CN116162869B - A fatigue-resistant steel plate in marine environment and its production method - Google Patents
A fatigue-resistant steel plate in marine environment and its production method Download PDFInfo
- Publication number
- CN116162869B CN116162869B CN202211611544.2A CN202211611544A CN116162869B CN 116162869 B CN116162869 B CN 116162869B CN 202211611544 A CN202211611544 A CN 202211611544A CN 116162869 B CN116162869 B CN 116162869B
- Authority
- CN
- China
- Prior art keywords
- steel
- fatigue
- steel plate
- controlled
- rolling
- 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.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—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
- 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
- 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
- C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
-
- 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
- C22C38/18—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
- 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
- C21D2211/002—Bainite
-
- 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
-
- 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
- C21D2211/005—Ferrite
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 invention discloses an anti-fatigue steel plate in marine environment and a production method thereof, wherein the production method of steel grade component content C:0.02-0.04％,Si:0.15-0.3％,Mn:0.4-0.6％,V:0.04-0.06％,N:0.008-0.012％,Cu:0.2-0.4％,Ni:1-2％,Mo:0.1-0.2％,Re:0.021-0.034％,Cr:1.5-2％,REM:0.03-0.05％,Sn:0.05-0.1％,Ti：0.001-0.005wt％,P:0.015-0.02％,S:≤0.005％. comprises the steps of feeding steel billets into a furnace to a temperature less than or equal to 80 ℃, adopting multi-stage heating, discharging the steel billets out of the furnace to a temperature of 960-1000 ℃, starting rolling at a finish rolling temperature of over 910 ℃, reducing pass rolling amount of 20-30%, cooling after rolling at a cooling speed of 2-5 ℃ per second, adopting a stacking or heat preservation treatment mode to regulate and control, and keeping the temperature to be 250-400 ℃. The steel grade solves the fatigue-corrosion coupling problem faced by the ocean structure under the condition of strong storm and high wave load in the south China sea environment.
Description
Technical Field
The invention belongs to the technical field of metal material preparation, and particularly relates to an anti-fatigue steel plate in a marine environment and a production method thereof.
Background
The area of the south sea area is 356 ten thousand square kilometers, which is the main channel for east-west communication, and about 90% of the energy inlets in the current stage of China can pass through the south sea area. In addition, the south sea has extremely rich natural resources and strategic values, is one of the most rich sea areas, and has more than 300 hundred million tons of petroleum resources, more than 680 hundred tons of oil and gas equivalent combustible ice resources and the maximum wind energy and wave energy resources.
The south sea area has unique high temperature (the ocean surface temperature is 25-28 ℃ and is up to 30 ℃), high salt (the Cl - deposition rate is 1.12mg/100cm 2 d or more), strong storm (the maximum wave height is about 30 m) and other strong corrosiveness and fatigue damage environmental factors, the natural environment is harsh, and the material corrosion problem is quite remarkable. According to the ISO9223 classification standard, the corrosion grade of the material in the area can reach the highest grade C5, and the water surface ship, the offshore floating platform, the island reef building and the equipment which are in service under the environment at present can be corroded seriously in a premature manner when compared with other areas even if corrosion protection measures are taken. According to statistics, the failure rate of equipment in the service of the south China sea area is about 3 times that of other sea areas and about 10 times that of the continental area. Causing economic losses of nearly trillion yuan to the country each year. The south sea environment comprises island construction, resource exploitation platforms, offshore living auxiliary equipment, offshore clean energy development equipment and the like, mainly adopts a steel structure, and the steel consumption can reach 100 ten thousand tons/year in the future 5-10 years along with the gradual implementation of national ocean and south sea strategies.
In addition to being faced with a severe and complex ocean environment with high salt and high temperature in the service process, the south ocean engineering structure is often subjected to repeated actions of environmental loads such as sea wind, sea wave, ocean current and the like and operation dynamic loads, for example, an ocean platform with the design life of 20-25 years can achieve hundreds of millions of times of alternating stress circulation times caused by wave action in the service period. In addition, the marine environment is used for constructing engineering structures, particularly ocean platforms, which often support various devices with a total mass of hundreds of tons, so that the devices bear extremely large working stress, the devices are large in size and thickness, joint defects such as microcracks, air holes, slag inclusion and unfused are extremely easy to become crack sources of corrosion and fatigue, and the fatigue toughness of the devices is reduced, so that the problems of fatigue must be considered in the use of the marine engineering structures and the service process of the marine engineering structures. At present, research and development of special materials in severe environments of south China sea are not systematic, related researches are mainly carried out on corrosion resistance of materials, the patent of China application number 201710075154.0 is 'high corrosion resistance low alloy steel suitable for high-temperature coastal environments', corrosion resistance is superior to that of Q235 carbon steel and other weather resistant steels, a high Ni system is adopted, alloying is carried out by matching with elements such as Cu and Mo, the problems are high cost, and the problems are caused due to high alloying and carbon equivalent and welding performance, and at present, no report is available on the fatigue resistant steel of the materials under the conditions of strong corrosion, strong storm and high wave load in the south China sea.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide an anti-fatigue steel plate in a marine environment and a production method thereof, which solve the problem of fatigue-corrosion coupling faced by marine structures with strong storm and high wave load conditions.
In order to solve the problems, the technical scheme adopted by the invention is that the anti-fatigue steel plate in the marine environment comprises the following chemical components in percentage by weight, wherein the balance of C:0.02-0.04wt％,Si:0.15-0.3wt％,Mn:0.4-0.6wt％,V:0.04-0.06wt％,N:0.008-0.012wt％,Cu:0.2-0.4wt％,Ni:1-2wt％,Mo:0.1-0.2wt％,Re:0.021-0.034wt％,Cr:1.5-2wt％,REM:0.03-0.05wt％,Sn:0.05-0.1wt％,Ti：0.001-0.005wt％,P:0.015-0.02wt％,S:≤0.005wt％, is Fe and unavoidable impurities.
Further, the steel sheet contains 55-70% bainite+23-35% ferrite (containing 6-12% acicular ferrite) structure in terms of area percentage, contains V (C, N) and Mo 2 C nano-phases dispersed and precipitated with an average size of 15-25nm, the average spacing of these phases is 1.2-2.5 μm, contains Cu nano-phases with an average size of 17-25nm, and the average spacing of the phases is 1-2 μm.
Further, the size of the V (C, N) and Mo 2 C nano-phase which are dispersed and separated out is 10-30nm, and the size of the Cu nano-phase is 15-30nm.
Further, the average grain size of the steel sheet surface layer-1/8 thickness is 15-25 μm.
Further, the yield strength of the steel is 420-460 mpa, the yield ratio is less than or equal to 0.75, the impact energy at minus 40 ℃ is not less than 180J, the elongation is more than or equal to 20%, and the reduction of area is more than or equal to 68%.
Further, the test sample is not broken when the loading stress ratio is 0.1, the frequency is 90HZ, the highest stress is 0.7Rel, and the cycle number reaches 10 7, -20 degrees CCTOD delta m is more than 0.62mm.
Further, by adopting a circumferential immersion test of simulating a splash zone of the seawater in the south China sea, the corrosion resistance is 84-86% compared with that of 3Ni system steel.
The invention relates to a production method of an anti-fatigue steel plate in a marine environment, which comprises smelting, continuous casting, billet heating, rolling and off-line treatment, and comprises the following specific contents:
Heating the steel billet, namely cold charging the steel billet into a furnace at a temperature of less than or equal to 80 ℃ and adopting multi-stage heating, wherein the total time of 500-950 ℃ is controlled to be 0.2-0.3min/mm, the total time of 1150-1180 ℃ is controlled to be within 0.1min/mm, and the total time of 1120-1150 ℃ is controlled to be 0.2-0.4min/mm;
Rolling and cooling control, namely rolling the billet after the billet is discharged from the furnace to 960-1000 ℃ and starting the rolling, wherein the final rolling temperature is controlled to be above 910 ℃, the pass reduction is controlled to be 20-30%, and the cooling speed after rolling is controlled to be 2-5 ℃ per second;
3) And (3) performing off-line treatment, namely performing second-stage precipitated phase and internal stress regulation by adopting a stacking or heat preservation treatment mode after the steel plate is off-line, wherein the heat preservation regulation temperature is 250-400 ℃.
Further, the steel grade is smelted by adopting a converter, the Ti element in molten iron is controlled below 0.005%, and Si and Mn are used for deoxidization.
Further, the steel billet is prepared by converter smelting and continuous casting, the surface temperature of the steel billet begins to be cooled at 830-910 ℃, the cooling speed is controlled at 3-9 ℃ per second, and then the steel billet is heated at 220-370 ℃ by adopting low-temperature heating treatment.
The anti-fatigue steel plate produced according to the scheme has the following beneficial effects:
1. The corrosion resistance of the steel plate is greatly improved through the addition and the synergistic effect of the composite microelements. The simulated circumferential immersion test of the splash zone of the seawater in the south China sea is adopted, the corrosion resistance is 84-86% higher than that of the steel in a 3Ni system (64 d), and the corrosion resistance is improved by 14-16%.
2. Has better comprehensive mechanical property, structural safety and weldability, the yield strength is 420-460 mpa, the yield ratio is less than or equal to 0.75, the impact power at minus 40 ℃ is not less than 180J, the elongation is more than or equal to 20%, and the area shrinkage is more than or equal to 68%.
3. The loading stress ratio is 0.1, the frequency is 90HZ, when the highest stress is 0.7Rel, and the cycle number reaches 10 7, the test sample is not broken, and the minus 20 DEG CCTOD delta m is more than 0.62mm.
Detailed Description
The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other examples of modifications and alterations will be apparent to those skilled in the art based on the examples herein, and are intended to be within the scope of the invention. It should be understood that the embodiments of the present invention are only used for illustrating the technical effects of the present invention, and are not used for limiting the scope of the present invention.
Aiming at the problem that no material is available under the complex environment conditions of strong corrosion and heavy wave load in the south China sea, the developed steel has good mechanical property, corrosion resistance and fatigue resistance, and the corrosion resistance of the steel plate is greatly improved through the addition and synergistic effect of the composite trace elements and the matched preparation process. The fatigue resistance steel with the fatigue limit more than 310MPa (-20 DEG CCTOD is more than or equal to 0.6 mm) is developed. Can solve the fatigue-corrosion coupling problem faced by marine structures under the condition of strong storm and high wave load in the south China sea environment. Provides an effective solution for the safe service of the marine structure in the strong storm marine environment such as the south China sea.
The steel composition of the present invention will be described in detail below, and unless otherwise specified, it is shown that the% content of each element is based on weight.
The invention relates to an anti-fatigue steel plate in a marine environment, which comprises the following chemical components in percentage by weight, wherein the balance of C:0.02-0.04wt％,Si:0.15-0.3wt％,Mn:0.4-0.6wt％,V:0.04-0.06wt％,N:0.008-0.012wt％,Cu:0.2-0.4wt％,Ni:1-2wt％,Mo:0.1-0.2wt％,Re:0.021-0.034wt％,Cr:1.5-2wt％,REM:0.03-0.05wt％,Sn:0.05-0.1wt％,Ti：0.001-0.005wt％,P:0.015-0.02wt％,S:≤0.005wt％, is Fe and unavoidable impurities.
C:0.02-0.04wt%
The element C is a main phase transformation control element forming a matrix corrosion resistant structure with 55-70% of bainite+23-35% of ferrite (containing 6-12% of acicular ferrite) contained in the steel plate, is an important element for ensuring the strength of the steel grade, and is suitable for promoting the generation of important micro cathode phases V (C, N) and Mo 2 C in the invention and controlling the precipitation of massive carbides of Cr, and the phases are beneficial to improving the corrosion resistance of the steel, and more C is unfavorable to the corrosion resistance and weldability of the steel under the component system of the invention, so the content of C is 0.02-0.04wt%.
Si:0.15-0.3wt%
The Si element has a certain effect on strengthening and forming surface oxides with Cr, cu and Sn, so that the corrosion resistance is effectively improved, the Si element is one of the important deoxidizers, but too high Si can reduce the compactness of a rust layer on the surface of the steel grade, and the content of the Si is controlled to be 0.15-0.3wt%.
Mn:0.4-0.6wt%
Mn plays a certain role in the combination control of strengthening and fatigue performance, is one of the important deoxidizers, and can reduce the corrosion resistance of steel too much, influence the solid solution effect of the corrosion resistant element in the steel and be unfavorable for the fatigue resistance because too low, so that the content of Mn is controlled to be 0.4-0.6wt%.
V:0.04-0.06wt%
The V element mainly plays an important role in the toughness, fatigue resistance and corrosion resistance of steel in a precipitation strengthening mode, the V element mainly forms V (C, N) with C and N in proper proportion, and as the steel material is a multi-phase structure formed by multi-element alloying, the control of the proportion of a cathode and an anode in a micro-area is very important, and the control of the corrosion resistance of a refined, dispersed, uniform and distributed cathode design relative to a complex structural system of the steel material is very important. In the present invention, under the control of cathode phase and the element configuration of V, C, N, cr, etc., V (C, N) with the average interval of 1.2-2.5 microns and with the average interval of 10-30nm is produced in the steel matrix, so as to prevent fatigue and other crack growth. The content of V is 0.04-0.06wt% based on the above design.
N:0.008-0.012wt%
The N element is mainly used for promoting the compound precipitation of V (C, N) and Fe 3 C of fine particles, and in addition, the solid solution N is beneficial to improving the corrosion resistance of steel, and the fatigue resistance is not beneficial to the excessively low.
Cu:0.2-0.4wt%
Cu is an important element for corrosion resistance and mechanical property improvement of the invention. On the one hand, in early stage of corrosion, after the surface is subjected to preliminary corrosion, an enriched layer and an oxide layer are formed, no remarkable segregation behavior is improved, in addition, a nano phase with an average size of 17-25nm is formed in the steel plate, the average distance of the phases is 1-2 mu m, after the surface rust layer is destroyed, a large number of fine cathode phases are further formed, a special cathode size and distribution control system is formed with V (C, N), mo 2 C and Fe 3 C, the corrosion speed is controlled, the improvement and control of weldability are facilitated, and excessive Cu is unfavorable for further exertion of corrosion resistance and fatigue performance, and unnecessary cost is increased, so that the Cu is controlled to be 0.2-0.4wt%.
Ni:1-2wt%
The invention adopts low Mn component design, so that Ni can more effectively promote the generation of Fe 3O4 oxide, and Ni 2+ in a rust layer can more effectively occupy the gap position of Fe 3O4 to form stable and compact intermetallic compound of Fe and Ni, thereby preventing Cl - from diffusing to a matrix, reducing acidification and improving the PH value of electrolyte in the rust layer, and further fully achieving the corrosion resistance by only adopting 1-2wt% of Ni.
Mo:0.1-0.2wt%
The Mo element can densify the rust layer and is combined with Si and Cu simultaneously, so that the formed oxide film is effective for initial corrosion, and the Mo 4 2- is eluted with the anodic reaction of the steel material, and the Mo 4 2- is distributed on the rust layer, thereby generating ion selection and resisting the invasion of Cl - of the corrosion promoting factor. In addition, the addition of Mo is beneficial to improving the low-temperature and high-temperature stability of the dispersed phase of V and Cu, and simultaneously separating out 10-30nmMo 2 C, so that the pitting corrosion resistance and the fatigue resistance of the alloy are improved. Too high Mo will deteriorate toughness, too low adversely affecting fatigue resistance, and thus is controlled to 0.1 to 0.2wt%.
Re:0.021-0.034wt%
Re element is uniformly distributed between dendrite stems and dendrite in the solidification process, is an important solid solution strengthening element, has the corrosion potential of about 0.3V, can enable the corrosion potential to positively shift, effectively improves the corrosion potential of a matrix, reduces the corrosion current of a system and improves the corrosion resistance of steel. In addition, the proper amount of Re and Ni and Cu can effectively promote the anode passivation and improve the cathode efficiency, and the anode current in the passivation area is several orders of magnitude smaller than the current of activation dissolution, so that the corrosion resistance of the alloy is effectively improved by utilizing the cathode element. The addition of Re helps to improve the low and high temperature stability of the dispersed phases of V and Cu. In addition, the compound addition of Re and V, ni can effectively control the toughness control problem caused by the addition of elements such as Sn, and the like, so that the content is controlled to be 0.021-0.034wt%.
Cr:1.5-2wt%
In addition, in the component design of the multi-element system, solid solution elements such as Cr and the like are fully dissolved in a matrix, the solid solution capacity of V is reduced, the precipitation behavior of the V is improved, the effect of controlling thermodynamic and kinetic changes of V (C, N) is indirectly played, and after the stable rust layer is formed by the compounding effect of the elements such as Cr, V, the inductive reactance effect tends to completely disappear, so that the fatigue resistance and the pitting resistance of the material are optimally matched, and the fatigue resistance performance is excessively low. The Cr content of the present invention is controlled to be 1.5-2wt% as required for the environment.
REM:0.03-0.05wt%
On the one hand, REM rare earth elements can change the size of cathode phases such as V (C, N), improve the dispersity, improve the potential and reduce the cathode effect, and as the content reaches 0.03-0.05wt%, the REM rare earth elements are fully dissolved in a matrix to play a role in improving the potential of the matrix and directly generate corrosion resistance, while RE absorbed by the mismatch positions of grain boundaries, subgrain boundaries and educts plays a role in balancing the segregation of elements such as Cr, cu, and the like, thereby reducing inter-crystal and inter-phase corrosion caused by the segregation.
Sn:0.05-0.1wt%
On one hand, sn element reduces the energy level of steel in a simple substance solid solution mode, weakens the electrochemical activity of the steel, is beneficial to forming oxides such as SnO and the like to be deposited on the corrosion front, promotes the generation of alpha-FeOOH, and compacts an oxide layer together with the alpha-FeOOH, when the Sn element is dissolved together with Fe, the ionic Sn element can be combined with Cl -, the local PH value is improved, the corrosion process is controlled to be accelerated, and the Sn element is controlled to be 0.05-0.1wt% according to the environmental requirement.
Ti:0.001-0.005wt%
Ti element contributes to control of the initial grain size, but too much N element is consumed to affect the strength and corrosion resistance of the steel, for which the Ti of the present invention is controlled to be 0.001-0.005wt%.
P:0.015-0.02wt%
The P element is mainly used for reducing the anodic polarization degree, promoting the uniform dissolution of steel and accelerating the oxidation rate of iron, promoting the formation of a non-static protective film, and being matched with Re, cu and the like to resist the invasion of Cl -, but too much P reduces the weldability of the steel, and the converter smelting process is taken as an example, and special control is not needed, so that the P is controlled to be 0.015-0.02wt%.
S:≤0.005wt%
S, sulfide formed by the element accelerates corrosion and reduces toughness of the steel sheet, so that the sulfur content needs to be strictly controlled to be less than or equal to 0.005wt%.
The balance of Fe and unavoidable impurities in the present invention may be Fe and unavoidable impurities in addition to the above-mentioned steel components. Unavoidable impurities cannot be completely removed as impurities which are not artificially mixed in a general steel manufacturing process, and the meaning thereof can be easily understood by those skilled in the art of general steel manufacturing. Moreover, the present invention does not completely exclude the addition of other components in addition to the steel components described above.
The microstructure of the present invention is described in further detail below.
The invention relates to an anti-fatigue steel plate in marine environment, wherein the average grain size of the surface layer-1/8 thickness of the steel plate is 15-25 mu m, the steel plate contains 55-70% of bainite+23-35% of ferrite (containing 6-12% of acicular ferrite), the percentage is area percentage, the steel plate contains dispersed V (C, N) and Mo 2 C nano phases, the sizes of the phases are 10-30nm, the average size is 15-25nm, the average spacing is 1.2-2.5 mu m, the dispersed Cu nano phases are 15-30nm, the average size is 17-25nm, and the average spacing of the phases is 1-2 mu m.
The production process of the present invention is described in further detail below.
The production method of the anti-fatigue steel plate in the marine environment comprises smelting, continuous casting, billet heating, rolling and cooling control and off-line treatment, and comprises the following specific contents:
Smelting, namely smelting the steel grade by adopting a converter, refining and vacuum degassing. Si and Mn are used for deoxidization, and the use of Al is strictly controlled, because the addition of Al consumes N element and has harmful effect on the surface quality of a steel billet, and the introduction of Ti element (controlled below 0.005%) is strictly controlled in similar molten iron, so that the precipitation effect of V and Cu is affected, and the formation of carbonitrides such as Ti, al and Nb is avoided, which is unfavorable for corrosion resistance.
The continuous casting is that the billet is manufactured by converter smelting and continuous casting, and the compact rust layer is realized in order to control the initial surface grain size of the continuous casting billet and the solid distribution of Re, W, mo, cu, ni, cr and other elements. When the billet is taken out, the rapid cooling mode is adopted for pretreatment, the temperature of the cold surface is controlled to be 830-910 ℃, the cooling speed is controlled to be 3-9 ℃ per second, the billet is not suitable for hot charging, the low-temperature heating treatment is adopted, the treatment temperature is 220-370 ℃, and the surface quality and the thermal stress distribution of the billet are controlled.
And heating the steel billet, namely controlling the temperature of cold charging of the steel billet into a furnace to be less than or equal to 80 ℃, adopting multi-stage heating, wherein the total time of 500-950 ℃ is controlled to be 0.2-0.3min/mm, the total time of 1150-1180 ℃ is controlled to be within 0.1min/mm, and the total time of 1120-1150 ℃ is controlled to be 0.2-0.4min/mm. The aim is to control the initial distribution of alloying elements and trace elements before hot working. Due to the distribution and composition of grains, particularly grain boundaries, there is a great influence on corrosion, and therefore, it is necessary to reasonably control the initial grain size.
Rolling under controlled temperature and pressure, namely rolling a specific billet after being discharged from a furnace to 960-1000 ℃ and rolling the billet at a finishing temperature above 910 ℃, wherein the pass reduction is controlled to 20-30%, and the billet rapidly passes through an austenite phase transformation zone in a rapid cooling mode after rolling, wherein the cooling speed is controlled to 2-5 ℃ per second, and the aim is to balance phase transformation and grain size. The grain size of the surface is controlled, the average grain size of the surface layer-1/8 thickness of the steel plate is controlled to be 15-25 mu m, the distribution state of surface corrosion-resistant elements is controlled, the precipitation of elements such as V, cu, mo and the like is inhibited, the supercooling of components in steel is improved, the balance of mechanical property and corrosion resistance can be ensured by controlling the grain size of the surface, and 55-70% bainite+23-35% ferrite (containing 6-12% acicular ferrite) is formed as a matrix corrosion-resistant structure in the process.
And (3) performing off-line treatment, namely performing second-stage precipitated phase and internal stress regulation and control by adopting a stacking and heat preservation treatment mode after the steel plate is off-line, wherein the heat preservation temperature is 250-400 ℃, so that on one hand, the hardness of the surface layer can be regulated and controlled, the mechanical property of the surface of the steel plate is improved, and on the other hand, finer precipitates are formed, and the overall corrosion resistance of the steel plate is improved. V (CN), VN and Mo 2 C which are dispersed and separated out and have the size of 10-30nm (average size of 15-25 nm) are generated in the regulated steel matrix, the average spacing of the phases is 1.2-2.5 mu m, meanwhile, a Cu nano phase with the size of 15-30nm (average size of 17-25 nm) is also present in the matrix, and the average spacing of the phases is 1-2 mu m.
According to the chemical composition and the production process, the actual smelting composition of the invention is shown in table 1, the actual process parameters of the invention are shown in tables 2-4, and the physical properties are shown in tables 5-8.
Table 1 example ingredients
| C | Si | Mn | V | N | Cu | Ni | Mo | Re | Cr | RE | Sn | P | S | Ti | |
| 1 | 0.02 | 0.3 | 0.57 | 0.041 | 0.01 | 0.25 | 1.58 | 0.18 | 0.025 | 2 | 0.04 | 0.09 | 0.016 | 0.002 | 0.03 |
| 2 | 0.02 | 0.17 | 0.56 | 0.04 | 0.009 | 0.4 | 1.02 | 0.09 | 0.024 | 1.81 | 0.03 | 0.07 | 0.019 | 0.002 | 0.02 |
| 3 | 0.03 | 0.19 | 0.43 | 0.043 | 0.011 | 0.21 | 1.77 | 0.18 | 0.034 | 1.76 | 0.035 | 0.09 | 0.018 | 0.002 | 0.02 |
| 4 | 0.02 | 0.27 | 0.46 | 0.041 | 0.008 | 0.39 | 1.24 | 0.17 | 0.032 | 2 | 0.03 | 0.08 | 0.016 | 0.001 | 0.03 |
| 5 | 0.03 | 0.16 | 0.6 | 0.05 | 0.009 | 0.33 | 1.36 | 0.2 | 0.021 | 1.96 | 0.04 | 0.05 | 0.015 | 0.003 | 0.01 |
| 6 | 0.03 | 0.22 | 0.41 | 0.059 | 0.007 | 0.3 | 1.92 | 0.15 | 0.031 | 1.59 | 0.043 | 0.09 | 0.019 | 0.001 | 0.03 |
| 7 | 0.03 | 0.18 | 0.46 | 0.046 | 0.009 | 0.29 | 1.62 | 0.15 | 0.022 | 1.93 | 0.04 | 0.07 | 0.02 | 0.002 | 0.03 |
| 8 | 0.02 | 0.17 | 0.55 | 0.045 | 0.008 | 0.32 | 1.45 | 0.14 | 0.034 | 1.85 | 0.042 | 0.06 | 0.016 | 0.003 | 0.01 |
| 9 | 0.02 | 0.29 | 0.42 | 0.052 | 0.012 | 0.25 | 2 | 0.16 | 0.026 | 1.5 | 0.05 | 0.08 | 0.019 | 0.002 | 0.03 |
| 10 | 0.03 | 0.2 | 0.42 | 0.05 | 0.008 | 0.37 | 1.84 | 0.19 | 0.027 | 1.82 | 0.037 | 0.09 | 0.015 | 0.002 | 0.03 |
Table 2 pretreatment of steel
Table 3 heating process
Table 4 rolling process and off-line process
TABLE 5 Steel sheet Structure proportion
Table 6 tensile and impact Properties of examples
Table 7 fatigue properties of examples
Table 8 Corrosion resistance of the examples (g/m 2. H)
It should be noted that the above embodiments are merely for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solution described in the above embodiments may be modified or some or all of the technical features may be equivalently replaced, and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present invention.
Claims (7)
1. An anti-fatigue steel plate in marine environment is characterized in that the steel comprises the chemical components of C:0.02-0.04wt％,Si:0.15-0.3wt％,Mn:0.4-0.6wt％,V:0.04-0.06wt％,N:0.008-0.012wt％,Cu:0.2-0.4wt％,Ni:1-2wt％,Mo:0.1-0.2wt％,Re:0.021-0.034wt％,Cr:1.5-2wt％,REM:0.03-0.05wt％,Sn:0.05-0.1wt％,Ti：0.001-0.005wt％,P:0.015-0.02wt％,S:≤0.005wt％, percent of Fe and unavoidable impurities in balance, wherein the steel plate comprises 55-70 percent of bainite+23-35 percent of ferrite structure in percentage by area, V (C, N) and Mo 2 C nano phases which are dispersed and separated out in average size of 15-25nm, the average spacing of the phases is 1.2-2.5 mu m, cu nano phases which are 17-25nm in average size are contained, the average spacing of the Cu nano phases is 1-2 mu m, 23-35 percent of ferrite contains 6-12 percent of acicular ferrite, the dispersed and separated V (C, N) and Mo 2 C nano phases are 10-30nm in size, the Cu nano phase size is 15-30nm, and the average grain size of the surface layer-1/8 thickness of the steel plate is 15-25 mu m.
2. The anti-fatigue steel plate in the marine environment according to claim 1, wherein the yield strength of the steel is 420-460 MPa, the yield ratio is less than or equal to 0.75, the impact energy at minus 40 ℃ is not less than 180J, the elongation is not less than 20%, and the area shrinkage is not less than 68%.
3. The fatigue resistant steel sheet according to claim 1, wherein the sample is not broken when the number of cycles reaches 10 7 at a loading stress ratio of 0.1, a frequency of 90HZ and a maximum stress of 0.7Rel, -20 ° CCTOD >0.62mm.
4. The anti-fatigue steel plate in the marine environment according to claim 1, wherein the corrosion resistance is 84-86% compared with the 3Ni system steel by adopting a simulated seawater splash zone periwinkle test.
5. The production method of the anti-fatigue steel plate in the marine environment according to any one of claims 1 to 4, which is characterized by comprising smelting, continuous casting, billet heating, rolling and cooling control and off-line treatment, and comprises the following specific contents:
Heating the steel billet, namely cold charging the steel billet into a furnace at a temperature of less than or equal to 80 ℃ and adopting multi-stage heating, wherein the total time of 500-950 ℃ is controlled to be 0.2-0.3min/mm, the total time of 1150-1180 ℃ is controlled to be within 0.1min/mm, and the total time of 1120-1150 ℃ is controlled to be 0.2-0.4min/mm;
Rolling and cooling control, namely rolling the billet after the billet is discharged from the furnace to 960-1000 ℃ and starting the rolling, wherein the final rolling temperature is controlled to be above 910 ℃, the pass reduction is controlled to be 20-30%, and the cooling speed after rolling is controlled to be 2-5 ℃ per second;
and (3) performing off-line treatment, namely performing second-stage precipitated phase and internal stress regulation by adopting a stacking or heat preservation treatment mode after the steel plate is off-line, wherein the heat preservation regulation temperature is 250-400 ℃.
6. The method for producing a steel plate with fatigue resistance in marine environment according to claim 5, wherein the steel grade is smelted by a converter, the Ti element in molten iron is controlled below 0.005%, and Si and Mn are used for deoxidization.
7. The method for producing a steel plate resistant to fatigue in a marine environment according to claim 5, wherein the steel billet is produced by converter smelting and continuous casting, the steel billet surface temperature starts to cool at 830-910 ℃, the cooling rate is controlled at 3-9 ℃ per second, and then the steel billet is heated at 220-370 ℃ by adopting low-temperature heating treatment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211611544.2A CN116162869B (en) | 2022-12-14 | 2022-12-14 | A fatigue-resistant steel plate in marine environment and its production method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211611544.2A CN116162869B (en) | 2022-12-14 | 2022-12-14 | A fatigue-resistant steel plate in marine environment and its production method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116162869A CN116162869A (en) | 2023-05-26 |
| CN116162869B true CN116162869B (en) | 2025-03-25 |
Family
ID=86415419
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211611544.2A Active CN116162869B (en) | 2022-12-14 | 2022-12-14 | A fatigue-resistant steel plate in marine environment and its production method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116162869B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113549818A (en) * | 2021-06-29 | 2021-10-26 | 鞍钢股份有限公司 | High-performance steel plate for corrosion resistance in marine full immersion zone and production method thereof |
| CN114836694A (en) * | 2022-05-27 | 2022-08-02 | 鞍钢股份有限公司 | Seawater corrosion fatigue resistant ultrahigh-strength steel for ship and manufacturing method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020084332A1 (en) * | 2018-10-23 | 2020-04-30 | Arcelormittal | Hot-rolled steel plate and a method of manufacturing thereof |
-
2022
- 2022-12-14 CN CN202211611544.2A patent/CN116162869B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113549818A (en) * | 2021-06-29 | 2021-10-26 | 鞍钢股份有限公司 | High-performance steel plate for corrosion resistance in marine full immersion zone and production method thereof |
| CN114836694A (en) * | 2022-05-27 | 2022-08-02 | 鞍钢股份有限公司 | Seawater corrosion fatigue resistant ultrahigh-strength steel for ship and manufacturing method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116162869A (en) | 2023-05-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN102732799B (en) | Acid corrosion resistant steel for soleplate in hull and production method thereof | |
| CN114836694B (en) | A marine anti-seawater corrosion fatigue ultra-high-strength steel and its manufacturing method | |
| CN101994064A (en) | Weathering steel with yield strength of 550MPa level and manufacturing method thereof | |
| CN108118249A (en) | A kind of crude oil carrier oil cargo tank upper deck anti-corrosion steel plate and its manufacturing method | |
| CN101994063A (en) | Weathering steel with yield strength of more than 700MPa and manufacturing method thereof | |
| CN110760765B (en) | 600 MPa-grade quenched and tempered steel plate with ultralow cost, high elongation and strain aging embrittlement resistance and manufacturing method thereof | |
| CN114959418B (en) | A kind of anti-seawater corrosion fatigue high-strength steel for ships and its manufacturing method | |
| CN102517494B (en) | Rolled steel for wind-power flange and preparation method thereof | |
| CN116200682A (en) | A high-strength high-toughness low-temperature marine steel plate and its manufacturing method | |
| CN115747637A (en) | Economical marine atmospheric corrosion resistant steel and production method thereof | |
| CN109023070A (en) | Steel for salt-resistant soil corrosion-resistant buried structure and manufacturing method thereof | |
| CN116162869B (en) | A fatigue-resistant steel plate in marine environment and its production method | |
| CN114746568A (en) | Normalized heat-treated steel sheet having good low-temperature impact toughness and method for producing same | |
| CN116288064B (en) | Ultra-high strength corrosion-resistant low-temperature marine engineering steel plate and manufacturing method thereof | |
| CN117947335A (en) | High-strength corrosion-resistant steel for photovoltaic pile foundation and manufacturing method thereof | |
| CN116334476B (en) | Anti-fatigue coating steel plate and production method thereof | |
| CN109023071A (en) | Neutral soil corrosion resistant steel for buried structure and manufacturing method thereof | |
| CN108265226A (en) | The offshore wind farm steel and manufacturing method of yield strength >=460MPa | |
| CN108342665A (en) | A kind of fixed marine drilling platform steel and production method | |
| CN116179969B (en) | Anti-collision steel in marine environment and production method thereof | |
| CN116145049B (en) | Steel plate for marine environment coating and production method thereof | |
| CN116219320B (en) | Lightweight pile steel in marine environment and production method thereof | |
| CN116200656B (en) | A coating steel plate with high ductility and production method thereof | |
| CN105714191A (en) | Normalized corrosion-resistant wind power steel with yield strength of at least 440 MPa and production method thereof | |
| CN116288066B (en) | Steel plate for construction in marine environment and production method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |