158results about How to "Low carbon equivalent" patented technology

The invention belongs to the field of metal materials and discloses a large-thickness and high-strength quenched and tempered steel plate and a production method thereof. The steel plate mainly consists of the following chemical components by weight percentages: not more than 0.18% of C, 0.1-0.4% of Si, not more than 1.2% of Mn, 0.7-1.7% of Ni, 1.0-1.5% of Cr, 0.4-0.6% of Mo, 0.03-0.08% of V, 0.02-0.04% of Al, 0.0005-0.0020% of B, Fe and unavoidable impurities. The molten steel designed according to the components of the invention can be rolled into the large-thickness steel plate by smelting process, casting process, heating process, rolling process, water cooling process and quenching and tempering process. The steel plate has the advantages of reasonable component design, good comprehensive properties and low production cost, can be applied to off-shore oil production platform engineering, power stations, engineering scaffolds and other industries and has good application prospect.

The invention discloses a high-strength X100 pipe line steel hot rolling flat plate and a method for manufacturing the same. The steel comprises the following chemical components in percentage by weight: 0.02 to 0.08 percent of C, 0.10 to 0.35 percent of Si, 1.65 to 2.20 percent of Mn, 0.005 to 0.020 percent of P, less than or equal to 0.003 percent of S, 0.04 to 0.11 percent of Nb, 0.008 to 0.030 percent of Ti, 0.02 to 0.045 percent of Als, one or more of less than or equal to 0.60 percent of Ni, less than or equal to 0.30 percent of Mo and less than or equal to 0.30 percent of Cu, and the balance of Fe and inevitable impurities. The manufacturing method comprises the following steps that: the heating temperature of a plate blank is between 1,160 and 1,280 DEG C, the rough rolling temperature is between 1,070 and 1,150 DEG C, the finish rolling temperature is between 830 and 950 DEG C, the finish cooling temperature is between 300 and 550 DEG C, and the controlled cooling speed is between 15 and 30 DEG C / S. By using the method, a complex phase structure mainly comprising the following bainites can be obtained. By adopting the complex phase structure, the yield strength of the pipe line steel hot rolling flat plate reaches 690 to 825MPa, the tensile strength reaches over 780MPa, the impact energy at a temperature of 20 DEG C below zero is more than or equal to 200J, and the shearing area of DWTT at a temperature of 15 DEG C below zero is more than or equal to 90 percent; and the rolling resistance and the straightening resistance are reduced, and the operating rates of the rolling machine and the straightening machine are improved.

The invention discloses a production method of a wide and heavy steel plate with excellent ultra-low-temperature toughness used for offshore wind power, belonging to the technical field of rolling of the wide and heavy steel plate used for offshore wind power through a continuous coasting blank. The production process comprises the steps of: molten iron, converter smelting, LF (Ladle Furnace) refining, RH (Ruhstahl Hausen) vacuum degassing, continuous casting, steel blank check, heating, phosphorous removal, rough rolling, fine rolling, ACC (Activated Calcium Carbonate) water cooling, straightening, cooling in pile, shearing, shot blasting, normalizing, checking and storage. According to the European EN110225 standard, on the basis of the continuous casting blank, through adding micro-alloying elements, such as Nb, V, Ti and the like, and reasonably controlling rolling, a cooling process and a normalizing heat treatment method, the production yield strength is 355-410 MPa, the strength of extension is 470-550 MPa, the coefficient of elongation is 26-36%, the average value of the percentage of contraction of a section in a direction Z is 35-81%, the impact absorbing energy of a core part of the steel plate at ultra-low temperature of -60 DEG C is 100-240 J, and meanwhile, the wide and heavy steel plate has steel with good using performance as well as the thickness is 40-130 mm, and the specification is S355G8+N.

The invention relates to a 110Kg level high tensile steel plate with the yield strength not less than 960MPa. The steel plate comprises the following chemical components by weight percentage: 0.14 to 0.18 percent of C, 0.20 to 0.50 percent of Si, 0.90 to 1.30 of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S, 0.70 to 0.10 percent of Ni, 0.04 to 0.08 percent of V, 0.020 to 0.060 percent of Nb, 0.020 to 0.060 percent of Al, 0.30 to 0.80 percent of Cr, 0.30 to 0.60 percent of Mo, 0.010 to 0.030 percent of Ti, 0.0010 to 0.0030 percent of B, and the balance being Fe and inevitable impurities. Through the reasonable design of alloy components and mainly the control on quenching and tempering process, the thickness of the obtained steel plate can reach 80mm. The steel plate has high yield strength, high welding performance, high cold bending performance, good low temperature toughness, good steel plate profile, and excellent comprehensive performance. The steel plate can be widely applied to the manufacturing of engineering machinery and has bright application prospect.

The invention belongs to the field of metal materials, and relates to a novel high strength steel board low in density, high in strength and good in anti-corrosion performance, in particular to component design and a preparation method of the novel automobile-used steel. The automobile-used steel board is characterized by comprising the following specific chemical compositions by mass percentage: 0.60-0.70 percent of C, 0.30-0.40 percent of Si, 10.0-15.0 percent of Mn, 5.0-10.0 percent of Al, less than 0.005 percent of P, less than 0.003 percent of S and Fe and unavoidable impurities in balancing amount. The preparation process comprises the following steps: performing smelting according to the chemical compositions, and forging casting blank material into a steel blank; heating the steel blank to 1,130-1,170 DEG C, keeping the temperature for 2 hours, and performing multi-pass hot-rolling deformation, wherein the rolling starting temperature ranges from 1,030-1,070 DEG C, the rolling stopping temperature ranges from 850-900 DEG C, the accumulated deformation amount ranges from 80 percent to 85 percent, and the rolling temperature is from 200 DEG C to 250 DEG C; after hot rolling, further performing solution treatment of the steel board, keeping the temperature at 1,000-1,050 DEG C for 0.5-1 hour, and performing water quenching treatment; taking a dual-phase organization combining austenite and ferrite, and obtaining the lower density and high toughness automobile-used steel board.

The invention provides a high-flexibility wear-resistant steel plate, which is characterized by comprising the following chemical components by weight percent: 0.04 to 0.11 percent of C, 0.10 to 0.50 percent of Si, 0.50 to 1.50 percent of Mn, less than 0.015 percent of P, less than 0.010 percent of S, 0 to 0.60 percent of Cr, 0 to 0.50 percent of Mo, 0 to 0.80 percent of Ni, 0 to 0.050 perent of Nb, 0.005 to 0.0040 percent of B, 0.010 to 0.060 percent of Al and 0.005 to 0.060 percent of Ti, and the surplus is Fe and inevitable foreign matters; and the content of Si, Mn and Cr satisfies that: Si+Mn+Cr is less than or equal to 2.4 percent and more than or equal to 1.30 percent; and the content of Mo, Ni and Nb satisfies that: Mo+Ni+Nb is less than or equal to 1.10 percent more than or equal to 0.10 percent. The hardness of the high-flexibility wear-resistant steel plate is more than 350 HB, the longitudinal impact power is more than 100J at the temperature of minus 40 DEG C, the micro-structure is of bainite or martensite, and the welding performance is excellent. The wear-resistant steel plate has simple and easy production technology and excellent low-temperature flexibility and welding performance.

The invention provides a double-phase steel plate which comprises 0.07-0.098 of C, 0.1-0.4 of Si, 1.95-2.2 of Mn, 0.3-0.6 of Cr, less than or equal to 0.015 of P, less than or equal to 0.004 of S, less than or equal to 0.005 of N, 0.015-0.04 of Nb, 0.015-0.04 of Ti, 0.015-0.045 of Al, and 0.002-0.004 of B or 0.2-0.4 or Mo, wherein Pcm equals to C+Si / 30+Mn / 20+2P+4S which is less than or equals to 0.24; and the double-phase steel plate also comprises the balance of Fe and unavoidable impurities. The invention also provides a manufacturing method of the double-phase steel plate. The high-strength uniform-performance double-phase steel plate can be obtained by the proper composition design and manufacturing technology, and the manufacturing requirements on parts of a high-strength automobile body can be better met.

The invention discloses X120 level pipeline steel with low crack sensitivity and high toughness and a production method. The X120 level pipeline steel comprises the following designed components (wt%): 0.02-0.08wt% of C, 1.5-2.1wt% of Mn, at most 0.5wt% of Si, at most 0.018wt% of P, at most 0.0020wt% of S, 0.01-0.02wt% of Ti, 0.04-0.11wt% of Nb, at most 0.08wt% of V, 0.0030wt% of B, 0.01-0.04wt% of Als, 0.1-0.40wt% of Mo, 0.3-0.5wt% of Ni, at most 0.40wt% of Cu, at most 0.30wt% of Cr and the balance of Fe and unavoidable filth. The invention meets the following formulae: the sum of Mo, Ni, Cuand Cr is smaller than or equal to 1.4 and the sum (Pcm) of C, Si / 30, (Mn+Cu+Cr) / 20, Ni / 60, Mo / 15, V / 10 and 5B is smaller than or equal to 0.23; and the production method comprises the following steps: smelting; heating a continuous casting blank to 1,100-1,250 DEG C; roughly rolling and controlling the finishing temperature at 1,000-1,100 DEG C; finely rolling and controlling the finishing temperature at 800-900 DEG C; resting a steel plate for 10-60 seconds; and cooling with the final coldness temperature of at most 450 DEG C. The invention has little content of the added alloy as well as low cost and crack sensitivity of the steel plate and is beneficial to large-scale production.

The invention relates to a high-ductility Class F extra thick rack steel plate used at a low temperature and a manufacturing method of the steel plate. The steel plate takes Fe as a basic element and comprises C, Si, Mn, P, S, Cr, Mo, Ni, Cu, Al, V, Nb, N, B and the balance of Fe and impurity elements, wherein the carbon equivalent CEV is 0.75 pounds. The manufacturing method sequentially comprises the procedures of electric furnace smelting, LF (Ladle Furnace) refining, VD (Vacuum Distillation) refining, die casting, ingot heating, cogging rolling, slow cooling control, billet heating, rolling, thermal refining and the like. The thickness of the rack steel plate can reach 180mm, the yield strength is above 690MPa, the tensile strength is between 790-930MPa, the elongation<3> is 20%, the Z-direction performance (percentage reduction of area)<3> of the steel plate is 35%, the Charp impact work below -60 DEG C is greater than 100J, and the comprehensive mechanical property is excellent.

The invention discloses ultra high strength ship plate steel and a production method thereof. A plate blank comprises the following components in percentage by weight: 0.02-0.09 percent of C, 0.1-0.4 percent of Si, 0.5-1.6 percent of Mn, 0.01-0.04 percent of Alt, 0.02-0.05 percent of Nb, 0.008-0.02 percent of Ti, 0.3-0.7 percent of Cr, 0.2-0.5 percent of Mo, 0.5-1 percent of Ni, 0.2-1 percent of Cu, less than 0.013 percent of P, less than 0.005 percent of S, less than 0.0012 percent of O, less than 0.0045 percent of N, less than 0.00015 percent of H and the balance of Fe and inevitable impurities. The production method comprises the following steps of heating the plate blank with the thickness of 220-300 mm before rolling at the temperature of 1250 DEG C; starting rough rolling at the starting temperature of not less than 1100 DEG C; starting finish rolling at the temperature of not more than 910 DEG C, and stopping finish rolling at the temperature of 870-890 DEG C; rolling a steel plate with the thickness of 10-60 mm; rapidly entering ACC to control cooling at the cooling speed of 8-12 DEG C / s after finish rolling; returning red at the temperature of 650-680 DEG C; and tempering for 90-180min at the temperature of 500-680 DEG C. The product has good comprehensive mechanical property.

The invention provides a high-performance quenched and tempered steel plate with 80 kg carbon equivalent and a manufacturing method of the high-performance quenched and tempered steel plate. The high-performance quenched and tempered steel plate comprises the following ingredients by weight percent: 0.05 to 0.12 percent of C, 0 to 0.20 percent of Si, 1.20 to 1.60 percent of Mn, 0 to 0.013 percent of P, 0 to 0.003 percent of S, 0.10 to 0.30 percent of Cu, 0.10 to 0.40 percent of Ni, 0.10 to 0.30 percent of Cr, 0.05 to 0.30 percent of Mo, 0.035 to 0.065 percent of Als, 0.005 to 0.011 percent of Ti, 0.015 to 0.045 percent of V, 0 to 0.0060 percent of N, 0.001 to 0.004 percent of Ca, 0.0006 to 0.0013 percent of B, and Fe in balancing amount. By adopting a low-C low-Si high-Mn low-N-(Ti+N+B) microalloyed steel ingredient system as the foundation, and optimizing recrystallization rolling control, quenching and tempering process, the invention has the advantages that the microstructure of the steel plate is tiny tempered martensite or tempered lower bainite; the average size of colonies is lower than 25 Mum; the yield strength is larger than or equal to 690MPa; the tensile strength is larger than or equal to 780 MPa; the Charpy impact power (single value) at -40 DEG C is equal to or larger than 100 J; moreover, the Charpy impact power (single value) of a welding heat affected zone (HAZ) at -40 DEG C is equal to or larger than 47 J, and the stretch rate Delta 5 thereof is equal to or larger than 15 percent.

The invention relates to low-carbon-equivalent low-temperature-usable high-thickness toothed rack steel and a manufacturing method thereof. The toothed rack steel comprises the following chemical components: C, Si, Mn, P, S, Cr, Mo, Ni, Cu, Al, V, N, B and the balance of Fe and impurity elements, wherein the carbon equivalent CEV is less than 0.65. The manufacturing method sequentially comprises the steps of KR molten iron pretreatment, converter smelting, LF and RH refining, continuous casting, continuous casting blank heating, rolling, thermal refining and the like. The thickness of the toothed rack steel plate manufactured by the invention can be up to 152.4mm, the yield strength is above 690Mpa, the tensile strength is 790-930MPa, the elongation percentage is 319%, and the Charpy impact energy at -60 DEG C is more than 100J. Besides, the toothed rack steel is favorable in comprehensive mechanical property, convenient in production process and low in cost.

The invention relates to an easy-to-weld ultra-thick steel plate with high strength and high toughness suitable for minus 60 DEG C. The steel plate comprises the chemical ingredients of 0.05% to 0.10% of C, 0.2% to 0.3% of Si, 1.3% to 1.6% of Mn, 0.02% to 0.04% of Al, 0.03% to 0.05% of Nb, 0.03 to 0.05% of V, 0.1% to 0.3% of Cr, 0.1% to 0.4% of Ni, 0.1% to 0.3% of Mo, 0.1% to 0.3% of Cu, 0.01% to 0.02% of Ti, 0% to 0.015% of P, 0% to 0.002% of S, and 0% to 0.007% of N; the carbon equivalent is not larger than 0.43, and Pcm is not larger than 0.20. According to the steel plate, the thickness ranges from 70 mm to 120 mm, the yield strength is 460 MPa or more, and under the temperature of minus 60 DEG C, both the Charpy impact energy at the position, with the thickness one quarter that of the thickness of the steel plate, of the steel plate and the Charpy impact energy at the position, with the thickness one half that of the thickness of the steel plate, of the steel plate are larger than or equal to 100 J. The easy-to-weld ultra-thick steel plate with high strength and high toughness is made through the steps of KR hot metal pretreatment, converter smelting, ladle furnace refining, RH vacuum degassing, continuous casting, slow cooling, casting blank heating, rolling, straightening, pile slow cooling, quenching, tempering and the like.

The invention relates to steel for a 300MPa-grade automobile structural part and a production method for the steel. The steel comprises the following main components in percentage by weight: 0.06-0.08 percent of C, 0.05-0.09 percent of Si, 0.30-0.45 percent of Mn, 0.025-0.055 percent of Al, 0.015-0.025 percent of P, less than or equal to 0.006 percent of S, 0.010-0.019 percent of Nb, less than or equal to 0.006 percent of N and the balance of Fe and impurities. The production method comprises the production steps of molten iron desulfurization, converter smelting, ladle argon blowing, continuous casting, heating of a casting blank, hot rolling, winding, conventional pickling, cold rolling, continuous operation and flattening for later use. The production method disclosed by the invention has the advantages of short process flow, lower energy consumption and stable mechanical property; and in addition, on the premise that the yield strength of 300-340MPa and the tensile strength of 390-445MPa are met, the elongation percentage is not lower than 31 percent, the plastic strain ratio r is 1.45-1.80, a strain hardening index n is 0.16-0.20, a wide-cold test bending is 180 degrees and a bending diameter d is equal to 0; and in a metallographic structure, an equiaxed ferrite is 85-90 percent and a granular pearlite is 10-15 percent.

The invention discloses a high-strength high-toughness X100 pipeline steel hot-rolled steel strip. The steel strip comprises the following chemical elements in percentage by mass: 0.015 to 0.090 percent of C, 0.1 to 0.5 percent of Si, 1.50 to 1.79 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.003 percent of S, 0.10 to 0.40 percent of Cr, 0.03 to 0.10 percent of Nb, 0.001 to 0.100 percent of Zr, 0.01 to 0.035 percent of Ti, 0.31 to 0.60 percent of Mo, 0.10 to 0.40 percent of Cu, 0.10 to 0.50 percent of Ni, 0.0010 to 0.0050 percent of Ca, 0.02 to 0.045 percent of Al, less than or equal to 0.010 percent of N, less than or equal to 0.008 percent of O and the balance of Fe and other inevitable impurities. Correspondingly, the invention also discloses a method for manufacturing the steel strip. The hot-rolled steel strip has high comprehensive mechanical properties and manufacturability and comprises simple components.

The invention discloses a resource-saving Q345 low-alloy series steel plate and a production method thereof. The steel plate comprises the following chemical components in percent by weight: 0.15 to 0.18 percent of C, 0.15 to 0.50 percent of Si, 1.10 to 1.25 percent of Mn, not more than 0.030 percent of P, not more than 0.035 percent of S, 0 to 0.045 percent of Alt, not more than 0.44 percent of carbon equivalent, and the balance of Fe and inevitable impurities. The production process of the steel plate comprises 150 t converter, LF external refining, slab continuous casting, slab heating, steckel mill controlled rolling, controlled cooling, thermal straightening, cooling, shearing and mark warehousing. The resource-saving Q345 low-alloy series steel plate, produced by the production method, has the yield strength of 360 to 420 MPa, the tensile strength of 500 to 550 MPa, and the elongation of 24 to 32%, and acicular ferrite with the thickness of 3 to 6 mm, polygonal ferrite, degenerate perlite and a small amount of granular bainite are arranged on the surface layer of the steel plate.

The present invention relates to steel with high intensity and weatherability used for low alloy power rods and the preparation method thereof. The weathering steel has the chemical composition and the weight percentage content that C is 0.06-0.12 percent, Si is 0.15-0.35 percent, Mn is 1.0-1.40 percent, S is less than or equal to 0.030 percent, P is less than or equal to 0.030 percent, Cu is 0.15-0.30 percent, Al is less than 0.04 percent, Nb is 0.01-0.03 percent, and the residual is Fe and microimpurity. The present invention performs combined blown converter smelting, LF ladle refining, soft argon blowing, and sheet billet continuous casting by using the prior equipment and the conventional process production, and performs microalloying treatment through adjusting the content of partial elements. By accurately controlling the processing condition, the economic weathering steel with good atmospheric corrosion resistant performance and comprehensive mechanical performance can be produced.

The invention discloses an HB400-grade wear-resisting steel plate and a production method thereof. The steel plate comprises the following chemical components in percentage by weight: C 0.05-0.15wt%, Si 0.4-1.4wt%, Mn 0.5-2.0wt%, P <0.012wt%, S <0.003wt%, Mo 0-0.5%, Nb 0.01-0.08%, Cu 0.20-1.0%, Co 0-1.0%, B 0.0010-0.0025wt%, Al 0.02-0.04wt%, Ti 0.004-0.030wt%, and the balance of Fe and inevitable impurities, wherein the content of Mo and Nb needs to satisfy the condition that the Mo+Nb is not less than 0.023C+0.059Ti+1.71B and not more than 2.574C+0.62Mn+10.36Ti +2.11B. The invention reduces production cost by adding some cheap alloy elements; and when the value of carbon equivalent Ceq is not more than 0.45, the HB400-grade wear-resisting steel plate has good welding performance.

The invention discloses an oxidation-resistant alloying grey cast iron and a preparation method of the oxidation-resistant alloying grey cast iron. The cast iron comprises the following components by mass percentage: 3.0-3.2% of C, 1.8-2.0% of Si, 0.50-0.70% of Mn, 0.10-0.50% of Cr, 0.20-0.30% of Ni, 0.03-0.50% of Mo, 0.5-3.0% of Al, 0.05-0.08% of Sr, 0.005-0.15% of Zn, and the balance of Fe and inevitable impurities. The preparation method comprises the steps of melting raw materials, culturing and processing, and pouring, wherein the tapping is carried out at 1450 to 1550 DEG C after melting; the molten iron is processed by being flushed in a ladle and cultured and processed along with the flow, and then slagged and casted. According to the oxidation-resistant alloying grey cast iron provided by the invention, the organization of the grey alloying cast iron material is structured by distributing 6-8 grades of D type graphite with little graphite of A type on a ferrite substrate, so that higher toughness, high heat conductivity and high-temperature oxidization resistance can be achieved, and good casting technical performance can be ensured as well; and the oxidation-resistant alloying grey cast iron can be applied to manufacturing a glass die and a light alloy metal type casting die which can bear the heat impacting of high-temperature formed liquid and cold-heat alternating stress for a long time.

The invention discloses a high-strength steel plate for ocean engineering and a production method thereof. The production method comprises the working procedures of smelting, continuous casting, heating, rolling, heat stacking and heat treatment, wherein the molten steel obtained in the smelting procedure comprises the following chemical ingredients with contents in percentage by mass: 0.05-0.09% of C, 0.10-0.30% of Si, 1.1-1.35% of Mn, not greater than 0.010% of P, not greater than 0.003% of S, 0.15-0.4% of Ni, 0.15-0.35% of Cr, 0.10-0.30% of Mo, 0.020-0.050% of Nb, 0.03-0.05% of V, 0.020-0.050% of TAl, and balance Fe and inevitable impurities; a quenching and tempering process is adopted in the heat treatment procedure; during the quenching process, a heating temperature is 880-910 DEG C, and a total heating time is PLC +(20-40) minutes; and during the tempering process, a heating temperature is 580-620 DEG C, a total heating time is 1.5-2 minutes per millimetre, and air cooling is carried out after discharge. According to the method disclosed by the invention, through adjustment and optimization for the proportion of alloy elements in the steel plate, and quenching and low-temperature short-time tempering, good mechanical properties of the steel plate can be guaranteed under a low-carbon-equivalent condition, and the steel plate is enabled to have good structure, comprehensive property and welding property.

The invention relates to a nitrogen and boron alloying high tenacity hardfacing flux-cored wire. The skin of the nitrogen and boron alloying high tenacity hardfacing flux-cored wire adopts a mild-carbon steel strip, and the core part is filled with alloy or mineral powder, and is pulled into a wire. The nitrogen and boron alloying high tenacity hardfacing flux-cored wire is characterized in that nitrogen and boron compounds, such as NaN3, BN and the like and a rear earth oxide are added into flux-cored powder to realize the surfacing metal nitrogen and boron alloying. The flux-cored wire comprises chemical components (weight percentage) including 1.0-3.0 % of carbon, 35-40% of chromium, 1.0-2.0% of niobium, 3.0-8.0% of boron, 2.0-5.0% of nitrogen, 1.0-2.0% of molybdenum, 1.0-2.5% of rare earth oxide, and the balance of iron or other impurities. Because the flux-cored wire adopts nitrogen and boron to replace part of carbon alloying surfacing metal, the hardness of a surfacing layer is high, and the highest hardness can reach HRC 66-69. The nitrogen and boron alloying high tenacity hardfacing flux-cored wire has the advantages of favorable toughness and outstanding wear resistance. The nitrogen and boron alloying high tenacity hardfacing flux-cored wire can be mainly used for the surfacing repair and the composite manufacturing of easily-damaged parts of ferrous metallurgy equipment, building machinery and the like.

The invention relates to EH47 crack arrest steel for a large container ship. The chemical components of a steel plate comprise, by mass, 0.03%-0.06% of C, 0.15%-0.50% of Si, 1.50%-2.00% of Mn, smallerthan or equal to 0.008% of P, smaller than or equal to 0.0050% of S, 0.050%-0.080% of Nb, 0.020%-0.050% of V, 0.008%-0.020% of Ti, 0.80%-1.30% of Ni, 0.10%-0.30% of Cr and 0.10%-0.30% of Cu. The manufacture technology process of the steel plate comprises the steps of smelting, continuous casting, reheating, TMCP rolling and controlled cooling. The steel plate obtains fine and uniform acicular ferrite in the whole thickness, the strength is moderate, the toughness is excellent, the good brittle fracture resistance is achieved, namely, the CTOD characteristic value delta is larger than or equal to 0.15 mm at -60 DEG C, and the crack arrest performance is excellent, namely, Kca is larger than or equal to 6,500 N / mm<3 / 2>.

The invention relates to a winter welding construction method of a long-distance transport pipeline, which is characterized by comprising the following steps of: pairing pipes, setting up a heat-preservation shed around the orifices of the pipes to be welded before welding to preserve heat and dehumidify, and carrying out all-position welding on the pipes by using a cellulose manual underhand welding method and a semiautomatic underhand welding method in a welding process, wherein the manual welding is adopted for root welding and the semiautomatic welding is adopted for other welding; heating a welded junction at 100-150 DEG C by using an electric heater after finishing welding and keeping a constant temperature for half an hour, then immediately wrapping the completed welded junction and covering with felt, binding by using a rubber belt and preserving heat for above 24 hours. The winter welding construction method of the long-distance transport pipeline has the advantages of overcoming the defect that the welding construction of the long-distance transport pipeline cannot be carried out in winter due to cold climate in northern areas and ensuring the normal welding construction of the long-distance transport pipeline in winter, has high welding quality and is suitable for welding high-intensity pipelines mainly made from X65 and the like. The winter welding construction method of the long-distance transport pipeline is characterized by low carbon equivalent, low sensitivity index of welding cold crack and high low-temperature toughness and is mainly used for the long-distance transport pipelines of petroleum, natural gas, slurry and the like.

The invention relates to an ultrahigh-strength steel plate, which comprises, by weight percentage, 0.25-0.35% of C, 0.20-0.60% of Si, 0.8-2.0% of Mn, no more than 0.010% of P, no more than 0.005% of S, 0.02-0.06% of Al, 0.30-1.00% of Cr, 0.20-0.60% of Mo, 0.01-0.05% of Ti, 0.001-0.005% of B, no more than 1.0% of Ni, and the balance of Fe and unavoidable impurities. A production method of the ultrahigh-strength steel plate includes: smelting the components, obtaining a blank or ingot by casting; heating the bank or ingot to 1180-1250 DEG C prior to rolling, rolling in the first stage in a recrystallization area, performing multi-pass high reduction rolling with accumulative deformation not less than 80%; rolling in the second stage in a non-recrystallization area, finish rolling temperature being controlled at 870 to 930 DEG C); accelerating to cool the rolled steel plate to below 200 DEG C; and tempering at 200+ / -20 DEG C to obtain the steel plate 4-15mm thick. The yield strength of the steel plate is not less than 1400MPa, the tensile strength of the steel plate is not less than 1800MPa, and Charpy impact power Akv at -20 DEG C is not less than 20J.

The invention discloses a p reparation method for hot-rolled low-density steel with the strength and ductility product being greater than or equal to 40 GPa.% and belongs to the field of metal materials. Chemical components of the hot-rolled low-density steel with the strength and ductility product being greater than or equal to 40 GPa.% comprise, by mass, 0.6-1.0% of C, 8-12% of Mn, 7-11% of Al, 0.01-0.2% of V, less than or equal to 0.003% of P, less than or equal to 0.002% of S and the balance Fe and inevitable impurities. The preparation process comprises the steps of smelting, forging, hot rolling and solid solution hardening treatment, the structure of the obtained low-density steel comprises annealing twins, precipitates of nanoscale vanadium exist in the twins, and the strengthening effect is obvious. The steel has the characteristics of low density and high strength and ductility, and the strength and ductility product is greater than or equal to 40 GPa.%.

The invention relates to a production process for effectively preventing marine anchor chain round steel from generating cracks. A preparation method includes the steps of an electric furnace smelting procedure, a refining procedure outside an LF, a square billet continuous casting procedure and a rolling procedure. Chemical components are reasonably designed, the carbon equivalent is controlled, Ti microalloy reinforcement is added, the content of P and S is controlled to be smaller than or equal to 0.015%, the content of N is controlled to be smaller than or equal to 70 ppm, the content of residual elements of Cu, Nb and the like is reasonably controlled, the LF is well sealed, the soft blowing flow of argon is reasonably controlled, molten steel is prevented from absorbing nitrogen, aluminum deoxidation is enhanced, the soft blowing time of the argon is properly prolonged, whole-process protective casting is adopted for the continuous casting, the pulling speed and the superheat degree are low, proper protective slag is selected, the straightening temperature is raised, continuously cast billet enters a pit to be slowly cooled, the tapping interval is well controlled in a rolling manner, the compression ratio is increased, and a reasonable heat treatment process is selected. The marine anchor chain round steel produced through the method is simple in procedure and low in cost, vacuum treatment is not needed, and the technical problems that marine anchor chain round steel produced at present is bad in surface quality, high in crack occurrence ratio, not stable in quality and the like are solved.

The invention discloses a Q420E steel plate with low carbon equivalent and high toughness. The steel plate comprises the following chemical components in percentage by weight: 0.06-0.08% of C, 0.35-0.45% of Si, 1.3-1.5% of Mn, less than or equal to 0.02% of P, less than or equal to 0.005% of S, 0.025-0.035% of Nb, 0.0015-0.003% of Ca, 0.017-0.03% of Als and the balance of iron and impurities. The invention also discloses a production method of the Q420E steel plate with low carbon equivalent and high toughness. The Q420E steel plate disclosed by the invention is simple in preparation process, low in production cost and good in surface quality; the Q420E steel plate with low carbon equivalent, high toughness and good surface quality can be obtained by adding a trace amount of Nb on the basis of a conventional C-Mn steel by virtue of appropriate heating, controlled rolling and controlled cooling processes.

The invention provides an acid-corrosion-resistant X70MS pipeline steel hot rolled coil and a manufacturing method thereof. The acid-corrosion-resistant X70MS pipeline steel hot rolled coil comprisesthe following components including, by mass, 0.03% to 0.10% of C, 1.10% to 1.40% of Mn, 0.10% to 0.20% of Si, 0.010% to 0.030% of Al, 0.15% to 0.55% of Cr, 0.15% to 0.45% of Mo, 0.005% to 0.025% of Ti, 0.050% to 0.080% of Nb, 0.020% to 0.040% of V, 0.15% to 0.30% of Ni, not larger than 0.0002% of B, not larger than 0.012% of P, not larger than 0.0020% of S, not larger than 0.0060% of N, not largerthan 0.0018% of O, not larger than 0.0005% of H and the balance Fe and inevitable inclusions. Compositions and mechanical property of the acid-corrosion-resistant pipeline steel X70MS products meet the API 5L standard, the acid corrosion resistance performance meets international HIC resistant and SSCC resistant related standard requirements, the good welding technology performance is obtained, and the requirements for producing materials for oil and gas pipelines are met.

The invention provides a high-tenacity steel and a steel plate adaptive to high heat input welding and a production method thereof. The high-tenacity steel and steel plate comprise the following compositions by weight percent: 0.045-0.075% of C, 0.20-0.40% of Si, 1.20-1.60% of Mn, 0.015-0.025% of Nb, 0.02-0.06% of Al, 0.006-0.020% of Ti, 0.020-0.060% of N, P is no more than 0.015%, S is no more than 0.003% and the balance Fe and inevitable impurities. The invention also provides a production method for the steel plate, including smelting, continuous casting, heating, rolling and cooling. The invention adopts low C-moderate Mn-low Si-micro Nb and Ti-no B series of steel grade, and improves the strength, low-temperature tenacity and weldability of the steel plate by strengthening the control of thermo-mechanical rolling and post-rolling accelerated cooling technology.

The invention discloses an ultrahigh-strength X100 pipeline steel plate with excellent crack resistance. The steel plate comprises the following chemical components: 0.03-0.06% of C, 0.20-0.50% of Si, 1.80-2.10% of Mn, no more than 0.005% of S, no more than 0.010% of P, 0.20-0.50% of Ni, 0.20-0.40% of Mo, 0.20-0.50% of Cr, 0.20-0.50% of Cu, 0.050-0.080% of Nb, 0.015-0.035% of Ti, no more than 0.004% of N, no more than 0.004% of O, no more than 0.002% of H, no less than 0.015% of Als and the balance of Fe and trace impurities; Pcm is no more than 0.25%. The invention also discloses a preparation method of the steel plate. A shock crack of a V-shaped gap of the steel plate can exceed 55J, the shock crack can expand over 160J, and the crack resistance is good.