31results about How to "Improve high heat input welding performance" patented technology

Disclosed are a high-heat-input welding thick steel plate and a manufacturing method thereof. The manufacturing method includes following steps: a) smelting, refining and continuous casting; b) rolling; and c) cooling. Steel consists of components including, by weight percentage, from 0.05 to 0.09% of C, from 0.10 to 0.30% of Si, from 1.3 to 1.7% of Mn, from 0.005 to 0.03% of Ti, from 0.003 to 0.025% of Nb, from 0.001 to 0.01% of S, smaller than or equal to 0.015% of P, smaller than or equal to 0.006% of N, from 0.0005 to 0.01% of Mg, smaller than or equal to 0.01% of Al, smaller than or equal to 0.003% of Ca, more than one of smaller than or equal to 0.3% of Cu, smaller than or equal to 0.4% of Ni and smaller than or equal to 0.002% of B, and the balance Fe; and Ti/Nb is larger than or equal to 1.2, deoxidant Mn, Si, Al, Ti, Ca and Mg are successively added in a steel liquid deoxidizing process, wherein (Mg+Ca)/Mn is larger than or equal to 0.3 for micrometer impurities with the grain size larger than or equal to 1.0 micrometer in the steel, (Mg+Ca)/Mn is larger than or equal to 0.1 for sub-micron impurities with the grain size ranging from 0.1 micrometer to 1.0 micrometer in the steel, and Ti/Mn is larger than or equal to 0.07. A large quantity of impurities which are distributed in a dispersion manner are formed, growth of austenite grains in a welding heat affected zone can be restrained, growth of intra-granular ferrite is promoted, and the high-heat-input welding performance of the thick plate is greatly improved.

A preparation method of easy welding high strength toughness X80 pipe line steel for magnesium treatment belongs to the production field of low alloy high strength steel, including first preparing materials according to constituent mixing rate, then smelting in a vacuum induction furnace, forging casting blank and controlling rolling and cooling. The preparation method is characterized in that the heating temperature is 1170-1230 DEG C prior to forging blank residues; the thermal time is 60-120min; and the beginning temperature of coarse rolling is 1100-1180 DEG C; the finishing temperature of coarse rolling is no less than 980 DEG C, the temperature-holding thickness of intermediate blank is 45-50mm; the beginning temperature of finish rolling is no more than 880 DEG C; the finishing temperature of finish rolling is 780-810 DEG C; the pressing rate of finish rolling is more than 3T (T: target thickness of finished products); and the target thickness of finished products is 10-15mm. After finish rolling, the product rapidly enters ACC for cooling control, with the cooling speed being 15-35 DEG C/s. the self-tempering temperature is 400-550 DEG C. The produced high strength toughness X80 pipe line steel has typical acicular ferrite tissue, as well as favorable comprehensive mechanical property and high input energy welding property.

The invention provides a thick steel plate capable of being welded at a large heat input and a manufacturing method thereof. The manufacturing method comprises the following steps: (1) smelting and casting, wherein the thick steel plate is prepared from the following components in percent by weight: 0.05-0.09% of C, 0.10-0.30% of Si, 1.2-1.6% of Mn, not greater than 0.02% of P, 0.001-0.006% of S, 0.2-0.4% of Ni, 0.15-0.3% of Cu, 0.005-0.03% of Ti, 0.0005-0.01% of Mg, 0.001-0.006% of N, not greater than 0.05% of Al, not greater than 0.005% of Ca, not greater than 0.02% of REM, and not greater than 0.003% of B and the balance of Fe and unavoidable impurities, and Ti/N is no less than 1 and is not greater than 6, and Mg/(Al+Ti) is no less than 0.02; (2) rolling; (3) cooling. According to the thick steel plate capable of being welded at the large heat input and the manufacturing method thereof, tiny dispersion-distribution inclusion can be formed; by controlling the (Mg+Ca)/(Al+Ti) ratio and the surface density of micron inclusion with the diameter of no less than 1 micrometer and the (Mg+Ca)/(Al+Ti) ratio and the surface density of sub-micron inclusion with the diameter of 0.1-1 micrometer, a base metal with the tensile strength of no less than 510 MPa is obtained; when the welding heat input is 200-400 kJ/cm, the average charpy impact energy of the steel plate at -40 DEG C is more than 50 J.

The invention relates to low-temperature steel for engineering machinery and a production method thereof. The steel is suitable for higher heat input welding and comprises the following chemical components by weight percent: 0.06-0.08% of C, 0.15-0.25% of Si, 1.6-1.9% of Mn, 0.05-0.07% of Nb, 0-0.30% of Mo, 0-0.0020% of B, 0.08-0.14% of Ti, 0.01-0.06% of Al, not more than 0.02% of P, not more than 0.010% of S, not more than 0.008% of N and the balance of Fe and inevitable impurities. The production method is characterized by controlling the heating temperature, precision rolling inlet temperature, finish rolling temperature, finished cooling temperature and annealing temperature. The material can ensure the transverse universal coiling impact energy at minus 20 DEG C to be more than 47J, and meanwhile, the HAZ (heat affected zone) strength and toughness of the steel plate can meet the mechanical property requirements of the base metal under 20KJ/cm welding property energy.

The invention discloses a method for raising large heat input weldability of a thick steel plate, comprising the following steps: 1) smelting and casting to form a steel plate: adding deoxidizers in the deoxidation process of the liquid steel according to the following types and order: Mn, Si, Al, Ti, and Ca and/or Mg, controlling the initial oxygen place in the liquid steel when Mn deoxidation is carried out in casting, adding Fe2O3 powder to let the oxygen content in the liquid steel be 0.001-0.008 wt%, wherein, the steel plate comprises 0.05-0.09 wt% of C, 0.10-0.30 wt% of Si, 1.3-1.7 wt% of Mn, 0.005-0.02 wt% of Ti, no larger than 0.015 wt% of P, no larger than 0.01 wt% of S, no larger than 0.006 wt% of N, no larger than 0.004 wt% of Ca, and the balance consisting of Fe; in the steel, the volumn density of TiN deposition with the particle size of less than 500 nm is larger than 9.0*107 PCs/mm<3>, the average particle size is less than 80 nm, and the proportion of the deposition with the particle size of less than 100 nm is larger than 75 %; 2) rolling and cooling. The large amount of nano TiN deposition with dispersive distribution formed by the invention can inhibit the growth of austenite crystals in the heat affected zone, and greatly raise the large heat input weldability of the thick steel plate.

The invention discloses a method for improving the high heat input welding performance of thick steel plates. The method comprises the following steps of: 1) smelting and casting to obtain an ingot, wherein deoxidants are added in the deoxidation process of molten steel, the adding sequence of the deoxidants is Mn and Si, Al, Ti, and Ca, a Mg deoxidant is added in the casting process of the molten steel, and the initial oxygen potential during the deoxidation of Mg is accurately controlled by adding Fe2O3 powder into a casting ingot mould; and 2) rolling and cooling. In the method, microfine dispersive distribution and Mg-containing inclusions, which are formed by adding the deoxidants in the deoxidation process of the molten steel and adding the Fe2O3 powder into the casting ingot mould to accurately control the oxygen potential during the deoxidation of the Mg, can inhibit the growth of austenite grains in a welding heat affected zone, and promotes the growth of ferrite in the grains, so that the high heat input welding performance of the thick steel plates is greatly improved.

The invention relates to a large heat input energy welding high-strength EH36 steel plate which is made of the following components in percentage by weight through smelting: 0.06-0.18% of C, 0.15-0.50% of Si, 1.10-1.60% of Mn, less than or equal to 0.012% of P, less than or equal to 0.003% of S, 0.10-0.40% of Ni, 0.010-0.030% of Nb, less than or equal to 0.010% of Al, 0.010-0.030% of Ti, 0.001-0.010% of Ca and the balance of Fe and inevitable impurities. The maximum thickness of the steel plate is 100mm, the yield strength of the steel plate is greater than or equal to 355MPa, the tension strength of the steel plate is greater than or equal to 510MPa, and the low-temperature impact absorption energy KV2 of the steel plate at minus 40 DEG C is greater than or equal to 150KJ. A production method of the steel plate comprises the following steps: carrying out smelting, LF/RH (Ladle Furnace/Ruhrstahl Heraeus) refining, continuous casting, heating, rolling, and rapid cooling, thereby obtaining a finished product of the steel plate. The steel plate produced by using the method provided by the invention has the characteristics of high purity, high strength, good low-temperature impact resistance, good toughness when the maximum input line energy is 300KJ/CM, and the like, can be widely applied to fields such as shipbuilding, bridges and building structures, and has wide application prospects.

The invention discloses a thick steel plate with a low carbon equivalent and excellent welding heat affected zone toughness and a manufacturing method of the same. The manufacturing method comprises the following steps: 1) smelting, refining and continuously casting the ingredients in the following percentage by mass: 0.045-0.075% of C, 0.10-0.30% of Si, 1.3-1.6% of Mn, not greater than 0.015% of P, 0.001-0.01% of S, 0.20-0.40% of Ni, 0.005-0.03% of Ti, 0.003-0.08% of Al, 0.0005-0.005% of Ca, not greater than 0.02% of REM, not greater than 0.02% of Zr, 0.0005-0.005% of B, 0.001-0.006% of N, 0.32-0.36% of Ceq, 0.0005-0.005% of Bef, and the balance of Fe and inevitable impurities; 2) rolling; and 3) cooling. According to the manufacturing method disclosed by the invention, inclusions with fine dispersed distribution can be formed, and by controlling the surface density of the micron inclusions with diameters of not less than 1 micron, Ca/Al ratio, the length-width ratio of the inclusions and the surface density of the submicron inclusions with diameters of less than 1 micron, the tensile strength of the base material is not less than 510 MPa, the weld heat input is 200-400 kJ/cm, and the average Charpy impact energy of a welding heat affected zone at minus 40 DEG C is greater than 100 J, therefore, excellent impact toughness is achieved.

The invention belongs to the field of steel material preparation, and particularly relates to a low-yield-ratio marine steel plate with good welding performance and a manufacturing method thereof. Thelow-yield-ratio marine steel plate comprises the following components of, by weight, 0.05%-0.09% of C, 0.1%-0.4% of Si, 1.0%-1.5% of Mn, less than or equal to 0.02% of P, less than or equal to 0.02%of S, 0.005%-0.03% of Als, 0%-0.6% of Ni, 0%-0.3% of Cu, 0.008%-0.05% of Nb, 0.005%-0.03% of Ti, 0.002%-0.01% of N, 0.02%-0.08% of V, 0%-0.3% of Mo, and the balance Fe and inevitable impurities, wherein the yield ratio of the steel plate is less than or equal to 0.80, the carbon equivalent Ceq is less than or equal to 0.41, and Pcm is less than or equal to 0.21. According to the low-yield-ratio marine steel plate with the good welding performance and the manufacturing method thereof, a certain content of N element is added, and second phase dispersion precipitation of V, Ti element is matched,so that the high-heat input welding performance and the low-temperature impact toughness of the steel plate are improved; and chemical components and the processes of high finish rolling temperature,low water inlet high red returning temperature and low cooling speed are combined, so that the high service safety with the yield ratio being less than or equal to 0.8 can be obtained, and a corresponding production process is formed while the high-service safety steel plate which is easy to weld with high heat input is obtained.

The invention discloses a control method for a nano-scaled precipitate in a thick steel plate for high heat input welding. Deoxidizers are added during smelting and casting of molten steel, wherein the types and the adding sequence for the deoxidizers are that: (Mn+Si), Al, Ti and (Ca+Mg); Mg content is 0.0005-0.007 percent; oxygen level in the molten steel is required to be adjusted during Mg deoxidization; accurate control is performed by adding Fe2O3 powder into a cast ingot casting mould; the amount of added Fe2O3 powder is 0.001-0.008 percent of oxygen content in the molten steel; the volume density of the precipitates of less than 500nm in steel is more than 9.0*107 per cubic millimeter; the average particle size is less than 80.0nm; and the proportion of the precipitates of less than 100nm is more than 75 percent. A large number of nano-scaled precipitates with small sizes are formed by the method and are finely dispersed and distributed in the steel; suppression of austenite grain growth of a welding heat affected zone is facilitated; and the high heat input welding performance of the thick plate is improved.

The invention discloses a thick steel plate with excellent tenacity for an excellent-tenacity welding heat affected zone and a manufacturing method thereof. The method comprises the following steps: 1) smelting, refining and continuously casting, wherein the thick steel plate comprises the following components by mass percent: 0.05-0.09% of C, 0.10-0.30% of Si, 1.2-1.6% of Mn, no more than 0.02% of P, 0.001-0.006% of S, 0.20-0.40% of Ni, 0.15-0.3% of Cu, 0.005-0.03% of Ti, 0.003-0.1% of Al, 0.0005-0.005% of Ca, no more than 0.02% of REM, no more than 0.02% of Zr, 0.0002-0.005% of B, 0.001-0.006% of N and the balance of Fe and inevitable impurities, wherein Ti/N is smaller than or equal to 6 and greater than or equal to 1; 2) rolling; 3) cooling. By adopting the manufacturing method, occluded foreign inclusions in fine dispersed distribution can be formed. By controlling the surface density of a micron occluded foreign substance of which the diameter is greater than or equal to 1 micron, the Ca/Al ratio and the length-width ratio of the occluded foreign inclusions, the surface density, the Ca/Al ratio and the length-width ratio of micron inclusions of which the diameter is greater than or equal to 1 micron, the surface density of a submicron occluded foreign substance of which the diameter is smaller than 1 micron, the tensile strength of base metal is greater than or equal to 510MPa, the welding line energy is 200-400 kJ/cm, and the welding heat affected zone has good impact toughness.

The invention belongs to the technical field of low-alloy high-strength steel and particularly relates to a yield strength 690 MPa class steel plate capable of bearing high heat input welding and a manufacturing method of the yield strength 690 MPa class steel plate. The steel plate comprises chemical components including 0.01%-0.04% of C, 0.1%-0.3% of Si, 1.7%-2.2% of Mn, 0.01%-0.05% of Nb, 0.01%-0.05% of V, 0.005%-0.025% of Ti, 0.001%-0.008% of P, 0.001%-0.005% of S, 0.05%-0.5% of Cu, 0.05%-0.5% of Ni, 0.05%-0.5% of Cr, 0.05%-0.5% of Mo, 0.0005%-0.0025% of B, 0.001%-0.005% of N, 0.00002%-0.0002% of H, 0.001%-0.005% of O 0.001%-0.015% of Al, one of Mg and Ca and the balance Fe. Ti-Mg-O or Ti-Ca-O compound occluded foreign substances accounts for 10% or higher in occluded foreign substances with the size being 0.2 micron to 3 microns, and in addition, an average of 1%-50% of Ti is contained; and the number of the occluded foreign substances with the size being 3 microns or higher in the steel plate is smaller than or equal to 120 pieces/mm<3>. An LD-RH-LF-RH smelting process is adopted, and when oxygen in molten steel is fixed to be 150 ppm to 300 ppm, Ti and Mg or Ca are added; and two-stage controlled rolling and controlled cooling are adopted. The steel plate has good toughness performance and can bear 100 kJ/cm to 200 kJ/cm high heat input welding.

The invention relates to a high-strength thick steel plate for large heat input welding. The high-strength thick steel plate comprises, by weight percent, 0.07-0.10% of C, 0.05-0.15% of Si, 1.5-1.8% of Mn, not more than 0.01% of P, not more than 0.005% of S, 0.02-0.10% of Al, 0.006-0.02% of N, 0.005-0.015% of Ti, 0.10-0.25% of Cr, 0.0015-0.0025% of B, not more than 0.0030% of O, and the balance Fe and other inevitable impurity. A manufacture method of the high-strength thick steel plate includes: smelting in a converter or an electric furnace, secondary refining in a vacuum furnace, casting ingots, reheating the ingots, and performing TMCP (thermal mechanical control processing) and fast cooling to obtain the steel plate. The thick steel plate with a high strength of 600MPa is low in cost, and has excellent low-temperature toughness in the large heat input welding.

The invention discloses a large heat input welding 670MPa-grade steel plate. The large heat input welding 670MPa-grade steel plate comprises the following chemical elements in percentage by mass: 0.08%-0.12% of C, 0.80%-1.20% of Mn, 0.2%-0.6% of Cr, 1.5%-1.9% of Ni, 0.3%-0.5% of Mo, 0.1%-0.3% of Cu, 0.02%-0.05% of V, 0.001%-0.01% of Al, 0.006%-0.012% of Ti, 0.0008%-0.0014% of B, 0.001%-0.006% of N and the balance of Fe and other inevitable impurities. In addition, the invention also discloses a manufacturing method of the large heat input welding 670MPa-grade steel plate. The manufacturing method comprises the following steps: (1) smelting and casting; (2) rolling; and (3) quenching and tempering thermal treatment, wherein the quenching heating temperature is 900-980 DEG C, and then water quenching is carried out; and the tempering heating temperature is 600-700 DEG C. The large heat input welding 670MPa-grade steel plate has good energy welding performance and aging impact performance, and can be effectively used as a welding structure material to be applied to the field of ocean engineering.