Method for producing low-carbon steel and ultra-low-carbon steel by VD, LF and VD processes

The invention discloses a method for producing low-carbon steel and ultra-low-carbon steel by vacuum decarburization (VD), ladle furnace (LF) and vacuum degassing (VD) processes. By the method, the requirement of smelting a low-carbon steel plate and an ultra-low-carbon steel plate is met by the conventional VD equipment and the like of enterprises on the premise of not adding Ruhrstahl Heraeus (RH) vacuum decarburization equipment and the like; and under the condition of low profit of the enterprises at the present stage, large investment in the large-scale starting of new equipment and equipment modification is avoided, investment is saved for companies, the conventional equipment is fully utilized, the capital investment of the enterprises at the present stage is greatly reduced, and sufficient preparation time is provided for starting the new equipment after the market situation and the profit of the enterprises are improved in the future.

Q345q-series super-thick bridge steel plate and production method thereof

The invention discloses a Q345q-series super-thick guaranteed performance and flaw detection bridge steel plate comprising the following chemical components in percentage by mass: 0.08-0.16 percent of C, 0.20-0.50 percent of Si, 1.15-1.60 percent of Mn, not more than 0.020 percent of P, not more than 0.010 percent of S, not more than 0.12 percent of microalloyed element (V+Nb+Ti+Ni), 0.010-0.050 percent of AlS and the balance of Fe and residual elements; and carbon equivalent is not more than 0.43. The invention also discloses a production method of the steel plate, comprising the steps of rolling, cooling, straightening, cooling in pile and thermal treatment. In the rolling, the cooling and the straightening, the 130 mm super-thick Q345qD(E) steel plate is successfully developed in the production line of a converter, die casting, mill rolling and normalization thermal treatment through carrying out reasonable composition design, die casting, TMCP (Thermal Mechanical Control Process) rolling ...

Weather-proof structural steel S355K2W thick plate and production method

The invention discloses a 60-120mm improved weather-proof structural steel S355K2W thick plate and a production method thereof. The weather-proof structural steel S355K2W thick plate comprises the following chemical components by mass percent: 0.08-0.15% of C, 0.20-0.45% of Si, 1.20-1.45% of Mn, less than or equal to 0.018% of P, less than or equal to 0.007% of S, 0.015-0.050% of Als, less than or equal to 0.15% of Nb+V+Ti, 0.45-0.70% of Cr, 0.30-0.50% of Cu, and the balance of Fe and residual elements. A technological process of the weather-proof structural steel S355K2W thick plate comprises the steps of high-quality molten iron and KR molten iron pretreatment, a 100/120t top-bottom combined blowing converter, LF (ladle furnace) refining, vacuum degassing treatment, casting blank pile cooling for 24-60h, a pusher type heating furnace, a 3800m rolling mill, ACC (accelerated) laminar cooling, an 11-roll thermal straightener, pile cooling, finishing, external inspection, fault detection ...

Hardening and tempering method for alloy steel 40Cr steel plate

The invention discloses a hardening and tempering method for an alloy steel 40Cr steel plate. The alloy steel 40Cr steel plate with the thickness of 80 mm below comprises the following chemical components in percentage by weight (wt%): 0.38 to 0.43 of C, 0.20 to 0.35 of Si, 0.60 to 0.75 of Mn, less than or equal to 0.018 of P, less than or equal to 0.010 of S, 0.85 to 1.00 of Cr, 0.005 to 0.015 of Als, and the balance of Fe and residual elements. The hardening and tempering method adopted by the invention comprises the following steps of: hardening at the temperature of 840 DEG C; keeping the temperature for the time t of 0.5 minutes; tempering at the temperature of 500 DEG C; and keeping the temperature for the time t of 3 minutes. The method has the advantages of improving steel plate weldability, ensuring the high-strength performance index of the steel plate and meeting ideal requirements of a user by hardening and tempering treatment.

Steel plate made of high-rise building steel Q345EZ25 and production method thereof

The invention discloses a steel plate made of a high-rise building steel Q345EZ25 and a production method of the steel plate. The steel plate made of the high-rise building steel Q345EZ25 with the thickness of 120mm comprises the following chemical components according to mass percent: 0.15-0.25 C, 0.17-0.30 Si, 1.20-1.80 Mn, less than or equal to 0.018 P, less than or equal to 0.005 S, 0.010-0.035 Ti, 0.15-0.35 Nb, 0.15-0.30 Als, and the balance of Fe and residual elements. The production method comprises of the following steps: converter smelting, LF refining, pouring, casting blank heating, rolling, slow cooling, and heating treatment. With the reasonable design of the chemical components, the cleanliness of the steel is guaranteed through the LF technology, the processes like heating, rolling, and normalizing treatment are conducted effectively to develop successfully the 120mm high buildings steel, wherein the yield strength of the steel plate is controlled to 340-380 MPa, the tensile ...

Method for manufacturing extremely thick flaw detection steel plate with low alloy content and high strength

The invention disclose a method for manufacturing a extremely thick flaw detection steel plate with low alloy content and high strength, comprising the following steps of: a, heating for the first time; b, rolling for the first time; c, cooling in piles for the first time; d, heating for the second time; e, rolling for the second time, f, cooling in piles; g, finishing; h, thermally treating; and i, testing and putting in storage. In the extremely thick flaw detection steel plate with low alloy content and high strength, which is manufactured through the method disclosed by the invention, the yield strength is controlled in 285-330MPa, and the average yield strength reaches 310MPa, which exceeds 55MPa compared with the standard yield strength; the tensile strength is controlled in 495-550MPa, and the average tensile strength reaches 507MPa, which is 57MPa greater than the standard tensile strength; the elongation is controlled in 25%-29%, and the average elongation reaches 26%, which is ...

High-tensile quenched and tempered steel plate for large-thickness structures and production method thereof

The invention discloses a high-tensile quenched and tempered steel plate for large-thickness structures and a production method thereof, wherein the high-tensile quenched and tempered steel plate comprises the following chemical compositions in percentage by weight: less than or equal to 0.19% of C, less than or equal to 0.50% of Si, 1.00-1.60% of Mn, less than or equal to 0.015% of P, less than or equal to 0.003% of S, less than or equal to 0.20% of microalloying elements (Nb+V+Ti+Ni), less than or equal to 0.050% of Als, and the balance of Fe and residual elements. By reasonably taking a chemical composition design on composite multicomponent microalloying elements and adopting an LF+VD (ladle refining + vacuum degassing)process, the purity of the steel plate is ensured, and the sum of levels of various inclusions is not more than 3.0; and by utilizing a thermo mechanical control process and adopting normalizing treatment, the grain fineness number of the steel plate reaches level 9.0 ...

Low-carbon low-silicon high-quality carbon structural steel and production method thereof

The invention discloses a low-carbon low-silicon high-quality carbon structural steel and a production method thereof. The structural steel comprises the following chemical components in percentage by weight: less than or equal to 0.06% of C, less than or equal to 0.03% of Si, 0.35-0.50% of Mn, less than or equal to 0.018% of P, less than or equal to 0.012% of S, 0.005-0.025% of Als, and the balance of Fe and residual elements. The production method disclosed by the invention comprises the following steps: KR (knotted reactor) hot metal pretreatment of high-quality hot metal, processing with a top-bottom combined blowing converter, pre-deoxidization of molten steel, alloying of molten steel, final deoxidization process of molten steel, argon blowing process, continuous casting and casting blank stack cooling. In order to ensure the high quality of molten steel smelted with converter, the good quality of raw and auxiliary materials used in the converter smelting process must be guaranteed ...

Ultra-thick low-alloy high-strength Q345-series steel plate and production method thereof

The invention discloses an ultra-thick low-alloy high-strength Q345D(E) steel plate which comprises the following chemical components in mass percentage: 0.08-0.16 percent of C, 0.20-0.50 percent of Si, 1.15-1.60 percent of Mn, not less than 0.020 percent of P, not less than 0.010 percent of S, not less than 0.20 percent of microalloyed element (Nb+Ti+Ni+Cr), not less than 0.050 percent of Als and the balance of Fe and residual elements, wherein the carbon equivalent weight is not less than 0.43. The invention also discloses a production method of the steel plate, which comprises the following steps of: converter smelting, LF refining, vacuum refining, pouring, heating, controlled cooling, slow cooling and heat processing; the steel purity is ensured by reasonably adopting the chemical component design of lower-carbon low-manganese multi-component compound microalloy elements, the grade sum of various inclusions does not exceed 3.0, crystal grains are finer, the rolling control state reaches ...

Large-thickness steel plate for low-temperature pressure container and production process thereof

The invention discloses a large-thickness steel plate for a low-temperature pressure container and a production process thereof. The large-thickness steel plate for the low-temperature pressure container comprises the following chemical components in percentage by mass: 0.14%-0.18% of C, 0.30%-0.45% of Si, 1.20%-1.50% of Mn, not greater than 0.015% of P, not greater than 0.005% of P, not greater than 0.005% of S, 0.015%-0.030% of Als, 0.025%-0.035% of Nb, 0.010%-0.020% of Ti, 0.40%-0.60% of Ni, and the balance of Fe and residual elements. A process flow is as follows: high-quality molten iron and KR (Kambara Reactor) molten iron pre-treating, passing through a 100/120-ton top-bottom combined blowing converter, LF (Low Frequency) refining, vacuum degassing treatment, casting blank cooling in heap for 24 hours, heating, 3800-m rolling, ACC (Activated Calcium Carbonate) laminar cooling, passing through a 11-roller thermal straightener, cooling in heap, finishing, externally inspecting, detecting ...

Low-alloy Q345D thick plate produced without adding micro-alloy elements and production method thereof

The invention discloses a low-alloy Q345D thick plate produced without adding micro-alloy elements and a production method thereof. The method disclosed by the invention is characterized in that on the premise of not adopting vacuum decarburization equipment such as an RH and the like, through using the existing equipment such as a VD (vacuum degasser) and the like of enterprises, the requirements for smelting low-carbon steel plates and extreme low carbon steel plates are met, therefore, under the condition that the profits of the enterprises at the present stage are not high, a heavy investment in large-scale equipment replacement and remodeling is avoided, thereby saving the investment for the enterprises, completely using the existing equipment of the enterprises, greatly reducing the capital investment of the enterprises at the present stage, and providing abundant preparation time for equipment replacement after the market situation takes a favorable turn in the future and the profits ...

Method for improving purity of molten steel in argon station

The invention discloses a method for improving purity of molten steel in an argon station, which comprises the following steps of: (1) adding 30 to 60kg of lime, 20 to 40kg of calcium carbide and 130 to 160kg of premelted refining slag into a steel ladle before argon blowing, and increasing argon quantity for strongly blowing argon, wherein the strong argon blow standard is that the sum of the diameters of blown open holes of the molten steel is controlled to be between 400 and 600mm; (2) after strongly blowing argon for 1 to 3 minutes, adding aluminum wires into the steel ladle; (3) after strongly blowing argon for 6 minutes together, reducing argon quantity for softly blowing argon, wherein the soft argon blow standard is that the sum of the diameters of blown open holes of the molten steel is controlled to be between 200 and 400mm, and the soft argon blow time is ensured to be more than or equal to 6 minutes; and (4) making the total argon blow time for the molten steel in the argon ...

Steel plate for low-alloy high-strength structured steel Q460E-Z35 and production method thereof

The invention discloses a steel plate of a low-alloy series steel material Q460E-Z35 with the thickness specification lower than 40mm, and a production method thereof. The steel plate comprises the following chemical ingredients in by weight percent (wt%): less than or equal to 0.17 percent of C, less than or equal to 0.45 percent of Si, 1.15 to 1.55 percent of Mn, less than or equal to 0.018 percent of P, less than or equal to 0.005 percent of S, less than or equal to 0.20 percent of microalloyed elements comprising V, Nb and Ti, less than or equal to 0.035 percent of Als, and the balance Fe and residual elements. The production method comprises the following steps: knotted reactor (KR) molten iron pretreatment, converter smelting process, ladle furnace refining process, continuous casting and pouring, heating, rolling, cooling controlling and slow cooling. Due to the technical scheme, in the production process, the mechanical performance of the steel plate is ensured, the lamellar tearing ...

Ultra-thick low-alloy high-strength Q345-series steel plate and production method thereof

The invention discloses an ultra-thick low-alloy high-strength Q345D(E) steel plate which comprises the following chemical components in mass percentage: 0.08-0.16 percent of C, 0.20-0.50 percent of Si, 1.15-1.60 percent of Mn, not less than 0.020 percent of P, not less than 0.010 percent of S, not less than 0.20 percent of microalloyed element (Nb+Ti+Ni+Cr), not less than 0.050 percent of Als and the balance of Fe and residual elements, wherein the carbon equivalent weight is not less than 0.43. The invention also discloses a production method of the steel plate, which comprises the following steps of: converter smelting, LF refining, vacuum refining, pouring, heating, controlled cooling, slow cooling and heat processing; the steel purity is ensured by reasonably adopting the chemical component design of lower-carbon low-manganese multi-component compound microalloy elements, the grade sum of various inclusions does not exceed 3.0, crystal grains are finer, the rolling control state reaches ...

Method for improving internal quality of medium plate

Steel plate made of bainite structure high-strength toughness structural steel Q550D(E) and production method thereof

The invention discloses a steel plate made of bainite structure high-strength toughness structural steel Q550D(E) and a production method thereof. The steel plate comprises the following chemical ingredients in percentage by mass: 0.05-0.15 percent of C, 0.10-0.40 percent of Si, 1.40-1.65 percent of Mn, less than or equal to 0.010 percent of P, less than or equal to 0.005 percent of S, less than or equal to 0.30 percent of micro alloying element (V+Nb+Ti+Mo+B), less than or equal to 0.050 percent of Als and the balance of Fe and residual elements. The production method comprises the following steps of: pretreating molten iron; smelting in a converter; refining in an LF (Ladle Furnace); carrying out VD (Vacuum Degassing); carrying out continuous steel casting; heating; carrying out TMCP (Thermo Mechanical Control Process) rolling; controlling cold; and stacking for slow cooling. In the invention, in the rectifying and reforming processes from molten steel treatment to steel plate stacking ...

Heating-processing technology for improving mechanical property of high-intensity extra-thick plate

The invention provides a heating-processing technology for improving the mechanical property of a high-intensity extra-thick plate, and the heating-processing technology can be used for improving the mechanical property of a normalizing high-intensity extra-thick plate and improving the normalizing qualification rate of the extra-thick plate. A water-cooling working procedure is added in the normalizing process of the extra-thick plate and is used for replacing air cooling for normalizing; the normalizing cooling speed is quickened, the phase-transition temperature of a steel plate is lowered, and the growth of microalloy element carbonitride can be inhibited, so that a small quantity of ferrite and a large quantity of thinner perlite structure can be obtained, and intensity, plasticity, low temperature brittleness and the like can be improved so as to guarantee the intensity of the steel plate and improve the qualification rate of the steel plate.

Method for improving internal quality of medium plate

The invention discloses a method for improving internal quality of a medium plate, which comprises the following steps of: (1) a KR hot metal pretreatment process; (2) a converter smelting process; (3) a continuous casting process; (4) a heating process; (5) a rolling process; (6) a water cooling process; and (7) a stack cooling process. Due to the technical scheme, a problem that an out-of-furnace refining production process flow for improving the internal quality (flaw detection eligibility rate) of a steel plate is long is solved, the production process flow is optimized, and the method has the characteristics of low cost, low energy consumption and high production efficiency; and through a proper steel rolling process, the mechanical properties of the steel plate can be ensured, the internal quality (flaw detection eligibility rate) of the steel plate is improved, the production process can be simplified, the process flow is shortened, the production energy consumption is reduced and ...

Q345q-series super-thick bridge steel plate and production method thereof

The invention discloses a Q345q-series super-thick guaranteed performance and flaw detection bridge steel plate comprising the following chemical components in percentage by mass: 0.08-0.16 percent of C, 0.20-0.50 percent of Si, 1.15-1.60 percent of Mn, not more than 0.020 percent of P, not more than 0.010 percent of S, not more than 0.12 percent of microalloyed element (V+Nb+Ti+Ni), 0.010-0.050 percent of AlS and the balance of Fe and residual elements; and carbon equivalent is not more than 0.43. The invention also discloses a production method of the steel plate, comprising the steps of rolling, cooling, straightening, cooling in pile and thermal treatment. In the rolling, the cooling and the straightening, the 130 mm super-thick Q345qD(E) steel plate is successfully developed in the production line of a converter, die casting, mill rolling and normalization thermal treatment through carrying out reasonable composition design, die casting, TMCP (Thermal Mechanical Control Process) rolling ...

Super-thick Q390GJC-Z35 steel plate for high-rise buildings and production method thereof

The invention discloses a super-thick Q390GJC-Z35 steel plate for high-rise buildings and a production method thereof. The super-thick Q390GJC-Z35 steel plate comprises the following chemical compositions in percentage by mass: less than or equal to 0.19 percent of C, less than or equal to 0.50 percent of Si, 1.00 to 1.60 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.003 percent of S, less than or equal to 0.20 percent of microalloyed elements (Nb+V+Ti+Ni), less than or equal to 0.050 percent of Als and the balance of Fe and residual elements. By reasonably designing the chemical compositions of multiple composite microalloy elements, the cleanliness of steel is ensured by a low frequency (LF)+vacuum degassing (VD) process, the level of the sum of various inclusions does not exceed 3.0, the grain size of the steel reaches 9.0-10.0 level through control rolling and control cooling and normalizing treatment, and the super-thick steel plate for the high-rise ...

Hot rolling steel plate made of weldable fine grain structural steel S355ML and production method thereof

The invention discloses a steel plate made of weldable fine grain structural steel S355ML and a production method thereof. The steel plate contains the following chemical components in percentage by weight: 0.08-0.14% of C, 0.20-0.50% of Si, 1.20-1.60% of Mn, less than or equal to 0.018% of P, less than or equal to 0.005% of S, less than or equal to 0.07% of micro-alloying element (Nb and Ti), less than or equal to 0.050% of Als and balance of Fe and residual elements. The production method provided by the invention comprises the steps of smelting with a rotating furnace, LF (Low Frequency) refining, vacuum refining, continuous casting, heating, rolling, controlled cooling and slow cooling. The substance quality of the product provided by the invention reaches the weldable fine grain structural steel S355ML capable of protecting properties and protecting flaw detection. The redundant amount of the properties of the S355ML is relatively large; the yield strength is 390-450MPa, and the redundant ...

400-420mm large-thickness low-alloy high-strength constructional steel and production method thereof

The invention discloses 400-420mm large-thickness low-alloy high-strength constructional steel and a production method thereof. The 400-420mm large-thickness low-alloy high-strength constructional steel comprises the following chemical components in percentage by weight: not more than 0.18% of C, 0.20-0.40% of Si, 1.30-1.55% of Mn, not more than 0.015% of P, not more than 0.003% of S, 0.010-0.035% of Als and the balance of Fe and unavoidable impurities. In the invention, refined grain elements of Nb, V, Ti and the like are not added so that the cost of metallurgy and the content of molten steel inclusions are reduced; the processes of normalizing and wind-cooling refined grains are utilized so as to ensure the quality of the products to match the standard and the use requirements. The production processes are simple, and the constructional steel can be produced in batch. In addition, the applied strengthening mechanisms comprise a structure strengthening mechanism, a fine grains strengthening ...

Method for recycling converter steelmaking dust

The invention provides a method for recycling converter steelmaking dust. According to the method, fly ash collected by a dry dedusting device and steelmaking dust mud collected by wet dedusting are used, and a certain amount of oxidized iron scale, lime and bentonite are adopted, all the components are fired in a pellet shaft furnace, wherein the temperature of a combustion chamber in the pellet shaft furnace reaches 1020-1030 DEG C, and the temperature of a roasting zone reaches 940 DEG C, material distribution and blanking are uniform. The produced pellet can be returned back to the converter for making steel so as to substitute for part of magnesium or aluminum slagging agent for slagging in earlier stage of smelting and substitute for ores for regulating temperature in middle and later periods of smelting. By adopting the method, the yield of metal can be effectively improved, environment pollution caused by steelmaking dust can be reduced, dephosphorizing efficiency of the converter ...

Q460D steel for low-alloy high-strength structure of below 50mm and production method thereof

The invention discloses Q460D steel for a low-alloy high-strength structure of below 50mm and a production method thereof. The steel comprises the following chemical components in percentage by weight: 0.14 to 0.17 percent of C, 0.25 to 0.40 percent of Si, 1.45 to 1.55 percent of Mn, less than or equal to 0.018 percent of P, less than or equal to 0.005 percent of S, less than or equal to 0.20 percent of micro-alloying elements (V, Nb and Ti), less than or equal to 0.035 percent of Als and the balance of Fe and residual elements, wherein carbon equivalent (Ceq) is controlled to be less than 0.43 percent; carbon and manganese are mainly used for improving the strength of a steel plate; the combined addition amount of the Nb, V and Ti is controlled to be between 0.085 and 0.11 percent, and the Nb, V and Ti are mainly used for refining crystal grains and improving the plasticity and toughness of the steel plate; and yield strength is controlled to be between 470 and 490MPa, tensile strength ...

Large-thickness Cr-Mo system 12Cr2Mo1R container steel and production method thereof

The invention discloses large-thickness Cr-Mo system 12Cr2Mo1R container steel and a production method thereof. Under the process sequences of high quality molten iron and KR molten iron pretreatment, 100 ton top and bottom combined blown converter, argon-blowing treatment, low frequency (LF) furnace refinement, die casting pouring, walking beak reheating furnace, 3800-meter rolling mill, activated calcium carbonate (ACC) laminar flow cooling, 11 roller hot strainghtener, stack cooling, tempering, finishing, outer detecting, fault detecting and warehousing, various property indexes of the container steel are ensured through tempering, thereby meeting the idea demands of users. In the production method, fine grain elements such as Nb, V, Ti and the like are not added; and the large-thickness container steel is produced by virtue of a low carbon equivalent design, a controlled rolling and controlled cooling process and a tempering production process, is a 12Cr2Mo1R steel plate with the thickness ...

Hot-rolled weldable steel plate with fine grain structure and production method of steel plate

The invention discloses a hot-rolled weldable steel plate with a fine grain structure and a production method of the steel plate. The hot-rolled weldable steel plate with the fine grain structure comprises the following chemical components by mass percent: 0.10-0.15% of C, 0.20-0.50% of Si, 1.40-1.60% of Mn, not more than 0.015% of Mn, not more than 0.003% of S, not more than 0.15% of micro alloying elements, not more than 0.050% of Als and the balance of Fe and residual elements. The production method comprises the following technological processes: pretreatment of high-quality molten iron and KR molten iron, 100/120t top-bottom combined blowing converter, LF furnace purification, vacuum degassing, cooling a casting blank in a heap for 24 hours, heating, 3800m of rolling mill, ACC laminar cooling, 11-roller hot straightening machine, cooling in a heap, finishing, appearance inspection, flow detection and warehousing. The hot-rolled weldable steel plate has the beneficial effects that ( ...

Low-alloy Q345E medium plate and production process thereof

The invention discloses a low-alloy Q345E medium plate produced without adding micro-alloy element and a production process thereof. The low-alloy Q345E medium plate comprises the following chemical components in percentage by weight: 0.13-0.19% of C, 0.20-0.50% of Si, 1.30-1.60% of Mn, less than or equal to 0.020% of P, less than or equal to 0.010% of S, 0.015-0.050% of Als, and the balance of Fe and residual elements. The process disclosed by the invention comprises the following steps: KR (knotted reactor) hot metal pretreatment of high-quality hot metal, processing with a top-bottom combined blowing converter, LF ((ladle furnace) refining, casting blank stack cooling, processing with a heating furnace, rolling, ACC (accelerated cooling) laminar flow cooling, processing with a hot straightener, stack cooling, finishing, external inspection, flaw detection and storage. The invention has the beneficial effects that: compared with the traditional Q345E, precious alloys such as Nb, Ti and ...

Method for straightening buckled pipeline steel plate with thickness less than 20mm at normal temperature

The invention discloses a method for straightening a buckled pipeline steel plate with the thickness less than 20mm at normal temperature. During halt of a rolling machine, straightening workers are organized to straighten the buckled pipeline steel plate with the thickness less than 20mm repeatedly straightened by multiple straightening process on a hot straightening machine under small pressure, so that the buckled steel plate subjected to cold straightening can reach the national standard that the unevenness is within 2011mm, thus the overall yield of pipeline steel is greatly improved, and the cost pressure caused by repeated production can be relieved. The invention has the beneficial effects that, compared with a large enterprise adopting a normalizing furnace to straightening the buckled pipeline steel, the normal-temperature cold straightening does not consume fuel or need corresponding manpower or material resource support, thus the production cost can be greatly reduced; the cold ...

Heat treatment process for improving comprehensive performance of Q345 low alloy structural steel

The invention discloses a heat treatment process for improving the comprehensive performance of Q345 low alloy structural steel, which comprises the following process steps of: (1) quenching, namely preheating an empty furnace to the temperature of between 860 and 920 DEG C, stabilizing for a certain time, putting low alloy structural steel into the furnace, heating to the temperature of between 860 and 920 DEG C, preserving heat for a certain time, and immediately performing water cooling to room temperature; and (2) tempering, namely preheating the furnace to the temperature of between 550 and 650 DEG C, putting the quenched low alloy structural steel into the furnace, heating to the temperature of between 550 and 650 DEG C, preserving the heat for a certain time, taking out and cooling in air. Compared with the prior art, the heat treatment process has the advantage that: the mechanical properties of the steel are obviously improved, wherein the tensile strength is more than 510MPa, ...

Low-alloy high-strength structural-steel extra-thick board Q460C and production method thereof

The invention discloses a low-alloy high-strength structural-steel extra-thick board Q460C and a production method thereof, the extra-thick board comprises the following chemical constituents in percentage by weight (with wt% as a unit): C: not more than 0.20, Si: not more than 0.60, Mn: 1.40-1.60, P: not more than 0.020, S: not more than 0.005, microalloying elements (V+Nb+Ti+Ni): not more than 0.25, Als: not less than 0.015, and the balance of Fe and residual elements. The microalloying elements are selected reasonably, the elements V, Nb, Ti, and Ni are added in best match, and therefore, the double effects of precipitation strengthening and fine-grain strengthening are fully exerted to ensure that each performance index of a pressure vessel board can meet the requirement of national standard on 120mm under the premise of not reducing plasticity and toughness.

Method for flattening super-thick steel plates with temperature

The invention discloses a method for flattening super-thick steel plates with temperature. In the method, medium temperature tempering for the super-thick steel plates eliminates the internal stress of the steel plates, the yield strength and tensile strength of the steel plates cannot be reduced, and the impact toughness and the elongation of the steel plates are improved to some extent; and thetime for hoisting the discharged steel plates to a flatting machine is strictly controlled to be less than or equal to 10 minutes, and the flattening temperature of the steel plates is ensured, so that the flattening effect of the steel plates with temperature is ensured. In the method, steel plate residual temperature after the super-thick steel plates are normalized is utilized for flattening, and the flattening temperature is 300 to 500DEG C; steel plate stack cold and destacking residual temperature is utilized to flatten No.45 steel plates, and the flattening temperature is 200 to 400DEGC; ...

160mm-thick Q345E-Z35 steel plate for high-rise buildings and production method thereof

The invention discloses a 160mm-thick Q345E-Z35 steel plate for high-rise buildings and a production method thereof. The steel plate guarantees performance and flaw detection. The steel plate comprises the following chemical components by weight percent (wt%): not more than 0.19wt% of C, not more than 0.50wt% of Si, 1.20-1.60wt% of Mn, not more than 0.015wt% of P, not more than 0.003wt% of S, notmore than 0.20wt% of microalloying elements (Nb, V, Ti and Ni), not more than 0.050wt% of Als and the balance Fe and residual elements. The invention has the following beneficial effects: the aim that the total level of various inclusions is not beyond 3.0 is achieved by rationally adopting the chemical component design of multiple complex microalloying elements and the ladle furnace (LF) plus vacuum degassing (VD) process to ensure the cleanliness of steel, and the grain size of steel is ensured to reach 9.0 level through controlled rolling and controlled cooling as well as normalizing treatment ...

Q345B protected flaw detection steel plate and production method thereof

The invention discloses a low-alloy series Q345B protected flaw detection steel plate with thickness specification of less than 50 millimeters and a production method thereof. The steel plate comprises the following chemical components in percentage by mass: less than or equal to 0.18 percent of C, less than or equal to 0.45 percent of Si, less than or equal to 1.40 percent of Mn, less than or equal to 0.018 percent of P, less than or equal to 0.005 percent of S, less than or equal to 0.020 percent of Ti, less than or equal to 0.015 percent of Als, and the balance of Fe and residual elements. The production method comprises molten iron pretreatment, converter smelting, ladle furnace (LF) refining, continuous steel casting, casting blank heat transfer to a steel mill, casting blank heating, rolling, cold control, stacking and slow cooling. Because the technical scheme is adopted, compared with the prior art, the production method has the advantages of short production period, energy conservation ...

Wind power flange steel and production process thereof

The invention discloses wind power flange steel and a production process thereof. The wind power flange steel comprises the following components in percentage by weight: C: 0.14-0.17, Si: 0.25-0.40, Mn: 1.35-1.50, P: smaller than or equal to 0.015, S: smaller than or equal to 0.003, V: smaller than or equal to 0.015-0.030, Nb: smaller than or equal to 0.025-0.040, Al: 0.030-0.045, N: smaller thanor equal to 0.004, H: smaller than or equal to 0.0001, O: smaller than or equal to 0.002, and As-Cu-Cu mixture: smaller than or equal to 0.1. The invention adopts a continuous-casting method to produce and manufacture the wind power flange steel. The integral process flows comprise the following steps: optimizing molten steel; pretreating KR molten steel; carrying out argon-stirring treatment in atop and bottom blowing converter of 120 tons; refining in an LF furnace; carrying out VD vacuum degassing treatment; continuously casting; cooling in pile; testing; and entering a warehouse. Comparedwith ...

Cr-Mo ASTM A387 Gr22CL2 pressure vessel steel and production method thereof

The invention provides a limit-thickness Cr-Mo ASTM A387 Gr22CL2 pressure vessel steel and a production method thereof. The Cr-Mo ASTM A387 Gr22CL2 pressure vessel steel comprises the following chemical components in percentage by mass: 0.08-0.16 wt% of C, 0.20-0.50 wt% of Si, 0.30-0.60 wt% of Mn, at most 0.015 wt% of P, at most 0.005 wt% of S, 0.020-0.060 wt% of Als, 2.0-2.5 wt% of Cr, 0.9-1.1 wt% of Mo and the balance of Fe and residual element. The production method comprises the following steps: pretreatment of high-quality molten iron and KR molten iron, 120t top/bottom blown converter, argon blowing by Ar station, LF (ladle furnace) refining, VD (vacuum degasser) vacuum degassing, water-cooled die casting, dead soaking pit heating, 3800mm rolling mill, ACC laminar cooling, straightening, cooling in pile, heat treatment, finishing, outer inspection, flaw detection and warehousing. The steel plate is cast by a 48t water-cooled ingot die, so the cooling and solidifying time is shortened ...

Q345C steel plate and production method thereof

The invention discloses a low alloy series Q345C steel plate with the thickness specification below 50mm and a production method thereof. The steel plate comprises the chemical components by weight percent (wt%): less than or equal to 0.18% of C, less than or equal to 0.40% of Si, 1.05-1.40% of Mn, less than or equal to 0.020% of P, less than or equal to 0.010% of S, 0.010-0.020% of microalloy element Ti, 0.010-0.035% of Als and the balance Fe and residual elements. The production method of the steel plate comprises the following steps: selecting high-quality molten iron, carrying out KR molten iron pretreatment, adopting a top and bottom combined blown converter, blowing argon, ladle furnace (LF) refining, casting blank, stacking and cooling, heating by using a heating furnace, rolling by using a 3800mm rolling mill, ACC laminar cooling, straightening by a hot straightener, carrying out stacking and cooling on the steel plate, finishing, detecting and entering in a warehouse. Compared ...

High-strength steel plate Q460GJE-Z35 for extra-thick high-rise building structure and production method thereof

The invention discloses a high-strength steel plate Q460GJE-Z35 for an extra-thick high-rise building structure and a production method thereof. The production method comprises the following steps of KR (Knotted Reactor) desulfurization, transferring to a converter, LF (Ladle Furnace) refining, VD (Vacuum Degassing) vacuum treatment, casting, mold cooling for 8 hours after reaching the steel ingot stripping time, cleaning (completion of cleaning within 8 hours), charging and rolling at the rolling temperature, heating, descaling, rolling through a 3,800mm rolling mill, straightening, cooling in heap, external examination, flaw detection, heat treatment, finishing and warehousing. With a rational component design, molded casting, heating and heat treatment, the yield strength of the obtained product is 440-480MPa; the tensile strength of the obtained product is 540-630MPa; the elongation rate of the obtained product is 24-27%; the impact energy of the obtained product at the temperature ...

Q345GJ series structural steel plates for ultra-thick building and production method thereof

The invention discloses a Q345GJ series structural steel plates for an ultra-thick building and a production method thereof. In the Q345GJ series steel plate, the yield strength is controlled at 335-420MPa, the tensile strength is controlled at 505-585MPa, the elongation ratio is controlled at 25-29%, the V-shaped shock power at 0 DEG C is controlled at 156-190J, the yield ratio is 0.62-0.81 and is 0.69 in average, the single lamellar tearing resisting capacity is 32-48% and is 40.2% in average, and the performance indexes completely satisfy the Q345GJCZ35 development requirement. In addition, the steel plate tissues subjected to controlled rolling are ferrite and pearlite and has the grain size up to 8-9 level. After normalizing treatment, the ferrite and pearlite tissues in the steel plate are more uniform, and the grains are refined to reach 10.5 level.

Q345R-Z35 super-thick steel plate resisting HIC (hydrogen induced crack) pressure vessel and production method thereof

The invention discloses a Q345R-Z35 super-thick steel plate resisting an HIC (hydrogen induced crack) pressure vessel and a production method thereof. The super-thick steel plate is characterized by comprising the following components by mass percent (wt%): less than or equal to 0.20% of C, less than or equal to 0.55% of Si, 1.20-1.60% of Mn, less than or equal to 0.025% of P, less than or equal to 0.005% of S, less than or equal to 0.10% of micro-alloying element, more than or equal to 0.015% of Als, and the balance Fe and residual elements. The production method comprises the following steps: molten iron KR desulfuration, converter smelting, refining by a ladle furnace (LF), vacuum degassing (VD), die casting and pouring, steel ingot heating, rolling, activated calcium carbonate (ACC) cooling, straightening, steel plate cooling in heap and normalizing heat treatment and the like. The super-thick steel plate of the invention develops the steep plate for the super-thick pressure vessel ...

X70 steel plate for low-cost pipe fittings and production method thereof

The invention discloses an X70 steel plate for low-cost pipe fittings and a production method thereof. The steel plate comprises the following chemical components in percentage by mass (unit, wt%): 0.04-0.08% of C, 0.20-0.40% of Si, 1.50-1.65% of Mn, less than or equal to 0.010% of P, less than or equal to 0.005% of S, less than or equal to 0.40% of micro-alloy elements (V, Nb, Ti, Mo and Ni), less than or equal to 0.050% of Als, and the balance of Fe and residual elements. The production method disclosed by the invention comprises the following steps: hot metal pretreatment, smelting with a converter, LF (ladle furnace) refining, VD (vacuum degassing) vacuum refining, continuous casting, heating, rolling, cooling control and slow cooling of stack. The steel purity is ensured with LF+VD process by reasonably adopting the chemical component deign of low carbon, low manganese and multiple composite micro-alloy elements, and the total level of various impurities is not over 3.0; the grain ...

Q420GJD-Z35 steel plate with thickness of less than or equal to 60 millimeters for high-rise building and production method thereof

The invention discloses a Q420GJD-Z35 steel plate with thickness of less than or equal to 60 millimeters for a high-rise building and a production method thereof. The steel plate comprises the following chemical components in percentage by mass: 0.10 to 0.17 percent of C, 0.20 to 0.50 percent of Si, 1.20 to 1.60 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.005 percent of S, less than or equal to 0.10 percent of microalloyed elements (Nb+V+Ti), less than or equal to 0.050 percent of Als and the balance of Fe and residual elements. The production method comprises the steps of performing converter smelting, ladle furnace (LF) refining, vacuum refining, continuous casting, heating, rolling, cooling control, slow cooling and heat treatment. Optimized components and a rolling process are controlled strictly, so that the material quality of the product reaches the Q420GJD-Z35 level, the yield strength is controlled to be between 400 and 480 MPa, the tensile ...

75-mm Z15 series steel plate prepared by rolling 250-mm casting blank and production method of 75-mm Z15 series steel plate

The invention discloses a 75-mm Z15 series steel plate prepared by rolling 250-mm casting blank which comprises the following chemical components in percentage by mass: 0.08-0.16 wt% of C, 0.20-0.50 wt% of Si, 1.15-1.60 wt% of Mn, at most 0.020 wt% of P, at most 0.010 wt% of S, at most 0.20 wt% of microalloying elements (Nb+Ti), at most 0.050 wt% of Als, and the balance of Fe and residual elements. The production method comprises the following steps: converter smelting, LF (ladle furnace) refining, vacuum refining, casting, heating, rolling, controlled cooling, slow cooling and heat treatment. The chemical components of low-carbon low-manganese multi-element compound microalloying elements are reasonably designed, and LF and VD (vacuum degasser) techniques are used for ensuring the cleanliness of the steel, so that the total grade of various inclusions does not exceed 3.0; and by effectively taking the measures above, thickness-property Z15 steel plate by rolling 250mm continuous casting ...

Steel plate for low-alloy high-strength structured steel Q460C and production method thereof

The invention discloses a high-strength structured steel plate for a low-alloy series steel material Q460C with the thickness specification lower than 40mm, and a production method thereof. The steel plate comprises the following chemical ingredients in by weight percent (wt%): less than or equal to 0.17 percent of C, less than or equal to 0.40 percent of Si, 1.20 to 1.55 percent of Mn, less than or equal to 0.018 percent of P, less than or equal to 0.005 percent of S, less than or equal to 0.20 percent of microalloyed elements comprising V, Nb and Ti, less than or equal to 0.035 percent of Als, and the balance Fe and residual elements. The production method comprises the following steps: molten iron pretreatment, converter smelting, ladle furnace (LF) refining, continuous casting, casting blank heating, rolling, cooling controlling and stacking for slow cooling. Due to the technical scheme, on the premise that the comprehensive quality is ensured, the method has the advantages of low cost ...

Low-alloy medium-thickness steel plate Q345D-Z35 and production process thereof

The invention discloses a low-alloy medium-thickness steel plate Q345D-Z35 produced without adding microalloy elements and a production process thereof. The steel plate contains the following chemical components in percentage by mass (with wt% as a unit): 0.10 to 0.18 percent of C, 0.20 to 0.45 percent of Si, 1.20 to 1.60 percent of Mn, less than or equal to 0.018 percent of P, less than or equal to 0.005 percent of S, 0.015 to 0.050 percent of Als and the balance of Fe and residual elements. The production method comprises the following steps of: pretreatment with high-quality molten iron or KP molten iron, blowing in a top and bottom combined blown converter, ladle furnace (LF) refining, vacuum degassing treatment, casting blank cooling in pile, treatment in a heating furnace, rolling, ACC (Active Calcium Carbonate) laminar cooling, treatment in a hot straightening machine, cooling in pile, finishing, external inspection, flaw detection and warehousing. The steel plate has the advantages ...

Crack-free steel Q245R medium-thickness plate for pressure container and production method

The invention discloses a crack-free steel Q245R medium-thickness plate for a pressure container and a production method. The Crack-free steel Q245R medium-thickness plate for pressure container and production method comprises the following chemical components in percentage by weight ( unit, weight percent): less than or equal to 0.20 weight percent of C, less than or equal to 0.35 weight percent of Si, 0.70 to 1.00 weight percent of Mn, less than or equal to 0.015 weight percent of P, less than or equal to 0.010 weight percent of S, less than or equal to 0.080 weight percent of micro alloy elements (V+Nb+Ti), more than or equal to 0.020 weight percent of Als, and the balance of Fe and residual elements. In the invention, clean steel process control is adopted to protect pouring in the whole process so as to ensure the nitrogen absorption in a production process is reduced as much as possible; a proper amount of silicon calcium line is added to modify sulfide and ensure that the content ...

120 mm Q460 structural steel plate and production method thereof

The invention discloses a 120 mm Q460 structural steel plate and a production method thereof. The 120 mm Q460 structural steel plate comprises the following chemical components by weight percentage: 0.15-0.18 wt% of C, 0.30-0.45 wt% of Si, 1.30-1.60 wt% of Mn, P being less than or equal to 0.015 wt%, S being less than or equal to 0.005 wt, 0.015-0.030 wt% of Als, 0.030-0.050 wt% of Nb, 0.010-0.020 wt% of Ti, and the balance of Fe and residual elements. In the smelting process, the harmful elements such as P and S are strictly controlled to ensure that the purity of the molten steel basically achieves the clean steel level. In the follow-up rolling heating process, in order to prevent that the internal grain of the billet is thick and big, the heating temperature is properly reduced to avoid that the internal original austenite grain of the billet is grown excessively. The steel plate production method adopts the normalized thermal treatment technology to obtain pearlites and ferritic structures ...

Low-alloy Q345D-Z25 medium plate and production process thereof

The invention discloses a low-alloy Q345D-Z25 medium plate and a production process thereof. The low-alloy Q345D-Z25 medium plate comprises the following chemical components in percentage by weight: 0.13-0.18% of C, 0.20-0.45% of Si, 1.30-1.60% of Mn, less than or equal to 0.018wt% of P, less than or equal to 0.007% of S, 0.015-0.050% of Als, and the balance of Fe and residual elements. The process disclosed by the invention comprises the following steps: KR (knotted reactor) hot metal pretreatment of high-quality hot metal, processing with a top-bottom combined blowing converter, LF ((ladle furnace) refining, vacuum degassing process, casting blank stack cooling, processing with a heating furnace, rolling, ACC (accelerated cooling) laminar flow cooling, processing with a hot straightener, stack cooling, finishing, external inspection, flaw detection and storage. The invention has the beneficial effects that: compared with the traditional Q345DD-Z25, precious alloys such as Nb, Ti and the ...