CN112746218B - Low-cost, high-crack-resistance and high-heat-input-welding YP 420-grade steel plate and manufacturing method thereof - Google Patents
Low-cost, high-crack-resistance and high-heat-input-welding YP 420-grade steel plate and manufacturing method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- 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
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
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- 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
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- 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
Abstract
A YP 420-grade steel plate with low cost, high crack resistance and large heat input and a manufacturing method thereof adopt low-C-ultralow-Si-high-Mn-Nb series low-alloy steel as a base, reduce the content of Al in the steel as much as possible, reduce Ti-B microalloying Mn/C more than or equal to 22, B/N more than or equal to 0.27 and less than or equal to 0.38, and reduce the content of [ (% Mn) +3.16 (% Si) +22.36 (% P) +11.65 (% S)]X (% C) is not more than 0.16, Ca is treated and the Ca/S ratio is controlled to be 1.0 to 3.0 and (% Ca) × (% S)0.28≤1.0×10‑3(ii) a Optimizing a TMCP (thermal mechanical control processing) process to ensure that the microstructure of the finished steel plate is fine ferrite and a small amount of fine bainite distributed in a dispersed manner, and the average grain size of the microstructure is below 15 mu m; the uniform and excellent low-temperature toughness and crack arrest characteristic of the base metal steel plate are obtained, and the low-temperature toughness of HAZ during large heat input welding is also excellent, namely the base metal steel plate is KV at 50 ℃ below zero2Not less than 100J, welding simulation Heat Affected Zone (HAZ) -50 ℃ KV2Not less than 47J; the method is particularly suitable for icebreaking ship shells, ocean platforms, cross-sea bridges, ocean wind power structures, port machinery and the like in ice sea areas, and can realize stable and batch industrial production with low cost.
Description
Technical Field
The invention relates to a YP 420-grade steel plate with low cost, high crack arrest and large heat input welding capability and a manufacturing method thereof, wherein the yield strength is more than or equal to 420MPa, the tensile strength is more than or equal to 520MPa, the Charpy impact power (single value) at minus 50 ℃ is more than or equal to 100J, and the steel plate with large heat input welding capability (the Charpy impact power (single value) at minus 50 ℃ of a welding heat affected zone of the large heat input steel plate is more than or equal to 47J).
Background
As is well known, low-carbon (high-strength) low-alloy steel is one of the most important engineering structural materials, and is widely used in petroleum and gas pipelines, offshore platforms, ship manufacturing, bridge structures, boiler pressure vessels, building structures, automobile industry, railway transportation and machinery manufacturing. The properties of low carbon (high strength) low alloy steel depend on its chemical composition, the process regime of the manufacturing process, where strength, toughness and weldability are the most important properties of low carbon (high strength) low alloy steel, which ultimately depend on the microstructure state of the finished steel. With the continuous forward development of science and technology, people put forward higher requirements on the toughness and weldability of steel, namely, the comprehensive mechanical property and the service performance of the steel plate are greatly improved while the lower manufacturing cost is maintained, so that the consumption of steel is reduced, the cost is saved, and the self weight, the stability and the safety of steel components are reduced. At present, the research surge of developing a new generation of high-performance steel materials is raised in the world, and better microstructure matching is obtained through alloy combination design, a rolling control/TMCP (thermal mechanical control processing) technology or an online heat treatment process, so that the steel plate has better strength and toughness, strong plasticity matching, seawater corrosion resistance, welding property and fatigue resistance; the steel plate provided by the invention is a wide and thick steel plate for heavy steel structures, which is developed at low cost by adopting the technology, has high toughness, strong plastic matching and excellent low-temperature toughness and can be welded by high heat input.
In The prior art, when a thick steel plate with yield strength of more than or equal to 420MPa and low-temperature impact toughness of more than or equal to 34J at-60 ℃ is manufactured, a certain amount of Ni or Cu + Ni element (more than or equal to 0.30%) is generally added into The steel, so that The manufacturing cost is relatively high [ The Firth (1986) international Symposium and inhibition on offset metals and Engineering, 1986, Tokyo, Japan, 354; "DEVELOPMENTS IN MATERIALS FOR ARCTIC OFFSHORE STRUCTURES; "Structural Steel Plates for arrangement Use Produced by Multipurose accepted Cooling System" (Japanese), Tokawasaki iron technology, 1985, Nos. 168-72; "Application of accessed consistent For Producing 360MPa Yield Strength Steel plates of up to 150mm in Thickness with Low Carbon Equivalent", accessed consistent Rolled Steel, 1986, 209-219; "High Strength Steel Plates For Ice-Breaking Vessels Produced by Thermo-Mechanical Control Process", Accelerated Co-vibrating Rolled Steel, 1986, 249-260; "420 MPa Yield Strength Steel Plate with Superior frame Structure for extraction offset Structure", Kawasaki Steel technical report, 1999, No.40, 56; "420 MPa and 500MPa Yield Strength Steel Plate with High HAZ to microwave Process by TMCP for offset Structure", Kawasaki Steel technical report, 1993, No.29, 54; "Toughness Improvement in Bainite Structure by Thermo-Mechanical Control Process" (Japanese) Sumitomo Metal, Vol.50, No.1(1998), 26; "Steel plate for ocean platform Structure used in icy sea area" (Japanese), Steel research, 1984, No. 314, 19-43 ] to ensure excellent low temperature toughness of base steel plate, and when welding with heat input of < 50KJ/cm, the toughness of HAZ in heat affected zone can reach-60 ℃ KV2Not less than 34J; however, when welding is carried out with an ultra-high heat input (not less than 100KJ/cm), the low-temperature toughness of the welding Heat Affected Zone (HAZ) is generally difficult to achieve, and the low-temperature toughness of the Heat Affected Zone (HAZ) is seriously degraded. A large number of Patent documents only describe how to realize the low-temperature toughness of a base steel plate, how to obtain excellent low-temperature toughness of a Heat Affected Zone (HAZ) under welding conditions is less, how to ensure less and less low-temperature toughness of the Heat Affected Zone (HAZ) particularly when welding with ultra-high heat input, and in order to ensure the low-temperature toughness of the steel plate, a certain amount of Ni or Cu + Ni element is generally added into the steel, and the low-temperature toughness of the Heat Affected Zone (HAZ) of the steel plate with ultra-high heat input can rarely reach-60 ℃ (Japanese Patent No. Sho 63-93845, No. Sho 63-79921, No. Sho 60-258410, No. Hei 4-285119, No. Hei 4-308035, No. Hei 3-264614, No. Hei 2-250917, No. Hei 4-143246, U.S. Pat. 4 Patent4855106、US Patent5183198、US Patent4137104)。
At present, only the Nippon Nissian iron company (U.S. Pat. No.4, 4629505 and European Patent WO 01/59167A1) which improves the low-temperature toughness of the Heat Affected Zone (HAZ) of the welded steel plate with ultra-large heat input adopts the oxide metallurgy technology, namely in the process of welding with large heat input, TiN particles are dissolved and lose the effect due to the action of high temperature for a long time in the vicinity of a fusion line, and Ti2O3More stable than TiN and does not dissolve even when reaching the melting point of steel. Ti2O3The particles can become the needle ferrite nucleation positions in the austenite crystals, promote the needle ferrite (acicular ferrite-AF) nucleation in the austenite crystals, effectively divide the austenite crystals, refine the HAZ structure and form a high-strength high-toughness needle ferrite structure; also, japanese JFE has developed a high heat input weldable steel sheet designed by Ti-Al-B-N combination and matched with a special high B content wire, in the course of high heat input welding heat cycle, BN particles precipitated first in the welding heat affected zone are formed as intragranular ferrite heterogeneous nucleation sites, intragranular ferrite nucleation is promoted, coarse austenite grains in the welding heat affected zone are divided to obtain uniform and fine ferrite + pearlite grains, and excellent low temperature toughness and crack arrest characteristics are ensured in the high heat input welding heat affected zone of the steel sheet (まてりあ, 43 coil No. 3 in 2004, p.232).
Disclosure of Invention
The invention aims to provide a YP 420-grade steel plate with low cost, high crack arrest and large heat input welding capability and a manufacturing method thereof, wherein the low-temperature toughness and crack arrest characteristic of a base metal steel plate are uniformly and excellently combined through low-cost alloy combination design and combined with a TMCP manufacturing process, and the low-temperature toughness of HAZ during large heat input welding is also excellent, namely the base metal steel plate is KV at 50 ℃ below zero2Not less than 100J, welding simulation Heat Affected Zone (HAZ) -50 ℃ KV2Not less than 47J; not only the TMCP steel plate with excellent comprehensive performance is produced with low cost, but also the manufacturing period of the steel plate is greatly shortened; is particularly suitable for icebreaking ship shells, ocean platforms, cross-sea bridges, ocean wind power structures, port machinery and the like in ice sea areas, and can realize stable and batch industrial production with low cost。
In order to achieve the purpose, the technical scheme of the invention is as follows:
the invention starts from alloy combination design, adopts low-C-ultralow-Si-high Mn-Nb series low-alloy steel as a base, reduces the content of Al in the steel as much as possible, and reduces Ti-B microalloying Mn/C to be more than or equal to 22, B/N to be more than or equal to 0.27 and less than or equal to 0.38, and the contents of [ (% Mn) +3.16 (% Si) +22.36 (% P) +11.65 (% S)]X (% C) is not more than 0.16, Ca is treated and the Ca/S ratio is controlled to be 1.0 to 3.0 and (% Ca) × (% S)0.28≤1.0×10-3(ii) a Optimizing the TMCP Process, i.e. { TBeginning rolling×[(％C)+(％Mn)/6]×VCooling rate}/(ξ×TFinish rolling×TStopping cooling)≥7.1×10-5The microstructure of the finished steel plate is fine ferrite and a small amount of fine bainite which is distributed in a dispersed mode, the average grain size of the microstructure is below 15 mu m, the uniform and excellent low-temperature toughness and crack arrest characteristics of the base steel plate are obtained, and simultaneously the low-temperature toughness of HAZ during large heat input welding is also excellent, namely the base steel plate is KV at 50 ℃ below zero2Not less than 100J, welding simulation Heat Affected Zone (HAZ) -50 ℃ KV2Not less than 47J; and enables low alloy cost manufacturing.
Specifically, the YP 420-grade steel plate with low cost, high crack resistance and high heat input welding capacity comprises the following components in percentage by weight:
C：0.035％～0.075％
Si：0.01～0.10％
Mn：1.45％～1.75％
P：≤0.013％
S：≤0.0025％
Nb：0.010％～0.030％
Ti：0.008％～0.015％
Al：≤0.010％
B：0.0015％～0.0030％
N：0.0050％～0.0080％
Ca：0.001％～0.003％，
the balance of Fe and other inevitable impurities; and the content of the elements must satisfy the following relation at the same time:
Mn/C≥22；
0.27≤B/N≤0.38；
[(％Mn)+3.16(％Si)+22.36(％P)+11.65(％S)]×(％C)≤0.16；
ca treatment and Ca/S ratio controlled between 1.0 to 3.0, and (% Ca) × (% S)0.28≤1.0×10-3；
{TBeginning rolling×[(％C)+(％Mn)/6]×VCooling rate}/(ξ×TFinish rolling×TStopping cooling)≥7.1×10-5Wherein, in the step (A),
Tbeginning rollingIs the non-recrystallization initial rolling temperature in K;
Tfinish rollingIs the non-recrystallization finish rolling temperature in K;
Tstopping coolingFor accelerated cooling stop temperature, the unit is K;
xi is the accumulated rolling reduction rate of non-recrystallization controlled rolling, and the unit is percent;
Vcooling rateThe accelerated cooling rate of the steel plate is expressed in K/s.
Mn/C is more than or equal to 22: improving the microstructure form, and homogenizing and refining ferrite grains; meanwhile, the precipitation size of carbides inside tempered bainite is reduced, the distribution and the morphology of the carbides inside the tempered bainite are improved, the intrinsic low-temperature impact toughness of the bainite is improved, the uniform and fine grains and excellent intrinsic toughness of a steel plate complex phase structure (ferrite and a small amount of bainite) are ensured, and the ductile-brittle transition temperature of the steel plate is lower than minus 50 ℃.
B/N is more than or equal to 0.27 and less than or equal to 0.38: the BN precipitation with sufficient quantity and dispersed distribution in the large heat input welding heat affected zone is ensured, and simultaneously the base metal steel plate and the welding heat affected zone have certain existence of solid solution B atoms. The following effects are realized: A) under the conditions of ultralow carbon and low carbon equivalent, the balance of high strength, high strength and low-temperature toughness of the base metal steel plate is ensured through the high hardenability of the solid solution B; secondly, solid solution B inhibits the formation of ferrite of the side plate strip with thick austenite crystal boundary in a large heat input welding heat affected zone, promotes the formation of ferrite in austenite crystal, and improves the low-temperature toughness of the large heat input welding heat affected zone; B) in the process that the steel plate is welded by large heat input, BN dispersed in a welding heat affected zone promotes ferrite nucleation in austenite crystal, divides coarse prior austenite crystal grains in the heat affected zone, refines the microstructure of the heat affected zone and improves the low-temperature toughness of the heat affected zone by large heat input; this is one of the key technologies of the present invention.
[ (% Mn) + +3.16 (% Si) +22.36 (% P) +11.65 (% S) ] × (% C). ltoreq.0.16: the segregation of the central part of the steel plate is inhibited, and the crack arrest characteristic and the weldability of the steel plate are improved; the formation of a large heat input welding heat affected zone M-A is inhibited, the number of the heat affected zones M-A is reduced, the size of the heat affected zone M-A is reduced, the phase change of polygonal ferrite in the heat affected zone and the decomposition of the M-A in the welding heat cycle process are promoted, the low-temperature toughness and the crack arrest characteristic of the large heat input welding heat affected zone are improved, and the safety and reliability of a welding structure are greatly improved; this is one of the key technologies of the present invention.
Ca treatment, and the Ca/S ratio is controlled to be between 1.0 and 3.0 and (% Ca) × (% S)0.28≤1.0×10-3: the influence of the inclusions on low-temperature toughness and weldability is reduced to the minimum while the spheroidization of the sulfide is ensured, and meanwhile, Ca (O, S) particles are uniformly and finely distributed in the steel, so that the growth of austenite grains in a large heat input welding heat affected zone is inhibited, and the low-temperature toughness and crack arrest characteristics of the welding heat affected zone are improved.
{TBeginning rolling×[(％C)+(％Mn)/6]×VCooling rate}/(ξ×TFinish rolling×TStopping cooling)≥7.1×10-51) ensuring that austenite has enough strain accumulation in the process of controlling rolling without recrystallization of the steel plate, and precipitating a large amount of fine and uniform proeutectoid ferrite in the subsequent accelerated cooling process; 2) the austenite which is not transformed is enriched with carbon by separating out the eutectoid ferrite, thus improving the stability of the austenite which is not transformed, ensuring that the austenite is transformed into bainite at lower temperature, and the bainite structure crystal group has small size and excellent intrinsic toughness; 3) through matching of chemical components and a TMCP (thermal mechanical control processing) process, the microstructure of the steel plate is uniform and fine ferrite and a small amount of fine bainite, and under the conditions of ultralow C, low carbon equivalent Ceq and low alloy cost, the steel plate has high strength, excellent low-temperature toughness and crack arrest characteristics, can bear high heat input welding, and has excellent low-temperature toughness and crack arrest characteristics in a welding heat affected zone; this is one of the key technologies of the present invention.
In the composition design of the steel of the invention:
c has great influence on the strength, low-temperature toughness, elongation and weldability of the TMCP steel plate, particularly on the weldability with large heat input, and the C content in the steel is expected to be controlled to be lower from the aspects of improving the low-temperature toughness and the weldability with large heat input of the TMCP steel plate; however, from the aspects of strength, low-temperature toughness and crack arrest characteristics of steel plate steel and control of microstructure and manufacturing cost in the production and manufacturing process, the content of C is not suitable to be controlled to be too low; too low C content easily causes too high grain boundary mobility, the base metal steel plate and welding HAZ microstructure grains are coarse and easily form a mixed crystal structure, and the too low C content in the steel causes the grain boundary weakening and seriously degrades the low-temperature toughness of the base metal steel plate and the welding HAZ; therefore, the reasonable range of the C content is 0.035 to 0.075 percent.
Si promotes molten steel deoxidation and can improve the strength of a steel plate, but Si deoxidizes little by adopting Al, Si can improve the strength of the steel plate, but Si seriously damages the low-temperature toughness, elongation and weldability of the steel plate, particularly under the condition of high heat input welding, Si not only promotes the formation of M-A islands, but also the formed M-A islands are large in size and uneven in distribution, and the low-temperature toughness and crack arrest characteristics of a welding Heat Affected Zone (HAZ) are seriously damaged, so that the Si content in the steel is controlled to be as low as possible, and the Si content is controlled to be 0.01-0.10% in consideration of the economy and operability of a steelmaking process.
Mn, the most important alloying element, improves the strength of the steel sheet, expands the austenite phase region, and reduces Ar in the steel3Point temperature, refining TMCP steel plate crystal grains to improve the low-temperature toughness and crack arrest characteristics of the steel plate, promoting the formation of low-temperature phase transformation structure and improving the strength of the steel plate; however, Mn is easy to segregate in the molten steel solidification process, particularly when the Mn content is high (particularly when the C content in the steel is high), not only is casting operation difficult caused, but also conjugate segregation phenomenon is easy to occur with elements such as C, P, S, so that segregation and porosity of the central part of a casting blank are increased, and the region with serious central segregation of the casting blank is easy to form abnormal structures in the subsequent TMCP and welding processes, so that low-temperature toughness and crack arrest characteristics of a steel plate are low, and cracks appear on a welding joint; therefore, according to the C content range, the proper Mn content range is selected for TMThe CP steel plate is extremely important and is suitable for the Mn content of 1.45-1.75%.
P as harmful impurities in steel has great damage effect on the mechanical properties of the steel, especially low-temperature impact toughness, crack arrest characteristics, elongation and weldability (especially high heat input weldability), and the lower the requirement is, the better the theory is; however, considering steel-making workability and steel-making cost, the P content of TMCP steel sheet required to be weldable with large heat input, -50 ℃ toughness, high strength and weldable with large heat input needs to be controlled to be less than 0.013%.
S has great damage effect on low-temperature toughness and crack arrest characteristics of steel as harmful inclusions in the steel, more importantly, the S is combined with Mn in the steel (particularly when the Mn content is high) to form MnS inclusions, the plasticity of MnS enables the MnS to extend along the rolling direction in the hot rolling process to form MnS inclusion bands along the rolling direction, the low-temperature impact toughness and quality characteristics, the elongation rate, the Z-direction performance and the weldability (particularly large heat input weldability) of the steel plate are seriously damaged, and meanwhile, the S is a main element generating hot brittleness in the hot rolling process, and the lower the S is required to be better in theory; however, considering steel-making operability, steel-making cost and logistics smoothness principle, the S content of the TMCP steel plate which can be welded at high heat input, has-50 ℃ toughness and high strength, can be welded at high heat input and has higher Mn content needs to be controlled to be less than 0.0025 percent.
In order to ensure that certain solid-solution B atoms in the steel are partially aggregated at an austenite crystal boundary in the TMCP process, inhibit the formation of grain boundary ferrite, promote the formation of low-temperature phase transformation structure bainite/martensite in the TMCP process and realize high strength under the conditions of ultralow carbon and low carbon equivalent; secondly, enough B atoms in the steel are combined with N atoms in the welding heat circulation process to generate a certain amount of BN particles which are dispersed and distributed, so that ferrite grains are formed in austenite grains in the large heat input welding process, the original coarse austenite grains are segmented, the microstructure of a large heat input welding heat affected zone is refined, and the low-temperature toughness of the welding heat affected zone is improved; therefore, the content of the B element in the steel is not less than 0.0015 percent; however, when the B content in the steel is too high, a large amount of coarse Fe is precipitated on the prior austenite grain boundary23(CN)6Severely embrittled base metal steel plate and low-temperature toughness and crack-stopping property of welding heat affected zoneThe cold and hot processing characteristics, the service bearing and the crack resistance and crack arrest characteristics of the steel plate are rapidly deteriorated due to the plasticity and the plasticity, and the safety of the steel plate in the service process cannot be guaranteed, so that the content of the steel plate B cannot exceed 0.0030 percent.
The affinity of Ti and N is far greater than that of B and N, when a small amount of Ti is added, N is preferentially combined with Ti to generate TiN particles which are dispersed and distributed, thereby inhibiting austenite grains from excessively growing in the TMCP process and improving the low-temperature toughness and crack arrest characteristics of the steel plate; more importantly, the growth of crystal grains in a heat affected zone (a zone far away from a fusion line) in the large heat input welding process is inhibited to a certain extent, and the low-temperature toughness and the crack arrest characteristic of the heat affected zone are improved; the effect of adding too little Ti (0.008%) is not great, and when the Ti content is added too much (0.015%), the BN particles in the steel are inhibited from being separated out, so that the quantity of the BN particles is rare, and the low-temperature toughness of a large heat input welding heat affected zone cannot be improved; in addition, when the content of Ti in the steel is extremely high, most of N in the steel is combined by Ti, so that the content of solid solution B in the steel is too high, and the low-temperature toughness and the high heat input weldability of the steel plate are influenced; therefore, the suitable Ti content range is 0.008 to 0.015 percent.
The purpose of adding trace Nb element into the steel is to control rolling without recrystallization and improve the strength and toughness of the TMCP steel plate, and when the addition amount of Nb is less than 0.010 percent, the strengthening capability of the steel plate is insufficient except the rolling control function which cannot be effectively exerted; when the addition amount of Nb exceeds 0.030 percent, the formation of upper bainite (Bu) and the secondary precipitation embrittlement of Nb (C, N) are induced under the condition of high heat input welding, and the low-temperature toughness of a heat-affected zone (HAZ) of the high heat input welding is seriously damaged, so that the Nb content is controlled between 0.010 percent and 0.030 percent, the optimal rolling control effect is obtained, the toughness/strength and plasticity matching of the TMCP steel plate is realized, and the toughness of the HAZ of the high heat input welding is not damaged.
Enough BN particles are ensured to promote ferrite nucleation in a large heat input welding heat affected zone, coarse prior austenite grains in the heat affected zone are segmented, the microstructure of the large heat input welding heat affected zone is refined, the low-temperature toughness of the large heat input welding heat affected zone is improved, and the content of N in steel is not less than 0.0050%; however, when the content of N in the steel is too high, all B atoms in the steel are combined with N atoms, and after BN particles are generated, solid solution B atoms do not exist in the steel, so that the strength of the steel plate with ultralow C and low carbon equivalent components is low, and the development requirement cannot be met; in addition, the excessive N content in the steel reaches the increase of solid solution N atoms in a large heat input welding heat affected zone, and the low-temperature toughness of the welding heat affected zone is seriously degraded; therefore, the N content in the steel cannot exceed 0.0080%.
In order to ensure that a sufficient amount of BN particles are formed in the steel and to suppress the generation of a large amount of AlN particles, the upper limit of the Al content in the steel must be controlled; therefore, Al in the steel should not be higher than 0.010%.
The Ca treatment of the steel can further purify the molten steel on one hand, and the modification treatment of the sulfide in the steel on the other hand can lead the sulfide to become non-deformable, stable and fine spherical sulfide, inhibit the hot brittleness of S, improve the low-temperature toughness, the elongation and the Z-direction performance of the steel plate and improve the anisotropy of the toughness of the steel plate. The addition amount of Ca depends on the content of S in steel, the addition amount of Ca is too low, and the treatment effect is not great; the addition of Ca is too high, the formed Ca (O, S) has too large size and increased brittleness, and can be used as a starting point of fracture crack, reduce the low-temperature toughness and elongation of steel, and simultaneously reduce the purity of the steel and pollute molten steel; therefore, the appropriate range of the Ca content is 0.0010% to 0.0030%.
The invention relates to a method for manufacturing YP 420-grade steel plates with low cost, high crack resistance and large heat input welding, which comprises the following steps:
1) smelting and casting
Smelting and continuously casting the components into a plate blank;
2) heating the plate blank, wherein the heating temperature is controlled to be 1080-1150 ℃;
3) rolling, the total compression ratio (slab thickness/finished steel plate thickness) of steel plate is more than or equal to 3.0
The first stage is common rolling;
rolling is controlled in the second stage by adopting non-recrystallization, the rolling start temperature is controlled to be 750-820 ℃, the rolling pass reduction rate is more than or equal to 7 percent, the accumulated reduction rate is more than or equal to 50 percent, and the final rolling temperature is 740-780 ℃;
4) cooling down
After rolling control is finished, the steel plate is conveyed to cooling equipment, and then accelerated cooling is carried out on the steel plate, the steel plate is cooled at the temperature of 730-770 ℃, the cooling speed is more than or equal to 6 ℃/s, the cooling temperature is stopped at 350-600 ℃, then the steel plate is naturally cooled to 350 ℃ and then slowly cooled, and the slow cooling process is that the temperature of the steel plate is kept for at least 24 hours under the condition that the temperature surface of the steel plate is more than 300 ℃.
According to the components of the steel plate, the heating temperature of the plate blank is controlled between 1080 ℃ and 1150 ℃, so that the austenite grains of the plate blank are not abnormally grown while the Nb in the steel is completely dissolved into austenite in the heating process of the plate blank.
The total compression ratio (slab thickness/finished steel plate thickness) of the steel plate is more than or equal to 3.0, so that rolling deformation is ensured to penetrate through the core part of the steel plate, and the microstructure and the performance of the central part of the steel plate are improved.
The first stage is common rolling, continuous rolling is carried out by adopting the maximum rolling capacity of a rolling mill, the capacity of a rolling line is improved to the maximum extent, and meanwhile, the deformed billet is ensured to be recrystallized, and austenite grains are refined.
And the second stage adopts non-recrystallization controlled rolling, and according to the Nb content range in the steel, in order to ensure the non-recrystallization controlled rolling effect, the controlled rolling initial rolling temperature is controlled to be 750-820 ℃, the rolling pass reduction rate is more than or equal to 7 percent, the cumulative reduction rate is more than or equal to 50 percent, and the final rolling temperature is 740-780 ℃.
After the controlled rolling is finished, the steel plate is immediately conveyed to accelerated cooling equipment, and then accelerated cooling is carried out on the steel plate; the steel plate is cooled at the temperature of 730-770 ℃, the cooling speed is more than or equal to 6 ℃/s, the cooling stopping temperature is 350-600 ℃, then the steel plate is naturally cooled to 350 ℃ and then is subjected to slow cooling dehydrogenation, and the slow cooling process is that the temperature of the steel plate surface is kept for at least 24 hours under the condition that the temperature is more than 300 ℃.
The invention has the beneficial effects that:
the steel plate is combined with the TMCP manufacturing process through low-cost alloy combination design, so that the TMCP steel plate with excellent comprehensive performance is produced at low cost, the manufacturing period of the steel plate is greatly shortened, great value is created for enterprises, and the green and environment-friendly manufacturing process is realized.
The high performance and high added value of the steel plate are collectively shown in that the steel plate has high strength, excellent low-temperature toughness and crack arrest characteristics, and simultaneously the weldability (especially the large heat input weldability) of the steel plate is also excellent, so that the problems that the steel plate obtains high strength and excellent low-temperature toughness and crack arrest characteristics under the conditions of ultralow C and low carbon equivalent are successfully solved, and the safety stability and crack arrest propagation characteristics of a large heavy steel structure are greatly improved; the good weldability (especially the large heat input single pass welding) saves the manufacturing cost of the user steel component, greatly shortens the manufacturing time of the user steel component and creates great value for users.
Drawings
FIG. 1 is a photograph of a microstructure (1/4 thickness) of example 3 of the present invention;
Detailed Description
The invention is further illustrated with reference to the following figures and examples.
The steel plate components of the embodiment of the invention are shown in table 1, tables 2 to 3 are process parameters of the embodiment of the invention, and table 4 is performance parameters of the steel of the embodiment of the invention.
As can be seen from FIG. 1, the microstructure of the steel plate is fine ferrite + a small amount of fine dispersed bainite, and the average grain size of the microstructure is below 15 μm; the base steel plate has excellent low-temperature toughness and crack arrest characteristics, and the HAZ has excellent low-temperature toughness during high heat input welding, and can be produced in batches at low alloy cost. The uniform and excellent low-temperature toughness and crack arrest characteristic of the base metal steel plate are obtained, and the low-temperature toughness of HAZ during large heat input welding is also excellent, namely the base metal steel plate is KV at 50 ℃ below zero2Not less than 100J, welding simulation Heat Affected Zone (HAZ) -50 ℃ KV2Not less than 47J; and enables low alloy cost manufacturing.
The steel plate of the invention is designed by low-cost alloy component combination and is combined with TMCP manufacturing process, not only the TMCP steel plate with excellent comprehensive performance is produced with low cost, but also the manufacturing period of the steel plate is greatly shortened, great value is created for enterprises, and the green environmental protection of the manufacturing process is realized. The high performance and high added value of the steel plate are collectively shown under the conditions of ultralow carbon and low carbon equivalent, the steel plate has excellent strength and toughness, strong plastic matching and crack arrest characteristics, meanwhile, the weldability (especially large heat input weldability) of the steel plate is also excellent, and the safety stability and the brittle fracture resistance of a large heavy steel structure are greatly improved; the good weldability saves the manufacturing cost of the user steel member, shortens the manufacturing time of the user steel member, and creates great value for users, so that the steel plate is not only a product with high added value and environmental protection.
The steel plate is mainly used for offshore wind power structures, icebreaker shells, ocean platforms, cross-sea bridges, port machinery, south pole research station steel structures and the like, can realize low-cost stable batch industrial production, and breaks technical monopoly and technical barriers of foreign low-temperature structural steel.
With the development of national economy and the requirement of building a conservation-oriented harmonious society in China, ocean development has reached the daily agenda, and ocean engineering construction in China, particularly offshore wind power construction of green energy, is emerging at present; the low-temperature structural steel plate which can be subjected to high heat input and is a key material in the manufacturing industry of ocean engineering construction and related equipment has wide market prospect.
Claims (6)
1. The YP 420-grade steel plate has low cost, high crack resistance and high heat input welding capacity, and comprises the following components in percentage by weight:
C：0.035％～0.075％
Si：0.01～0.10％
Mn：1.45％～1.75％
P：≤0.013％
S：≤0.0025％
Nb：0.010％～0.030％
Ti：0.008％～0.015％
Al：≤0.010％
B：0.0015％～0.0030％
N：0.0050％～0.0080％
Ca：0.001％～0.003％，
the balance of Fe and other inevitable impurities; and the content of the elements must satisfy the following relation at the same time:
Mn/C≥22；
0.27≤B/N≤0.38；
[(％Mn)+3.16(％Si)+22.36(％P)+11.65(％S)]×(％C)≤0.16；
ca treatment, and the Ca/S ratio is controlled to be 1.0 to 3.0, and (% Ca) × (% S)0.28≤1.0×10-3；
{TBeginning rolling×[(％C)+(％Mn)/6]×VCooling rate}/(ξ×TFinish rolling×TStopping cooling)≥7.1×10-5Wherein, in the step (A),
Tbeginning rollingIs the non-recrystallization initial rolling temperature in K;
Tfinish rollingIs the non-recrystallization finish rolling temperature in K;
Tstopping coolingFor accelerated cooling stop temperature, the unit is K;
xi is the accumulated rolling reduction rate of non-recrystallization controlled rolling, and the unit is percent;
Vcooling rateThe accelerated cooling rate of the steel plate is expressed in K/s.
2. The low-cost, high crack-arrest, high heat input weldable YP420 grade steel sheet of claim 1, wherein the microstructure is fine ferrite + a small amount of fine dispersed bainite, and the microstructure has an average grain size of 15 μm or less.
3. The YP 420-grade steel plate with low cost, high crack-arrest and high heat input weldability according to claim 1 or 2, characterized in that the yield strength of the steel plate is not less than 420MPa, the tensile strength is not less than 520MPa, and the charpy impact energy single value at-50 ℃ is not less than 100J.
4. The method of manufacturing a low-cost, high crack-arresting, high heat input weldable YP420 grade steel sheet of claim 1, comprising the steps of:
1) smelting and casting
Smelting and continuously casting the components according to the claim 1 into a slab;
2) heating the plate blank, wherein the heating temperature is controlled to be 1080-1150 ℃;
3) rolling, wherein the total compression ratio of the steel plate, namely the thickness of the plate blank/the thickness of the finished steel plate is more than or equal to 3.0
The first stage is common rolling;
rolling is controlled in the second stage by adopting non-recrystallization, the rolling start temperature is controlled to be 750-820 ℃, the rolling pass reduction rate is more than or equal to 7 percent, the accumulated reduction rate is more than or equal to 50 percent, and the final rolling temperature is 740-780 ℃;
4) cooling down
After rolling control is finished, the steel plate is conveyed to cooling equipment, and then accelerated cooling is carried out on the steel plate, the steel plate is cooled at the temperature of 730-770 ℃, the cooling speed is more than or equal to 6 ℃/s, the cooling temperature is stopped at 350-600 ℃, then the steel plate is naturally cooled to 350 ℃ and then slowly cooled, and the slow cooling process is that the temperature of the steel plate is kept for at least 24 hours under the condition that the temperature surface of the steel plate is more than 300 ℃.
5. The method for producing a low-cost, high crack-arresting, large heat input weldable YP420 grade steel sheet as claimed in claim 4, wherein the microstructure of the steel sheet is fine ferrite + a small amount of fine dispersed bainite, and the average grain size of the microstructure is 15 μm or less.
6. The method for producing a low-cost, high crack-arresting, high heat input weldable YP420 grade steel plate as claimed in claim 4, wherein the steel plate has a yield strength of 420MPa or more, a tensile strength of 520MPa or more, and a Charpy impact energy of-50 ℃ or more, as a single value or more, of 100J or more.
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Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04308035A (en) * | 1991-04-06 | 1992-10-30 | Nippon Steel Corp | Production of steel plate for structural use excellent in toughness at low temperature |
| JPH11100641A (en) * | 1997-09-29 | 1999-04-13 | Kawasaki Steel Corp | Hot rolled steel plate with composite structure, excellent in impact resistance and formability, and its production |
| CN102428198A (en) * | 2009-05-22 | 2012-04-25 | 杰富意钢铁株式会社 | Steel material for high heat input welding |
| CN102534376A (en) * | 2012-02-29 | 2012-07-04 | 江苏省沙钢钢铁研究院有限公司 | Steel plate with excellent low-temperature toughness in large heat-input weld heat affected zone and production method thereof |
| CN102851589A (en) * | 2011-06-29 | 2013-01-02 | 宝山钢铁股份有限公司 | Steel for low temperature structure with low yield ratio and capable of performing ultrahigh heat input and manufacture method thereof |
| CN103987869A (en) * | 2011-12-14 | 2014-08-13 | 杰富意钢铁株式会社 | Steel material for high-heat-input welding |
| CN104046899A (en) * | 2014-06-27 | 2014-09-17 | 宝山钢铁股份有限公司 | 550MPa-grade steel sheet capable of being welded at high heat input and manufacturing method thereof |
| CN104561796A (en) * | 2014-12-19 | 2015-04-29 | 宝山钢铁股份有限公司 | High-quality steel plate capable of resisting fatigue crack growth and manufacturing method thereof |
| CN104651714A (en) * | 2013-11-19 | 2015-05-27 | 新日铁住金株式会社 | Steel sheet |
| CN105603322A (en) * | 2016-01-29 | 2016-05-25 | 宝山钢铁股份有限公司 | Steel plate with super-low cost, 800MPa-grade high toughness and excellent weldability and manufacture method thereof |
| CN108624819A (en) * | 2017-03-24 | 2018-10-09 | 宝山钢铁股份有限公司 | Low cost, high heat-input weld 460MPa grades of crack arrest steel plates and its manufacturing method |
| CN108677096A (en) * | 2018-08-13 | 2018-10-19 | 东北大学 | A kind of strategic oil reserve tank steel plate and its manufacturing method based on Oxide Metallurgy |
| JP2019023322A (en) * | 2017-07-21 | 2019-02-14 | 新日鐵住金株式会社 | Steel plate and method for manufacturing steel plate |
| CN110195193A (en) * | 2018-02-27 | 2019-09-03 | 宝山钢铁股份有限公司 | Low cost, 800MPa grades of hardened and tempered steel plates of high tenacity and superior weldability and its manufacturing method |
| CN110616300A (en) * | 2018-06-19 | 2019-12-27 | 宝山钢铁股份有限公司 | Low-temperature steel with excellent CTOD (carbon to steel) characteristics and manufacturing method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
-
2019
- 2019-12-30 CN CN201911396570.6A patent/CN112746218B/en active Active
Patent Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04308035A (en) * | 1991-04-06 | 1992-10-30 | Nippon Steel Corp | Production of steel plate for structural use excellent in toughness at low temperature |
| JPH11100641A (en) * | 1997-09-29 | 1999-04-13 | Kawasaki Steel Corp | Hot rolled steel plate with composite structure, excellent in impact resistance and formability, and its production |
| CN102428198A (en) * | 2009-05-22 | 2012-04-25 | 杰富意钢铁株式会社 | Steel material for high heat input welding |
| CN104087829A (en) * | 2009-05-22 | 2014-10-08 | 杰富意钢铁株式会社 | Steel material for high heat input welding |
| CN102851589A (en) * | 2011-06-29 | 2013-01-02 | 宝山钢铁股份有限公司 | Steel for low temperature structure with low yield ratio and capable of performing ultrahigh heat input and manufacture method thereof |
| CN103987869A (en) * | 2011-12-14 | 2014-08-13 | 杰富意钢铁株式会社 | Steel material for high-heat-input welding |
| CN102534376A (en) * | 2012-02-29 | 2012-07-04 | 江苏省沙钢钢铁研究院有限公司 | Steel plate with excellent low-temperature toughness in large heat-input weld heat affected zone and production method thereof |
| CN104651714A (en) * | 2013-11-19 | 2015-05-27 | 新日铁住金株式会社 | Steel sheet |
| CN104046899A (en) * | 2014-06-27 | 2014-09-17 | 宝山钢铁股份有限公司 | 550MPa-grade steel sheet capable of being welded at high heat input and manufacturing method thereof |
| CN104561796A (en) * | 2014-12-19 | 2015-04-29 | 宝山钢铁股份有限公司 | High-quality steel plate capable of resisting fatigue crack growth and manufacturing method thereof |
| CN105603322A (en) * | 2016-01-29 | 2016-05-25 | 宝山钢铁股份有限公司 | Steel plate with super-low cost, 800MPa-grade high toughness and excellent weldability and manufacture method thereof |
| CN108624819A (en) * | 2017-03-24 | 2018-10-09 | 宝山钢铁股份有限公司 | Low cost, high heat-input weld 460MPa grades of crack arrest steel plates and its manufacturing method |
| JP2019023322A (en) * | 2017-07-21 | 2019-02-14 | 新日鐵住金株式会社 | Steel plate and method for manufacturing steel plate |
| CN110195193A (en) * | 2018-02-27 | 2019-09-03 | 宝山钢铁股份有限公司 | Low cost, 800MPa grades of hardened and tempered steel plates of high tenacity and superior weldability and its manufacturing method |
| CN110616300A (en) * | 2018-06-19 | 2019-12-27 | 宝山钢铁股份有限公司 | Low-temperature steel with excellent CTOD (carbon to steel) characteristics and manufacturing method thereof |
| CN108677096A (en) * | 2018-08-13 | 2018-10-19 | 东北大学 | A kind of strategic oil reserve tank steel plate and its manufacturing method based on Oxide Metallurgy |
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