CN105980588A - Steel plate and method for manufacturing same - Google Patents

Steel plate and method for manufacturing same Download PDF

Info

Publication number
CN105980588A
CN105980588A CN201480067195.XA CN201480067195A CN105980588A CN 105980588 A CN105980588 A CN 105980588A CN 201480067195 A CN201480067195 A CN 201480067195A CN 105980588 A CN105980588 A CN 105980588A
Authority
CN
China
Prior art keywords
steel plate
toughness
steel
less
precipitate
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
Application number
CN201480067195.XA
Other languages
Chinese (zh)
Other versions
CN105980588B (en
Inventor
宫克行
一宫克行
木津谷茂树
长谷和邦
远藤茂
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Steel Corp
JFE Engineering Corp
Original Assignee
NKK Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by NKK Corp filed Critical NKK Corp
Publication of CN105980588A publication Critical patent/CN105980588A/en
Application granted granted Critical
Publication of CN105980588B publication Critical patent/CN105980588B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/50—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for welded joints
    • 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
    • C22C38/14—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
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/004—Dispersions; Precipitations

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

The present invention provides a steel plate that contains prescribed steel plate components, B is restricted to less than 0.0003%, and the remainder comprises Fe and unavoidable impurities. The steel plate contains Ti, Nb and Mo in a range in which the quantity of Ti ([Ti]), the quantity of Nb ([Nb]) and the quantity of Mo ([Mo]) satisfies the relationship ([Nb])/([Ti]) + ([Nb]) + ([Mo])equal to and greater than 0.3, and precipitates have an average particle size of 20 nm or less. A thick steel plate with high tensile strength can thus be obtained, said steel plate: being suitable for use in steel structures such as marine structures, ships, pressure vessels and penstocks; having a yield stress (YS) of at least 460 MPa; and having excellent low-temperature toughness (CTOD characteristics) in multilayer weld zones affected by weld heat and strength and toughness (PWHT characteristics) after being heat treated during welding.

Description

Steel plate and manufacture method thereof
Technical field
The present invention relates to the high tension steel for iron structure things such as marine structure, boats and ships, pressure vessel, penstocks Plate and manufacture method thereof, more particularly, it relates to heavy wall high-tensile steel and manufacture method thereof, the yield stress (YS) of described steel plate is More than 460MPa, the not only intensity/tenacity excellent of steel plate, and the low-temperature flexibility of multilamellar weld part (CTOD characteristic) and welding are executed Man-hour, the strength and toughness (PWHT characteristic) after heat treatment (PWHT) was also excellent.
Background technology
It is processed into the knot of desirable shape through solder joints for the steel plate of boats and ships, marine structure, pressure vessel etc. Structure thing.Therefore, from the viewpoint of works safety, for these steel plates, it is naturally required that intensity is high, tenacity excellent, But also the tenacity excellent in the solder joint portion (welding metal, heat affected zone) when requiring to implement welding.
In the past, as the metewand of steel plate toughness, mainly use the absorption energy utilizing Charpy-type test to obtain, But in recent years, in order to improve reliability further, use Experimeneal research on high (Crack Tip Opening more Displacement Test, hereinafter referred to as CTOD test).This test is: for implementing fatigue at the position of toughness to be evaluated The test film of presplitting carries out 3 bendings, mensuration will prerupture crack opening amount (amount of plastic deformation), thus evaluate fragility break Bad generation resistance.
Owing to using fatigue precracking at CTOD in testing, the most atomic little region becomes toughness evaluation portion.Therefore, at steel When plate exists local embrittlement region, even if Charpy-type test obtains good toughness, the most also show in CTOD tests Relatively low value is shown.
In the steel plate that thickness of slab is thicker etc., by complicated heating process welding heat affected zone (hereinafter also referred to HAZ) by Easily produce above-mentioned local embrittlement region in multiple-bead deposit, and weld bond (welding metal and the border of mother metal), butt welding mouth are again Be heated to 2 alpha regions part (is formed coarse grain by the welding of the 1st circulation, and by follow-up welding passage be heated to ferrite and The scope of 2 alpha regions of austenite, hereinafter referred to as 2 alpha region reheating portions) easily become local embrittlement region.
Here, for weld bond, being exposed to the high temperature of slightly less than fusing point during due to welding, therefore austenite crystal is thick Change, under the effect of ensuing cooling, easily become the top bainite structure that toughness is low, the therefore toughness of substrate self mutually It is easily reduced.And then, for junction surface, easily generate Widmannstatten structure (widmanstatten structure), island horse The brittle microstructures such as family name's body (hereinafter also referred to M-A), when generating this brittle microstructures, the toughness of steel plate reduces the most further.
Here, in order to make the toughness of welding heat affected zone improve, such as, TiN fine dispersion is made to form suppression in steel plate The ferrite transformation core of the coarsening of austenite crystal the technology being used are practical.But, for weld bond, It is heated to the temperature range of TiN fusing sometimes, owing to the low-temperature flexibility of weld part requires that the harshest heating-up temperature is the highest, therefore It is difficult to show the above-mentioned action effect making TiN fine dispersion.
In order to solve these problems, patent documentation 1, patent document 2 discloses that following technology: by rare earth element (REM) Combine interpolation together with Ti, make minuteness particle be scattered in steel plate, thus suppress the grain growth of austenite, make toughness of welded zone Improve.
Meanwhile, patent documentation 1, patent documentation 2 also proposed and make the scattered technology of Ti oxide, by the ferrite core life of BN One-tenth ability and oxide disperse the technology being combined and improve tough by adding Ca, REM to control the form of sulfide The technology etc. of property.
It addition, Patent Document 3 discloses the technology making Ti oxide be dispersed in steel to improve HAZ toughness.
Additionally, for 2 alpha region reheating portions, disclose techniques below: reheated by 2 alpha regions, carbon poly collection Become the region of austenite in anti-phase, cooling can generate the fragile bainite structure containing island-like martensite, the toughness of steel Reduce, in order to prevent this toughness from reducing, make the low Cization of steel plate composition, low Siization, suppress the generation of island-like martensite to improve tough Property, the intensity (such as, patent documentation 4 and 5) of mother metal is guaranteed by adding Cu.
Here, the rate of cooling after the technology described in patent documentation 4 takes rolling is set to less than 0.1 DEG C/sec, and Make the method that Cu particle separates out in this process, but there is the problem manufacturing stability.
It addition, in the technology described in patent documentation 5, by N/Al ratio is set to 0.3～3.0, it is suppressed that AlN's is thick The degraded toughness that bigization, the harmful effect of solid solution N cause, but it is the easiest to control the technology of solid solution N by Ti.
It should be noted that for the YS thick-wall materials more than 460MPa, sometimes implement after heat when welding procedure Process (PWHT).Now, owing to mother metal is heated the most simultaneously, even if therefore standing PWHT process, it is also necessary to keep mother metal characteristic, In the past, in order to suppress intensity when being heated to reduce, usual interpolation formed the element of precipitate at such a temperature.
Prior art literature
Patent documentation
Patent documentation 1: Japanese Patent Publication 03-053367 publication
Patent documentation 2: Japanese Laid-Open Patent Publication 60-184663 publication
Patent documentation 3: No. 3697202 publications of Japanese Patent No.
Patent documentation 4: No. 3045856 publications of Japanese Patent No.
Patent documentation 5: No. 4432905 publications of Japanese Patent No.
Summary of the invention
The problem that invention is to be solved
Here, the technology described in patent documentation 1 and 2 with the steel few compared with low-intensity and alloying element amount as object, but In the case of the thick-wall materials that higher intensity and alloying element amount are many, owing to HAZ organizes the formation of without ferritic tissue, because of There is the problem that can not be suitable in this.
It is difficult to make Ti oxide stably fine dispersion asking in steel it addition, the technology described in patent documentation 3 exists Topic.
Additionally, guaranteed intensity by Cu precipitate and the situation that causes toughness to reduce is more, guaranteeing the low-temperature flexibility of steel plate Aspect has problems.It addition, for the steel employing Cu precipitation strength described in patent documentation 5, exist at PWHT The problem that during reason, Cu particle growth obtains greatly, intensity easily reduces.
Additionally, in recent years, for the iron structure things such as boats and ships, marine structure, pressure vessel, penstocks, with It to maximize, it is desirable to further high intensity.
Steel for these iron structure things mostly such as are the thick-wall materials of more than thickness of slab 35mm, therefore, in order to ensure Yield stress is 460MPa level and above intensity thereof, and the composition of steel system more containing alloying element to be added is favourable 's.
But, for the high strength steel many with the alloying element amount weld bond as object, the toughness in 2 alpha region reheating portions For raising, study the most fully.Therefore, for the steel plate characteristic after guaranteeing PWHT, conventional merely adds Add precipitation element to be difficult to keep intensity and toughness.
The present invention solves the problems referred to above well, its object is to provide a kind of heavy wall high tension steel and manufacturer thereof Method, described heavy wall high tension steel is applicable to the iron structure things such as marine structure, boats and ships, pressure vessel, penstocks, its surrender Stress (YS) is more than 460MPa (in the present invention, the situation meeting this YS being referred to as high-tension), the sweating heat shadow of multilamellar weld part When the low-temperature flexibility (CTOD characteristic) in sound portion, welding procedure, intensity and toughness (PWHT characteristic) after heat treatment are excellent.
The method solving problem
The present inventor etc. have been repeated further investigation to solve the problems referred to above, it is thus achieved that following opinion.
A () CTOD characteristic is evaluated with the test film of steel plate gross thickness, the center segregation portion that therefore composition is assembled becomes The starting point destroyed.
Therefore, in order to improve the CTOD characteristic of welding heat affected zone, will easily assemble with the form of the center segregation of steel plate Control of element be appropriate amount be effective to suppress the hardening in center segregation portion.It addition, become final set when molten steel solidification Gu the steel billet center in portion, C, Mn, P, Ni and Nb are higher than the concentration class of other element, therefore, by the addition with these elements The hardness being controlled suppressing center segregation portion as the hardness number in center segregation portion is effective.
B (), in order to make the toughness of welding heat affected zone improve, effectively utilizes TiN to suppress to weld the austenite near weld bond The coarsening of crystal grain is effective.Particularly when control to be appropriate amount by Ti/N ratio, then TiN fine uniform structure can be disperseed In steel.
C the crystallization of the Ca compound (CaS) added for the purpose of the morphology Control of sulfide is used for improving welding by () The toughness of heat affected zone is effective.
Compared with oxide, CaS separates out crystal at low temperatures, therefore, it is possible to fine dispersion equably.Therefore, by by Ca Addition and add time molten steel in dissolved oxygen content control at proper range, even if CaS crystal separate out after also ensure that Solid solution S, therefore MnS separates out on the surface of CaS and forms complex sulfide.The thin band of Mn is formed around this MnS, because of This promotes ferrite transformation further.
D () is by adding to form Nb and Ti of precipitate, Mo, it is possible to make in the fabrication stage of steel plate Even if use the PWHT scope of 2～4 hours (at about 550～650 DEG C implement) carry out heating also will not coarsening Mo, The fine precipitation of composite carbon nitride of Ti, Nb.
In the past, YS significantly reduces more than steel plate intensity after PWHT of 460MPa level, but for the steel plate of exploitation, Know by making fine Mo, Ti, Nb miscible precipitate (carbide, nitride or carbonitride) stably exist, it is possible to keep Precipitation strength, can suppress the reduction of armor plate strength.Additionally, it is known that due to the existence of fine Mo, Ti, Nb miscible precipitate, The toughness of steel plate can also be kept simultaneously.
The present invention completes based on above-mentioned opinion, and the main points of the present invention are as follows.
1. a steel plate, it has a following steel plate composition:
In terms of quality %, containing C:0.020～0.090%, Si:0.01～0.35%, Mn:1.40～2.00%, P: Less than 0.008%, below S:0.0035%, Al:0.010～0.060%, Ni:0.40～2.00%, Mo:0.05～0.50%, Nb:0.005～0.040%, Ti:0.005～0.025%, N:0.0020～0.0050%, Ca:0.0005～0.0050%, O: Less than 0.0035%,
The scope that Ceq is 0.420～0.520% of following formula (1) defined, meets following formula (2), formula (3) and formula (4), and by B suppression less than 0.0003%, surplus is made up of Fe and inevitable impurity,
Described steel plate has the precipitate that mean diameter is below 20nm, and this precipitate contains Ti, Nb and Mo, and Ti amount The content range of ((Ti)), Nb amount ((Nb)) and Mo amount ((Mo)) meets the relation of (Nb)/((Ti)+(Nb)+(Mo)) >=0.3.
Ceq=[C]+[Mn]/6+ ([Cu]+[Ni])/15+ ([Cr]+[Mo]+[V])/5 ... (1)
1.5≤[Ti]/[N]≤4.0…(2)
0 ＜ { [Ca]-(0.18+130 × [Ca]) × [O] }/1.25/ [S] ＜ 1.5 ... (3)
5.5[C](4/3)+15[P]+0.90[Mn]+0.12[Ni]+7.9[Nb](1/2)+0.53[Mo]≤3.70…(4)
Wherein, the content (quality %) of element M during [M] represents steel plate.
Steel plate described in the most above-mentioned 1, wherein, possibly together with selected from Cu in terms of quality % in described steel plate composition: be less than 0.7%, the one in Cr:0.1～1.0% and V:0.005～0.05% or two or more.
Steel plate described in the most above-mentioned 1 or 2, wherein, possibly together with selected from Mg:0.0002 in terms of quality % in described steel plate composition ～the one in 0.0050% and REM:0.0010～0.0200% or 2 kinds.
4. a manufacture method for steel plate, the method includes: will have the steel plate composition according to any one of above-mentioned 1～3 Steel be heated to 950～1150 DEG C after, the accumulation reduction ratio of the temperature range being implemented in more than 900 DEG C is more than 30%, little In the hot rolling that accumulation reduction ratio is 30～70% of the temperature ranges of 900 DEG C, then with the rate of cooling of more than 1.0 DEG C/sec extremely It is cooled to 500 DEG C less.
The manufacture method of the steel plate described in the most above-mentioned 4, wherein, after described cooling, real at 450～650 DEG C further Execute temper.
The effect of invention
According to the present invention it is possible to obtain the yield stress (YS) being applicable to the Large Steel iron construction things such as marine structure is More than 460MPa, the CTOD characteristic of multilamellar weld part and the heavy wall high-tensile steel of PWHT excellent and manufacture method thereof, because of This is the most exceedingly useful.
Accompanying drawing explanation
Fig. 1 is the figure of the relation illustrating intensity, change in toughness and precipitate/size composition in PWHT heat treatment.
Fig. 2 is to illustrate that the TEM replica of the precipitate in steel plate is observed (TEM replica observation) and divided with EDX The figure of analysis result.
Detailed description of the invention
Hereinafter, the present invention is specifically described.
First, according to each composition, for being grouped into by the one-tenth of steel plate (hereinafter also referred to as thick-wall materials) in the present invention, (steel becomes Point) reason that is defined in above-mentioned scope is described in detail.It should be noted that unless otherwise specified, following institute is represented The steel plate stated becomes the % being grouped into refer to quality %.
C:0.020～0.090%
C (carbon) is to ensure that as element necessary to the intensity of high-tensile steel.When adding less than 0.020%, hardenability Reduce, in order to ensure intensity, need to add Cu, Ni, Cr and Mo etc. in a large number and improve the element of hardenability, cost can be caused to increase. On the other hand, when interpolation is more than 0.090%, toughness of welded zone can be made to reduce.Therefore, making C amount is 0.020～0.090% Scope.It is preferably 0.020～the scope of 0.080%.
Si:0.01～0.35%
Si (silicon) is as deoxidant element and the composition that adds for obtaining armor plate strength, in order to obtain these effects, Need to add more than 0.01%.On the other hand, when adding more than 0.35% in a large number, the reduction of weldability and welding can be caused to connect The reduction of seam toughness.Accordingly, it would be desirable to the scope making Si amount be 0.01～0.35%.It is preferably 0.01～0.23%.
Mn:1.40～2.00%
For Mn (manganese), in order to ensure armor plate strength and solder joint intensity, need to add more than 1.40%.Another Aspect, when interpolation is more than 2.00%, can make weldability reduce, and hardenability is excessive, makes steel plate toughness and solder joint toughness fall Low.Therefore, the scope making Mn amount be 1.40～2.00%, more preferably 1.40～1.95%.
Below P:0.008%
P (phosphorus) as impurity element can make steel plate toughness and toughness of welded zone reduce, and particularly it is in weld part When content is more than 0.008%, CTOD characteristic significantly reduces, and is therefore less than 0.008%, preferably less than 0.006%.Need Being noted that although it is desirable to reduce the content of P as far as possible, but consider from viewpoints such as refining costs, its lower limit is 0.002% left side Right.
Below S:0.0035%
S (sulfur) is impurity element, containing when having more than 0.0035%, steel plate and toughness of welded zone can be made to reduce, therefore make It is less than 0.0035%, preferably less than 0.0030%.It should be noted that although it is desirable to reduce the content of S as far as possible, but from The viewpoints such as refining cost consider, its lower limit is about 0.0004%.
Al:0.010～0.060%
Al (aluminum) is the element for adding deoxidation of molten steel, needs containing more than 0.010%.On the other hand, if Add more than 0.060%, the most not only make steel plate and toughness of welded zone reduce, also can be mixed into weldering owing to welding the dilution that cause Meet metal portion, so that toughness reduces, be therefore defined to less than 0.060%, preferably 0.017～0.055%.Need explanation It is that in the present invention, Al amount is to be measured by the Al of acid-soluble Al (also referred to as Sol.Al etc.) defined.
Ni:0.40～2.00%
Ni (nickel) is for improving armor plate strength and the effective element of toughness, also has for improving weld part CTOD characteristic Effect.In order to obtain this effect, need to add more than 0.40%.On the other hand, Ni is expensive element, and excessively adds meeting Easily producing damage at billet surface when casting, the therefore contained upper limit is 2.00%.
Mo:0.05～0.50%
Mo (molybdenum) plays an important role in the present invention, is effective to the high intensityization of steel plate by appropriate interpolation Element.When this is hardenability and tempering, softening resistance improves the effect brought.Make and answering that Ti, Nb are formed it addition, also have Close the effect that precipitate keeps fine, strengthening thick-wall materials and suppression toughness to reduce.In order to obtain these effects, need containing The Mo of more than 0.05%.On the other hand, when containing excess, the toughness of thick-wall materials can be had undesirable effect, therefore make Mo The upper limit of amount is 0.50%.It should be noted that Mo amount more preferably 0.08～the scope of 0.40%, and more preferably 0.16～the scope of 0.30%.
Nb:0.005～0.040%
Nb (niobium) forms the non-recrystallization region of austenite in low temperature range, therefore by implementing to roll in this temperature range System, it is possible to seek the tissue miniaturization of steel plate, high tenacity.It addition, Nb has the effect improving hardenability, and by compound Add Mo, Ti and there is anti-softening effect when improving tempering, be for improving the effective element of armor plate strength.In order to obtain this A little effects, need the Nb containing more than 0.005%.On the other hand, containing when having more than 0.040%, degraded toughness can be made, therefore The upper limit of Nb amount is 0.040%, preferably 0.035%.
Ti:0.005～0.025%
Ti (titanium) forms TiN when molten steel solidification and separates out, the coarsening of the austenite in suppression weld part, contributes to carrying The toughness of high weld part.And then added by compound together with Mo, Nb, there is anti-softening effect when improving tempering.But, Containing less than 0.005% time, its effect is little, on the other hand, containing have more than 0.025% time, TiN coarsening, it is impossible to obtain steel Plate, the toughness of weld part improve effect, therefore, and the scope making Ti be 0.005～0.025%.
N:0.0020～0.0050%
N (nitrogen) and Ti, Al react and form precipitate, thus make crystal grain miniaturization, make steel plate toughness be improved. And be the indispensable element of the TiN for forming suppression weld part tissue coarsening.In order to play these effect, need containing The N of more than 0.0020%.On the other hand, when adding the N more than 0.0050%, solid solution N can make steel plate, the toughness of weld part shows Write and reduce, cause solid solution Nb to reduce along with the miscible precipitate generating Ti and Nb, thus cause intensity to reduce, therefore so that it is The upper limit is 0.0050%.
Ca:0.0005～0.0050%
Ca (calcium) is to improve the element of toughness by fixing S.In order to obtain this effect, need to add at least 0.0005%.On the other hand, even if containing having more than 0.0050%, its effect also reaches saturated, therefore, 0.0005～ Ca is added in the range of 0.0050%.
Below O:0.0035%
O (oxygen) can make the degraded toughness of steel plate when more than 0.0035%, is therefore less than 0.0035%, is preferably Less than 0.0028%.It should be noted that although it is desirable to reduce the content of O as far as possible, but consider from viewpoints such as refining costs, under it Limit value is about 0.0010%.
Ceq:0.420～0.520%
In the case of the Ceq of following formula defined is less than 0.420%, it is impossible to obtain the thick-wall materials intensity of 460MPa level. On the other hand, if it exceeds 0.520%, then the weldability of thick-wall materials, toughness of welded zone reduce, and are therefore 0.520% Hereinafter, preferably 0.440～the scope of 0.520%.It should be noted that following [M] represents element M content (matter in steel Amount %).It addition, the element not contained calculates with 0.
Ceq=[C]+[Mn]/6+ ([Cu]+[Ni])/15+ ([Cr]+[Mo]+[V])/5
[Ti]/[N]: 1.5～4.0
When the value of [Ti]/[N] is less than 1.5, the TiN amount of generation reduces, and the solid solution N not forming TiN can make the tough of weld part Property reduce.On the other hand, if the value of [Ti]/[N] is more than 4.0, then TiN coarsening, toughness of welded zone can be made to reduce.Therefore, The value of [Ti]/[N] in the range of 1.5～4.0, preferably 1.8～3.5.
0 ＜ { [Ca]-(0.18+130 × [Ca]) × [O] }/1.25/ [S] ＜ 1.5
{ [Ca]-(0.18+130 × [Ca]) × [O] }/1.25/ [S] is Ca and S representing and effectively controlling oxide morphology The value of ratio of atomic concentration, can be controlled at proper range by the dissolved oxygen content in molten steel by the addition of Ca and when adding It is adjusted, also referred to as ACR (atomic concentration ratio, Atomic Concentration Ratio).Although can be according to this ACR Value speculates the form of sulfide, and the ferrite transformation generation core CaS being defined as in the present invention making high temperature not melt is fine Scattered index.
Here, in the case of ACR value is less than 0, CaS crystal will not be separated out.Therefore, S analyses with the form of single MnS Go out, easily in welding heat affected zone solid solution, it is impossible to obtain ferrite and generate core.It addition, the MnS individually separated out stretches when rolling Long, the toughness of steel plate can be caused to reduce.Thus, in the present invention, need to make ACR value more than 0.
On the other hand, in the case of ACR value is more than 1.5, the increasing proportion of the oxide in Ca system field trash, as Phase change core and the ratio of sulfide that plays a role reduces, it is impossible to obtain the effect improving toughness.Therefore, need in the present invention Make ACR value less than 1.5.
Therefore, if controlling ACR value more than 0 and less than 1.5, to be then effectively formed answering based on CaS Close sulfide, it is possible to become ferrite and generate core and effectively play a role.It should be noted that ACR value be preferably 0.15～ The scope of 1.30, the scope of more preferably 0.20～1.00.
5.5[C](4/3)+15[P]+0.90[Mn]+0.12[Ni]+7.9[Nb](1/2)+0.53[Mo]≤3.70
The above-mentioned formula left side (5.5 [C](4/3)+15[P]+0.90[Mn]+0.12[Ni]+7.9[Nb](1/2)+0.53[Mo]) It is the hardness number in the center segregation portion of the composition composition being easily gathered in center segregation portion, is referred to as in the following description Ceq*Value.
CTOD test is the test carried out under whole steel plate thickness, therefore, comprises center segregation and center at test film In the case of the composition of segregation is assembled significantly, generate hardening region at welding heat affected zone, test accordingly, as CTOD, it is impossible to Obtain good result.
Therefore, in the present invention, by by Ceq*Value controls at proper range excessive to the hardness suppressing center segregation portion Increase, even if also can obtain the CTOD characteristic of excellence at the weld part of the thicker steel plate of thickness of slab.
Ceq*The proper range experiment of value is tried to achieve, Ceq*When value is more than 3.70, CTOD characteristic reduces, and is therefore Less than 3.70, preferably less than 3.50.It should be noted that Ceq*The lower limit of value is not particularly limited, from productive viewpoint Deng consider, preferably about 2.2.
It addition, in the present invention, in addition to above-mentioned required composition, in order to improve hardenability, it is also possible to containing selected from Cu: One less than 0.7%, in Cr:0.1～1.0% and V:0.005～0.05% or two or more.
Cu: less than 0.7%
By adding Cu (copper), it is possible to increase armor plate strength.But, add and hot rolling can be made to reduce, therefore more than 0.7% It is limited to less than 0.7%, preferably 0.1～0.6%.
Cr:0.1～1.0%
Cr (chromium) is the effective element making steel plate high intensity, contains more than 0.1% to play this effect.But, If containing excess, then toughness can be had undesirable effect, therefore in the case of containing, preferably 0.1～the model of 1.0% Enclose, more preferably 0.2～the scope of 0.8%.
V:0.005～0.05%
V (vanadium) is intensity and the effective element of toughness containing more than 0.005% to raising steel plate, but exceedes at content When 0.05%, toughness can be caused to reduce, therefore in the case of containing, preferably 0.005～0.05%.
Additionally, in the present invention, in addition to above-mentioned required composition, in order to improve HAZ toughness, it is also possible to containing selected from Mg (magnesium): the one in 0.0002～0.0050% and REM:0.0010～0.0200% or 2 kinds.
Mg and REM is dispersion based on oxide and has toughness and improve the element of effect.In order to demonstrate such effect Really, Mg, the REM of more than 0.0010% of more than 0.0002% are added.On the other hand, though add Mg more than 0.0050%, REM more than 0.0200%, its effect is the most only to reach saturated.Therefore, in the case of adding these elements, preferably it is respectively Above-mentioned scope, more preferably Mg:0.0005～0.0020%, REM:0.0020～0.0150%.
Composition beyond above-mentioned steel plate composition is Fe and inevitable impurity, and particularly B (boron), at steel plate from austenite During the cooling of region, segregation suppresses ferrite transformation in austenite grain boundary, generates the bainite structure containing a large amount of M-A, therefore, The shortcoming being especially in the presence of the tissue embrittlement making welding heat affected zone.Therefore, in the present invention, the amount of the B in steel plate needs suppression Less than 0.0003%.
It addition, in steel plate, the change in size of precipitate is few before and after PWHT, need to keep the strength and toughness of steel plate.Fig. 1 In show after PWHT the pass of intensity/change in toughness (Δ TS, Δ vTrs) before and after precipitation size and precipitate composition, PWHT System, it addition, show in Fig. 2 that the TEM replica of precipitate in steel is observed and EDX analysis result.
About intensity, toughness, from the viewpoint of stability, the change before and after PWHT be respectively necessary for meeting Δ TS be 5～- 15MPa, Δ vTrs are the scope of 10～-5 DEG C.Therefore, as shown in Figure 1, in order to meet this scope, need precipitate is average Size suppression Ti amount (being expressed as (Ti)), Nb in below 20nm, and precipitate measures (being expressed as (Nb)) and Mo amount (represents For (Mo)) need to meet the relation of (Nb)/((Ti)+(Nb)+(Mo)) >=0.3.
It addition, from the table 1 of the EDX analysis result of precipitate in the steel shown in Fig. 2, above-mentioned precipitate be Ti, The precipitate of Nb and Mo, as long as the Ti amount in precipitate, Nb amount and Mo amount meet (Nb)/((Ti)+(Nb)+(Mo)) >=0.3 Relation, the most above-mentioned precipitate can be at least the precipitate of Nb, it is also possible to is meeting in the range of this relation containing Ti Precipitate with Mo.It should be noted that in the present invention PWHT excellent refer to meet Δ TS be 5～-15MPa, Δ vTrs It it is the scope of 10～-5 DEG C.And, the precipitate (miscible precipitate) in the present invention refers to the precipitate of Mo, Ti, Nb, concrete and Speech is the carbide of Mo, Ti, Nb, nitride or carbonitride or their mixture.
Table 1
(computation of precipitate particle diameter)
The computation of the precipitate particle diameter in the present invention is carried out according to TEM complex method.I.e., suitably gather in steel The precipitation portion of the carbide of Ti, Nb and Mo, is then based on the observation in 100,000 times of 4 visual field, uses image procossing to obtain average etc. Effect circular diameter, as the particle diameter of precipitate.It should be noted that in the present invention, the mensuration as precipitate particle diameter is right The lower limit of elephant is 2nm.This is owing to the precipitate of the precipitate particle diameter less than 2nm is difficult to measure.
It follows that the manufacture method of the steel of the present invention is illustrated.The steel of the present invention is preferably by the system of following description The method of making manufactures.
In the range of using the usual method employing converter, electric furnace, vacuum fusion stove etc. to being adjusted to the invention described above The molten steel of steel plate composition carries out melting, then, makes steel billet through continuous casting process, then makes desired plate by hot rolling Thickness, then cools down, and implements temper further according to needs.It should be noted that in hot rolling in the present invention, to steel billet Heating-up temperature and reduction ratio specify.
It should be noted that in the present invention, unless otherwise specified, the temperature conditions of steel plate refers to steel plate The temperature of the temperature defined of thickness of slab central part.The temperature of thickness of slab central part can be by thickness of slab, surface temperature and cooling condition etc. Obtained by simulation calculating etc..For example, it is possible to obtained in thickness of slab by the Temperature Distribution using calculus of finite differences to calculate thickness of slab direction The temperature in heart portion.
Billet heating temperature: 950～1150 DEG C
In order to make to be present in the casting flaw pressing effectively of steel billet by hot rolling, billet heating temperature is set to 950 DEG C Above.On the other hand, if by heating steel billet to the temperature more than 1150 DEG C, then austenite crystal coarsening and make the tough of steel plate Property reduce, therefore the upper limit of heating-up temperature is set to 1150 DEG C.
The accumulation reduction ratio of the hot rolling of the temperature range of more than 900 DEG C: more than 30%
Make it innoxious and by making austenite crystal recrystallization be formed fine to utilize the pressing of casting flaw Microstructure, the accumulation reduction ratio of the hot rolling of the temperature ranges of more than 900 DEG C is set to more than 30%.If this is because, Less than 30%, then the oversize grain generated when heating remains and has undesirable effect the toughness of steel plate.It should be noted that The upper limit of the accumulation reduction ratio of the hot rolling of the temperature range of more than 900 DEG C is not particularly limited, and industrial is about 95%.
The accumulation reduction ratio of the hot rolling of the temperature range less than 900 DEG C: 30～70%
Due to the austenite crystal recrystallization the most fully rolled in this temperature range, the therefore austenite after rolling Grain deformation is flat, in this condition, becomes the state that internal strain that inside comprises the defects such as a large amount of Zona transformans is high.They Play a role as the driving force of ferrite transformation, thus promote phase transformation.
But, when accumulation reduction ratio is less than 30%, the accumulation of the internal energy that internal strain causes is not enough, therefore, it is difficult to Occur ferrite transformation to make steel plate toughness reduce, on the other hand, if accumulation reduction ratio is more than 70%, promote polygon the most on the contrary The ferritic generation of shape, it is impossible to take into account high intensity and high tenacity.Therefore, in the present invention, will be less than the temperature range of 900 DEG C The accumulation reduction ratio of hot rolling is set to the scope of 30～70%.
Rate of cooling when being cooled at least 500 DEG C: more than 1.0 DEG C/sec
After hot rolling, rate of cooling is set to more than 1.0 DEG C/sec, accelerates to be cooled at least 500 DEG C.This be due to Enough armor plate strengths cannot be obtained when rate of cooling is less than 1.0 DEG C/sec.If it addition, stopping cold in the temperature higher than 500 DEG C But, then the tissue point rate of ferrite+pearlite increases, it is impossible to take into account high intensity and the high tenacity of thick-wall materials.Need explanation It is that the lower limit of the stopping temperature accelerating cooling is not particularly limited, and can be cooled to room temperature.
Temperature: 450～650 DEG C
In the case of carrying out temper in the present invention, when temperature is less than 450 DEG C, enough tempering can not be obtained Effect.On the other hand, if be tempered at a temperature of more than 650 DEG C, then precipitate becomes thick and makes toughness reduce, by force Degree reduces, the most preferred.
It addition, for the temper of the present invention, due to carbide during by using sensing heating can suppress to be tempered Coarsening, the most more preferably.In such a situation it is preferred that make the steel plate central temperature calculated by the simulation of calculus of finite differences etc. It it is 450～650 DEG C.
It should be noted that in the present invention, in the case of obtaining the desired performances of steel plate such as TMCP steel plate, also Above-mentioned temper can not be carried out.
The thickness of the thick-wall materials of the present invention is more than 15mm.Therefore, in the present invention, heavy wall refers to that the thickness of steel is More than 15mm, can obtain the scope that thickness is 40～100mm of the steel of effect of the present invention.It should be noted that above-mentioned heavy wall Manufacturing condition beyond the manufacturing condition of high tension steel sets according to usual way.
For the heavy wall high tension steel of the present invention, not only inhibit austenite crystal thick of welding heat affected zone Changing, and the ferrite transformation generation core making high temperature not melt disperses imperceptibly, the tissue thus making welding heat affected zone is micro- Refinement, therefore can obtain high tenacity.Even if it addition, being again heated to 2 alpha regions under the effect of thermal cycle when multilamellar is welded Region, is also micronized by the tissue initially welding the welding heat affected zone formed, and therefore, reheats region not at 2 alpha regions The toughness of phase change region is improved, then the austenite crystal of phase transformation also occurs miniaturization such that it is able to reduce what toughness reduced Degree.And, by generating the miscible precipitate of Ti, Nb, Mo imperceptibly, form CTOD characteristic and the heavy wall of PWHT excellent High-tensile steel.
Embodiment
It follows that embodiments of the invention are illustrated.
Using there is shown in table 2 steel billet of casting continuously becoming steel serial number A being grouped into～Z as raw material, then carry out Hot rolling shown in table 3 and heat treatment, manufactured the steel plate of thickness 50～150mm.As the evaluation methodology of steel plate, tension test As follows: in the way of the length direction of test film and the rolling direction of steel plate are vertical, to take JIS4 from thickness of slab 1/2 position of steel plate Number test film, determines yield stress (YS) and hot strength (TS).
It addition, Charpy-type test is as follows: from thickness of slab 1/2 position of steel plate with the length direction of test film and rolling of steel plate The vertical mode in direction processed takes JIS4 2mmV notch test sheet, absorption energy vE when determining-40 DEG C-40℃.Need explanation , in the present embodiment, YS >=460MPa, TS >=570MPa and vE will be met-40DEG C >=test film of all conditions of 200J It is evaluated as steel plate characteristic good.
The evaluation of toughness of welded zone is as follows: use レ type groove, makes the submerged-arc welding utilizing welding heat input 35kJ/cm The multiple-bead deposit seam connect and formed, using the welding weld bond of the flat side of thickness of slab 1/2 position of steel plate as Charpy-type test Incision site, determine absorption energy vE during-40 DEG C of temperature-40℃.Then, the meansigma methods of 3 test films is met vE-40℃ The test film of >=150J is judged to that toughness of welded zone is good.
It addition, using the welding weld bond of flat side as the incision site of CTOD test film, measure δ-10 DEG C (when being-10 DEG C CTOD value), the situation that minima is more than 0.5mm of middle for experiment quantity 3 CTOD value (δ-10 DEG C) is judged to that welding connects The CTOD characteristic of seam is good.
Additionally, taked the precipitation portion in steel by TEM complex method, image procossing is passed through in observations based on 100,000 times, 4 visuals field Obtain average equivalent circular diameter, as precipitation size.It addition, select particle diameter substantially near meansigma methods by EDX Precipitate, obtains this precipitate composition, obtains average (Nb) as 3/((Ti)+(Nb)+(Mo)).
For the steel plate characteristic variations after PWHT, Δ TS (=TS (after PWHT)-TS (before PWHT)), Δ vTrs are obtained (=vTrs (after PWHT)-vTrs (before PWHT)).For PWHT heat treatment, keep 4 hours at 580 DEG C, and will heat up, Cooling rate is set to 70 DEG C/h and carries out.
Table 3 describes hot-rolled condition, heat treatment condition and steel plate characteristic, the Charpy impact of above-mentioned weld part simultaneously Steel plate characteristic variations after result of the test and CTOD result of the test, precipitation size/composition, PWHT.
As shown in table 2, steel sequence number A～E are the steel meeting the present invention, and steel sequence number F～Z are that any one of composition of steel is at this Comparison steel beyond bright scope.It addition, sample No.1,2,5,6,8 and 11 of table 3 are example, obtain in welding weldering Mouthful Charpy-type test result, welding the three-point bending CTOD result of the test of weld bond, steel plate in precipitation size/composition and The all items of PWHT characteristic is satisfied by the result of target.
On the other hand, the steel plate composition of sample No.3,4,7,9,10,12～31, manufacturing condition, precipitation size/composition In at least one outside the scope of the present invention, steel plate characteristic, welding weld bond Charpy-type test result, welding weld bond three Any result/characteristic in some bending CTOD result of the test, PWHT characteristic is unsatisfactory for target.It should be noted that in table 3, The project of horizontal line refers to measure the meaning of this project.
In addition we know, for the steel of the example obtained according to the present invention, the yield stress (YS) of steel plate is More than 460MPa, Charpy-type test absorb energy (vE-40DEG C) it is more than 200J, armor plate strength, toughness are the most excellent, even and Solder joint weld bond, vE-40DEG C be also more than 150J, CTOD value be more than 0.5mm, the toughness of welding heat affected zone is the most excellent.Separately Outward, if the mean diameter of precipitate is below 20 μm and (Nb)/((Ti)+(Nb)+(Mo)) >=0.3, the then steel plate after PWHT Characteristic is the most excellent.On the other hand, it is known that the comparative example departed from the scope of the present invention only has obtained any characteristic in above-mentioned characteristic Poor steel plate.

Claims (5)

1. a steel plate, it has a following steel plate composition:
In terms of quality %, containing C:0.020～0.090%, Si:0.01～0.35%, Mn:1.40～2.00%, P:0.008% Below, below S:0.0035%, Al:0.010～0.060%, Ni:0.40～2.00%, Mo:0.05～0.50%, Nb: 0.005～0.040%, Ti:0.005～0.025%, N:0.0020～0.0050%, Ca:0.0005～0.0050% and O: Less than 0.0035%,
The scope that Ceq is 0.420～0.520% that following formula (1) specifies, meets following formula (2), formula (3) and formula (4), and By B suppression less than 0.0003%, surplus is made up of Fe and inevitable impurity,
Described steel plate has the precipitate that mean diameter is below 20nm, and this precipitate contains Ti, Nb and Mo, and Ti amount The content range of ((Ti)), Nb amount ((Nb)) and Mo amount ((Mo)) meets the relation of (Nb)/((Ti)+(Nb)+(Mo)) >=0.3,
Ceq=[C]+[Mn]/6+ ([Cu]+[Ni])/15+ ([Cr]+[Mo]+[V])/5 ... (1)
1.5≤[Ti]/[N]≤4.0…(2)
0 ＜ { [Ca]-(0.18+130 × [Ca]) × [O] }/1.25/ [S] ＜ 1.5 ... (3)
5.5[C](4/3)+15[P]+0.90[Mn]+0.12[Ni]+7.9[Nb](1/2)+0.53[Mo]≤3.70…(4)
Wherein, the content (quality %) of the element M during [M] represents steel plate.
Steel plate the most according to claim 1, wherein, possibly together with selected from Cu in terms of quality % in described steel plate composition: be less than 0.7%, the one in Cr:0.1～1.0% and V:0.005～0.05% or two or more.
Steel plate the most according to claim 1 and 2, wherein, possibly together with selected from Mg in terms of quality % in described steel plate composition: One in 0.0002～0.0050% and REM:0.0010～0.0200% or 2 kinds.
4. a manufacture method for steel plate, the method includes: will have the steel plate composition according to any one of claims 1 to 3 Steel be heated to 950～1150 DEG C after, the accumulation reduction ratio of the temperature range being implemented in more than 900 DEG C is more than 30%, little In the hot rolling that accumulation reduction ratio is 30～70% of the temperature ranges of 900 DEG C, then with the rate of cooling of more than 1.0 DEG C/sec extremely It is cooled to 500 DEG C less.
The manufacture method of steel plate the most according to claim 4, wherein, after described cooling, further at 450～650 DEG C Lower enforcement temper.
CN201480067195.XA 2013-12-12 2014-12-10 Steel plate and its manufacture method Active CN105980588B (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2013-257401 2013-12-12
JP2013257401 2013-12-12
PCT/JP2014/083321 WO2015088040A1 (en) 2013-12-12 2014-12-10 Steel sheet and method for manufacturing same

Publications (2)

Publication Number Publication Date
CN105980588A true CN105980588A (en) 2016-09-28
CN105980588B CN105980588B (en) 2018-04-27

Family

ID=53371334

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201480067195.XA Active CN105980588B (en) 2013-12-12 2014-12-10 Steel plate and its manufacture method

Country Status (6)

Country Link
US (1) US20160312327A1 (en)
EP (1) EP3081662B1 (en)
JP (1) JP5950045B2 (en)
KR (1) KR101846759B1 (en)
CN (1) CN105980588B (en)
WO (1) WO2015088040A1 (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019037749A1 (en) * 2017-08-23 2019-02-28 宝山钢铁股份有限公司 Steel for use in low-temperature pressurized vessel and manufacturing method therefor
CN110114495A (en) * 2016-12-22 2019-08-09 株式会社Posco Acidproof heavy wall steel and its manufacturing method with excellent low-temperature flexibility and rear heat treatment characteristic
CN110408840A (en) * 2018-04-27 2019-11-05 宝山钢铁股份有限公司 Superhigh intensity Marine Engineering Steel and its manufacturing method with excellent welding point CTOD performance
CN112779463A (en) * 2019-11-01 2021-05-11 株式会社神户制钢所 High-tension steel plate with excellent low-temperature toughness of base metal and joint and manufacturing method thereof
CN113366138A (en) * 2019-03-19 2021-09-07 杰富意钢铁株式会社 Method for manufacturing high manganese steel cast sheet, high manganese steel sheet, and method for manufacturing high manganese steel sheet
CN114763593A (en) * 2021-01-12 2022-07-19 宝山钢铁股份有限公司 Marine engineering steel with high humidity and heat atmosphere corrosion resistance and manufacturing method thereof
CN116171335A (en) * 2020-09-30 2023-05-26 杰富意钢铁株式会社 Steel plate

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3128024B1 (en) * 2014-03-31 2018-09-26 JFE Steel Corporation Welded joint
EP3128033B1 (en) * 2014-03-31 2019-05-22 JFE Steel Corporation High-tensile-strength steel plate and process for producing same
KR20170074319A (en) * 2015-12-21 2017-06-30 주식회사 포스코 Thick steel sheet having excellent low temperature toughness and resistance to hydrogen induced cracking, and method of manufacturing the same
WO2018181564A1 (en) * 2017-03-30 2018-10-04 Ｊｆｅスチール株式会社 High strength steel sheet for sour-resistant line pipe, method for manufacturing same, and high strength steel pipe using high strength steel sheet for sour-resistant line pipe
JP6816739B2 (en) * 2018-04-05 2021-01-20 Ｊｆｅスチール株式会社 Steel plate and its manufacturing method
KR102209581B1 (en) * 2018-11-29 2021-01-28 주식회사 포스코 The steel plate having excellent heat affected zone toughness and method for manufacturing thereof
CN111270169A (en) * 2018-12-05 2020-06-12 河南城建学院 Ni-containing alloy steel plate with excellent low-temperature toughness and production method thereof
CN109652733B (en) * 2019-01-07 2021-01-26 南京钢铁股份有限公司 690 MPa-grade super-thick steel plate and manufacturing method thereof
CA3134477C (en) * 2019-03-28 2023-09-05 Jfe Steel Corporation Steel material for line pipes, method for producing the same, line pipe, and method for producing the line pipe
CN112251569A (en) * 2020-09-11 2021-01-22 南京钢铁股份有限公司 Method for improving yield strength of Q460 grade high-strength steel plate

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001247932A (en) * 2000-03-08 2001-09-14 Nippon Steel Corp High ctod secured steel for low temperature use
CN102124133A (en) * 2008-03-31 2011-07-13 杰富意钢铁株式会社 High-tensile strength steel and manufacturing method thereof
WO2013145770A1 (en) * 2012-03-29 2013-10-03 Ｊｆｅスチール株式会社 Low yield ratio high-strength steel plate having superior strain aging resistance, production method therefor, and high-strength welded steel pipe using same

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60152626A (en) 1984-01-20 1985-08-10 Kawasaki Steel Corp Method for stabilizing toughness of high tension steel for welded structure
JPS60184663A (en) 1984-02-29 1985-09-20 Kawasaki Steel Corp High-tensile steel for low temperature service for welding with large heat input
JPS63211535A (en) 1988-02-10 1988-09-02 Hitachi Ltd Manufacture of osmium-coated impregnated type cathode
JPH0353367A (en) 1989-07-20 1991-03-07 Toshiba Corp Decentralized information processing system
JPH0792360B2 (en) 1989-07-10 1995-10-09 防衛庁技術研究本部長 Metal combustor manufacturing method
JPH06184663A (en) 1992-05-15 1994-07-05 Kobe Steel Ltd Ceramic-reinforced aluminum alloy composite material
JP3697202B2 (en) 2001-11-12 2005-09-21 新日本製鐵株式会社 Steel with excellent toughness of weld heat affected zone and method for producing the same
KR100776470B1 (en) 2003-11-27 2007-11-16 수미도모 메탈 인더스트리즈, 리미티드 High tensile steel excellent in toughness of welded zone and offshore structure
JP4507669B2 (en) * 2004-03-31 2010-07-21 Ｊｆｅスチール株式会社 Manufacturing method of low yield ratio steel for low temperature with excellent weld toughness
JP5055774B2 (en) * 2005-03-17 2012-10-24 Ｊｆｅスチール株式会社 A steel plate for line pipe having high deformation performance and a method for producing the same.
KR100851189B1 (en) * 2006-11-02 2008-08-08 주식회사 포스코 Steel plate for linepipe having ultra-high strength and excellent low temperature toughness and manufacturing method of the same
KR100868423B1 (en) * 2006-12-26 2008-11-11 주식회사 포스코 High strength api-x80 grade steels for spiral pipes with less strength changes and method for manufacturing the same
WO2011096456A1 (en) * 2010-02-08 2011-08-11 新日本製鐵株式会社 Production method for thick steel plate
JP5177310B2 (en) * 2011-02-15 2013-04-03 Ｊｆｅスチール株式会社 High tensile strength steel sheet with excellent low temperature toughness of weld heat affected zone and method for producing the same
CN102691015A (en) * 2011-03-25 2012-09-26 宝山钢铁股份有限公司 YP500MPa-level thick steel plate with excellent low-temperature toughness and manufacturing method thereof
JP5304925B2 (en) * 2011-12-27 2013-10-02 Ｊｆｅスチール株式会社 Structural high-strength thick steel plate with excellent brittle crack propagation stopping characteristics and method for producing the same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001247932A (en) * 2000-03-08 2001-09-14 Nippon Steel Corp High ctod secured steel for low temperature use
CN102124133A (en) * 2008-03-31 2011-07-13 杰富意钢铁株式会社 High-tensile strength steel and manufacturing method thereof
WO2013145770A1 (en) * 2012-03-29 2013-10-03 Ｊｆｅスチール株式会社 Low yield ratio high-strength steel plate having superior strain aging resistance, production method therefor, and high-strength welded steel pipe using same

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110114495A (en) * 2016-12-22 2019-08-09 株式会社Posco Acidproof heavy wall steel and its manufacturing method with excellent low-temperature flexibility and rear heat treatment characteristic
US11649519B2 (en) 2016-12-22 2023-05-16 Posco Co., Ltd Sour-resistant heavy-wall steel plate having excellent low-temperature toughness and post-heat treatment characteristics and method for manufacturing same
WO2019037749A1 (en) * 2017-08-23 2019-02-28 宝山钢铁股份有限公司 Steel for use in low-temperature pressurized vessel and manufacturing method therefor
CN110408840A (en) * 2018-04-27 2019-11-05 宝山钢铁股份有限公司 Superhigh intensity Marine Engineering Steel and its manufacturing method with excellent welding point CTOD performance
CN113366138A (en) * 2019-03-19 2021-09-07 杰富意钢铁株式会社 Method for manufacturing high manganese steel cast sheet, high manganese steel sheet, and method for manufacturing high manganese steel sheet
CN112779463A (en) * 2019-11-01 2021-05-11 株式会社神户制钢所 High-tension steel plate with excellent low-temperature toughness of base metal and joint and manufacturing method thereof
CN116171335A (en) * 2020-09-30 2023-05-26 杰富意钢铁株式会社 Steel plate
CN114763593A (en) * 2021-01-12 2022-07-19 宝山钢铁股份有限公司 Marine engineering steel with high humidity and heat atmosphere corrosion resistance and manufacturing method thereof

Also Published As

Publication number Publication date
EP3081662A1 (en) 2016-10-19
US20160312327A1 (en) 2016-10-27
CN105980588B (en) 2018-04-27
KR20160088375A (en) 2016-07-25
WO2015088040A1 (en) 2015-06-18
EP3081662A4 (en) 2016-12-07
JPWO2015088040A1 (en) 2017-03-16
KR101846759B1 (en) 2018-04-06
WO2015088040A8 (en) 2016-05-06
JP5950045B2 (en) 2016-07-13
EP3081662B1 (en) 2019-11-13

Similar Documents

Publication Publication Date Title
CN105980588B (en) Steel plate and its manufacture method
CN103874777B (en) The high-tensile steel of the excellent in low temperature toughness of welding heat affected zone and its manufacture method
CN101541994B (en) Weld steel pipe with excellent low-temperature toughness for high-strength line pipe and process for producing the same
JP5162382B2 (en) Low yield ratio high toughness steel plate
KR20150094793A (en) High-tensile strength steel and manufacturing method thereof
CN107109589A (en) The steel for high strength pressure vessel material and its manufacture method of tenacity excellent after PWHT
US20060016526A1 (en) High-strength steel for welded structures excellent in high temperature strength and method of production of the same
JP2009041079A (en) Steel for welded structure having excellent toughness in weld heat-affected zone, method for producing the same, and method for producing welded structure
CN105829565A (en) Ultrahigh-strength welded structural steel having excellent toughness in welding heat-affected zones thereof, and production method therefor
CN104603313A (en) Thick-walled, high tensile strength steel with excellent CTOD characteristics of the weld heat-affected zone, and manufacturing method thereof
CN106133168B (en) High-tensile steel and its manufacturing method
CN105579602A (en) Thick steel sheet having excellent CTOD properties in multi-layer welded joints and method for producing same
CN109689912A (en) High input energy welding steel material
JP4891836B2 (en) Steel plate with excellent toughness of weld heat affected zone in high heat input welding
CN105899702B (en) Steel material for welding
CN102443742B (en) High-strength steel plate with 980 mpa or above tensile strength excellent in low temperature toughness of multilayer welding joint portion
WO2017094593A1 (en) Non-heat-treated steel sheet having high yield strength in which hardness of a welding-heat-affected zone and degradation of low-temperature toughness of the welding-heat-affected zone are suppressed
JP5818343B2 (en) Thick steel plate with excellent toughness in weld heat affected zone
CN106574316A (en) Method of manufacturing steel plate for high-heat input welding
CN108603267A (en) High input energy welding steel material
CN106133165A (en) Welding point
CN110073020A (en) Weldability and the excellent high tensile hot rolled steel sheet and its manufacturing method of ductility
JP7485920B2 (en) Intermediate bending roll steel pipe
WO2016068094A1 (en) High-tensile steel sheet having excellent low-temperature toughness in weld heat-affected zone, and method for manufacturing same
JPS6293312A (en) Manufacture of high tensile steel stock for stress relief annealing

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant