7372 results about "Sheet steel" patented technology

The invention provides automobile steel with low cost and high strength ductility balance and a preparation method thereof, belonging to the technical field of automobile steel. A multiphase, metastable and multiscale M<3> type organization structure is obtained based on reasonable design of chemical composition and partition of alloy elements and crucially based on the control of martensite phasetransformation, the repartition of solute such as C/Mn and the like and the austenite inverse phase transformation. The invention is characterized in that the martensite structure is obtained by using 0.02-0.50 wt%C and 3.50-9.00 wt%Mn in the cooling process of the inductrial production of steel plates and steel coils and the like; and superfine adverse transformation austenite and alpha phase substrate can be obtained through the partition of Mn and C in the heat preserving process between 100 DEG C below Acl and Acl, thus realizing the industrial production of hot rolled sheets and cold rolled sheets with high strength ductility balance used in automobiles. The invention has the advantages that the intensity is 0.7-1.3 GPa, the extension rate is 55-30% and the strength ductility balanceis 35-55 GPa%.

The present invention provides a weather resistant steel plate, which comprises components of, by mass percent, 0.02 to 0.10 of C, 0.10 to 0.40 of Si, 1.0 to 1.6 of Mn, less than or equal to 0.025 of P, less than or equal to 0.015 of S, 0.20 to 0.50 of Cu, 0.30 to 0.60 of Cr, 0.10 to 0.50 of Ni, less than or equal to 0.40 of Mo, less than or equal to 0.060 of Nb, less than or equal to 0.060 of V,0.010 to 0.035 of Ti, less than or equal to 0.0030 of B, less than or equal to 0.0050 of Ca, 0.015 to 0.050 of Al, and the balance Fe and other unavoidable impurities. Correspondingly, the present invention also provides a manufacturing method of the weather resistant steel plate. Through reasonable distribution ratio of alloy components, the method provided in the invention can obtain a high-strength and high-toughness weather resistant steel plate with good corrosion resisting performance, high yield strength and tensile strength, and excellent low temperature impact toughness. The steel plate also possesses good weldability, being able to carry out welding without preheating or employ lower preheating temperature welding. The steel plate provided in the invention can be widely applied to large-scale steel structure engineering such as building structures, bridges, etc.

A coated steel material excellent in corrosion resistance and a method of producing the same, wherein a coated steel material has on the surface of the steel sheet a Zn-alloy coating layer containing 1-10 wt % of Mg, 2-19 wt % of Al and 0.01-2 wt % of Si, where Mg and Al satisfy Mg (%)+Al (%)<=20%, the balance being Zn and unavoidable impurities, and has a coating layer structure of a Mg intermetallic compound or the like. As a base metal treatment, it is preferably provided with a Ni coating layer. The coated Zn-alloy coated steel sheet may have provided on the coating layer, as an intermediate layer, a chromate film layer, and, as an upper layer, an organic coating layer. The Zn-alloy coating layer may further contain one or more of 0.01-1 wt % of In, 0.01-1 wt % of Bi and 1-10 wt % of Sn. The coated steel material may be painted.

A hot-dip galvanized steel sheet having both high strength and good formability. A process for producing said hot-dip galvanized steel sheet without requiring additional steps of surface grinding and pre-plating.The hot-dip galvanized steel sheet is produced by forming a hot-dip galvanizing layer on a base cold-rolled steel sheet composed of C (0.02-0.20 mass %), Mn (1.50-2.40 mass %), Cr (0.03-1.50 mass %), Mo (0.03-1.50 mass %), 3Mn+6Cr+Mo (no more than 8.1 mass %), Mn+6Cr+10 Mo (no less than 3.5 mass %), Al (0.010-0.150 mass %), and Fe as the principal component, with Ti limited to 0.01 mass % or less, Si limited to 0.04 mass % or less, P limited to 0.060 mass % or less, and S limited to 0.030 mass % or less, and said base steel sheet having the composite microstructure composed mainly of ferrite and martensite.

The invention relates to weathering steel with the yield strength of 550MPa level and the advantages of excellent toughness and high corrosion resistance, and a manufacturing method thereof. The weathering steel comprises the following components: 0.02 to 0.08wt% of C, 0.15 to 0.55wt% of Si, 0.2 to 1.0wt% of Mn, less than or equal to 0.01wt% of P, less than or equal to 0.006wt% of S, 0.2 to 0.5wt% of Cu, 2.5 to 7.0wt% of Cr, 0.2 to 1.2wt% of Ni, 0.02 to 0.06wt% of Nb, 0.01 to 0.05wt% of Al, less than or equal to 0.05wt% of N, 0.01 to 0.10wt% of Ti and the balance of Fe and the unavoidable impurities. The steel plate made of the steel has the yield strength more than 550MPa and excellent toughness, and the relative corrosion rate is simultaneously reduced by one time on the basis of the traditional weathering steel so as to satisfy the requirement of enhancing the corrosion resistance of the steel for railway vehicles and reach the purposes of prolonging the service duration and reducing the maintenance cost.

The invention discloses a mould for manufacturing a fissure surface of a rock like test block. The mould comprises a sliding groove, a sheet steel locating rod, a protractor, a sliding rod and a sheet steel, wherein the sliding groove is a long strip type metal component provided with a straight groove hole; the sheet steel locating rod is a metal rod; the sliding rod is a metal rod marked with ascale; a sheet steel fixing sheet is a hard sheet provided with a notch and stuck on the bottom surface of the test block mould; the sliding groove is fixed on the top of the side wall of the test block mould; the sheet steel locating rod is fixed above the sliding groove; the circle centre of the protractor passes through any bolt and is fixed above the sheet steel locating rod; the sliding rod passes through holes at two ends of the sheet steel locating rod and is vertical to the sheet steel locating rod; one end of the sheet steel is fixed in a through groove of the sheet steel locating rod; and the other end of the sheet steel is clamped in the notch of the sheet steel fixing sheet. The mould disclosed by the invention is capable of conveniently and rapidly adjusting parameters of thefissure surface of the test block, such as an inclination angle, an interval, a communication rate and the like. The mould is easy to process and can be repetitively utilized, thus, the manufacture efficiency and the precision of the test block are increased.

The invention relates to a process for producing an ultra-thick plate and belongs to the field of rolling and producing an ultra-thick steel plate in the metallurgical industry. The invention mainly overcome the defect of producing the ultra-thick steel plate by a traditional model casting manufacturing blank and an electro-slag remelting manufacturing blank. The method comprises the following steps: cutting and fixing lengths of the blanks, mechanically conditioning the blanks (eliminating, leveling and cleaning a single-surface oxide layer of a casting blank with a milling machine, a planer or a shot blast); clamping an assembly (relatively superposing the cleaning surfaces of the two blanks after processing, placing the two blanks oppositely and clamping the blanks); mounting the blanks in a vacuum chamber of an electronic beam welding machine for purpose of vacuuming; sewing the assembly on the electronic beam welding seal edge, heating the assembly in a furnace and rolling the assembly through temperature control; and then producing the ultra-thick steel plate. Compared with the traditional electro-slag remelting production process, the process has the advantages of high production efficiency, reduced electric power consumption, less investment of production devices and low production cost. Compared with the traditional die casting production process, the process solves the problem of segregation and looseness of a large-scale die casting ingot center part; the finished product ratio is high; and the finished product ratio of blank assembly is over 90 %.

The invention proposes a high-strength dual-phase cold rolled steel sheet having an excellent deep drawability, wherein the steel sheet has a composition comprising C: 0.01-0.08 mass %, Si: not more than 2.0 mass %, Mn: not more than 3.0 mass %, P: not more than 0.10 mass %, S: not more than 0.02 mass %, A1: 0.005-0.20 mass %, N: not more than 0.02 mass % and V: 0.01-0.5 mass %, provided that V and C satisfy a relationship of 0.5xC/12<=V/51<=3xC/12, and the remainder being Fe and inevitable impurities, and has a microstructure consisting of a ferrite phase as a primary phase and a secondary phase including martensite phase at an area ratio of not less than 1% to a whole of the microstructure and a high-strength dual-phase galvanized steel sheet comprising a galvanized coating on the above steel sheet as well as a method of producing the same.

The invention is a technique for strongly integrating a galvanized steel sheet and a resin molded article. A hot-dip galvanized steel sheet “Z18” is immersed in an aqueous solution for aluminum degreasing at 75° C. for 7 minutes, to form roughness having an RSm of 0.8 to 2.3 μm and an Rz of 0.3 to 1.0 μm on the surface. The surface is covered with convex protrusions having a diameter of about 100 nm, and a chromate treatment layer appears in the surface. In other words, three conditions suitable for bonding are satisfied thereby. A resin composition comprising 70 to 97 wt % of polyphenylene sulfide and 3 to 30 wt % of a polyolefin resin is injected onto the surface. The resin composition penetrates into ultra-fine irregularities and is cured in that state, whereby a composite in which the galvanized steel sheet and the resin molded article are strongly integrated is obtained. The shear rupture strength of the composite is extremely high, in excess of 20 MPa.

The invention provides a high-strength cold-rolled plate with favorable forming property and a preparation method thereof. The high-strength cold-rolled plate comprises the following chemical components: 0.05-0.6% of C, being more than or equal to 0.3% and being less than 0.8% of Si, 0.5-4.0% of Mn, being more than ore equal to 0.2% of P, being more than or equal to 0.002% of S, being more than or equal to 0.1% of Al, being more than or equal to 0.01% of N, and the balance of Fe and inevitable impurities. The preparation method comprises the following steps: smelting, continuous-casting, hot-rolling, cold-rolling and continuous-annealing, wherein annealing temperature is higher than that of Ac3, holding time is 3-30 minutes; quickly cooling to 100-600 DEG C at the rate of 30-100 DEG C/s, keeping the temperature for 3-30 minutes, and finally cooling to room temperature at the rate of 5-30 DEG C/s. The invention adopts low-silicon low-aluminum component design and heat treatment technique; the strength level of the produced bainite TRIP steel is greater than 780 MPa; and the produced bainite TRIP steel has favorable strength, plasticity, extensibility, chambering property and coating property.

The invention provides 1,000 MPa cold-rolled hot-dip galvanized dual-phase steel and a manufacturing method thereof, belonging to the technical field of cold-rolled hot-dip galvanized high-strength steel plates. The chemical components in mass percentage of the cold-rolled hot-dip galvanized dual-phase steel are: 0.06 to 0.18 percent of C, less than or equal to 0.1 percent of Si, 1.2 to 2.5 percent of Mn,0.05 to 0.5 percent of Mo, 0.05 to 0.6 percent of Cr, 0.005 to 0.05 percent of Al, 0.01 to 0.06 percent of Nb, 0.01 to 0.05 percent of Ti, less than or equal to 0.02 percent of P, less than or equal to 0.01 percent of S, less than or equal to 0.005 percent of N, the balance being Fe and inevitable impurities. The manufacturing method adopts Cr or Mo to replace Si, so as to enlarge an austenitic and ferritic two-phase region and improve the hardenability of the dual-phase steel, and meanwhile, the manufacturing method improves the strength of toughness of the steel by adding Nb or Ti refined grains, so as to ensure that the steel has good weldability and usability, and the strength grade of the steel can reach over 1,000 Mpa.

Disclosed is a dual-phase steel sheet having low yield ratio, excellent in the balance for strength-elongation and for strength-stretch flange formability, and also excellent in bake hardening property containing (on the mass% basis). C: 0.01-0.20%, Si: 0.5% or less, Mn: 0.5-3%, sol. Al: 0.06% or less (inclusive 0%), P: 0.15% or less (exclusive 0%), and S: 0.02% or less (inclusive 0''), and in which the matrix phase contains tempered martensite; tempered martensite and ferrite; tempered bainite; or tempered bainite and ferrite, and the second phase comprises 1 to 30% of martensite at an area ratio based on the entire structure.

The invention belongs to the field of welding, in particular to a process method applicable to marine engineering large thick steel plate submerged arc welding in low-temperature environment, which comprises a welding method, welding material selection, a welding order, a welding process and the selection and control of various welding process parameters. The method renders with carbon dioxide gas protection welding, and fills and faces through an automatic submerged arc welding; stops welding when the welding reaches more than two thirds of the thickness of a large groove during the welding process, clears chips on the back side and completes the welding of the other side; finally completes the welding of the first side; strictly controls all relevant process parameters of the welding during the welding process, and solves the problems of poorer anti-crack toughness of welding seams and heat affected zones caused by too high cooling speed of the welding seams and too high temperature; can ensure good anti-crack toughness of a welding seam connector without heat treatment after welding; and can meet the requirements of welding of an E36 plate with the thickness of 35 to 77mm under the working environment at the temperature of above -30DEG C, simplifies the production process, shortens the production cycle and reduces the cost.

The invention provides a production method of an ultrahigh strength steel plate for cold forming and the steel plate. The method comprises the steps of smelting, casting, hot rolling, cold rolling, heating the cold-rolled steel plate through a continuous annealing production line with rapid cooling treatment to the austenite temperature, holding the temperature for a certain time, carrying out quenching treatment, obtaining a steel plate with the main structure of M+A and carrying out distribution treatment in a bell type annealing furnace. The steel plate comprises the following components in percentage by mass: 0.02-0.60% of C, 0.05-3.5% of Si, 0.20-3.50% of Mn, P more than or equal to 0.005 but less than or equal to 0.50%, S not more than 0.05%, 0.02-3.00% of Al, Cr not more than 0.50%, Ni not more than 3.00%, Cu not more than 0.50%, Mo not more than 1.50%, V not more than 0.50%, Ti not more than 0.20%, Nb not more than 0.20% and the balance of Fe and unavoidable impurities. The steel plate produced by adopting the method provided by the invention has the advantages of high strength and capability of cold forming and the process route of Q&P steel industrial production is effectively solved.

The invention relates to a steel plate surface polishing device, in particular to a steel plate surface polishing device for hardware machining. The steel plate surface polishing device for hardware machining aims to achieve the technical purposes that manual labor is not needed, the requirement for professional operation skills is not high, operation is easy, the price-performance ratio is high, the safety coefficient is high, and harm of the operation environment to health of operators is small. In order to achieve the technical purposes, the steel plate surface polishing device for hardware machining comprises a bottom plate, a first sliding rail, a first sliding block, a collection tank, a fixing stop block, a spring, a supporting rod, a first bearing pedestal, a first air cylinder, a disc and the like, wherein the first sliding rail is arranged in the middle of the top of the bottom plate. Through ingenious cooperation of the components, the effects that manual labor is not needed, the requirement for professional operation skills is not high, operation is easy, the price-performance ratio is high, the safety coefficient is high, and harm of the operation environment to health of the operators is small are achieved.

The invention belongs to the field of roll steel, in particular to a low-yield strength anti-ageing continuous annealing cold-roll steel sheet and a production method thereof, which solves the technical problem that stable-performance low-yield strength anti-ageing cold-roll steel sheets are difficult to be produced on a machine set with worse equipment level. The technical scheme of the invention is characterized by providing the low-yield strength anti-ageing cold-roll steel sheet and the production method thereof. The method of the invention can be implemented on the machine set with worse equipment level; and by adopting the method of the invention, the stable-performance low-yield strength anti-ageing cold-roll steel sheet can be produced, and the technical problem existing in the field of roll steel for a long term can be overcome.

The invention provides a kind of hot-rolled double-sided enamel-used nickelclad, the chemical components of which is: C 0.02%-0.06%, Si <=0.50%, Mn 0.15%-0.40, P <=0.15%, S <=0.006%, N<=0.003%, Ti 0.08%-0.20%, Als 0.005%-0.055%, Ti/C 2.2-5,unavoidable impurities and Fe as balance. The architecture of the nickelclad is ferrite with grain diameter = 2 mum-20 mum under hot rolling conditions, and TiC particles (diameter < 20nm is uniformly distinguished in the architecture. V 0.015%-0.060% and/or Cr 0.05%-0.20% can also be added. The production method of the clad is: producing unburnt earthenware with continuous cast method, heating to 1180-1260DEG C, descaling with high-handed water, rough rolling, finish rolling for 5-7 passes at 1100-960 DEG C and finally at 920DEG C-840DEG C, continuously cooling to 450- 630DEG C at a speed of >=30DEG C/S in 0-7S, and coiling. The nickelclad has the advantages of good performance and high strength, and can meet the requirement of large scaled engineering fembers.

The invention discloses a low-welding crack sensitivity steel board and manufacturing method, which comprises the following parts: not more than 0.07% C, 0.15-0.40% Si, 1.00-1.60% Mn, not more than 0.015% P, not more than 0.010% S, not more than 0.30% Cu, not more than 0.50% Ni, not more than 0.30% Cr, not more than 0.30% Mo, not more than 0.08% V, not more than 0.08% Nb, 0.010-0.020% Ti, not more than 0.003% B, Fe and inevitable impurity. The invention is characterized by the following: (1)displaying lower welding crack sensitivity component with Pcm not more than 0.20%; (2)mating the strength and flexibility reasonably with fitful yielding ratio; (3)making the price and property of the steel board superior to the congeneric import product; (4)making the maximum breadth of steel board to 4000mm; (5)simplifying the technique to ensure higher flatness without quenching water.

The invention discloses a controlling method of iron oxide sheet of rolled band steel surface of middle-thin board blank, which is characterized by the following: controlling component; proceeding heat load directly; heating to remove phosphor; rolling under high temperature; forcing to cool; controlling Si content in the steel; eliminating red ferric oxide on the surface of heat roll steel; fitting for the steel with not more than 0.18%C, not more than 0.20% Si, not more than 1.50% Mn, not more than 0.015% P, not more than 0.01% S and Nb, V and Ti.

Disclosed are an ultra-high-strength steel sheet having both a tensile strength of as high as 1400MPa or above and excellent formability and an advantageous process for manufacturing the same. A high-strength steel sheet having both a composition which contains by mass C: 0.12 to 0.50%, Si: 2.0% or less, Mn: 1.0 to 5.0%, P: 0.1% or less, S: 0.07% or less, Al: 1.0% or less, and N: 0.008% or less with the balance being Fe and unavoidable impurities, and a structure which comprises, in terms of area fraction, autotempered martensite: 80% or more, ferrite: less than 5%, bainite: 10% or less, and retained austenite: 5% or less and in which the average number of precipitated iron carbide particles of 5nm to 0.5[mu]m in the autotempered martensite is 5OE04 or above per mm2.

The present invention provides, in a hot dip plating system having an annealing furnace for hot dip plating steel sheet containing Si, a continuous annealing and hot dip plating method and system causing internal oxidation without causing surface oxidation of the Si in the steel and avoiding a drop in the plating ability of the steel sheet and retardation of alloying, that is, a continuous annealing and hot dip plating method using an annealing furnace having, in order, a front heating zone, rear heating zone, soaking zone, and cooling zone and a hot dip plating bath, comprising heating or soaking the steel sheet at a steel sheet temperature of a temperature range of at least 300° C. or more by indirect heating, making an atmosphere of the zones one comprised of hydrogen H: 1 to 10 vol % and a balance of nitrogen and unavoidable impurities, making a steel sheet peak temperature during heating at the front heating zone 550 to 750° C. and making the dew point less than −25° C., making dew points of the following rear heating zone and soaking zone −30° C. to 0° C., and making a dew point of the cooling zone less than −25° C.

The invention relates to a pressure cooker, in particular to an electrical pressure cooker, which comprises an upper cover, a sealing ring, an internal bladder, an external bladder, a shell and a controller. The sealing ring is mounted on the upper cover; the sealing ring seals the upper cover and the external bladder after the upper cover covered the shell; a steam communicating device is arranged between the two bladders. The invention has rational structure design with the internal bladder be made of aluminium, iron, ceramic and red porcelain material for it is free from being limited by pressure and the external bladder made of thick steel plate, which largely enhances the pressure beared and realizes the real high temperature and pressure. It is proved by experiment that the invention can fulfill the requirement of the traditional pressure cooker of 80KP to 100 KP. Besides, a pressure sensor of the invention is quick for sensing the pressure and rapid and precious for transferring signals together that the installation of the pressure sensor has no requirement, thus rapidly improving the production efficiency of the overall machine and also the safety and prolonging the service life. The external bladder can deduce the temperature and pressure quickly and the upper cover can be opened safely in short time.

The invention provides a hot rolled steel plate with excellent low-temperature toughness for a thick submerged pipeline and a production method of the hot rolled steel plate. The hot rolled steel plate comprises the following chemical components by weight percentage: 0.02%-0.07% of C, 0.15%-0.40% of Si, 1.0%-1.70% of Mn, less than or equal to 0.020% of P, less than or equal to 0.003% of S, less than or equal to 0.06% of Nb, less than or equal to 0.025% of Ti, less than or equal to 0.06% of V, less than or equal to 0.20% of Mo, less than or equal to 0.25% of Cu, 0.10%-0.30% of Ni, less than orequal to 0.25% of Cr, less than or equal to 0.008% of N, 0.010%-0.040% of Al, more than or equal to 2 of Al/N and the rest Fe and inevitable impurities. According to the steel for the submerged pipeline with the thickness being over 28mm, disclosed by the invention, the transversal and longitudinal bending strength can reach over 480MPa or 510MPa, the transversal and longitudinal tensile strengthcan reach over 560MPa or 600 MPa, the transversal impact toughness at the temperature of 60 DEG below zero is larger than or equal to 400 J, the transversal DWTT (Drop-Weight Tear Test) shearing areaat the temperature of 25 DEG C below zero is larger than or equal to 85%, simultaneously, the corrosion resistant of the steel plate is excellent, and the result of a 96-hour HIC (Hydrogen Induced Cracking) test conforms to the requirements of the standard 0284 of the NACE (National Association of Corrosion Engineers). The hot rolled steel plate is suitable to be as a raw material for manufacturing a pipeline for submerged oil and gas transmission.

The invention provides a high strength cold-rolled plate with excellent formability, containing: no more than 0.0040% of C, 0.02-0.15% of Si, 0.20-1.00% of Mn, 0.02-0.09% of P, 0.015-0.06% Ti, 0.01-0.05% of Nb, and the rest being Fe. The production method comprises: smelting, continuous casting, hot-rolling, cold rolling and continuous annealing, wherein the heating temperature of the hot-rolled billet is 1170-1270 DEG C, the finishing temperature of hot-rolling is 850-960 DEG C, and the coiling temperature is 650-760 DEG C; the cold rolling reduction percent is 60-82%; the annealing temperature is 760-880 DEG C, the thermal insulation time is 60-210s, the slow-cooling segment temperature is 630-700 DEG C, and the fast-cooling exit temperature is 300-500 DEG C; and the levelling elongationrate is 0.5-1.0%. The high strength steel plate containing phosphorus of the invention has the features of low carbon, microalloying and purity. The steel added with a certain amount of Nb and Ti hashigher plasticity. Using relevant rolling and annealing technique, the indexes of performance of the steel achieves the demand of high strength automobile stamping parts.

The invention provides a high-strength cold rolling transformation induced plasticity steel plate and a preparation method thereof. The high-strength cold rolling transformation induced plasticity steel plate comprises the following components by weight percentage: 0.1%-0.5% of C, 0.1%-0.6% of Si, 0.5%-2.5% of Mn, 0.02%-0.12% of P, less than or equal to 0.02% of S, 0.02%-0.5% of Al, less than or equal to 0.01% of N, 0.1%-1.0% of Cu and the rest Fe. The preparation method comprises the following steps of: (a) refining molten steel meeting a component condition, and casting into a blank; (b) rolling, wherein the heating temperature is 1,100-1,250 DEG C, the heat preservation time is 1-4h, the initial rolling temperature is 1,100 DEG C, the final rolling temperature is 750-900 DEG C, the coiling temperature is less than 700 DEG C, the thickness of a hot rolled steel plate is 2-4mm, and the cold rolling accumulated pressing amount is 40-80%; and (c) continuous annealing, wherein the annealing temperature is 700-Ac3+50 DEG C, the heat preservation time is 30-360s, the cooling speed is 10-150 DEG C/s, the aging temperature is 250-600 DEG C, the aging time is 30-1,200s, and the hot roller steel plate is cooled at the speed of 5-100DEG C/s to be at the room temperature. The steel plate disclosed by the invention has the bending strength of 380-1,000 MPa, tensile strength of 680-1,280 MPa and elongation of 15-30%.

A method for root pass welding steel plate and pipe is provided that uses pulse arc welding having a current pulse waveform exhibiting a low constant background current and fixed frequency. The welding process may be performed without a backer or backing material.

The invention discloses a hot galvanizing steel plate for a car. The hot galvanizing steel plate comprises the following chemical components by weight: C is more than or equal to 0.001% and is less than or equal to 0.003%, Mn is more than or equal to 0.05% and is less than or equal to 0. 15%, Si is less than or equal to 0.03%, P is less than or equal to 0.02%, S is more than or equal to 0.008% and is less than or equal to 0.015%, Alt is more than or equal to 0.02% and is less than or equal to 0.07%, Ti is more than or equal to 0.05% and is less than or equal to 0.09%, B is more than or equal to 0.0002% and is less than or equal to 0.010%, N is less than or equal to 0.004% and the balance of Fe and trace element. The invention also discloses a method for producing the hot galvanizing steel plate for the car; according to the hot galvanizing steel plate for the car and the production method of the hot galvanizing steel plate, the sulfur content in steel making can be adjusted based on the mixture ratio of components, and the technology of hot rolling, continuous annealing, hot galvanizing steel and finishing are optimized, thus producing the continuous annealing hot galvanizing steel, so that the steel plate has the characteristics of high processing hardening index of n90 value, and the requirements on demand of expanding-formed car plate are satisfied.

Steel sheet having organic coating comprises: a zinc or a zinc alloy plated steel sheet or an aluminum or an aluminum alloy plated steel sheet; a composite oxide coating formed on the surface of the plated steel sheet and containing at least one metal selected from the group consisting of Mn and Al; and an organic coating formed on the composite oxide coating and containing a rust-preventive additive component.

The present invention provides a hot press method used for producing a high-strength member for an automobile and, in particular, a part which requires high-strength, such as an undercarriage component of an automobile. More specifically, the present invention provides an aluminum plated steel sheet or an aluminum-zinc plated steel sheet suitable for high temperature forming (hot forming) wherein high strength is obtained after high temperature forming, and a method of producing the same. Also, the present invention provides a hot dip aluminum plated steel sheet which suppresses the alloying reaction of a plated layer during press forming and has beautiful appearance, and an aluminum-system plated steel sheet for hot press having excellent after-painting corrosion resistance. Concretely, the present invention is a high-strength aluminum-system plated steel sheet excellent in heat resistance and after-painting corrosion resistance, characterized by having an Fe-Al-system coating containing, in mass, Mn and Cr of more than 0.1% in total on the surface of the steel containing, in mass, C: 0.05 to 0.7%, Si: 0.05 to 1%, Mn: 0.5 to 3%, P: not more than 0.1%, S: not more than 0.1% and Al: not more than 0.2%, and, in addition, one or more element(s) selected from among Ti: 0.01 to 0.8%, Cr: not more than 3% and Mo: not more than 1%, so as to satisfy the following expression (1): Ti + 0.5xMn + Cr + 0.5xMo > 0.4 ... 1

The invention belongs to construction field and relates to a self-resetting frame joint. The self-resetting frame joint comprises a concrete beam (1) and a concrete column (2). The concrete beam (1) and the concrete column (2) are connected through an unbonded low-relaxation prestressed steel strand (3) and an angle steel (9), a third steel pate (8) is disposed at the ends of the concrete beam (1), a first steel plate (5) is disposed on the place of the concrete column (2) near the beam side, a second steel plate (7) is disposed on the place of the concrete column (2) facing away from the beam side, and the unbonded low-relaxation prestressed steel strand (3) passing through the third steel pate (8) of beam ends and the first steel plate (5) of the column side is anchored in the outer side of the second steel plate (7) of the column side through an anchorage (10). The concrete beam (1) and the concrete column (2)are respectively connected with the angle steel (9) through a screw (4) and a nut (5), and the first steel plate (5) contacts with the third steel plate (8). The self-resetting frame joint has the advantages of stable structure under small earthquakes, large deformation structure with no damage under strong earthquakes, and self-resetting structure after earthquakes.