24 results about "Lower yield" patented technology

The invention belongs to the field of steel for automobiles, and particularly relates to low-yield-ratio 1180MPa-grade cold-rolled martensitic steel for automobiles and a preparation method. The steel comprises the following components in percentage by weight: 0.145%-0.175% of C, 0.20%-0.45% of Si, 1.75%-2.00% of Mn, less than or equal to 0.020% of P, less than or equal to 0.0050% of S, 0.08%-0.12% of Al, less than or equal to 0.0050% of N, 0.005%-0.008% of B, 0.03%-0.04% of Nb and the balance of Fe and other inevitable impurities. Through brand new matching design of component design and a heat treatment process, martensite serves as a matrix, a small amount of ferritic structures are introduced, the performance characteristic of the low yield ratio is successfully achieved, and the forming capacity of the 1180MPa-grade martensitic steel in the application process is effectively improved.

This invention provides a high-strength steel with a low yield strength ratio of 1100MPa and its production method. The steel plate has the following chemical composition by mass percentage: C 0.15~0.17%, Si 0.58~0.6%, Mn 2.53~2.6%, Cr 0.53~0.8%, Ni 1.44~1.6%, Mo 0.2~0.6%, Nb 0.052~0.08%, V 0.02~0.08%, Ti 0.019~0.03%, Al 0.01~0.05%, Cu 0.83~1.5%, with the balance being Fe and unavoidable impurities. The steel plate has a yield strength ≥1100MPa, a yield strength ratio ≤0.88, an elongation ≥14%, and an impact energy ≥30J at -40℃. The finished steel plate has a thickness of 15mm and a microstructure of tempered lath martensite. The high-strength steel plate of this invention, with a yield strength ≥1100MPa, yield strength ratio ≤0.88, elongation ≥14%, and impact energy ≥30J at -40℃, exhibits a low yield-to-tensile ratio. The advantage of this invention lies in the fact that the salt bath Q&P heat treatment process achieves a good balance between high strength and a low yield-to-tensile ratio.

The application discloses a kind of low yield ratio high toughness 9Ni steel and its short process preparation method, belong to high-performance special steel manufacturing field.9Ni steel chemical composition is as follows according to percentage by mass: C:0.03~0.06%, Si:0.10~0.25%, Mn:0.50~0.80%, P≤0.003%, S≤0.001%, Ni:8.70~9.70%, Mo:0.08~0.15%, Ti:0.010~0.025%, Ca:0.0010~0.0030%, Alt:0.030~0.060%, N:0.003~0.006%, O≤0.0015%, the rest is Fe and inevitable impurity.Preparation method uses the short process technology of '' controlled rolling + online direct quenching + offline tempering'', and steel plate has high safety, high toughness and high quality, is suitable for LNG storage tank and other fields.

The present invention relates to a steel material for use as a material for building structures, ship structures, marine structures, and the like. More specifically, the present invention relates to a low-yield-ratio steel material having excellent toughness in a welding heat-affected zone, and a method for manufacturing the same.

The invention belongs to the technical field of metallurgy, and relates to a production method of railway anti-seismic steel with a low yield ratio. Comprising the procedures of converter smelting, refining, continuous casting, hot rolling and cooling. The cooling process comprises the following steps: quickly cooling to 650 DEG C after rolling at the cooling speed of more than or equal to 20 DEG C / s and the pit entering temperature of more than or equal to 630 DEG C, and slowly cooling for more than or equal to 48 hours; the anti-seismic steel is composed of the following components in percentage by mass: 0.11-0.15% of C; si is equal to 0.10%-0.30%; mn is equal to 1.30 to 1.60 percent; p is less than or equal to 0.013%; s < = 0.008%; v is equal to 0.06 to 0.08 percent; ti is less than or equal to 0.02%; al > = 0.025%; and the balance of Fe and inevitable impurity elements. And the produced anti-seismic steel has the characteristics of high tensile strength, low yield ratio, good low-temperature impact performance and stable performance.

This invention proposes a low yield strength ratio steel plate for containers with a yield strength of 690 MPa and its manufacturing method. The steel plate composition, by weight percentage, is as follows: C: 0.04%–0.08%, Si: 0.10%–0.30%, Mn: 1.00%–2.00%, P: ≤0.010%, S: ≤0.005%, Nb: 0.10%–0.50%, V: 0.10%–0.50%, Ti: 0.02%–0.08%, Cr: 0.30%–0.60%, Ni: 0.60%–1.20%, Cu: 0.40%–0.80%, Al: 0.0035%–0.0055%, with the balance being Fe and unavoidable impurities. The production process of steel plates includes smelting, continuous casting, heating, rolling, cooling, and heat treatment. The final steel plate has a microstructure of tempered bainitic structure (90%–94% by volume) plus a small amount of ferrite (6%–10% by volume). The yield strength R of the steel plate... eL ≥690MPa, tensile strength R m 780~930MPa, yield strength ratio R eL / R m ≤0.85, elongation A≥18%, low-temperature impact toughness KV2≥100J at -70℃. The steel plate underwent a simulated post-weld heat treatment process to test its mechanical properties. The simulated post-weld heat treatment temperature was 550~650℃, and the holding time was 120~480min. Its mechanical properties were as follows: yield strength R... eL ≥690MPa, tensile strength R m 780~930MPa, yield strength ratio R eL / R m ≤0.85, elongation A≥18%, low temperature impact toughness KV2≥100J at -70℃.

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 invention discloses a rolling method of low-yield-ratio Q420qE bridge steel, and belongs to the technical field of steel. The steel comprises the following chemical components in percentage by weight: 0.08 to 0.11 percent of C, 0.15 to 0.30 percent of Si, 1.3 to 1.6 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.005 percent of S, 0.03 to 0.05 percent of Nb, 0.03 to 0.05 percent of V, 0.010 to 0.020 percent of Ti, 0.017 to 0.027 percent of Als and the balance of Fe and inevitable impurities. Through the process of controlled rolling, relaxation and controlled cooling, the yield ratio of the steel plate is reduced, the yield ratio is stably controlled to be 0.85 or below, and the yield ratio qualification rate of Q420qE is remarkably improved.

The invention relates to the technical field of composite plate performance evaluation, and provides a method and a system for predicting bonding strength of a metal composite plate prepared by rolling. According to the prediction method, a first plate body with low yield strength in the metal composite plate serves as a key side where deformation and fracture occur, and a judgment link and an iterative adjustment link are executed based on first rolling force of the first plate body and second rolling force of a second plate body; therefore, the optimal reduction rate of the first plate body is determined as one of key parameters through multiple times of iterative adjustment, and a bonding strength equation is established based on the first rolling temperature of the first plate body and the final strain parameter, so that prediction of the bonding strength of the metal composite plate is realized. Compared with the prior art, the prediction method does not need to depend on excessive experimental data, the bonding strength of the metal composite plate can be efficiently and rapidly predicted, the prediction efficiency can be improved, the test cost in production can be reduced, meanwhile, a scientific basis is provided for process optimization and product quality control, and therefore wider application of the steel / copper composite plate is promoted.

The utility model provides a mold for manufacturing a polyvinyl chloride (PVC) hollow pipe, and belongs to the technical field of injection molds. The problems that in the prior art, PVC hollow pipes are difficult to form, and the yield is low are solved. The mold for manufacturing the PVC hollow pipe comprises a core rod and a mold shell arranged on the outer side of the core rod in a sleeving mode, a mold cavity is formed between the mold shell and the core rod, a plurality of forming blocks arranged in the circumferential direction of the core rod at intervals are arranged on the inner side wall of the mold shell, and the forming blocks are in a long strip shape and are arranged in the axial direction of the core rod; the core rod is made of a heat conduction material, and an electric heating tube is inserted into the core rod. The injection molding machine has the advantage that the injection molding yield of the PVC hollow pipeline can be improved.

This invention discloses a method for producing 780MPa grade bridge steel with low yield strength ratio and high toughness. The chemical composition of the steel (by mass percentage) is: C = 0.05~0.06%, Si = 0.1%~0.2%, Mn = 1.30%~1.40%, P ≤ 0.006%, S ≤ 0.002%, Nb = 0.015%~0.025%, Ti ≤ 0.008%, Al... T =0.02%~0.05%, Cr=0.4%~0.5%, Ni=0.5%~0.6%, Cu=0.5%~0.6%, Mo=0.2%~0.3%, B=0.0035%~0.0040%, N≤30PPM, the remainder being Fe and unavoidable impurities, with a carbon equivalent Ceq≤0.50% and a crack sensitivity index Pcm≤0.23%. The process steps include: slab heating temperature of 1120~1150℃, two-stage rolling, finishing rolling temperature of 840~880℃ in the two-phase region; followed by online quenching with DQ to 260~300℃, and then tempering heat treatment at 500℃ to obtain a 780MPa grade bridge steel with low yield strength ratio and high toughness of lath bainitic + martensitic structure.

Provided is a low-yield ratio type extra-thick steel plate having excellent toughness and a thickness of greater than 100 mm without the need for special facilities. The low-yield ratio type extra-thick steel plate having a predetermined component composition and a thickness of over 100 mm is characterized by having a component composition in which a Ceq is defined by equation (1) and a plate thickness t [mm] satisfies 0.22t0.1≤Ceq≤0.50, (1): Ceq= [C]+[Mn] / 6+([Cr]+[Mo]+[V]) / 5+([Cu]+[Ni]) / 15 (in equation (1), a symbol of each element represents the content (mass%) of said element, which is 0 if said element is not added), wherein the average grain size of parent-phase ferrite is at most 25 μm, the area ratio of island martensite is 3-20%, the tensile strength is at least 520 MPa, the yield ratio is at most 80%, and the Charpy absorbed energy at 0 °C is at least 47 J.

The invention relates to the technical field of steel manufacturing, in particular to a hot-formed steel plate with low yield ratio and high strength and a manufacturing method of the hot-formed steel plate, and the manufacturing method comprises the following steps: (1) smelting; (2) continuous casting: casting the smelted molten steel into a casting blank through a continuous casting machine, and stacking and slowly cooling; (3) heating is conducted, specifically, the casting blank subjected to slow cooling is heated, and the tapping temperature is controlled to be 1160-1210 DEG C after heating; (4) rolling, wherein a rolling mode of two stages of rough rolling and finish rolling is adopted; and (5) water cooling: the rolled steel plate enters a water cooling area, the initial cooling temperature is controlled to be larger than or equal to 690 DEG C, and the final cooling temperature is controlled to be 500-560 DEG C. The steel plate provided by the invention has the characteristics of low yield ratio and high strength after being heated at high temperature.

The invention discloses a low-yield-ratio austenite wear-resistant steel plate and a manufacturing method thereof. The steel plate comprises the following chemical components in percentage by mass: 0.05%-0.12% of C, 12.0%-15.0% of Mn, 2.0%-4.0% of Al, 0.10%-0.25% of N, 1.0%-2.5% of Cr, less than or equal to 0.010% of P, less than or equal to 0.005% of S and the balance of Fe and inevitable impurities. The manufacturing method comprises the steps of smelting, continuous casting, heating, rolling, cooling and annealing. The steel plate provided by the invention is of an all-austenite structure, has the advantages of no magnetism, low density, high strength, high toughness, low yield ratio, excellent wear resistance and the like, and is suitable for light-weight wear-resistant parts of engineering machinery, marine equipment and the like.

This invention discloses a thin-gauge, low-yield, high-toughness 5Ni steel with the following chemical composition and mass percentages: C: 0.04–0.08%, Si: 0.15–0.25%, Mn: 0.30–0.60%, Ni: 4.75–4.95%, S≤0.005%, P≤0.008%, Alt: 0.020–0.050%, O≤20ppm, N≤40ppm, H≤2ppm, Cr+Cu+Mo≤0.30%, with the balance being Fe and impurities. The advantage of this invention is that it enables the steel to meet both low yield strength and high toughness requirements, while simultaneously ensuring excellent weldability and formability.

The present application relates to the technical field of low-carbon microalloyed steel production, and particularly relates to an economic low-yield-ratio thin-gauge L450M pipeline steel plate and a manufacturing method thereof, wherein the chemical composition of the steel plate is as follows in terms of percentage by weight: C: 0.05% to 0.07%, Si: 0.10% to 0.25%, Mn: 1.50% to 1.65%, P: less than or equal to 0.020%, S: less than or equal to 0.015%, Nb: 0.02% to 0.04%, Ti: 0.008% to 0.020%, Al: 0.015% to 0.04%, Cr: 0.25% to 0.30%, N: 0.003% to 0.006%, CE II W = C + Mn / 6 + (Cr + V + Mo) / 5 + (Cu + Ni) / 15: 0.36% to 0.40%, the balance being Fe and inevitable impurities, and the total amount of the impurity elements is less than 0.05%; the production process comprises the following steps: smelting of molten steel, off-furnace refining and degassing, continuous casting, heating of the cast blank, controlled rolling, relaxation, controlled cooling, and air cooling to room temperature; the present application is used for manufacturing the L450M hot-rolled steel plate with a thickness of 9 to 17.5 mm and a pipe diameter of less than or equal to 914 mm, and the problems of low rolling efficiency, large rolling resistance and difficult control of the plate shape are solved, and the steel plate has low cost, high strength and toughness, low yield ratio and high flatness.

The present application relates to a kind of low X90 grade pipeline steel hot-rolled coil of ratio of yield strength, chemical composition includes by weight percentage:C 0.05-0.07%, Si 0.20-0.40%, Mn 1.50-1.90%, Nb0.05-0.09%, Ti 0.01-0.02%, Cr 0.10-0.30%, Mo 0.10-0.20%, Ni 0.10-0.20%, 0≤P≤0.012%, 0≤S≤0.005%, Als 0.015-0.035%, the rest is Fe and inevitable impurities.The present application also relates to a kind of low X90 grade pipeline steel hot-rolled coil of ratio of yield strength manufacturing method.Through the technical scheme of the present application, the present application can effectively reduce the yield ratio in the production and application of X90 grade pipeline steel hot-rolled coil.

This invention belongs to the field of iron and steel metallurgy technology, specifically relating to a low yield strength ratio (1300MPa) hot-rolled coil and its manufacturing method. The low yield strength ratio (1300MPa) hot-rolled coil provided by this invention comprises, by weight percentage: C 0.20-0.30%, Si 1.2-1.8%, Mn 0.8-1.2%, P≤0.020%, S≤0.040%, Nb 0.02-0.10%, Al 0.02-0.06%, with the remainder being Fe and unavoidable impurities. The low yield strength ratio (1300MPa) hot-rolled coil of this invention exhibits a microstructure containing both high-strength martensite and soft ferrite, resulting in advantages such as high strength, low yield strength ratio, and good machinability.

The present invention provides a low-yield ratio 1030 MPa grade high-strength Q&P steel and a production process thereof. The chemical composition of the thick plate is, by mass percentage, as follows: C 0.15-0.17%, Si 0.4-0.6%, Mn 1.4-2.6%, Cr 0.4-0.8%, Ni 1.2-1.6%, Mo 0.2-0.6%, Nb 0.02-0.08%, V 0.02-0.08%, Ti 0.01-0.03%, Al 0.01-0.05%, Cu 0.8-1.5%, with the balance being Fe and unavoidable impurities. The production process utilizes the above composition, controlled rolling and controlled cooling, and an offline salt bath Q&P heat treatment process to produce a 15 mm thick low-yield ratio 1030 MPa grade high-strength steel. The controlled rolling and controlled cooling process adopts two-stage rolling, and after rolling, it is water-cooled to 400-420℃, and then air-cooled to room temperature. The heat treatment adopts the salt bath two-step Q&P process, with a complete austenitization temperature of 900-920℃, a salt bath quenching temperature of 200-250℃, a salt bath partitioning temperature of 350-400℃, and finally water-cooled to room temperature. The yield strength of the low yield ratio 1030MPa grade high-strength steel plate of the present invention is ≥1030MPa, the yield ratio is ≤0.85, the elongation is ≥14%, and the impact energy at -40℃ is ≥45J. The advantage of the present invention is that the salt bath Q&P heat treatment process is used to obtain a good performance match between high strength and low yield ratio.

The invention discloses a bridge steel plate and a manufacturing method thereof, and belongs to the technical field of steel, the bridge steel plate comprises the following chemical components in percentage by weight: 0.08-0.11% of C, 0.30-0.50% of Si, 1.50-1.70% of Mn, 0.030-0.060% of Nb, 0.040-0.070% of V, 0.010-0.040% of Ti and 0.015-0.050% of Als, a Mn-Nb-V-Ti component system is adopted, a low yield ratio control technology of a TMCP + T state bridge steel plate is developed, and by optimizing controlled cooling after rolling, the yield ratio of the steel plate is controlled to be smaller than that of the steel plate. The volume fraction of ferrite and bainite in a steel plate structure is effectively controlled, the high-performance requirement for the low yield ratio of the high-strength bridge steel plate is met, and stable batch economical production of the bridge steel plate with the thickness of 6-64 mm is achieved.

This invention discloses an isotropic bridge steel with low yield strength ratio and high toughness, and its manufacturing method. Its chemical composition by weight percentage is: C: 0.02–0.05%, Si: 0.25–0.45%, Mn: 1.00–1.40%, P≤0.01%, S≤0.003%, Nb: 0.02–0.05%, Ni: 0.40–0.70%, Cu: 0.25–0.45%, Mo: 0.10–0.20%, Cr: 0.50–0.80%, Ti: 0.005–0.02%, B: 0.001–0.0025%, Al: 0.01–0.04%, CEV: 0.36–0.52%, Pcm: 0.13–0.20%, I≥6.30, with the balance being iron and unavoidable impurities. The steel of this invention has excellent weather resistance and weldability, uniform overall plate performance, and minimal differences in transverse and longitudinal properties.

The application provides a kind of low yield ratio 500MPa grade marine atmospheric corrosion resistant steel and its manufacturing method, steel plate composition is according to percentage by weight: C:0.04%~0.06%, Si:0.10%~0.30%, Mn:0.60%~0.80%, P≤0.012%, S≤0.005%, Ni:2.5%~3.0%, Cu:0.35%~0.75%, Mo:0.35%~0.55%, Nb:0.03%~0.04%, Ti:0.006%~0.03%, Al:0.015%~0.040%, the balance is iron and inevitable impurities.The said component satisfies 24≤15[Mo]+ 6[Ni]+ 5[Cu]≤26, Pcm Value (%) ≤0.198%. The production method of the steel plate includes smelting, slab continuous casting, slab heating, controlled rolling, controlled cooling, heat treatment, the yield strength of the above-mentioned steel plate is greater than or equal to 500MPa, the tensile strength is greater than or equal to 630MPa, the elongation after fracture is greater than or equal to 18%, the impact energy at-80 ℃ KV 2 The steel plate can be used without coating under the condition that the thickness of the steel plate is less than or equal to 64mm, the chloride ion deposition amount is not higher than 0.61mdd.

The present invention relates to a low yield ratio marine steel having a yield strength of ≧750 MPa, the chemical composition of which is 0.06%-0.10% C, 0.1%-0.2% Si, 0.60%-1.0% Mn, P≦0.015%, S≦0.005%, 0.62%-1.20% Cu, 0.20%-0.50% Cr, 0.50%-1.20% Ni, 0.30%-0.70%, Nb≦0.06%, 0.02%-0.05% V, Ti≦0.02%, Al≦0.04%, and the balance being Fe and impurities, and a method for producing the same. In this invention, by using Cu-Mo-Nb-V-Ti composite strengthening and adjusting the controlled rolling and controlled cooling parameters, the microstructure of the steel plate is a mixed structure of martensite-bainite-nanoscale precipitates, which has high strain strengthening ability, low yield ratio, and good weldability. In this invention, the TMCP process is adopted, which has low manufacturing cost and high efficiency.

Provided are a square steel pipe having high strength, a low yield ratio, and excellent low-temperature toughness, a method for manufacturing the same, and a building structure having excellent earthquake resistance even in a low-temperature environment. Provided is a square steel pipe having flat plate parts and corner parts, the square steel pipe having a predetermined component composition, and containing, in a location at the center of the plate thickness of the flat plate parts, 80-95% ferrite by area ratio and a total of 5-20% by area ratio of at least one selected from the group consisting of pearlite, pseudo pearlite, and upper bainite, and having a microstructure in which the average crystal grain size df of ferrite is 5.0-20.0 µm, the average crystal grain size dp of pearlite and pseudo-pearlite is 3.0-18.0 µm, the ratio dp / df of dp to df is 0.60-1.00, and the total number density of pearlite and pseudo pearlite is 2,000 / mm2 or greater.