40 results about "Laminar cooling" patented technology

This application provides a method for preparing hot-rolled wide coils of 60Si2Mn spring steel with anti-strip breakage properties, and the hot-rolled wide coils thereof. The method includes: heating a 60Si2Mn spring steel slab to obtain a heated slab; hot-rolling the heated slab to obtain a hot-rolled wide strip steel with a width of 900-1500 mm; subjecting the hot-rolled wide strip steel to laminar flow cooling to obtain laminar flow cooled hot-rolled wide strip steel, wherein the laminar flow cooling consists of a pre-stage non-water cooling treatment and a post-stage rapid cooling treatment, with a target temperature of 760-800℃ for the pre-stage non-water cooling treatment and a cooling rate of 10-20℃ / s for the rapid cooling treatment; and coiling and cooling the laminar flow cooled hot-rolled wide strip steel to obtain hot-rolled wide coils of 60Si2Mn spring steel with anti-strip breakage properties. Using the embodiments of this application, hot-rolled wide coils of 60Si2Mn spring steel with anti-strip breakage properties can be produced, and they will not break during subsequent processing steps.

The application discloses a kind of automobile beam steels of tensile strength ≥650MPa and manufacturing method thereof, belong to hot-rolled steel strip technical field.The chemical composition of the steel is as follows in percentage by mass: C:0.05%~0.10%, Si:0.05%~0.25%, Mn:1.30%~1.80%, P:≤0.020%, S:≤0.0030%, Nb:0.04%~0.07%, Ti:0.03%~0.06%, the balance is Fe and inevitable impurities.Manufacturing method includes successively: hot metal desulphurization, converter blowing, argon blowing, LF furnace refining, continuous casting, rotary descaling, soaking, high-pressure water descaling, seven-stand finish rolling, laminar cooling and coiling.Continuous casting adopts liquid core reduction, soaking temperature is 1180~1250 DEG C, finish rolling temperature is 860~900 DEG C, coiling temperature is 600~650 DEG C, after 5m slight cooling of strip head by laminar cooling, it is cooled at 20~50 DEG C / s.The alloy cost of the application is low, process is simple, and the obtained steel plate has yield strength ≥550MPa, tensile strength ≥650MPa, elongation ≥17%, thinnest specification 1.5mm, with good shape, can realize "thin instead of thick" and "hot instead of cold".

This invention provides a hot continuous rolling method for controlling edge scaling during the roughing stage of interstitial steel, interstitial steel, and its applications. The method includes the following steps: providing a right-angle slab produced using a right-angle crystallizer; segmenting the right-angle slab to obtain a hot-rolled slab; subjecting the hot-rolled slab to roughing, finishing, laminar flow cooling, and coiling to obtain a hot-rolled coil of interstitial steel; wherein, during the roughing step, the corner temperature of the hot-rolled slab remains within the austenitic single-phase region. This invention offers a simple and convenient method that achieves stable control of edge quality during the roughing stage of interstitial steel hot continuous rolling, resulting in fewer surface defects, higher dimensional accuracy, and suitability for industrial-scale production.

The application discloses a method for improving the performance uniformity of medium-low chromium ferrite stainless steel, which comprises the following steps: controlling the carbon and nitrogen content of the medium-low chromium ferrite stainless steel as C<=0.045% and N<=0.045%; controlling the temperature of the heating furnace soaking section as 1150-1250 DEG C, the rough rolling inlet temperature as 1050-1200 DEG C, the finish rolling final rolling temperature as 900-1000 DEG C, not using the laminar cooling after the finish rolling, and the coiling temperature as >=650 DEG C; setting the heat preservation facilities beside the coiling unit, making the steel coil enter the heat preservation facilities after coiling, and controlling the time from the completion of coiling to the entering of the heat preservation facilities as <=10 min; and controlling the heat preservation time of the steel coil after entering the heat preservation facilities as 24-96 h. The application reduces the yield strength of the medium-low chromium ferrite stainless steel, improves the elongation after fracture of the medium-low chromium ferrite stainless steel, controls the hardness difference between the head and tail of the steel coil and the middle part of the steel coil as <=2, and thus improves the performance of the hot-rolled steel coil of the medium-low chromium ferrite stainless steel and improves the performance uniformity.

This invention discloses a high-strength cold-rolled steel with excellent baking performance, which contains Fe and unavoidable impurities, and also contains the following chemical elements in the following mass percentages: C: 0.06-0.10%, 0 < Si ≤ 0.05%, Mn: 0.40-0.7%, Al: 0.03-0.05%; the microstructure of the high-strength cold-rolled steel has recrystallized equiaxed ferrite with a volume fraction of more than 95%, and slender ferrite extending along the rolling direction with a volume fraction of 3-5%. This invention also discloses a method for manufacturing high-strength cold-rolled steel, comprising the following steps: smelting and continuous casting; hot rolling: the furnace exit temperature is 1150-1250℃, the hot rolling final rolling temperature is 830-890℃, the coiling temperature is 520-650℃, laminar flow cooling is adopted after rolling, and the rapid cooling rate of the laminar flow front section is 80-120℃ / s; pickling and cold rolling; continuous annealing: controlling the annealing homogenization temperature to be 680-750℃; leveling.

This invention provides a hot-rolled strip quality prediction method and system based on PINN modeling and cross-modal graph learning, belonging to the fields of industrial intelligent manufacturing and hot-rolled strip quality monitoring. The method first acquires historical production process variable data, strip quality data, and sensor monitoring data; it then constructs a temperature field model of the hot-rolled strip water-cooling process based on PINN, and uses the trained temperature field model to solve the continuous temperature field during the laminar cooling stage, extracting temperature field features; it constructs modal subgraphs for both temperature field features and sensor features, building a cross-modal full graph structure; a preliminary prediction model is built based on GNN, using the cross-modal full graph structure as the model input layer structure, and N base learners based on a residual learning strategy are introduced into the output layer. The trained preliminary prediction model and the N base learners constitute the hot-rolled strip quality prediction model. This invention achieves a deep integration of physical mechanisms and deep learning, significantly improving the accuracy and robustness of hot-rolled strip quality prediction.

This invention relates to the field of high-toughness energy steel manufacturing technology, specifically to thin-gauge, low-yield-strength-ratio L245-L450 pipeline steel, its preparation method, and applications. The thin-gauge, low-yield-strength-ratio L245-L450 pipeline steel, by mass fraction, contains 0.04-0.08% C, 0.10-0.25% Si, 0.70-1.40% Mn, P≤0.015%, S≤0.010%, 0.010-0.035% Nb, 0.010-0.020% Ti, 0-0.20% Cr, 0.010-0.035% Als, N≤0.0060%, with the remainder being Fe and unavoidable impurities. This invention aims to provide microstructure control targets and suitable composition-processes for a series of pipeline steel products with low yield strength ratios (L245-L450). By optimizing the alloy element ratios and laminar flow cooling process parameters (e.g., controlling the average cooling rate of the water-cooled section to 10-20℃ with 3-8 sets of centrally opened front-end manifolds), a feasible standardized common technology is formed, which stably controls the yield strength ratio of the product within the range of 0.82-0.86. This meets the PSL2 grade performance requirements specified in the national standard "Hot-rolled wide steel strip for oil and gas transmission pipelines" while also possessing low carbon equivalent, excellent low-temperature toughness, and a wide process window, ensuring the comprehensive mechanical properties of the material.

The application provides a rolling method for improving flatness of a 1100MPa high-strength steel hot-rolled coil and a hot-rolled plate, and belongs to the technical field of steel smelting. The method comprises the following steps: step 1: a rough rolling stage, dynamically adjusting the opening degree of side guides, and controlling the camber of the intermediate blank after rough rolling to be not more than a preset threshold value; step 2: a finish rolling stage, correcting the intermediate blank crown model setting value, setting the head target plate shape of the finish rolling outlet to a middle wave rolling strategy, and setting the tail target plate shape to a no wave shape rolling strategy; step 3: a cooling stage, controlling the laminar cooling header in a sparse opening mode, and prolonging the opening length of the cooling header; and step 4: a coiling stage, opening the cooling water of the mandrel at intervals, and dynamically adjusting the opening interval according to the mandrel temperature. The rolling method can significantly improve the flatness of the 1100MPa high-strength steel hot-rolled coil, reduce plate shape defects such as middle wave, edge wave and compound wave, and improve the product quality.

This invention relates to the field of automotive steel technology, specifically to a 220MPa grade low-wavyness hot-dip galvanized bake-hardening steel sheet, its manufacturing method, and its application. The main chemical elements are C, Si, Mn, P, Als, Nb, N, and S. The dissolved C content in the steel is 0.0008%–0.0015%, with the balance being iron and unavoidable impurities. This invention also discloses a manufacturing method for the above-mentioned bake-hardening hot-dip galvanized steel sheet, including steelmaking, continuous casting, slab heating, hot rolling, laminar flow cooling, pickling, hot-dip galvanizing, and leveling processes. The surface waviness Wsa of the produced steel sheet after 5% forming is... (1‑5) ≤0.35μm, increase in surface waviness ΔWsa (1‑5) With a thickness of ≤0.05μm and a yield strength of 220~280MPa, it meets the application requirements of water-based no-primer coating process for automotive exterior body panels.

This application relates to a hot-rolled pickled duplex steel and its preparation method, belonging to the field of strip steel production technology. The chemical composition of the duplex steel, by mass fraction, is: C: 0.05%~0.15%, Si: 0.15%~1.50%, Mn: 1.0%~2.0%, Al: 0.02%~0.10%, P≤0.015%, S≤0.006%, Cr: 0.1%~0.5%, Nb: 0.01%~0.05%, Ti: 0.01%~0.03%, Ni: 0.01%~0.40%, V: 0.001%~0.050%, with the remainder being Fe and unavoidable impurities. Through optimized C-Si-Mn-Cr-Nb-Ni composition system design, combined with controlled rolling and staged laminar flow cooling processes, a multiphase microstructure composed of ferrite and martensite was successfully obtained in the hot-rolled pickled duplex steel. This multiphase microstructure enables hot-rolled and pickled duplex steel to maintain high strength while retaining high elongation. Furthermore, a specific component ratio effectively suppresses softening in the weld heat-affected zone. This hot-rolled and pickled duplex steel is particularly suitable for passenger car chassis manufacturing, achieving a balance between lightweight design, high safety performance, and good manufacturability.

This invention discloses a method for manufacturing rolled stainless steel composite plates for marine engineering, comprising: layering a base carbon steel plate and a cladding stainless steel plate after surface treatment of the surfaces to be composited; welding and sealing the edges to form a sealed cavity and then evacuating the vacuum; performing gradient heating; feeding the heated billet into a rolling mill equipped with a multi-parameter collaborative control system, which uses a GRU neural network model to predict rolling parameter trends and generate feedforward control commands, while simultaneously generating feedback commands based on real-time interface bonding state deviations via a fuzzy PID controller, and dynamically adjusting the reduction schedule and rolling speed after fusion; and immediately performing laminar flow cooling after rolling. This method achieves precise control of the interface bonding state of the composite plate, improving product quality and performance.

The application discloses a laminar cooling uniformity optimization method and device, and belongs to the technical field of rolling control. The method comprises the following steps: determining a non-uniform distribution mode of damping overflow holes on the sidewall of an inlet water overflow pipe based on process parameters and cooling requirements of a laminar cooling system; constructing a fluid dynamics mathematical model based on the non-uniform distribution mode and the process parameters to show the fluid flow characteristics in the header; constructing a comprehensive evaluation function for evaluating the cooling performance in the width direction of the strip based on the fluid dynamics mathematical model; and obtaining optimal distribution parameters of the damping overflow holes when the comprehensive evaluation function is minimized. Through the design of the non-uniformly distributed damping overflow holes, the pressure loss of the cooling water along the pipeline in the header can be actively compensated, thereby realizing uniform distribution of the flow. The problem of uneven cooling in the width direction of the strip can be effectively solved, the cooling uniformity is significantly improved, the consistency of the microstructure and mechanical properties of the strip is ensured, and the product quality is improved.

The present application relates to strip steel continuous casting and rolling technical field, specifically a kind of thin strip steel continuous casting and rolling production line and rolling process, including the continuous casting machine, first descaling device, low-speed strong rolling mill, swing shear, first heat supplement device, second descaling device, rough rolling mill group, bar turning shear, reject device, second heat supplement device, third descaling device, finishing mill group, laminar cooling device, high-speed flying shear and coiler in turn along the rolling direction, first descaling device is located between the outlet of continuous casting machine and low-speed strong rolling mill, second descaling device is located before the entrance of rough rolling mill group, and third descaling device is located before the entrance of finishing mill group;Swing shear is arranged between low-speed strong rolling mill and first heat supplement device, and bar turning shear and reject device are arranged between rough rolling mill group and second heat supplement device.The present application greatly reduces the stringent requirements for the purity of molten steel and the content of sulfur and phosphorus, eliminates the deep pretreatment process, and reduces the steelmaking cost from the source.

This invention belongs to the field of metallurgical technology, and particularly relates to a low-cost, high-surface-quality galvanized hot-formed steel sheet production method. It includes the following steps: S1, using hot-rolled steel strip as raw material, controlling the coiling temperature of the hot-rolled steel strip to ≤550℃ through segmented laminar flow cooling; S2, pickling the hot-rolled steel strip using a composite pickling solution; S3, continuously galvanizing the pickled hot-rolled steel strip, wherein the heating temperature before galvanizing is ≤600℃. This invention eliminates the cold rolling and high-temperature annealing processes, fundamentally avoiding the internal oxidation defects of high-alloy hot-formed steel. The resulting steel sheet has a smooth surface without pitting or incomplete coating, and the interface between the coating and the substrate is clear and uniform. Simultaneously, the composite pickling solution improves pickling efficiency and reduces HCl volatilization. This invention has advantages such as low cost, high surface quality, and strong alloy adaptability.

Disclosed in the present application are an ultra-thin-gauge high-strength steel and a method for producing an ultra-thin-gauge high-strength steel on the basis of a discontinuous quenching line. The method comprises: providing molten steel, and subjecting the molten steel to converter smelting, external refining and Si-Ca treatment during the external refining, so as to obtain molten steel of high-strength steel, wherein a soft blowing treatment needs to be performed on the molten steel during the Si-Ca treatment, and the Ca / S ratio of the molten steel after the Si-Ca treatment is 1.0-3.0; continuously casting the molten steel of high-strength steel to obtain a continuously cast slab; heating the continuously cast slab to obtain a first heated slab; subjecting the first heated slab to rough rolling and finish rolling to obtain finish-rolled steel, wherein the rough rolling temperature is 1060°C to 1200°C, and the finishing temperature of the finish rolling is 860°C to 900°C; subjecting the finish-rolled steel to laminar cooling to obtain cooled steel, wherein the cooling rate is 40°C / s to 80°C / s; subjecting the cooled steel to pickling and cold rolling to obtain cold-rolled steel; subjecting the cold-rolled steel to levelling and quenching to obtain quenched steel; and subjecting the quenched steel to straightening and tempering to obtain ultra-thin-gauge high-strength steel having a thickness of less than or equal to 3 mm and a yield strength of greater than or equal to 960 MPa.

The utility model relates to a manifold for laminar cooling manifold belongs to strip steel processing technical field. Manifold sets up between control valve group, manifold, manifold includes inlet pipe, water equalizing pipe, branch pipe, and cooling water passes through inlet pipe and enters manifold, and cooling water is close to even distribution to manifold. The water equalizing pipe is equipped with sieve plate, and the sieve plate disperses the water flow of inlet pipe to each branch pipe. The flow velocity in inlet pipe and branch pipe is less than or equal to 2 m / s, the cross section area of water equalizing pipe is at least 2 times of the cross section area of inlet pipe, the sieve hole area sum is at least 2 times of the cross section area of inlet pipe, the sieve hole and branch pipe hole are arranged in dislocation, when inlet pipe and branch pipe are opposite, the sieve plate does not have hole in the area of 1.5 times of inlet pipe. The position of cooling water inlet pipe of this manifold on water equalizing pipe is adjusted, and the water output of each branch pipe is still consistent, so that cooling water is evenly distributed to each manifold, and the cooling effect is improved.

The application provides a post-rolling cooling plate shape control method for hot-rolled DP980 dual-phase steel, and belongs to the technical field of steel smelting. The method comprises the following steps: S1: grading the strip steel specification and the finishing mill outlet wave shape according to a preset grading rule; step S2: dynamically adjusting the target convexity value of the strip steel according to the grading result; S3: adjusting the cooling path and the cooling intensity in the post-rolling cooling process; S4: dynamically adjusting the edge shielding range of the laminar cooling area and the number of edge shielding devices to be started according to the strip steel specification; and S5: improving the coiling temperature, and setting a waterproof device between the pinch roll and the coiler to block the cooling water from flowing into the coiling area. The application can significantly improve the plate shape quality in the post-rolling cooling process of the hot-rolled DP980 dual-phase steel, effectively reduce the generation of defects such as double-edge wave, improve the surface quality and the qualified rate of the product, and reduce the quality objection risk of downstream customers.

The application discloses a method for preventing hot-rolled strip steel flat coil, and belongs to the technical field of hot-rolled strip steel production. The method comprises the following steps: hot rolling, laminar flow cooling, coiling and flattening. When the strip steel is discharged from the outlet of a finishing mill, the crown is less than or equal to 45 microns, the wedge shape is controlled to be between -10 microns and +10 microns, the wedge shape curve is a sinusoidal curve, and the center symmetry line is a wedge shape equal to 0. The cooling mode and the coiling parameters are set according to the specifications of the strip steel in the laminar flow cooling step and the coiling step. The crown and the wedge shape of the strip steel are effectively controlled, and the appropriate cooling mode and the coiling parameters are matched, so that the problem of the 500-600 MPa grade hot-rolled strip steel flat coil is effectively solved, the product performance meets the requirements, the flattening efficiency of the next step is increased by 8%-13%, and the strip steel yield is increased by 5%-10%.

This invention relates to the field of precision machining technology, specifically to a roller groove production and processing equipment and method. The equipment includes a main frame, on which a longitudinally moving base module and a workpiece fixing slide are mounted. A transverse moving module is mounted on a side-extending support frame of the operating base frame, and a vertical feed module is vertically mounted on the transverse moving module and fixed to a milling power cylinder via a lifting connecting plate. The milling power cylinder is equipped with an auxiliary liquid supply box, with multiple concentrically arranged liquid guiding needles at its bottom. A distance measuring and monitoring groove frame is located on the side of the transverse moving module, and a photoelectric displacement sensor is correspondingly mounted on the vertical feed module. An elastic sensor is embedded in the roller clamping assembly. This invention achieves micron-level precision machining of roller grooves through the synergy of direct end-effector position feedback, multi-ring laminar flow cooling curtains, constant force clamping, and multi-stage vibration damping structures, significantly improving groove position accuracy, dimensional consistency, and surface quality.

The utility model belongs to the plate strip steel cooling device technical field provides a laminar flow cooling water pipe of preventing the scale formation of lower header water nozzle, including laminar flow cooling water pipe body, manual valve, pneumatic valve and filter, connecting pipe and manual ball valve, laminar flow cooling water pipe body and cooling water main pipe between being provided with manual valve and pneumatic valve, and the filter is set between manual valve and pneumatic valve, and the both sides of pneumatic valve are connected through connecting pipe, and manual ball valve is set on connecting pipe;The device increases the filter before the laminar flow cooling water pipe, improves the purity of cooling water, simultaneously increases connecting pipe and manual ball valve at the side of pneumatic valve and makes the lower header water nozzle that does not need to invest production always in a small flow state, prevents scale formation;When needing to maintain and clean the nozzle, close the manual ball valve, completely stop the cooling water from spilling out of the nozzle, facilitate the operation of personnel maintenance and cleaning.

The utility model discloses a laminar cooling roller of novel structure, it includes roller, two axle head subassembly, every axle head subassembly includes connecting axle, inner web, outer web, and the connecting part of connecting axle and web is big in the middle, and both ends are small, and from inside to outside is divided into axle section I, axle section II, axle section III, and forms outer stop I, outer stop II, the inner hole of inner web cooperates with axle section I, and its outer end surface contacts with outer stop I, and the inner end surface of inner web and the inner end surface of connecting axle between the axial dimension is L1, the inner hole of outer web cooperates with axle section I, and its inner end surface contacts with outer stop II, and the inner end surface of inner web and the outer end surface of outer web between the axial dimension is L2, and the maximum clearance between the inner hole of inner web and axle section I, the inner hole of outer web and axle section III is 0.2mm. The utility model discloses laminar cooling roller satisfies dynamic balance requirement, makes the roller transfer stable, prolongs the life of roller, and guarantees the quality of strip steel.

This invention discloses a method for producing 540MPa grade hot-rolled duplex steel, mainly including: 1) steel smelting; 2) continuous casting; 3) heating and rolling of the continuously cast billet; 4) cooling, with laminar flow cooling after rolling for a three-stage cooling process. The chemical composition of the duplex steel, by weight percentage, includes: C: 0.05-0.07%, Si: 0.20-0.3%, Mn: 0.85-0.95%, P: ≤0.015%, S≤0.005%, Cr: 0.71~0.81%, Als: 0.022-0.030%, Ce: 0.0006~0.0012%, with the balance being Fe and unavoidable impurities. This invention, through reasonable composition design combined with appropriate rolling and cooling processes, obtains duplex steel plates with low yield strength ratio and high strength and toughness.

This invention discloses a laminar flow cooling control method for stainless steel, relating to the field of steel rolling technology. The method includes: determining the type and thickness of the stainless steel to be laminar flow cooled, and the target laminar flow cooling temperature; calculating the upper and lower valves to be opened and the cooling water volume required to reach the determined target laminar flow cooling temperature based on preset non-cooling valves that do not produce watermarks corresponding to different target laminar flow cooling temperatures, preset valve opening and cooling sequence corresponding to different target laminar flow cooling temperatures, and preset maximum cooling water volume of valves in the strong cooling zone corresponding to different stainless steel types and thicknesses; during actual rolling, dynamically increasing or decreasing the opened valves and their cooling water volume in sequence or in reverse sequence, and opening the corresponding blow valves according to preset blow valve opening rules based on the finally opened upper and lower valves. This invention can avoid laminar flow cooling watermarks on stainless steel, improve the shape of the cooled stainless steel sheet, and reduce the height of the double-sided wave.

This invention relates to the field of hydrogen transportation technology. The invention discloses a low-carbon bainitic hydrogen pipeline steel and its preparation method. By controlling the chemical composition of the material, including C: 0.025-0.050%, Si: 0.15-0.20%, Mn: 0.60-1.00%, Cr: 0-0.18%, Nb: 0.020-0.040%, Ti: 0.010-0.020%, P≤0.010%, S≤0.002%, Als: 0.015-0.035%, with the remainder being Fe and unavoidable impurities; and CE... pcm ≤0.10; and in conjunction with the smelting process of hot metal pretreatment-converter smelting-LF ladle refining-calcium treatment after refining-RH high vacuum circulation-continuous casting and the hot rolling process of slab reheating-high pressure descaling-rough rolling-intermediate billet cooling-finish rolling-laminar cooling-coiling, bainitic steel was prepared. The tensile strength of bainitic steel material is small in hydrogen and nitrogen environments, and the elongation after fracture decreases by only about 0.6% on average, with minimal strength reduction; the reduction of area loss rate is less than 31%, and the sensitivity to hydrogen embrittlement is weak, making it suitable for long-distance high-purity hydrogen transportation.

The application belongs to the technical field of mechanical equipment, and particularly discloses a bamboo shoot high-flux air-cooling quick-freezing device and process, which comprises a freezing tunnel chamber, a conveying mechanism and a high-flux circulating fan. Two ends of the freezing tunnel chamber are divided into two freezing cavities. Cold air spraying mechanisms are arranged in the two freezing cavities. Cold air entering mechanisms are arranged at the two ends of the freezing tunnel chamber and correspond to the positions of the two freezing cavities. The conveying mechanism is arranged below the freezing tunnel chamber and is used for conveying bamboo shoots. A plurality of folded plates are arranged below the cold air spraying mechanisms in the freezing tunnel chamber. The plurality of folded plates are arranged above the freezing tunnel chamber through suspension rods at the corners of the folded plates. A plurality of mesh holes are arranged in the plurality of folded plates. The application realizes the synergistic effect of low-temperature high-humidity laminar cooling and continuous tumbling disturbance, significantly improves the uniformity and quality of bamboo shoot quick freezing, and avoids the problems of dry consumption and freezing asynchronization.

This invention discloses a controlled rolling and controlled cooling method for steel plates used in high heat input welding, belonging to the field of metal rolling technology. The method includes smelting, billet heating, rolling, and cooling processes. The rolling process includes a finishing rolling step. In this step, after the billet is heated and austenitized, it is not rough rolled; the rough rolling reduction rate is 0%. It is directly air-cooled to the finishing rolling start temperature and then subjected to multiple finishing rolling passes. The finishing rolling start temperature is 820℃~900℃, and the total cumulative reduction rate is 85%~90%. The cooling process adopts laminar flow cooling. The cooling start temperature after finishing rolling is 700℃~750℃, the cooling rate is 1℃ / s~3℃ / s, and the final cooling temperature is 420℃~480℃. After final cooling, it is air-cooled to room temperature. This invention, without changing the existing composition system of high heat input welding steel, optimizes the controlled rolling and controlled cooling process to produce high heat input welding steel plates with stable welding performance and high strength and toughness.

This invention discloses a high-strength, high-ductility cold-rolled ultra-high-strength steel, which contains Fe and unavoidable impurities, and also contains the following chemical elements in the following mass percentages: C: 0.18-0.25%, Si: 0.55-1.75%, 0 < Al ≤ 0.75%, Mn: 1.8-2.2%; the area ratio of martensite + distributed martensite in its microstructure is ≥50%, and the area content of retained austenite is 12-17%. This invention also discloses a method for manufacturing the high-strength, high-ductility cold-rolled ultra-high-strength steel, comprising the steps of: smelting and continuous casting; hot rolling: heating, final rolling, laminar flow cooling, and coiling to obtain a hot-rolled coil; pickling and cold rolling, wherein the cold rolling deformation is ≤20%; and one-step continuous annealing.

The present application relates to a kind of low anisotropy high tough thick wall hot coil for spiral submerged arc welding pipe and its production method, C in steel:0.042%~0.055%, Si:0.15%~0.25%, Mn:1.10%~1.20%, P≤0.012%, S≤0.006%, Ti:0.021%~0.023%, Ce:0.002%~0.005%, Nb:0.04%~0.05%, Mo:0.21%~0.25%, and Mo / Nb=4.8~5.2;N≤0.004%, the rest is iron and impurity.Process flow includes hot metal pretreatment, converter smelting, secondary refining, continuous casting, slab heating, rolling, laminar flow cooling and coiling;The present application adopts economic and reasonable alloy design, matches appropriate production process, realizes the production of thick wall high tough pipeline hot coil of thin slab, simultaneously makes tensile anisotropy reduce to below 25MPa.

The laminar flow cooling manifold of the present application belongs to the field of hot-rolling laminar flow cooling manifold, and aims to make the height of water column sprayed by each nozzle tend to be consistent. The laminar flow cooling manifold comprises a main pipe and nozzles arranged on the main pipe in the axial direction, one end of the main pipe is an open water inlet end, and the other end is a closed closed end; an equalizing device is arranged in the main pipe; the equalizing device comprises a plurality of partitions which are evenly distributed around the main pipe in the axial direction; the inner ends of the partitions are fixed together, and the outer ends extend to the inner wall of the main pipe in the radial direction; a water supply small cavity is formed by surrounding the adjacent two partitions and the inner wall of the main pipe between the adjacent two partitions; and the extension lengths of the partitions in the axial direction of the main pipe are different; the nozzles are in communication with the water supply small cavity. The water inlet source is divided into multiple independent water inlet sources in the main pipe, and each water inlet source is finally supplied to different positions of the main pipe, thereby reducing the problem of uneven water spraying caused by the influence of pressure relief of the front nozzles on the nozzles at different positions, and making the height of water column sprayed by each nozzle tend to be consistent.