heat: 60kJ/mm]
48 0.20 48.0 488 25 32
49 0.20 54.0 467 26 32
50 0.20 50.0 495 40 47
51 0.20 52.0 476 32 38
52 0.20 51.5 495 29 36
53 0.20 50.0 511 35 41
54 0.20 51.0 507 41 48
55 0.20 52.0 507 29 35
56 0.20 52.5 495 58 65
57 0.20 62.5 501 47 53
58 0.20 72.5 499 40 47
59 0.20 52.5 497 62 68
60 0.20 60.0 503 46 53
61 0.20 75.0 499 32 38
62 0.09 108.9 495 52 59
63 0.08 122.5 499 38 44
64 0.06 163.3 500 18 25
65 0.20 9.0 499 41 48
66 110 0.09 499 17 23
67 0.20 52.0 476 59 65
Can carry out following investigation according to these results.At first, the prerequisite of the present invention's regulation is satisfied in test No.1～37, and the intensity of steel plate (mother metal) satisfies target, and HAZ toughness also fully satisfies the above target of average 100J.In addition also as can be known, even be under the such welding conditions of 15kJ/mm at heat energy, they also demonstrate sufficient HAZ toughness.
With respect to this, a certain prerequisite of test No.38～67 shortcoming the present invention regulations, certain specific character is deterioration thereupon.Wherein, test No.38～53,67 its chemical ingredientss are formed the scope that breaks away from the present invention's regulation, and (test No.51, the 67th, the P value is also big), though test No.54 chemical constitution satisfies, the P value breaks away from the scope of the present invention's regulation.Satisfy though test No.55～61,65 chemical ingredientss are formed, the Q value breaks away from the scope of the present invention's regulation.Satisfy though test No.62～64,66 chemical ingredientss are formed, the R value breaks away from the scope of the present invention's regulation.

Claims (9)

1. the steel plate of the tenacity excellent of the welding heat affected zone of excessive heat input welding, it is characterized in that, contain C:0.03～0.10% in quality %, Si:0.50% is following and contain 0%, Mn:1.0～2.0%, P:0.015% is following but do not contain 0%, S:0.0010% is following but do not contain 0%, Al:0.005～0.060%, Ti:0.008～0.030%, N:0.0050～0.010%, Ca:0.0015～0.0035% and O:0.0015% are following but do not contain 0%, and satisfy relation respectively by following (1)～(3) formula regulation
1.0≤[Ti]/[N]≤2.5 …(1)
Wherein, [Ti] and [N] represents the mass percentage content of Ti and N respectively,
2.0≤1000×([Ca]+2×[S]+3×[O])≤10.0 …(2)
Wherein, [Ca], [S] and [O] represent the mass percentage content of Ca, S and O respectively,
0.1≤[1000 * ([Ca]+2 * [S]+3 * [O])]/(solidification cooling)
≤100.0 …(3)
Average cooling rate when steel plate solidified when wherein, solidification cooling was represented to cast (℃/second).
2. steel plate according to claim 1 is characterized in that, it is following but do not contain 0% to contain B:0.0035%.
3. steel plate according to claim 1 is characterized in that, contain below Cu:2% but do not contain 0%, below the Ni:2% but do not contain 0% and below the Cr:1.50% but do not contain select 0% more than a kind.
4. steel plate according to claim 1 is characterized in that, it is following but do not contain 0% to contain Mo:0.5%.
5. steel plate according to claim 1 is characterized in that, contain Nb:0.035% following but do not contain 0% and/or V:0.1% following but do not contain 0%.
6. steel plate according to claim 1 is characterized in that, it is following but do not contain 0% to contain Mg:0.005%.
7. steel plate according to claim 1 is characterized in that, contain Zr:0.1% following but do not contain 0% and/or Hf:0.05% following but do not contain 0%.
8. steel plate according to claim 1 is characterized in that, contain Co:2.5% following but do not contain 0% and/or W:2.5% following but do not contain 0%.
9. steel plate according to claim 1 is characterized in that, it is following but do not contain 0% to contain REM:0.010%.
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