417 results about "Hot rolled" patented technology

The invention relates to a hot-rolled wire rod for a 2060MPa-grade stranded wire and a manufacturing method of the hot-rolled wire rod. Mn-Cr high-carbon chemical component design and rolling spinning are performed to form a wire rod, then online molten salt isothermal phase change treatment is performed, the wire rod is firstly subjected to front-section molten salt treatment and enters a sorbite phase region from an austenite state to form a structure taking a sorbite structure as a main structure, and then the wire rod is subjected to rear-section molten salt treatment, so that the hot-rolled wire rod is obtained. The method comprises the following steps of: firstly, carrying out heat treatment on the residual austenite, promoting the unconverted residual austenite to be converted into a sorbite structure, simultaneously promoting isothermal tempering of the structure and fusing of a part of sorbite lamellas, and finally, slowly cooling through a roller way to prepare a hot-rolled wire rod of which a microscopic structure comprises a mixed structure consisting of tempered sorbite, tempered ferrite and fused sorbite, so that the material cost can be controlled; the high-strength and high-plasticity performance matching of the wire rod is improved, the tensile strength is 1370-1420 MPa, the percentage reduction of area is 35%-40%, and the mechanical property fluctuation is reduced, so that the wire breaking risk in stranded wire production is reduced, and efficient and stable production is promoted.

A brazing-sheet manufacturing method includes superposing a core-material slab on or adjacent to at least one surface of a filler-material slab to form a clad slab, the core-material slab being composed of an aluminum material and the filler-material slab being composed of an Al—Si—Mg series alloy. Then, the clad slab is hot rolled to form a clad sheet having a core material layer composed of the aluminum material of the core-material slab and a filler material layer composed of the Al—Si—Mg series alloy of the filler-material slab. Then, the clad sheet is subjected to one or more passes of cold rolling. Either between cold-rolling passes or after the completion of the cold rolling, a surface of the clad sheet is etched using a liquid etchant that includes one or more inorganic acids. The liquid etchant does not contain fluorine atoms.

The invention discloses 750MPa-grade low-stress hot-rolled high-strength beam steel and a manufacturing method thereof, the method comprises the steps of smelting and continuous casting, casting blank slow cooling and soaking, rolling and segmented cooling, in the casting blank slow cooling and soaking step, the casting blank is cooled in air after red delivery, the furnace entering temperature is 300 DEG C or above, the soaking temperature is 1250-1290 DEG C, and the furnace staying time is 1-1.2 mm / min; in the rolling step, the initial rolling temperature of rough rolling ranges from 1100 DEG C to 1150 DEG C, the accumulated deformation of rough rolling is larger than or equal to 70%, the initial rolling temperature of finish rolling ranges from 950 DEG C to 1080 DEG C, and the final rolling temperature of finish rolling ranges from 810 DEG C to 880 DEG C; in the subsection cooling step, the first section is subjected to water cooling to 710-780 DEG C at the cooling speed of 10-25 DEG C / s and then is subjected to air cooling for 4-8 s, and then the second section is subjected to water cooling to the coiling temperature of 550-620 DEG C at the cooling speed of 30-50 DEG C / s. According to the low-stress hot-rolled high-strength large beam steel, the yield strength is larger than or equal to 700 MPa, the tensile strength is larger than or equal to 750 MPa, the ductility is larger than or equal to 20%, and the low-stress hot-rolled high-strength large beam steel not only has high strength, but also has good toughness and formability, and completely meets the requirements for use and performance of large beam steel in the industries of automobile manufacturing, engineering machinery and the like.

The manufacturing method comprises the following steps: rolling and spinning high-carbon and high-silicon components of Nb-Mo to form a wire rod, and then carrying out online molten salt strong isothermal toughening treatment, so that the wire rod is firstly subjected to front-section molten salt treatment and is rapidly cooled, and enters a sorbite phase region from an austenite state to form a structure taking a sorbite structure as a main structure; and then carrying out rear-section molten salt treatment, reducing the circulation volume of molten salt, promoting the unconverted retained austenite to be continuously converted into sorbite, carrying out isothermal tempering, promoting fusing of a part of sorbite lamellar layers, and finally carrying out slow cooling through a roller way, so as to prepare the hot-rolled wire rod of which the microscopic structure comprises a mixed structure consisting of tempered sorbite, ferrite and fused sorbite, according to the invention, abnormal tissues can be inhibited, the tensile strength is 1566-1616 MPa, the percentage reduction of area is 33%-38%, and the production efficiency is considered, so that the ultrahigh-strength stranded wire can be produced without off-line heat treatment, and the risk of wire breakage is reduced.

The invention belongs to the technical field of pipeline steel production, and discloses a hot continuous rolling production method of Mo and Ni-free X70M pipeline steel, which comprises the processes of slab heating, rough rolling, finish rolling, laminar cooling and coiling, and the pipeline steel comprises the following chemical components in percentage by mass: 0.060 to 0.090 percent of C, 0.10 to 0.25 percent of Si, 1.50 to 1.70 percent of Mn, 0.20 to 0.30 percent of Cr, 0.045 to 0.070 percent of Nb, 0.020 to 0.050 percent of Al, less than or equal to 0.005 percent of S, less than or equal to 0.012 percent of P, 0.020 to 0.030 percent of Ti, less than or equal to 0.0050 percent of N and the balance of Fe and inevitable impurities. According to the pipeline steel, Mo and Ni are not added, the alloy cost is extremely low, meanwhile, a hot rolled steel strip of the pipeline steel has good low-temperature tearing resistance and low yield ratio, and the safety in the pipeline service process can be guaranteed.

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2160MPa-grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod, after high-carbon components containing trace Nb are rolled and spun into a wire rod, the wire rod is subjected to online molten salt micro-quenching isothermal treatment, so that the wire rod is firstly subjected to front-section molten salt treatment and enters a bainite phase region from an austenite state, part of the austenite is promoted to be converted into bainite, and then the high-strength complex-phase hot-rolled wire rod is obtained. The method comprises the following steps: carrying out high-temperature tempering on the residual austenite, carrying out post-section molten salt treatment, increasing the molten salt temperature, promoting the unconverted residual austenite to be decomposed and converted into sorbite, carrying out isothermal tempering, and finally carrying out roller way slow cooling to prepare the hot-rolled wire rod of which the microscopic structure comprises a complex-phase structure consisting of tempered bainite, ferrite and tempered sorbite, so that network carbides and martensite structures can be inhibited, and the tensile strength of the hot-rolled wire rod is improved. And the structure type and toughness are regulated and controlled on line, the tensile strength is 1472-1505MPa, the percentage reduction of area is 31%-36%, the work hardening rate and the production efficiency of the hot-rolled wire rod are improved, and the production energy consumption is reduced, so that a high-strength grade stranded wire is obtained.

The invention relates to the technical field of high-strength steel hot roll bending forming processes, and provides a method, device and equipment for predicting hot bending forming springback based on simulation software. The method comprises the steps that a three-dimensional assembly model is constructed based on the geometric dimension of a roll forming machine; importing the three-dimensional assembly model into finite element software to simplify the three-dimensional assembly model; performing different types of grid division on different areas, and setting fixed boundary conditions and process parameters; pre-defining a temperature field for the bending area, and constructing a thermal-mechanical coupling constitutive model to obtain a temperature field simulation result; and establishing a simulation model by using a dynamic and static combined algorithm, and predicting the springback value. According to the method, finite element simulation is carried out on the bending process, the springback value is directly output through the node displacement difference, springback deformation is visualized through a post-processing tool, and high-precision prediction is achieved.

The invention relates to a hot-rolled wire rod for a 2300MPa-grade stranded wire and a manufacturing method of the hot-rolled wire rod, after high-Si and high-carbon components containing trace Nb are rolled and spun into a wire rod, the wire rod is subjected to online molten salt isothermal toughening treatment, so that the wire rod is firstly subjected to front-section molten salt treatment and is rapidly cooled, and enters a sorbite phase region from an austenite state to form a structure taking a sorbite structure as a main structure; the method comprises the following steps: carrying out hot rolling on the austenite, carrying out post-section molten salt treatment, reducing the molten salt temperature and the molten salt circulation amount, promoting the unconverted retained austenite to be continuously converted into sorbite, carrying out isothermal tempering, promoting fusing of a part of sorbite lamellar layers, and finally carrying out roller way slow cooling to prepare a hot-rolled wire rod of which the microscopic structure comprises tempered sorbite, ferrite and fused sorbite. According to the invention, the cross-section shrinkage rate is 35%-40%, the mechanical property same-circle difference is less than or equal to 48MPa, and the material cost and the production efficiency are both considered, so that off-line heat treatment is not needed, and the efficient and stable production of the ultrahigh-strength stranded wire is promoted.

The invention relates to a hot-rolled wire rod for a 2330MPa-grade stranded wire and a manufacturing method of the hot-rolled wire rod, after the wire rod is formed by rolling and spinning Cr-V high-carbon and high-silicon components, the wire rod is subjected to online molten salt isothermal toughening treatment, so that the wire rod is firstly subjected to front-section molten salt treatment and is rapidly cooled, and enters a sorbite phase region from an austenite state to form a structure taking a sorbite structure as a main structure; the method comprises the following steps: carrying out hot rolling on austenite, carrying out post-stage molten salt treatment, increasing the temperature of molten salt, reducing the circulation volume of molten salt, promoting unconverted retained austenite to be continuously converted into sorbite, carrying out isothermal tempering, promoting fusing of part of sorbite lamellas, and finally carrying out roller way slow cooling to prepare a hot-rolled wire rod with a microstructure comprising a mixed structure consisting of tempered sorbite, ferrite and fused sorbite, the material cost can be controlled, the tensile strength is 1558-1608 MPa, the percentage reduction of area is 34%-39%, the production efficiency and the energy consumption are both considered, off-line heat treatment is not needed, and efficient and stable production of the ultra-high-strength stranded wire is met.

The invention provides a steel pipe whole-process intelligent tracking system based on multi-mode sensing fusion, and relates to the technical field of ferrous metallurgy intelligent manufacturing. The system comprises the following modules: a visual perception module, which is used for collecting the appearance characteristics, the spatial position and the motion state of a steel pipe in the whole process of steel pipe tracking; the one-by-one tracking and decision-making module is used for constructing a closed-loop work flow comprising data acquisition, fusion processing, decision-making output and feedback optimization by deeply fusing visual perception information and multi-source industrial signals; and the control interaction module is in two-way communication with the bottom PLC and an upper computer, receives equipment signals, feeds back the equipment signals to the tracking module, issues a tracking / alarming instruction to the PLC and synchronizes data to the MES. According to the method, the problems of blind areas, information chain scission and manual dependence of traditional tracking are solved, the whole process of the hot-rolled seamless steel pipes from a cooling bed area to material frame bundling through saw cutting segmentation is achieved, and one-by-one accurate tracking and quality control are achieved.

Provided is a non-oriented electrical steel sheet that is excellent in iron loss and magnetic anisotropy under high magnetic flux and high frequency conditions, and a method for manufacturing the same. [Solution] A method for producing a grain-oriented electrical steel sheet includes the steps of heating a slab containing, by weight, 1.5 to 6.5% Si, 0.0005 to 3.5% Al, 0.01 to 3.0% Mn, 0.005 to 5.0% Cr, 0.0005 to 0.03% S, the balance being Fe and other unavoidable impurities, at 1050 to 1220°C, finish hot rolling the slab to obtain a hot-rolled sheet, hot-rolling the hot-rolled sheet at 850 to 1150°C for 30 to 300 seconds, cold-rolling the hot-rolled sheet that has been annealed to obtain a cold-rolled sheet, heating the cold-rolled sheet, and rolling the heated cold-rolled sheet. and final annealing at 600 to 1150°C for 10 to 300 seconds, wherein the cold rolling satisfies the following [Relationship 2], wherein the heating rate in the temperature range of 300 to 500°C during heating is 5 to 150°C / s, and the gas atmosphere in the temperature range of 500 to 750°C during the final annealing is composed of, by volume, 15 to 99.99% hydrogen, 0.0001 to 0.0030% oxygen, and the balance being an inert gas, and the oxygen content in the gas atmosphere in the temperature range of 800 to 1100°C during the final annealing is 1 to 1.5 times that in the temperature range of 500 to 750°C. [Relationship 2] Maximum temperature of cold-rolled sheet surface during cold rolling < 200 × cold rolling reduction / 100 + 40

A method of manufacturing a stainless steel is provided. The stainless steel contains C, Si, Mn, P, S, Cr, Ni, and N in predetermined amounts. A total volume fraction of Cr-based carbides with a grain size of 2.0 μm or more is ≤10%. A steel slab is held at 1200° C.-1350° C. for at least 30 minutes and then hot rolled to obtain a hot-rolled steel sheet. The hot-rolled steel sheet is coiled, where at least three rolling passes with a finish temperature of ≥1050° C. and a rolling reduction of ≥20% are performed, and a coiling temperature of the hot-rolled steel sheet is ≥600° C. The hot-rolled steel sheet is subjected to hot-rolled sheet annealing to obtain a hot-rolled and annealed steel sheet, where a holding temperature is 750° C.-900° C. and a holding time is ≥10 minutes.

Method of manufacturing a steel strip comprising the steps of: - casting a molten steel into a slab; - reheating the slab at a temperature of 1150°C or more for a time of 1 hour or more; - hot rolling the steel into a strip, preferably using an average F1 slab entry temperature of more than 1000°C; - coiling the hot rolled steel strip; - batch annealing the steel strip: - at a temperature in the intercritical range (i.e. between Ac1 and Ac3), preferably less than 700°C; - in a non-oxidizing and non-nitrogenizing atmosphere; - for a total annealing time of at least 5 hours, preferably at least 10 hours so as to obtain: a Mn enrichment in austenite such that the Mn content is at least 1.25 times the overall Mn content of the steel; and a C enrichment such that the C content is at least 1.2 times the overall C content of the steel; - cooling the steel after batch annealing in air, forced air or water quenching.

The utility model relates to the field of demolding equipment, in particular to non-contact type automatic air knife efficient demolding equipment of a traction-free cold and hot roller press, which comprises a frame, a calendering component and an air compressor, the calendering assembly used for pressing and spreading the materials to be processed into the thin film with the certain thickness is installed in the frame, one side of the frame is communicated with the air compressor used for enabling the pressed film materials to fall off from the surface of the roller, one side of the air compressor is communicated with the airflow connecting pipe, and one end of the airflow connecting pipe is communicated with the flow dividing pipe. The two ends of the flow dividing pipe communicate with two sets of electromagnetic valves, the upper end and the lower end of each set of electromagnetic valve communicate with two sets of air injection pipes, and each set of air injection pipes communicate with air blades. And the pressed film material can quickly and stably fall off from the roller part.

The invention relates to a thick hot-rolled spring wide steel plate, and belongs to the field of iron-based alloys. The steel comprises the following chemical components in percentage by mass: 0.47 to 0.55 percent of C, 0.17 to 0.37 percent of Si, 0.70 to 1.10 percent of Mn, 0.90 to 1.20 percent of Cr, 0.10 to 0.25 percent of V, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S and the balance of Fe and inevitable impurities, and the structure is uniform ferrite and pearlite. The production thickness ranges from 41 mm to 55 mm, the width is larger than 2000 mm, and the length is not smaller than 6000 mm; the straightness is less than or equal to 3mm / m, and the thickness tolerance range is within 1mm. The hardness is smaller than 280 HBW, the inclusions A, B, C and D are all smaller than 1.5 grades, and the sum of the inclusions A, B, C and D is smaller than or equal to 3.0 grades and is larger than or equal to 2.0 grades. High purity, longitudinal and transverse performance uniformity and accurate thickness control of the large-size spring steel plate are achieved, the thickness machining amount of the steel plate is reduced by four times compared with that of a forging technology, the higher yield is achieved, and the production cost of large-size springs is greatly reduced.

Provided is a hot rolled steel sheet having a predetermined chemical composition and a microstructure comprising, by area ratio, pearlite: 90 to 100% and pro-eutectoid ferrite: 0 to 10%, wherein the pearlite has an average lamellar spacing of 0.08 to 0.30 μm, and the percentage of cementite in the pearlite having a major axis length of more than 0.3 μm and an aspect ratio of less than 3.0 is less than 15%.

A hot rolled steel sheet having a composition comprising of the following elements,0.02 % ≤ Carbon ≤ 0.06 %, 1.1 % ≤ Manganese ≤ 1.60%,0.01% ≤ Aluminum ≤ 0.08 %, 0.01% ≤ Niobium ≤ 0.07%, 0.05 % ≤ Titanium ≤ 0.15%, 0.0005% ≤ Calcium ≤ 0.005%, 0% ≤ Phosphorus ≤ 0.03 %, 0 % ≤ Sulfur ≤ 0.015 %, 0 % ≤ Nitrogen ≤ 0.02%,and can contain one or more of the following optional elements 0.001% ≤ Silicon ≤ 0.09%, 0% ≤ Chromium ≤ 0.2%, 0 ≤ Copper ≤ 0.25%, 0% ≤ Nickel ≤ 0.2%,0% ≤ Vanadium ≤ 0.1%, 0 % ≤ Boron ≤ 0.003%, 0 % ≤ Magnesium ≤ 0.010%, 0% ≤ Cerium≤ 0.1%, 0% ≤ Zirconium ≤ 0.010%,the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel sheet comprising in area fraction, 35% to 75% Bainite, 25% to 65% ferrite, from 0% to 2% Pearlite and Martensite-Residual Islands from 0% to 2% wherein said hot rolled steel sheet has an inclusion density of 200 inclusions per square micro-meter, the inclusions having size of 2 microns or more being 25% or less of the total number of inclusions.

This application belongs to the field of target material production technology and discloses a method for preparing zirconium-yttrium alloy targets. First, zirconium is melted and cooled to obtain a zirconium ingot. Then, the zirconium ingot is flipped over and melted a second time. At the same time, metallic yttrium is added to the molten zirconium ingot to melt it to obtain a primary eutectic. Then, the primary eutectic is cooled to room temperature within 85 minutes to obtain a primary eutectic body. The primary eutectic body is then flipped over and melted a third time to obtain a secondary eutectic. Then, the primary eutectic is cooled to room temperature within 70 minutes to obtain a secondary eutectic body. Finally, the secondary eutectic body is machined, hot rolled, and hot isostatically pressed to obtain a zirconium-yttrium alloy target. This application improves the uniformity of zirconium and yttrium distribution by repeatedly flipping the zirconium ingot or eutectic body and remelting it. In addition, this application also discloses a zirconium-yttrium alloy target.

This invention provides a method for manufacturing oriented electromagnetic steel sheets that significantly improves manufacturability, and an apparatus for implementing the method. The method for manufacturing oriented electromagnetic steel sheets comprises the following series of steps: hot rolling a steel billet having a specified composition; hot-rolled sheet annealing; cold rolling once or twice with a total reduction rate of 80% or more from the thickness of the obtained hot-rolled sheet to the thickness of the cold-rolled product; recrystallization annealing; coating the steel sheet surface with an annealing separating agent; final product annealing; and planarization annealing for planarization. In this method for manufacturing oriented electromagnetic steel sheets, the grain boundary occupancy of recrystallized carbides in the hot-rolled sheet after annealing and before cold rolling is 80% or more, and the initial reduction during cold rolling is set to a strain rate of 200 / s or less, a reduction rate of 30% or less, and a steel sheet temperature of 90°C or less when biting into the rolls.

A hot rolled steel sheet having a composition comprising of the following elements 0.03% ≤ Carbon ≤ 0.070 %, 0.4 % ≤ Manganese ≤ 0.9%, 0.01% ≤ Aluminum ≤ 0.08 %, 0.01% ≤ Niobium ≤ 0.08%, 0.05 % ≤ Titanium ≤ 0.15%, 0.0005% ≤ Calcium ≤ 0.005%, 0% ≤ Phosphorus ≤ 0.03 %, 0 % ≤ Sulfur ≤ 0.015 %, 0 % ≤ Nitrogen ≤ 0.02%, 0.001% ≤ Silicon ≤ 0.09%,0% ≤ Chromium ≤ 0.2%, 0.% ≤ Copper ≤ 0.25%, 0% ≤ Nickel ≤ 0.2%, 0% ≤ Molybdenum ≤ 0.2%, 0% ≤ Vanadium ≤ 0.1%, 0 % ≤ Boron ≤ 0.003%, 0 % ≤ Magnesium ≤ 0.010%, 0% ≤ Cerium≤ 0.1%,0% ≤ Zirconium ≤ 0.010%, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of said steel sheet comprising in area fraction, 35% to 70% Bainite, 30% to 60% Ferrite, Pearlite from 1% to 5% wherein the said hot rolled steel sheet has an inclusion density of 110 inclusions per square micro-meter and the inclusions having a size of 2 microns or more being 22% or less of the total number of inclusions.

The application discloses a process for improving corner crack of 16MnCr5 steel hot-rolled blank, which comprises the steps of slow cooling before heating, heating, blooming rolling and slow cooling after rolling; the slow cooling before heating step: the blank is first slowly cooled for more than or equal to 72 hours; the heating step: the segmented heating control is adopted, the heating temperature of the first heating section is 850-950 DEG C, the heating temperature of the second heating section is 1110-1150 DEG C, the temperature of the soaking section is 1100-1180 DEG C, and the total heating time is controlled to be 4-5 hours; the blooming rolling step: nine passes of rolling are adopted, the reduction of the first four passes is 50-60 mm, the reduction of the middle four passes is 20-30 mm, and the reduction of the last pass is 10-20 mm; the hot-rolled blank is obtained; and the slow cooling after rolling step: the hot-rolled blank is slowly cooled for more than or equal to 72 hours. The application reduces or eliminates the generation of surface cracks of the wire rod, guarantees good hardenability of the product, and effectively improves the product quality.

The invention concerns a method for producing a 6xxx series aluminium sheet comprising the steps of homogenizing an ingot made from a 6XXX series aluminium alloy; cooling the homogenized ingot with a cooling rate in a range of from 150° C. / h to 2000° C. / h directly to the hot rolling starting temperature; hot rolling the ingot to a hot rolling final thickness and coiling at the hot rolling final thickness with such conditions that at least 90% recrystallization is obtained while controlling the temperatures of hot rolling, in particular the relationship between the hot rolling starting temperature and the hot rolling exit temperature and / or controlling the grain size after coiling; cold rolling to obtain a cold rolled sheet.

Provided are aluminum 3xxx series alloy products having improved thermal and electrical stability, and methods for forming such products. Methods include DC casting a molten aluminum alloy, withdrawing the aluminum alloy from the mold to form an ingot, homogenizing the ingot at a homogenization temperature from 500 °C to 650 °C for a period of time from 1 to 5 hours. Methods include reducing the temperature to a soaking temperature from 350 °C to 550 °C and soaking the ingot for a period of time from 1 to 15 hours. Methods include hot rolling the homogenized ingot to produce a hot rolled aluminum alloy, and cold rolling the hot rolled aluminum alloy to produce to an aluminum alloy product.

The utility model relates to the related technical field of hot rolling impressing processing, and discloses an improved temperature controller for hot rolling impressing processing, which comprises a box body, an equipment inner cavity is arranged in the box body, a temperature control heat dissipation assembly is arranged in the equipment inner cavity, the temperature control heat dissipation assembly comprises a shell, and the shell is internally provided with a temperature control module. A first partition plate, a second partition plate and a third partition plate are installed in the shell, the first partition plate and the second partition plate are installed on the outer side of the third partition plate, the first partition plate is arranged on the left side of the second partition plate, a water inlet cavity is formed between the first partition plate and the shell, and two extrusion springs are installed on the outer side of the first partition plate. Heat in the heat conduction cavity is dissipated outwards through a fourth partition plate, rotation of rotating blades facilitates more effective discharge of the heat, it is guaranteed that excessive heat accumulation cannot be generated during operation of the device, the heat energy transfer efficiency can be improved, and therefore the service life of the device is prolonged; and the water body in the water inlet cavity reaches the maximum pressure value.

A tempering-free wear-resistant hot rolled strip, includes components in percentage by weight: 0.08-0.22% of C, 0.1-0.55% of Si, 0.8-1.5% of Mn, less than or equal to 0.012% of P, less than or equal to 0.005% of S, 0.01-0.055% of Als, 0.005-0.019% of Ti, and less than or equal to 0.007% of N. A method for producing the same includes: desulfurizing molten iron, smelting desulfurized molten iron, and casting into a blank; heating the casting blank; performing rough rolling; performing finish rolling; performing rapid cooling; performing coiling; and performing conventional temper rolling. According to the present disclosure, on the premise that the tensile strength of a steel plate is greater than or equal to 1100 MPa and the elongation is greater than or equal to 12%, the steel plate has a surface Brinell hardness of 330-390 and a core hardness that is 95% or above of the surface hardness.

The utility model relates to the technical field of hot-rolled strip steel pickling, in particular to a hot-rolled strip steel pickling device which comprises a pickling tank, and an iron removal mechanism and a material clamping mechanism are arranged on the surface of the pickling tank. The fixing plate is fixedly connected to one side of the outer portion of the pickling tank, and the iron removing mechanism and the material clamping mechanism enable the upper grinding plate and the annular grinding plate in the descending state to clamp the hot-rolled strip steel to be pickled, and the two clamping plates in the moving state to be close to each other to clamp the end of the hot-rolled strip steel to be pickled. The two clamping plates in the axial moving state drag the clamped hot-rolled strip steel to be pickled, the upper polishing plate in the descending state is matched with the annular polishing plate in the rotatable state, and under dragging of the two clamping plates, friction polishing is conducted on a thick iron sheet on the surface of the hot-rolled strip steel to be pickled. Therefore, iron on the surface of the hot-rolled strip steel is polished once before the pickling process of the hot-rolled strip steel, pickling is performed after polishing is completed, and the pickling efficiency of the device on the hot-rolled strip steel is effectively improved.

The invention provides high-spheroidization-rate medium-carbon steel based on medium-low annealing temperature and a production method thereof.The method comprises the steps of a hot rolling process, specifically, a medium-carbon steel blank is subjected to hot continuous rolling, the hot rolling coiling temperature is controlled to be 650 + / -20 DEG C, and a lamellar pearlite structure is obtained; a cold rolling process: carrying out cold rolling on the hot rolled coil, controlling the total cold rolling reduction rate to be not less than 35%, and introducing high-density dislocation and distortion defects into a pearlite structure; the cold-rolled steel plate is placed in a cover annealing furnace, under the full hydrogen protection atmosphere, the cold point temperature in the furnace is controlled to be 700 + / -10 DEG C, the hot point temperature is 710 + / -10 DEG C, the heat preservation time is 4-8 hours, and the flaky cementite is fully spheroidized; according to the method, the spheroidization rate of the medium carbon steel reaches 90% or above successfully under the upper limit condition of the annealing temperature of 720 DEG C, the contradiction between insufficient equipment capacity and high-end product requirements is solved, and remarkable economic benefits are achieved.

The application discloses a method for preventing head and tail breakage of SK85 hot-rolled strip steel. The method comprises the following steps: increasing the length of the head and tail of the flying shear strip steel during the shearing process; reducing the input of the finishing rolling process water during the finishing rolling process; adopting the sparse cooling mode and the hot head and tail process during the layer cooling process; selecting the appropriate range of the strip steel, closing the front side water spraying function of the coiler, and controlling the coiling tension of the tail of the strip steel and increasing the number of the coiling assisting rollers during the coiling process. The technical scheme provided by the application can reduce the possibility of the head and tail breakage of the SK85 hot-rolled strip steel.

Provided is a method for manufacturing an ultra high-strength and high-ductility steel sheet having an excellent yield ratio. The method includes: heating a slab in a temperature range of 1050 to 1300° C.; finish hot rolling the heated slab in a temperature range of 800° C. to 1000° C.; winding the hot-rolled steel sheet in a temperature range of 50° C. to 750° C.; cold rolling the wound hot-rolled steel sheet at a reduction rate of 15% or higher after pickling; and annealing the cold-rolled steel sheet in a temperature range of 600° C. to 720° C. for 10 sec to 3,600 sec, or annealing in a temperature range of higher than 720° C. and 900° C. or lower for 10 sec to 3,600 sec and cooling, followed by a second annealing in a temperature range of 480° C. to 700° C. for 10 sec to 3,600 sec.