106 results about "High-strength low-alloy steel" patented technology

A composition and method of making a high-strength low-alloy hot-rolled steel sheet, strip, or plate bearing titanium as the principal or only microalloy strengthening element. The steel is substantially ferritic and has a microstructure that is at least 20% acicular ferrite. The steel has a minimum yield strength of at least 345 MPa (50 ksi) and even over 621 MPa (90 ksi) adding titanium as the lone microalloy element for strengthening, with elongation of 15% and more. Addition of vanadium, niobium, or a combination thereof can result in yield strengths exceeding 621 MPa (90 ksi). Effective titanium content, being the content of titanium in the steel not in the form of nitrides, oxides, or sulfides, is in the range of 0.01 to 0.12% by weight. The manufacturing process includes continuously casting a thin slab and reducing the slab thickness using thermomechanical controlled processing, including dynamic recrystallization controlled rolling.

Disclosed is a low alloy steel drug core welding wire used in the carbon dioxide arc welding. The components of the drug core and the content occupying the total weight of the welding wire(percent ratio) are as following: Ti01 3-6, Si 0.3-0.5, Mn 1.5-3.2, Si02 0.1-0.8,Zr02 0.1-0.5, Fe 2-7, Al plus Mg 0.5-1.2, Ni 0.5 -5, B 0.002-0.015, Ti 0.1-0.3; oxide or fluoride of alkali metal K, Na and Li is converted into the content of K, Na and Li, that is, 0.1-0.35; the content of fluoride F is 0.05-0.2; fluoride or oxide of rare earth metal is converted into the content of the rare earth metal, that is, 0.005-0.2; the product of the contents of C, Si and Mn in the welding wire is 0.058-0.11. The invention has good process property for the whole position welding of high strength low alloy steel, and can keep good stability of electric arc and welding operating property in the conditions of large current and fast-speed welding with smooth welding seam, high connecting intensity, good impact toughness minus 40 DEG C low temperature and good crack resistance.

The invention provides a high strength low alloy steel plate suitable for high heat input welding and is characterized in that the chemical composition (wt percent) of steel comprises 0.04 percent to 0.16 percent of C, 0.10 percent to 0.50 percent of Si, 0.40 percent to 1.8 percent of Mn, 0.020 percent to 0.050 percent of Nb, 0.006 percent to 0.030 percent of Ti, 0.0030 percent to 0.010 percent of N, 0.015 percent to 0.060 percent of Al and the rest, Fe and other inevitable impurities; meanwhile, C+Mn/6+Si/24+Ni/40+Cr/5+Mo/4+V/14 is less than or equal to 0.45 percent and the total amount of Ti and the total amount of N are that [Ti percent]T is more than or equal to 2.667[N percent]T-0.004667 percent; moreover, Ti microalloying is adopted to ensure that the Ti/N ratio in the second sort of particle generated ranges between 2.4 and 3.2. The manufacture method of the steel plate adopts austenite recrystallization zone and austenite non-recrystallization zone rolling and forced water cooling after rolling; moreover, when the steel plate is under 50 KJ/cm to 150 KJ/cm high heat input welding, the welding heat affected zone has excellent toughness. The invention has the advantages of simple production process, low cost and wide applicability.

The invention relates to a pearly high-strength low-alloy steel rail iron and manufacturing method. Its chemical composition percentage by weight includes: C:0.70-0.95%, Si:0.20-1.10%, Mn:0.50-1.50%, V:0.01-0.20%, Cr:0.15-1.20%, P: not less than 0.035%, S:not less than 0.035%, and Al: not less than 0.005%. The method includes the following steps: smelting; adding carburant and alloy; vacuum processing; billet heating; rolling; and cooling. The cooling speed is not more than 4.0 centigrade degree per second. The formed steel rail has good ware resistance and welding property. The method has simple technology and convenient operation.

Process for hot rolling of high-strength low-alloy steel cast in Compact Strip Production as a thin slab. The strain and temperature at initial roll stands where deformation occurs allows full recrystallization, and at latest roll stands where deformation occurs there is no recrystallization. Deformation is absent at strains and temperatures where partial recrystallization would occur, allowing increased recrystallization over conventional CSP rolling. The result may be beneficial for microalloyed high-strength low-alloy steel in permitting accurate ultrasonic testing of welds. The time allowed between deformation at passes through roll stands may be increased by eliminating deformation at one or more central roll stands. Combined with increased strain at the initial roll stands where the temperature of the steel is in the full recrystallization region, the process may result in a relatively fine and uniform austenite grain size.

The invention relates to a method for producing high-strength low-alloy steel. Wherein, it comprises smelting, refining, casting sheet blank, heating blank, removing phosphor, cooling and flattening; the smelting step uses pure steel, low phosphor, and low sulfur; in the casting step, the loose of blank and the aliquation are lower than B0.5level; in the heating step, vanadium+niobium+ titanium0.15%, nickel+chromium+copper<=0.50%, and the heating temperature is 1180-1220Deg. C; in the thermal rolling step, in the crystallize process, the deformation temperature is 1070-1000Deg. C, the deformation amount is 40-60%, and the rolling speed is 1.5-2.5m/s, and in the second step that rolling the non-crystallized area, the pressure is 200-400MPa, the rolling speed is 5-1.5m/s, and the deformation amount is 60-75%; and the interlayer cooling speed in the cooling step is 15Deg. C/s-25Deg. C/s.

The present invention discloses a straight-curved type casting machine low-alloy steel slab continuous casting full-rolling section narrow face cooling method, and is aimed at solving the problem of that on the casting blank surface corner portion of low-alloy steel the transverse crack can be easily produced. Said invention belongs to the field of metal continuous casting blank cooling and surface quality control technology. Said method is characterized by that in the full-rolling section of continuous casting straight-curved type casting machine slab said invention utilizes the nozzles which are symmetrically mounted at left side and right side of casting blank pouring direction to cool the narrow face of said casting blank, and adopts rectangular nozzles to symmetrically and simultaneously cool the narrow faces of left and right two sides of casting blank. Said invention also discloses a kind of rectangular nozzle for said method, the water outlet hole of its sprayer is a hole with rectangular section. Said invention can reduce casting blank cooling strength of full-rolling section under the crystallizer and can improve casting blank cooling uniformity, so that it can eliminate casting blank surface corner portion transverse crack defect of continuously-cast high-strength low-alloy steel whose steel quality is P510L, P590L, J55 and X52, etc.

The invention is a thick coal bed hydraulic shield support, able to implement synthetic mechanized mining of thick coal beds, comprising top beam, shield beam, seat, column, balancing jack, front link rod, rear link rod, displacive jack and operating valve set, where the top beam and shield beam are equipped with side push jacks, and long and short guide rods inside and equipped with side backplates and hinged mutually; the top and bottom ends of the balancing jack are equipped on the top beam and shield beam, respectively; the top and bottom ends of the column are arranged on the lower part of the top beam and the seat, respectively; the upper ends of the front and rear link rods are hinged at the rear end of the shield beam and the lower ends of them are hinged on the seat; the displacive jack is equipped on the seat; the operating valve set is equipped on the bottom surface of the top beam. And it has large height regulating range and high moving speed, and improves force bearing conditions of the support and prolongs the service life of the support. And the support is made of high-intensity low-alloy steel sheet, small- bulk and lightweight.

The invention discloses a polygonal ferrite-acicular ferrite two-phase steel plate/belt and a production method thereof and belongs to the technical field of high-strength low-alloy steel. The low-alloy steel comprises the following chemical components in percentage by weight: 0.03%-0.12wt% of C, 0.10wt%-1.5wt% of Si, 0.5wt%-2.1wt% of Mn, not more than 0.02wt% of P, not more than 0.01wt% of S, 0.02wt%-0.1wt% of Nb, 0.05wt%-0.45wt% of Mo, the balance being Fe and inevitable impurities. A few alloy elements including 0-0.4wt% of Cu, 0-0.5wt% of Ni, 0-0.5wt% of Cr and the like are added in the low-alloy steel. The production process comprises the following steps of: steel-making, continuous-casting, re-heating, rough-rolling, finish-rolling, cooling, relaxing and preserving the heat and quickly cooling. The polygonal ferrite-acicular ferrite two-phase steel plate/belt has the advantages of high toughness and plasticity in addition to high strength level, and is applicable to the vehicle plate filed and the pipeline steel filed with high requirements on strength, plasticity and toughness.

A side-spray scavenge system for the laminar-flow cooling water on the rolled high-strength low-alloy steel is composed of a conveying roller way for conveying the rolled steel on it, and a laminar-flow cooling unit with at least a group of side sprayers arranged at both sides of said roller way, connected to water inlet tube, and with at least one nozzle.

A 420 MPa-class low-carbon band steel with superfine crystal grains contains C (0.1-0.14 wt.%), Si (0.18-0.40), Mn (0.85-1.10), P (0-0.01), S (0-0.01) and Fe (rest). Its preparing process includes such steps as smelting, conticasting, coarse rolling, fine rolling, cooling, and winding. Its advantages are multi-phase structure including ferrite, bainite and pearlite, high yield strength (420-450 MPa), high tension strength (530-550 MKPa) and low cost. It can replace high-strength low-alloy steel.

An ultralow-hydrogen iron powder coated welding electrode for the high-strength low-alloy steel is composed of welding wire H08A or H08E and the coated layer prepared portionally from Fe powder, CaCO3, CaF2, Ti-Fe, feldspar, Mn powder, Ni powder, Cr-Fe, NaCO3 and sodium-water glass as adhesive.

The invention discloses a coated welding wire for welding low-alloy high-strength steel. The coated welding wire comprises a welding wire substrate and a coating which coats the surface of the welding wire substrate, wherein the welding wire substrate is made from the following components in percentage by weight: 0.029 to 0.041 percent of Ti, 0.01 to 0.015 percent of Al, 0.083 to 0.11 percent of Nb, 0.1 to 0.15 percent of C, 0.2 to 0.3 percent of Cr, 0.3 to 0.5 percent of Si, 0.01 to 0.03 percent of N, 1.4 to 1.7 percent of Ni, 0.1 to 0.6 percent of Mo, less than or equal to 0.002 percent of P, less than or equal to 0.002 percent of S, and the balance of iron and unavoidable impurities, wherein as specified by the following formula, K is between 0.013 and 0.032, K=29[Ti]+52[Al]+27[Nb]-100[N]; [Al], [Ti], [Nb] and [N] represent the weight percentage contents of Al, Ti, Nb and N in the welding wire substrate respectively. The invention further discloses a manufacturing method of the coated welding wire for welding the low-alloy high-strength steel. By adopting the coated welding wire, high strength of welding metal is ensured, the welding performance of the low-alloy high-strength welding wire is improved finitely, the occurrence of cold cracks is controlled, a low splashing rate is achieved, and the welding requirement of the high-strength low-alloy steel is met.

The invention discloses a high-strength low alloy steel force transfer rod. The force transfer rod comprises the following chemical elements in percentage by weight: 0.20-0.24% of carbon, silicon not more than 0.35%, 1.00-1.50% of manganese, nickel not more than 0.35%, 0.35-0.50% of chromium, molybdenum not more than 0.35%, 0.10-0.15% of vanadium, 0.05-0.20% of niobium, copper not more than 0.35%, sulfur not more than 0.035%, phosphorus not more than 0.035%, 0.018-0.025% of nitrogen, and the balance of iron. A coating force transfer rod is adopted; the data under general conditioners shows the initial cost is increased by 25-50% compared with general carbon steel; if accounted by the total project investment, the cost is increased only by 0.49-2.16%; but in consideration of long-time service life, the corrosion-resistant service life can reach 75 years or more; and if the saved maintenance cost at this time is calculated, the economical value is higher, and the force transfer rod is suitable for the national demands of sustainable development.

The invention relates to ultrahigh-strength low-alloy steel and a manufacturing method thereof. The alloy steel comprises the following components in percentage by weight: 0.40-0.42% of C, 0.20-0.30% of Si, 0.65-0.75% of Mn, not more than 0.002% of S, not more than 0.005% of P, 0.75-0.85% of Cr, 0.25-0.28% of Mo, 1.85-1.95% of Ni and the balance of Fe and inevitable impurities. The manufacturing method comprises the following steps: smelting raw materials by an electric furnace, refining outside the furnace, performing vacuum degassing, re-melting electroslag, forging and performing heat treatment to obtain the ultrahigh-strength low-alloy steel. Compared with the prior art, the ultrahigh-strength low-alloy steel manufactured by the manufacturing method provided by the invention has good mechanical properties, wherein the tensile strength Rm is not less than 1800MPa, the yield strength Rp 0.2 is not less than 1400Mpa, and the elongation rate A5 is not less than 10%; and the process for manufacturing the ultrahigh-strength low-alloy steel is simple and easy to operate.

The invention discloses a production method of an electrogalvanized high-strength low-alloy steel plate HC340LA+ZE for an automobile, and belongs to the technical field of steel smelting. The technological process included by the production method comprises the steps of molten steel smelting and plate blank forming through casting, hot continuous rolling, cold continuous rolling, continuous annealing, leveling and electrogalvanizing. Components of molten steel smelting comprise, by mass percent, 0.04%-0.09% of C, 0.10%-0.25% of Mn, 0.02%-0.06% of Al, 0.010%-0.019% of Nb, 0.031%-0.039% of Ti, 0.010%-0.030% of P, not larger than 0.05% of Si, not larger than 0.025% of S, 0.02%-0.09% of Cr, 0.01%-0.08% of Ni and the balance Fe and inevitable impurities. The requirement of HC340LA+ZE steel prepared through the production method for the technology is loose, a product has good impact performance at normal temperature, automobile body deformation during colliding can be reduced, and passengersafety can be ensured.

The invention relates to a vanadium oxide core-spun yarn for smelting vanadium microalloyed steel to increase the vanadium content, belongs to high-strength low-alloy steel, and particularly relates to a vanadium-content-increasing additive for external vanadium microalloyed steel refining. The vanadium oxide core-spun yarn comprises a yarn core and an outer cover, wherein the outer cover is tightly clad on the yarn core. The vanadium oxide core-spun yarn is characterized in that the yarn core is formed by fully mixing 60-75% of powdered vanadium oxide V2O5, 39-24% of a powdered reducing agent (aluminum powder), and the balance being impuritiesby weight percentage; the outer cover is a low-carbon steel strip, and the thickness is 0.32-0.45mm; the core-spun yarn is circular strip-shaped, and the diameter is phi 9-13mm; the weight ratio of the yarn core and the outer cover per meter is 1.16-1.22. The vanadium oxide core-spun yarn is prepared according to the steps of powder preparation, drying, batching, powder stirring, finished product packaging and checking. The vanadium oxide core-spun yarn has the advantages that the design is novel and the technical process of melting ferrovanadium is simplified; energy is saved, the consumption is reduced, and the production cost is reduced; the vanadium recovery rate is obviously improved, the defects of a large amount dust and the environmental pollution are further prevented, and the vanadium oxide core-spun yarn is beneficial to safe production.

Provided is a welding method for connecting the ultra-high strength low alloy steels, in order to obtain weldments with a tensile strength greater than about 900 MPa (130ksi). The welding line metal on the said weldments has a fracture toughness suited to low-temperature applications based on the known the fracture mechanics principle.

A 420 MPa-class low-carbon band steel with superfine crystal grains contains C (0.10-0.14 wt.%), Si (0.18-0.40), Mn (0.85-1.10), P (0-0.01), S (0-0.01) and Fe (rest), and is prepared through smelting, conticasting, heating, rolling twice, cooling and winding. Its advantages are multi-phase structure including ferrite, bainite and pearlite, high yield strength (420-450 MPa), high tension strength (530-550 MPa) and low cost. It can replace high-strength low-alloy steel.

A 520 MPa-class low-carbon band steel with superfine crystal grains contains C (0.12-0.15 wt.%), Si (0.5-0.40), Mn (1.10-1.30), Nb (0.007-0.015), P (0-0.01), S (0-0.01) and Fe (rest), and is prepared through smelting, conticasting, coarse rolling, fine rolling, cooling and winding. Its advantages are multi-phase structure including ferrite, bainite and pearlite, high yield strength (520-270 MPa), high tension strength (630-690 MPa) and low cost. It can replace high-strength low-alloy steel.