Abstract: Dual phase steel sheet is made using a time/temperature cycle including a soak at about 1340-1425F and a hold at 850-920F, where the steel has the composition in weight percent, carbon: 0.02-0.20; aluminum: 0.010-0.150; titanium: 0.01 max; silicon: 0.5 max; phosphorous: 0.060 max; sulfur: 0.030 max; manganese: 1.5-2.40; chromium: 0.03-1.50; molybdenum: 0.03-1.50; with the provisos that the amounts of manganese, chromium and molybdenum have the relationship: Mn+6Cr+10Mo)=at least 3.5%. The sheet is preferably in the form of a strip treated in a continuous galvanizing or galvannealing line, and the product is predominantly ferrite and martensite.

Abstract: A corrosion-resistant coated brass metal coated with a corrosion resistant alloy. The corrosion resistant alloy is a tin metal alloy or a tin and zinc metal alloy. The corrosion resistant metal alloy may also include one or more metal additives to improve the coating process and/or to alter the properties of the tin or tin and zinc metal alloy.

Abstract: Dual phase steel sheet is made using a time/temperature cycle including a soak at about AC1+45° F. to AC1+135° F. and a hold at 850-940F, where the steel has the composition in weight percent, carbon: 0.02-0.20; aluminum: 0.010-0.150; titanium: 0.01 max; silicon: 0.5 max; phosphorous: 0.060 max; sulfur: 0.030 max; manganese: 0.8-2.40; chromium: 0.03-1.50; molybdenum: 0.03-1.50; with the provisos that the amounts of manganese, chromium and molybdenum have the relationship: (Mn+6Cr+10 Mo)=at least 3.5%. The sheet is preferably in the form of a strip suitable for coating in a continuous galvanizing or galvannealing line, and the product is predominantly ferrite and martensite. The strip may be galvanized or galvannealed at a temperature within thirty degrees F. of the temperature of the bath.

Abstract: A corrosion-resistant coated base metal coated with a corrosion resistant alloy. The corrosion resistant alloy includes tin and zinc. The corrosion resistant coated base metal includes a heat created intermetallic layer primarily including copper and zinc.

Abstract: The present invention provides: a high-strength high-ductility hot-dip galvanized steel sheet and hot-dip galvannealed steel sheet having high fatigue resistance and corrosion resistance; a high-strength hot-dip galvanized steel sheet excellent in ductility, which improves non-plating defects and plating adhesion after severe deformation, and a method of producing the same; a high-strength and high-ductility hot-dip galvanized steel sheet having high fatigue resistance and corrosion resistance; a high-strength hot-dip galvanized steel sheet and hot-dip galvannealed steel sheet having superior appearance and workability, which suppresses the generation of non-plating defects, and a method of producing the same; and a high-strength hot-dip galvannealed steel sheet and a high-strength hot-dip galvanized steel sheet, which suppress non-plating defects and surface defects and have both corrosion resistance, in particular corrosion resistance in an environment containing chlorine ion, and high ductility, and a meth

Abstract: Process for the continuous hot-dip galvanizing of a steel strip (1) containing oxidizable addition elements in a proportion allowing the mechanical properties of the steel to be improved, in which process the strip passes through a galvanizing furnace (3) in a reducing atmosphere, this furnace consisting of heat treatment sections, for heating, soaking and cooling, and is then dipped into a galvanizing bath (2). The strip is subjected, upstream of the inlet section of the furnace, to an oxidation treatment under conditions as regards temperature, duration and oxygen content of a gas in which the strip is immersed, such that the oxidizable addition elements are essentially oxidized within the strip, before they can migrate to the surface in order to form thereat an oxide layer.

Abstract: A workpiece having regions of different ductility is made by first coating opposite faces of a flat sheet-metal workpiece of low ductility and then stripping the coating from the faces in one region of the workpiece while leaving the coating on the faces in another region of the workpiece. The workpiece is then deformed into a three-dimensional profile. Only the one uncoated region of the workpiece is heated and thereby hardened while not significantly heating the other coated region of the workpiece.

Abstract: A galvannealed steel sheet superior in workability wherein the steel sheet is characterized by containing silicon in an amount no less than 0.8 mass % and retained austenite in an amount no less than 3% (in terms of packing factor) and the alloy zinc plating is characterized by containing Zn—Fe alloy crystal grains which exist in its surface layer and have a specific crystal grain size such that the longer side of a crystal grain is no larger than twice the shorter side of a crystal grain and the number of crystal grains with an average particle size no smaller than 4 &mgr;m is no more than 5 per 70×50 &mgr;m. The steel sheet with alloy zinc coating has good mechanical properties (such as total elongation) and good plating surface slidability.

Abstract: A hardenable steel workpiece having two regions is first hardened so that both regions are of generally the same low ductility. Then only one of the regions is hot coated so as to increase the ductility of the one region while not heating and changing the ductility of the other region. The workpiece can be hardened by hot working or tempering. The hot coating can be done by dipping the one region in molten zinc.

Abstract: The present invention relates to a zinc-diffused nickel alloy coating for corrosion and heat protection and to a method for forming such a coating. The coating method broadly comprises the steps of forming a plain nickel or nickel alloy coating layer on a substrate, applying a layer of zinc over the nickel or nickel alloy coating layer, and thermally diffusing the zinc into the nickel alloy coating layer. The coating method may further comprise immersing the coated substrate in a phosphated trivalent chromium conversion solution either before or after the diffusing step. The substrate may be a component used in a gas turbine engine, which component is formed from a steel material.

Abstract: Diffusion metallic anticorrosive zinc-iron-aluminum coatings of iron and iron-based item surfaces, realized by heating of products at temperatures of 370−450° C. in a saturating powder mixture environment in a closed container. The coating compositions are multiphase-polymetallic, and comprise zinc, iron and aluminum. Other elements may be added to attain specific coating properties. This coating exhibits a high corrosion resistance (at least a 700-hour corrosion resistance level in a standard salt spray test), a relatively high hardness level and good adhesion to secondary coatings.

Abstract: The invention relates to a higher-strength steel strip or steel sheet comprising a predominantly ferritic-martensitic microstructure with a martensite content of between 4 and 20%, wherein the steel strip or steel sheet, apart from Fe and impurities due to smelting, comprises (in % by weight) 0.05-0.2% C, ≦1.0% Si, 0.8-2.0% Mn, ≦0.1% P, ≦0.015% S, 0.02-0.4% Al, ≦0.005% N, 0.25-1.0% Cr, 0.002-0.01% B. Preferably the martensite content is approximately 5% to 20% of the predominantly martensitic-ferritic microstructure. Such a higher-strength steel strip or steel sheet made from a dual phase steel comprises good mechanical/technological properties even after being subjected to an annealing process which includes an overageing treatment. Furthermore, the invention relates to a method for producing steel strip or steel sheet according to the invention.

Abstract: Dual phase steel sheet is made using a time/temperature cycle including a soak at about 1340-1425 F and a hold at 850-920 F, where the steel has the composition in weight percent, carbon: 0.02-0.20; aluminum: 0.010-0.150; titanium: 0.01 max; silicon: 0.5 max; phosphorous: 0.060 max; sulfur: 0.030 max; manganese: 1.5-2.40; chromium: 0.03-1.50; molybdenum:0.03-1.50; with the provisos that the amounts of manganese, chromium and molybdenum have the relationship: (Mn+6Cr+10 Mo)=at least 3.5%. The sheet is preferably in the form of a strip treated in a continuous galvanizing or galvannealing line, and the product is predominantly ferrite and martensite.

Abstract: Disclosed are a high strength hot-dip galvanized or galvannealed steel sheet, which has improved press formability and plating adhesion and is useful as a member for automobile, building, electric or other members, and a process for producing the same.

Abstract: The present invention relates to a zinc-diffused nickel alloy coating for corrosion and heat protection and to a method for forming such a coating. The coating method broadly comprises the steps of forming a plain nickel or nickel alloy coating layer on a substrate, applying a layer of zinc over the nickel or nickel alloy coating layer, and thermally diffusing the zinc into the nickel alloy coating layer. The coating method may further comprise immersing the coated substrate in a phosphated trivalent chromium conversion solution either before or after the diffusing step. The substrate may be a component used in a gas turbine engine, which component is formed from a steel material.

Abstract: To provide a steel sheet excellent in painting bake hardenability and anti aging property at room temperature: containing, in mass, 0.0001 to 0.20% of C, 2.0% or less of Si, 3.0% or less of Mn, 0.15% or less of P, 0.015% or less of S, and, in addition, 010% or less of Al and 0.001 to 0.10% of N so as to satisfy the expression 0.52Al/N<5 and, further, one or more of 2.5% or less of Cr, 1.0% or less of Mo and 0.1% or less of V so as to satisfy the expression (Cr+3.5MO+39V) ≧0.1, with the balance consisting of Fe and unavoidable impurities; having the value of BH170, evaluated after applying a 2% tensile deformation and then a heat treatment at 170° C. for 20 min., being 45 MPa or more, and any of the value of BH160, evaluated after applying a 2% tensile deformation and then a heat treatment at 160° C. for 10 min., and the value of BH150, evaluated after applying a 2% tensile deformation and then a heat treatment at 150° C. for 10 min.

Abstract: An object of the present invention is to provide a hot-dip galvanized steel sheet which is excellent in adhesion with a hot-dip galvanized zinc layer, and has high tensile strength and good formability even when a steel sheet containing Si and Mn in relatively larger amounts is used as a basis steel sheet. The hot-dip galvanized steel sheet is composed of: a basis steel sheet containing Si in an amount of 0.05 to 2.5% and Mn in an amount of 0.2 to 3%, by mass; a Fe plated layer formed on the basis steel sheet; and a hot-dip galvanized zinc layer formed on the surface layer of the basis steel sheet via the Fe plated layer, wherein oxides containing Si and/or Mn are discontinuously dispersed in the vicinity of the interface between the basis steel sheet and the Fe plated layer.

Abstract: The invention provides a galvannealed steel sheet which has an oxide layer having 10 nm or larger thickness on the plateau of the coating layer flattened by temper rolling. With the use of the galvannealed steel sheet, no powdering occurs during press-forming, and stable and excellent sliding performance is attained. By selecting the area percentage of the plateau of the flattened coating layer to a range from 20 to 80%, making the coating layer single layer of &dgr;1 phase, and letting &zgr; phase exist in the &dgr;1 phase, further improved sliding performance and anti-powdering property are obtained.

Abstract: A high strength dual phase cold rolled steel having controlled amounts of carbon, manganese, and molybdenum is used as a starting material in a hot-dip zinc coating process to manufacture a high strength dual phase cold rolled steel having a conventional galvanized or galvannealed coating applied to at least one surface thereof, the zinc coated steel product having a uniform coating of zinc in spite of the high manganese content of the steel.

Abstract: The present invention aims to produce a cold rolled metal coated multi-phase steel, characterized by a tensile strength of at least 500 MPa, a yield ratio (Re/Rm) lower than 0.65 in skinned conditions, lower than 0.60 in unskinned conditions, and with good metal coating adhesion behavior. In the case of the aluminized steel according to the invention, the steel also has superior resistance to temperature corrosion up to 900° C. and excellent mechanical properties at this high temperature. The hot metal coated steel product having a steel composition with a manganese content lower than 1.5%, chrome content between 0.2 and 0.5%, molybdenum content between 0.1 and 0.25%, and a relation between the chrome and molybdenum content as follows Cr+2 Mo higher than or equal to 0.7%, undergoes a thermal treatment in the hot dip metal coating line defined by a soaking temperature between Ac1 and Ac3, a primary cooling speed higher than 25° C./sec and a secondary cooling speed higher than 4° C./sec.

Abstract: A corrosion-resistant coated base metal coated with a corrosion resistant alloy. The corrosion resistant alloy includes tin and zinc. The corrosion resistant coated base metal includes a heat created intermetallic layer primarily including copper and zinc.

Abstract: A method of coating dual phase high strength cold rolled steel having controlled amounts of carbon, manganese, and molybdenum is used as a starting material in a galvanizing/galvannealing process. Conditions in a multi-zone furnace of the galvanizing line can be controlled in a conventional manner while still effectively coating the high strength steel. A dual phase high strength steel product is made having a uniform coating of zinc in spite of the high manganese content of the steel.

Abstract: The present invention describes an ultra-low carbon bake hardenable galvanized or galvannealed steel product, having a higher yield strength at the temperature of the molten zinc bath while maintaining a low yield strength and excellent bake hardening properties in a skinpassed condition, BH0 being higher than 35 MPa and BH2 higher than 40 MPa (GI) and BH0>20 MPa and BH2>30 MPa (GA), as well as having a superior paint appearance after stamping and painting. The content in the steel composition of the Ti is comprised between 3.42 N and 3.42 N+60 ppm for a fixed nitrogen content (N), and the Nb-content, comprised between 50 ppm and 100 ppm, is fixed so that no substantial precipitation of niobium carbides will occur during the process.

Abstract: A corrosion-resistant coated brass metal coated with a corrosion resistant alloy. The corrosion resistant alloy is a tin metal alloy or a tin and zinc metal alloy. The corrosion resistant metal alloy may also include one or more metal additives to improve the coating process and/or to alter the properties of the tin or tin and zinc metal alloy.

Abstract: A galvannealed steel sheet having excellent surface appearance and press formability, characterized in that a steel sheet comprises a galvannealed layer at least one surface of the steel sheet, the steel sheet comprising 0.001 to 0.005% by mass of C, 0.010 to 0.040% by mass of Si, 0.05 to 0.25% by mass of Mn, and 0.010 to 0.030% by mass of P, wherein the Si, Mn, and P satisfy the relation 0.030%≦Si+P+Mn/20≦0.070%, and its production method.

Abstract: The invention relates to a method for producing band-shaped steel for components which are produced by drawing and ironing. The invention also relates to a steel band which can be drawn or ironed and which has been produced by the inventive method. The hot strip is cold-worked in one or more steps at a ratio of the cold roll of at least 86%. Furthermore, at least one side of the band material is provided with a galvanically produced coating containing Ni, Co, Cu, Fe, Sn, In, Pd, Bi and/or the alloys thereof or with a roll-bonded coating containing Cu and/or brass and/or the alloys thereof. The aim of the invention is to carry out the inventive method with the fewest processing steps possible and with low production costs. The method therefore comprises the steps: etching, cold rolling in one or two steps, annealing the coiled band (coil-annealing), optionally rerolling the band. The hot strip preferably contains boron with a percentile of 0.0013 and 0.

Abstract: The method for manufacturing coated steel sheet has the steps of: immersing a steel sheet in a hot-dip coating bath to form an Al—Zn base coating layer containing 20 to 95 mass % Al on the steel sheet, forming a passivated layer on the coating layer; and applying thermal history to the coating layer. The thermal history is applied immediately after the steel sheet left the hot-dip coating bath or in a temperature range of from T(° C.) between 130° C. and 300° C. to 100° C.

Abstract: The object of the present invention relates to a plated steel material and a method of production the same, having enhanced corrosion resistance and workability required for outdoor and exposed uses such as structures, revetments, fishing nets, fences, etc.

Abstract: The present invention relates to a method for the manufacture of galvannealed metal sheet, wherein a hot strip is produced from an IF steel containing 0.01 to 0.1 wt. % silicon, wherein the hot strip is coiled at a coiler temperature no lower than 700° C. and no higher than 750° C., wherein a cold strip is rolled from the coiled hot strip, wherein the cold strip is recrystallisation-annealed in an annealing furnace in an annealing gas atmosphere, wherein the cold strip thus annealed is provided with a zinc coating in a zinc bath, and wherein the coated cold strip is post-annealed at a galvannealing temperature no lower than 500° C. and no higher than 540° C. The invention also relates to a galvannealed metal sheet which possesses improved adhesion of the coating layer to the base material and proposes a method which is suited for the manufacture of metal sheet having such properties.

Abstract: A method for annealing and galvanizing wires which comprises induction heating the wires in a first chamber at a first higher temperature to anneal the wires, cooling the wires to a second lower temperature in a second chamber and galvanizing the wires in a third chamber. The chambers are in serial communication and the heating, cooling and galvanizing steps are effected in an oxygen free atmosphere.

Abstract: A steel for forming a high strength steel sheet contains, in mass %, C: at most 0.04%, Si: at most 0.4%, Mn: 0.5-3.0%, P: at most 0.15%, S: at most 0.03%, Al: at most 0.50%, N: at most 0.01%, and Mo: 0.01-1.0%. Steel sheet formed from the steel is suitable for use as automotive panels.

Abstract: A metallurgical product, made of carbon steel and to be galvanized, which is in the form of a strip or of a sheet obtained from a continuously cast intermediate product having the following composition by weight: 0.0005%≦C≦0.15%; 0.08%≦Mn≦2%; Si≦0.040%; Altotal≦0.010%; Alsoluble≦0.004%; 0.0050%≦Ototal≦0.0500%; P≦0.20%; S≦0.10%; each of Cu, Cr, Ni, Mo, W, Co≦1%; each of Ti, Nb, V, Zr≦0.5%; each of Sn, Sb, As≦0.1%; B≦0.1%; N≦0.0400%; and the remainder being iron and impurities. Also, a process for obtaining a metallurgical intermediate product, which includes: producing in a ladle a liquid steel the composition of which is as above, and in which the dissolved oxygen content is maintained between 0.0050 and 0.0500% by the establishment of a chemical equilibrium between the metal and the ladle slag; and casting said steel on a continuous casting machine.

Abstract: This invention provides a plated steel wire with high corrosion resistance and excellent workability, wherein the average composition of the plating alloy in the plated steel wire comprises, in terms of weight percentage, Al: 4-20%, Mg: 0.8-5%, and if necessary one or more from among Si: ≦2%, Na: 0.001-0.1% and Ti: 0.01-0.1%, with the remainder Zn, and an Fe—Zn alloy layer of no greater than 20 &mgr;m thickness is present at the plating-base metal interface; it is produced by coating a steel wire with a molten zinc plating composed mainly of zinc as the first stage and then.coating it with a molten zinc alloy plating with the aforementioned average composition as the second stage. The maximum plating bath immersion time is 20 seconds, and the part of the plated steel wire drawn out from the plating bath is purged with nitrogen gas.

Abstract: The invention relates to a high strength hot-dip galvanized steel sheet consisting essentially of 0.03 to 0.25% C, 0.7% or less Si, 1.4 to 3.5% Mn, 0.05% or less P, 0.01% or less S, 0.05 to 1% Cr, 0.005 to 0.1% Nb, by mass, and balance of Fe, and being made of a composite structure of ferrite and secondary phase, and having an average grain size of the composite structure of 10 &mgr;m or smaller. Since the high strength hot-dip galvanized steel sheet of the present invention hardly induces softening at HAZ during welding, it is applicable to structural members of automobiles for “Tailor Welded Blanks” (TWB).

Abstract: A process and an alloy for galvanizing non-reactive steel and mixed or moderately reactive steel for providing a decorative spangle to the galvanized coating. The alloy contains 0.1 to less than 0.8 wt % tin, 0.05 to 0.2 wt % bismuth, 0.001 to 0.008 wt % aluminum, and optionally 0 to 0.1 wt % nickel, the balance zinc of commercial purity.

Abstract: The hot dip Zn galvanized steel sheet has excellent balance between tensile strength and ductility and excellent coating adhesion, an average composition of a base steel thereof includes: 0.05-0.25 mass % of C; not more than 2.0 mass % of Si; 1.0-2.5 mass % of Mn; and 0.005-0.10 mass % of Al, wherein the C content at the base steel surface layer portion right under a coating layer is not more than 0.02 mass %, the base steel structure contains not less than 50% of martensite phase, the martensite phase including both tempered martensite phase and fine size martensite phase, and the remaining portion of the base steel structure being formed by ferrite phase and residual austenite phase. A method of producing the hot dip Zn galvanizing steel sheet is described.

Abstract: Disclosed are a high-strength steel plate with excellent electromagnetic shield capacity and a method for manufacturing the same. The steel plate is manufactured from a composition comprising C, N and S in an amount of 0.0150% by weight or less in total; Mn in an amount of 0.2 to 0.8% by weight; Al in an amount of 0.6% by weight or less; Si in an amount of 0.4% by weight or less; Cu and/or Sn in an amount of 0.1 to 0.6% by weight in total; and Fe for the remainder, and inevitably present elements, whereby the steel plate can show excellent electromagnetic shield effect and hot-dip galvanization property.

Abstract: A hot-dip galvanized high-strength steel sheet having superior workability and galvanizability containing: 0.01% to 0.20% by weight of C; 1.0% by weight or less of Si; more than 1.5% to 3.0% by weight of Mn; 0.10% by weight or less of P; 0.05% by weight or less of S; 0.10% by weight or less of Al; 0.010% by weight or less of N; 0.010% to 1.0% by weight in total of at least one element selected from the group consisting of Ti, Nb, and V; and the balance being Fe and incidental impurities; in which the steel sheet has the metal structure in which the areal rate of the ferrite phase is 50% or more, the ferrite phase has an average grain diameter of 10 &mgr;m or less, and the thickness of a band-like structure composed of the second phase satisfies the relationship Tb/T≦0.005, where Tb is the average thickness in the sheet thickness direction of the band-like structure and T is the thickness of the steel sheet, and a method for producing the same.

Abstract: Disclosed is a cold-rolled steel sheet excellent in formability, panel shapeability and dent-resistance, comprising 0.005 to 0.015% by weight of C, 0.01 to 0.2% by weight of Si, 0.2 to 1.5% by weight of Mn, 0.01 to 0.07% by weight of P, 0.006 to 0.015% by weight of S, 0.01 to 0.08% by weight of sol. Al, not higher than 0.004% by weight of N (N≦0.004%), not higher than 0.003% by weight of O (O≦0.003%), 0.04 to 0.23% by weight of Nb, 1.0≦(Nb %×12)/(C %×93)≦3.0, and a balance of Fe and unavoidable impurities, said cold-rolled steel sheet meeting the relationship given below: exp(&egr;)×(5.29×exp(&egr;)−4.19)≦&sgr;/&sgr;0.2≦exp(&egr;)×(5.64×exp(&egr;)−4.49) where 0.002<&egr;≧0.096, &egr; represents a true strain, &sgr;0.2 represents a 0.2% proof stress, and &sgr; represents a true stress relative to &egr;.

Abstract: The invention relates to a high strength hot-dip galvanized and galvannealed steel sheets with excellent drawability for press forming and excellent plating adhesion that is useful as a member for automobiles, construction, electric devices and the like, and to a process for its manufacture. According to an embodiment of the invention, the steel sheet contains in terms of weight percent, C: 0.05-0.2%, Si: 0.2-2.0%, Mn: 0.2-2.5%, Al: 0.01-1.5%, Ni: 0.2-5.0%, P: <0.03% and S: <0.02%, the relationship between Si and Al being such that 0.4(%)≦Si+0.8 Al(%)≦2.0% and the remainder consisting of Fe and unavoidable impurities, the volume percentage of the retained austenite is 2-20% and the steel sheet surface wherein the relationship between the Ni and Si, Al in 0.5 &mgr;m of the steel sheet surface layer is such that Ni(%)≦¼ Si+⅓Al(%), has a Zn plating layer comprising Al: ≦1% with the remainder Zn and unavoidable impurities.

Abstract: The method for manufacturing galvanized steel sheet has a step of adjusting the surface texture thereof by blasting solid particles against the surface thereof. The surface texture is defined by at least one parameter selected from the group of parameters consisting of mean roughness Ra on the surface of steel sheet, peak count PPI on the surface of steel sheet, and filtered centerline waviness Wca on the surface of steel sheet. The galvanized steel sheet has a surface in dimple-pattern texture.

Abstract: To provide a steel sheet excellent in painting bake hardenability and anti aging property at room temperature: containing, in mass, 0.0001 to 0.20% of C, 2.0% or less of Si, 3.0% or less of Mn, 0.15% or less of P, 0.015% or less of S, and, in addition, 010% or less of Al and 0.001 to 0.10% of N so as to satisfy the expression 0.52Al/N<5 and, further, one or more of 2.5% or less of Cr, 1.0% or less of Mo and 0.1% or less of V so as to satisfy the expression (Cr+3.5MO+39V) ≧0.1, with the balance consisting of Fe and unavoidable impurities; having the value of BE170, evaluated after applying a 2% tensile deformation and then a heat treatment at 170° C. for 20 min., being 45 MPa or more, and any of the value of BH160, evaluated after applying a 2% tensile deformation and then a heat treatment at 160° C. for 10 min., and the value of BH150, evaluated after applying a 2% tensile deformation and then a heat treatment at 150° C. for 10 min.

Abstract: A method for annealing and galvanizing wires which comprises induction heating the wires in a first chamber at a first higher temperature to anneal the wires, cooling the wires to a second lower temperature in a second chamber and galvanizing the wires in a third chamber. The chambers are in serial communication and the heating, cooling and galvanizing steps are effected in an oxygen free atmosphere.

Abstract: A method is disclosed for laser lap welding a pair of metal members together. At least one of the pair of metals having a protective metal layer. Each of the metal members having a melt temperature greater than the melt temperature of the protective metal layer. The method includes placing one end of the pair of metal members in an overlapping relation to an other end of the pair of metal members to form an overlapping section. The method also includes inserting a metal alloying agent between the pair of metal members of the overlapping section to form a gap therebetween. A laser welder is used to join the pair of metal members and the alloy agent together so that the protective metal layer and the alloying agent are melted to form an alloy layer between the pair of metal members.

Abstract: A hot-dip galvanized steel sheet is produced by rough rolling a steel, finish rolling the rough rolled steel at a temperature of Ar3 point or more, coiling the finish rolled steel at a temperature of 700° C. or less, and hot-dip galvanizing the coiled steel at a pre-plating heating temperature of Ac1 to Ac3. A continuous hot-dip galvanizing operation is performed by soaking a pickled strip at a temperature of 750 to 850° C., cooling the soaked strip to a temperature range of 600° C. or less at a cooling rate of 1 to 50° C. per second, hot-dip galvanizing the cooled strip, and cooling the galvanized strip so that the residence time at 400 to 600° C. is within 200 seconds. The steel sheet has a structure consisting essentially of ferrite and martensite.

Abstract: A steel sheet having a composition comprising C: 0.05-0.20 mass %, Si: 0.3-1.8 mass %, Mn: 1.0-3.0 mass %, Fe of the balance and inevitable impurities is subjected to a primary step of primary heat treatment and subsequent rapid cooling to Ms point or lower, a secondary step of secondary heat treatment and subsequent rapid cooling, and a tertiary step of galvanizing treatment and rapid cooling, so as to turn the structure of the steel sheet into a composite structure of 20% or more by volume of tempered martensite, 2% or more by volume of retained austenite, ferrite and a low-temperature transformation phase. A galvanized layer is deposited on the surface of the steel sheet. It is preferred to cool the steel sheet to 300° C. at a cooling rate of 5 ° C./sec. or more after the galvanizing treatment. After the galvanizing treatment, alloying treatment may be conducted.

Abstract: A hot-dip galvanized steel sheet is produced by rough rolling a steel, finish rolling the rough rolled steel at a temperature of Ar3 point or more, coiling the finish rolled steel at a temperature of 700° C. or less, and hot-dip galvanizing the coiled steel at a pre-plating heating temperature of Ac1 to Ac3. A continuous hot-dip galvanizing operation is performed by soaking a pickled strip at a temperature of 750 to 850° C., cooling the soaked strip to a temperature range of 600° C. or less at a cooling rate of 1 to 50° C. per second, hot-dip galvanizing the cooled strip, and cooling the galvanized strip so that the residence time at 400 to 600° C. is within 200 seconds. The steel sheet has a structure consisting essentially of ferrite and martensite.

Abstract: The present invention provides a high strength thin excellent workability and galvanizability, having a composition comprising from 0.01 to 0.20 wt. % C, up to 1.0 wt. % Si, from 1.0 to 3.0 wt. % Mn, up to 0.10 wt. % P, up to 0.05 wt. % S, up to 0.10 wt. % Al, up to 0.010 wt. % N, up to 1.0 wt. % Cr, from 0.001 to 1.00 wt. % Mo, and the balance Fe and incidental impurities, wherein a band structure comprising a secondary phase has a thickness satisfying the relation Tb/T≦0.005 (where, Tb: average thickness of the band structure in the thickness direction of steel sheet; T: steel sheet thickness), and a manufacturing method thereof, and a manufacturing method of a high strength hot-dip galvanized steel sheet or a high strength galvannealed steel sheet applying hot-dip galvanizing or further galvannealing, and giving an excellent workability, a high tensile strength, and excellent galvanizability, coating adhesion and corrosion resistance.

Abstract: In order to provide a cost-effective, time saving method for producing aging-resistant strip consisting of aluminum-killed steel, for which, initially, a strip is produced in the usual manner by rolling and the rolled strip is annealed continuously, the still hot strip is wound into a coil and cooled to room temperature, the strip, cooled in the coil, being finally finished.

Abstract: A method and an apparatus for carrying out the annealing step of a galvannealing process in which strips and sheets, particularly of steel, are subjected after galvanizing to an annealing step by heating the coated material and subsequently holding at final annealing temperature, wherein, during annealing, the heating step is interrupted by at least one additional holding step and, thus, a stepwise increase of the temperature over time is adjusted.