Abstract: The method for treating the internal surface of a gas bottle includes the following steps: a) an incident laser treatment beam is introduced into a bottle through its mouth, approximately along the axis of the bottle; b) the laser beam is deflected in the bottle onto the internal surface of the bottle; c) a relative rotation between the bottle and the deflected laser beam is made approximately about the axis of the bottle; and d) a relative displacement between the bottle and the deflected laser beam is made so as to scan most of the internal surface of the bottle with the deflected laser beam. The apparatus for treating a bottle is designed to implement the steps of the method.

Abstract: The present invention relates to a grain-oriented electrical steel sheet excellent in magnetic properties, which are improved by irradiating laser beams onto the positions paired on the both surfaces of the steel sheet and forming fine closure domains, characterized in that the width of the closure domains in the rolling direction is 0.3 mm or less and the deviation in the rolling direction between the positions of the paired closure domains on the both surfaces is equal to or smaller than the width of said closure domains in the rolling direction. Further, the present invention relates to a grain-oriented electrical steel sheet excellent in magnetic properties, characterized in that the steel sheet has the marks of laser irradiation on its surface. Yet further, the present invention relates to a grain-oriented electrical steel sheet excellent in magnetic properties, characterized in that the substrate steel is not exposed at the portions of laser irradiation on the surface of the steel sheet.

Abstract: A method of laser marking which comprises applying a laser beam to a metal surface under the influence of an assist gas to produce durable, repeatable and striking colors on the metal surface. The method provides an easy and flexible alternative to conventional metal decorating techniques.

Abstract: This invention relates to a method of using a laser to produce alloyed bands or strips on the surface of a piston for an internal combustion engine. More specifically, the present invention relates to a laser alloying method to produce superior wear resistant properties for an aluminum internal combustion engine piston.

Abstract: A laser shock peening system includes an apparatus and method that senses a thickness of laser transparent confinement media flow, such as water. In one embodiment, the apparatus indicates a proper thickness, in another embodiment, the apparatus controls the flow rate of the confinement media using signals from probes of the apparatus. A first probe is used to sense a predetermined minimum thickness and another embodiment further includes a second probe to indicate a predetermined maximum thickness of the confinement media.

Abstract: Provided is a rare earth element-containing hydrogen storage alloy which fulfills at least one requirement selected from the requirements that (1) the total content of nonmetal elements present as impurities in the alloy matrix is not higher than 1,200 ppm by weight, (2) the total content of alkaline earth metal elements present as impurities in the alloy matrix is not higher than 100 ppm by weight, (3) the content of Mg present as an impurity in the alloy matrix is not higher than 80 ppm by weight, (4) the content of Cl present as an impurity in the alloy matrix is not higher than 10 ppm by weight, (5) the content of Pb present as an impurity in the alloy matrix is not higher than 100 ppm by weight, (6) the alloy has, in a surface layer covering from the alloy surface to a depth of 20 nm, an oxygen concentration that decreases sharply in the depth direction and is not higher than 10 weight % on the average in the surface layer defined above, (7) the alloy comprises Ni as a constituent element and contains,

Abstract: An on the fly method of laser shock peening a gas turbine engine part by continuously moving a metallic gas turbine engine part while continuously firing a stationary laser beam, which repeatably pulses between relatively constant periods, on a portion of the part with sufficient power to vaporize material on the surface of the portion of the part with the pulses around laser beam spots formed by the laser beam on the surface and form a region having deep compressive residual stresses extending into the part from the laser shock peened surface. Flowing a curtain of water over the surface upon which the laser beam is firing while moving the part until the laser shock peened surface is completely covered by laser beam spots at least once. The surface may covered by a paint which is then the material used to produce the plasma or the surface may be unpainted and the metal of the part is used to produce the plasma.

Abstract: A process for altering surface properties of a mass of metal alloy solder comprising a first metal and a second metal. The process comprises exposing the mass to energized ions to preferentially sputter atoms of the first metal to form a surface layer ratio of first metal to second metal atoms that is less than the bulk ratio. The solder may be located on the surface of a substrate, wherein the process may further comprise masking the substrate to shield all but a selected area from the ion beam. The sputtering gas may comprises a reactive gas such as oxygen and the substrate may be an organic substrate. The process may further comprise simultaneously exposing the organic substrate to energized ions of the reactive gas to roughen the organic substrate surface.

Abstract: A method of altering the properties of a solid material by varying the temperature of the solid material either before or after or both before and after laser shock processing the solid material. In addition, the method may be repeated for successive laser shock processing of the solid material.

Abstract: The present invention includes a method of repairing an annular metallic article and the repaired article itself which has an axially extending annular support and a projection generally radially extending therefrom. The projection has an associated operating radial height as measured from a radially facing annular first surface of the support and an associated shape. An upper portion of the projection is removed forming a stub extending away from the first surface and having a bonding surface at a stub end spaced apart from the first surface. A metallic material is metallurgically bonded to the bonding surface forming an annular heat affected zone in the stub bounded by the bonding surface. A first portion of the metallic material is removed to restore the projection to the operating height and shape. At least one annular outer surface of the tooth extending over at least a portion of the heat affected zone is laser shock peened, preferably after the first portion of the metallic material is removed.

Abstract: A target is laser shock peened by directing against an ablative coating thereon a laser beam pulse having a fluence, duration, and corresponding peak power effective for ablating the coating to form a plasma and shock wave therein. The plasma is confined adjacent the target to plastically deform the target by the shock wave to develop residual compressive stress therein. The pulse has a duration less than ten nanoseconds and a corresponding peak power for increasing coupling efficiency between the pulse and plasma.

Abstract: A test coupon is formed from a metallic strip having opposite first and second sides that generally define a plane of the strip and the strip includes a laser shock peened patch of the strip that has first and second laser shock peened surfaces on the first and second sides, respectively, first and second laser shocked regions having deep compressive residual stresses imparted by the laser shock peening extending into the strip from the first and second laser shock peened surfaces, respectively, and a deflection of a portion of the strip from a position of the portion before the laser shock peening. The deflection is formed by the laser shock peening such that at least a part and preferably substantially all of the deflection lies in the plane and the test coupon preferably includes an indicating means to indicate the deflection.

Abstract: High energy flux infrared heaters are used to treat an object having a surface section and a base section such that a desired characteristic of the surface section is physically, chemically, or phasically changed while the base section remains unchanged.

Abstract: The present invention provides a metallic article with at least one laser shock peened surface on at least a portion of the article and a plurality of volumetrically spaced apart laser shock peened protrusions extending into the article from said laser shock peened surface wherein the protrusions have deep compressive residual stresses imparted by laser shock peening (LSP). The invention may be further characterized by spaced apart circular laser beam spots on the surface from which the laser shock peened protrusions extend into the article such that the spots do not overlap.

Abstract: An electrochemical method of modifying the surface hardness of a non-allotropic metal member 10, comprising: (a) forming the member to near net-shape with at least one surface 12 to be hardened; (b) subjecting the surface 12 to rapid melting and resolidification by incidence of an electrical discharge between an electrode 16 and the surface 12 closely spaced thereto, the spacing containing an electrolyte with plasma forming capability, the surface 12 being hardened by crystallographic change of the globules resulting from substitutional alloying; and (c) cropping the surface grains 29 of the surface to increase load bearing capacity while retaining liquid retention capacity.

Abstract: A process for annealing a moving metal substrate, especially a steel sheet.

Abstract: The present invention provides a surface modification method that provides beneficial changes in surface properties, can modify a surface to a greater depth than previous methods, and that is suitable for industrial application. The present method comprises applying a thin-film coating to a surface of a substrate, then subjecting the coated surface to an ion beam. The ion beam power pulse heats the coated surface, leading to alloying between the material in the coating and the material of the substrate. Rapid cooling of the alloyed layer after an ion beam pulse can lead to formation of metastable alloys and microstructures not accessible by conventional alloying methods or intense ion beam treatment of the substrate alone.

Abstract: A hollow workpiece includes an outside surface through which a port opens to the hollow interior, and a laser peened area on the surface of the workpiece. The laser peened area is created on the surface while the hollow interior is at least partially filled with a substance other than air. A method of laser peening a hollow core gas turbine engine blade includes the steps of providing a hollow core gas turbine engine blade, filling the hollow core with a substance other than air, and then, laser peening the hollow core gas turbine engine blade.

Abstract: A belt for use in the casting of metals and a method for its manufacture in which a metal belt is first subjected to heat treatment, quenching and tempering to improve its strength and decrease its stretchability. Then the belt is treated to introduce surface irregularities to promote uniformity of heat transfer and to allow collection of surface gases and then the belt is subjected to further thermal treatment under controlled conditions to form an oxide layer thereon to minimize adhesion between the belt and the metal deposited thereon.

Abstract: At least one intermetallic compound A.sub.m1 B.sub.n1 (n1/m1>n0/m0) having a constitutional ratio of a metal B higher than that of an intermetallic compound A.sub.m0 B.sub.n0 is melted two or more times in a high vacuum atmosphere by using an electron beam. The metal B is gradually evaporated in accordance with passage of melting time. Thus, the composition of the intermetallic compound can be adjusted to be A.sub.m0 B.sub.n0. NbAl.sub.3 and Nb.sub.2 Al are used as starting materials, which are heated to an approximately intermediate temperature between melting points of them to obtain a single-phase of Nb.sub.2 Al. Alternatively, Nb.sub.3 Al and Nb.sub.2 Al are used as starting materials, which are heated to an approximately intermediate temperature between melting points of them to obtain a single-phase of Nb.sub.3 Al. It is possible to perform purification for removing impurities, and it is easy to adjust the stoichiometric ratio of the intermetallic compound.

Abstract: A surface hardening method, in which a surface layer on a thin steel plate member is stably melted and solidified to provide a high surface resistance against wear includes irradiation with a high density energy beam to melt a process surface portion of the steel member followed by rapid cooling. The melted surface portion includes a fully melted layer and an adjacent imperfectly or partially melted layer. At least the cooling to solidify the molten steel is performed in a short time period less than an austenitic transformation completion time at temperatures below melting, e.g., one-twentieth of the normal austenitic transformation time, and preferably both heating to melt the surface layer and cooling to solidify and harden the surface layer are performed in a time period less than the normal austenitic transformation completion time period. The high density energy beam can be divided to irradiate plural regions to melt the surfaces of the plural regions at the same time.

Abstract: A method and apparatus for redirecting moving plasma streams using a multiple array of magnetic field generators (e.g., permanent magnets or current bearing wires). Alternate rows of the array have opposite magnetic field directions. A fine wire mesh may be employed to focus as well as redirect the plasma.

Abstract: In order to harden the surface of workpieces having complex shapes without reviously applying absorption promoting surface layers, a mixture of inert gas and oxygen are supplied to the processing zone while the workpiece is exposed to laser radiation. The degree of absorption is maximized by adjusting at least one of the mixing ratio, the volume flow rate, and the processing temperature to conform to a nominal value.

Abstract: For a method for the formation of a frangible zone for fracture separation of a part, namely a connecting rod for internal combustion engines, by which method, in a fracture plane for the intended triggered break-away, a frangible zone is formed along a side of the plane, through which, ordered depressions with ribs are developed from the surface, there is proposed that in the case of a part comprised of ductile metal, the ribs are at least sectionally embrittled, i.e. penetratingly hardened, for intended formation of initial starting cracks.

Abstract: A steel machine component, such as a bearing race, has a critical surface of generally circular configuration. Here the steel of the machine component exists in a state of compression to improve the physical characteristics of the surface. To this end, high speed steel is melted along the full circumference of the surface. Upon cooling to room temperature some of the austenite in the steel transforms into martensite. Tempering converts much of the remaining austenite into martensite, so that the machine component at the surface is almost entirely martensite. Martensite normally occupies a greater volume than austenite, but since the layer of martensite so formed is confined by the underlying core of the machine component, the layer exists in a state of compression. The high speed steel is melted with a laser beam that makes a trace over the full surface of the machine component.

Abstract: A centrifugal plasma arc furnace is used to vitrify contaminated soils and other waste materials. An assessment of the characteristics of the waste is performed prior to introducing the waste into the furnace. Based on the assessment, a predetermined amount of iron is added to each batch of waste. The waste is melted in an oxidizing atmosphere into a slag. The added iron is oxidized into Fe.sub.3 O.sub.4. Time of exposure to oxygen is controlled so that the iron does not oxidize into Fe.sub.2 O.sub.3. Slag in the furnace remains relatively non-viscous and consequently it pours out of the furnace readily. Cooled and solidified slag produced by the furnace is very resistant to groundwater leaching. The slag can be safely buried in the earth without fear of contaminating groundwater.

Abstract: A workpiece is heated by first forming an ionized gas plasma around the workpiece. A positive potential is applied to the workpiece to accelerate electrons from the plasma into the workpiece. The workpiece is uniformly surface heated by the energy directed into the workpiece by the electrons. The workpiece is cooled by providing a flow of a pressurized liquid material such as carbon dioxide having a triple point. The liquid material is expanded through a nozzle to form solid particles that contact the surface of the workpiece and remove heat from it by subliming.

Abstract: A method and a device for the precision turning of a workpiece made of a heat-treatable steel permits a dry hard precision turning of hardened workpiece surfaces without tempering. In order also to allow precision turning and hardening of unhardened workpiece surfaces which are simultaneous in terms of production time, use is made of the local temporary heating of the workpiece caused by machining. The workpiece surface is heated further locally by the action of a laser beam, in the region directly behind the cutter, up to the transformation temperature of the material to be machined via an optical fiber integrated in the tool. The surface is then self-quenched and, as a result, hardened close to the surface. At the same time, the surface temperature at the point of action of the laser beam can be recorded thermographically and, this actual temperature signal can be used to adjust the power of the laser beam so as to maintain the desired temperature.

Abstract: A bainite forming process for treating a steel material reduces the time required for a complete thermal treatment as well as the cycle time for the thermal treatment device without necessitating any special means for handling the steel material. The steel material is heated to a temperature higher than the austenitic transformation point, and temporarily quenched to an intermediate point temperature higher than the martensitic transformation point. Then, the temperature of the steel material is again raised towards the range corresponding to bainitic transformation to form a bainitic structure. The reheating is discontinued before the temperature corresponding to the austenitic transformation point is reached, and the steel material is then quenched. In the heating steps, only the portion to be treated by the bainite forming process is locally irradiated with a high-density energy beam.

Abstract: A workpiece is heated by first forming an ionized gas plasma around the workpiece. A positive potential is applied to the workpiece to accelerate electrons from the plasma into the workpiece. The workpiece is uniformly surface heated by the energy directed into the workpiece by the electrons. The workpiece is cooled by providing a flow of a pressurized liquid material such as carbon dioxide having a triple point. The liquid material is expanded through a nozzle to form solid particles that contact the surface of the workpiece and remove heat from it by subliming.

Abstract: Metal workpieces are subjected to laser treatment in a liquefied gas, by passing the laser beam through a layer of liquid nitrogen in direct contact with the metal surface to be treated, thereby creating an amorphous state.

Abstract: A method for simultaneously annealing a metal or dielectric line and cleaning metal debris deposited in the vicinity of the line by generating an ultraviolet laser beam, focusing the ultraviolet laser beam onto the line, and exposing the line to the ultraviolet laser beam for a period of time sufficient to melt and reflow the line and evaporate small particles of debris. The method may also be used to repair metal or dielectric lines. Laser ablation forward metal deposition may be used in combination with the UV laser annealing method in order to perform the repair.

Abstract: A lockup clutch for torque converter which prevents engaging and disengaging shock when a transmission torque suddenly changes, includes a lockup clutch assembly, a lockup clutch piston operating the lockup clutch assembly, and a damper device disposed between the lockup clutch piston and an output member for absorbing changes of transmission torque occurring in association with the operation of the lockup clutch assembly. The lockup clutch piston is made of steel and has a thermally treated portion placed at a surface in contact with springs of the damper device wherein the thermally treated portion is hardened by rapid local melting with high density energy radiation such as electron beam followed by rapid cooling.

Abstract: Method for machining steel edges for skis or the like, the steel edge being at least partly rapidly heated, then rapidly cooled again and consequently hardened with the aid of a plasma jet. In order to provide a method, which in economic manner can ensure the uniform and precisely defined hardening of steel edges of skis and the like in a randomly long longitudinal portion and in which simultaneously the energy can be applied in a more gentle and planned manner and a less complicated guidance of the plasma jet is rendered possible, an electric arc is produced between the cathode and the anode of the plasma head and a gas flow is passed through said arc and the anode of the plasma head, accompanied by the production of a plasma jet and the steel edge to be hardened is electrically connected as an anode in synchronized manner with the plasma head anode, i.e.

Abstract: An aluminum alloy casting is provided high weldability by consisting of 3.5 to 12.0 Wt % of Si and hydrogen in a limited content to be less than or equal to 0.3 cc per 100 g of alloy. The aluminum alloy casting thus has strength and ductility suitable for application to a joint for automotive frames.

Abstract: A laser beam is shaped by eclisping it with a mask of desired shape. The shaped beam is used to drill a hole corresponding to the shape of the beam.

Abstract: A part of a light-water reactor, for example, a cladding for a light-water reactor has at least a portion made of an intermetallic compound, such as Ni.sub.3 Al, Ni.sub.2 Al.sub.3, TiAl, Ti.sub.3 Al, Pt.sub.2 Si, PtSi, FeAl.sub.2, CoAl, and MoSi.sub.2, thereby having limited irradiation degradation by fast neutrons, improved ductility and usability at high temperatures the intermetallic compound is produced by a process comprising a step of irradiating the intermetallic compound with at least one selected from the group consisting of a neutron, a light ion, and an electron. The intermetallic compound may contain a twin and a third additional element segregatedly present or forms a second phase at or near to a grain boundary.

Abstract: A laser shock peening apparatus includes a cavity dumping laser oscillator including in optical serial alignment a first mirror, a Pockels cell, a polarizer, a laser rod, and a second mirror defining a cavity having an optical length between the mirrors. The laser rod is optically pumped to generate a laser beam in the cavity, and the Pockels cell has selective wave retardation to allow the beam to oscillate between the mirrors and increase energy therein, followed in turn by dumping the beam into a laser amplifier. The laser amplifier directs the amplified pulse at a target for laser shock peening thereof. The cavity length is selected to develop a substantially square-wave laser pulse for temporally shaping the resulting pressure pulse at the target.

Abstract: A a method for laser heating a surface formed by a circular bore extending in a workpiece along a longitudinal bore axis includes providing a holder for holding a workpiece; directing a laser beam into the workpiece bore; and providing a mirror in the workpiece bore for directing the laser beam against a portion of the surface to be heated. The workpiece is cooled adjacent the portion of the surface to be heated by the workpiece holder. The workpiece and mirror are moved relative to each other longitudinally back and forth along the workpiece bore axis and rotatably about the workpiece bore axis, to produce a preselected pattern of heated area on the workpiece bore surface.

Abstract: The invention relates to a process for material treatment with diode radiation, especially laser diode radiation. To match the radiation profile to the treatment process, the process is so carried out that radiation emitted from a multiplicity of diodes is directed with a predetermined radiation profile upon the treated region of the workpiece and that a change in the intensity distribution in the radiation profile is effected by controlling the diode output power.

Abstract: A method of laser shock peening a metallic part by firing a laser on a laser shock peening surface of the part which has been adhesively covered by tape having an ablative medium, preferably a self adhering tape with an adhesive layer on one side of an ablative layer, while flowing a curtain of water over the surface upon which the laser beam is firing. Continuous movement is provided between the part and the laser beam while continuously firing the laser beam, which repeatably pulses between relatively constant periods, on a laser shock peening surface of the part. Using a laser beam with sufficient power to vaporize the ablative medium so that the pulses form laser beam spots on the surface and a region having deep compressive residual stresses imparted by the laser shock peening process extending into the part from the surface.

Abstract: A method of laser shock peening a metallic part by firing a laser on a laser shock peening surface of the part which has been adhesively covered by tape having an ablative medium, preferably, a self adhering tape with an adhesive layer on one side of an ablative layer and a confinement medium without flowing a confinement curtain of fluid over the surface upon which the laser beam is firing. Continuous movement is provided between the part and the laser beam while continuously firing the laser beam, which repeatably pulses between relatively constant periods, on a laser shock peening surface of the part. Using a laser beam with sufficient power to vaporize the ablative medium so that the pulses form laser beam spots on the surface and a region having deep compressive residual stresses imparted by the laser shock peening process extending into the part from the surface.

Abstract: The invention relates to a method for fabricating a piece of structural steel that includes thermal or thermomechanical treatment steps that could ordinarily lower the fatigue strength and shock and impact resistance of the steel piece. In the method of the invention a workpiece of microalloy steel is fabricated containing the following elements in the mounts indicated and having a bainitic structure:______________________________________ C 0.05-0.5 wt. % Mo 0-0.5 wt. % Mn 1-2 wt. % V 0-0.30 wt. % Si 0.05-1.5 wt. % B 0-0.010 wt. % Cr 0.1-1 wt. % Ti 0-0.030 wt. % Nb 0-0.1 wt. % ______________________________________The workpiece is then subjected to a treatment that includes a heating stage wherein at least a part of said piece is subjected to a temperature in the range 500.degree.-900.degree. C., followed by a cooling stage in which at least the part of the piece is subjected to cooling at a rate greater than 500.degree. C./hr.

Abstract: A medical endoscope has a superelastic-alloy force-transmitting element having at least one recess in its surface at a coupling site and being positively connected to a load-receiving component, the recess being formed by sublimation removal of material.

Abstract: Energy, such as from one or more lasers, is directed at the surface of a substrate to mobilize and vaporize a constituent element (e.g., carbide) within the substrate (e.g., steel). The vaporized constituent element is reacted by the energy to alter its physical structure (e.g., from carbon to diamond) to that of a composite material which is diffused back into the substrate as a composite material. An additional secondary element, which can be the same as or different from the constituent element, may optionally be directed (e.g., sprayed) onto the substrate to augment, enhance and/or modify the formation of the composite material, as well as to supply sufficient or additional material for fabricating one or more coatings on the surface of the substrate. The process can be carried out in an ambient environment (e.g., without a vacuum), and without pre-heating or post-cooling of the substrate. Articles formed by the disclosed processes are described, including three-dimensional objects.

Abstract: Energy, such as from one or more lasers, is directed at the surface of a substrate to mobilize and vaporize a constituent element (e.g., carbide) within the substrate (e.g., steel). The vaporized constituent element is reacted by the energy to alter its physical structure (e.g., from carbon to diamond) to that of a composite material which is diffused back into the substrate as a composite material. An additional secondary element, which can be the same as or different from the constituent element, may optionally be directed (e.g., sprayed) onto the substrate to augment, enhance and/or modify the formation of the composite material, as well as to supply sufficient or additional material for fabricating one or more coatings on the surface of the substrate. The process can be carried out in an ambient environment (e.g., without a vacuum), and without pre-heating or post-cooling of the substrate.

Abstract: There is disclosed a method of introducing magnetic anisotropy into a magnetic material, in which a laser beam is selectively radiated on the surface of a magnetic material to locally heat it, thereby forming a pattern of boundary phases for magnetically dividing a main phase of the magnetic material into a plurality of regions, and magnetic domains of the divided main phase regions are controlled to induce magnetic anisotropy in the main phase regions.

Abstract: (Object) IF-based, continuously cast slab essentially freed from defects such as surface defects, difficult production and poor strength, etc. of the product that the IF-based sheet steels have; sheet steels and a process for producing the same are provided.(Structure) A continuously cast slab of extremely low carbon steel comprising not more than 1.5% by mass of Si, not more than 2.0% by mass of Mn, not ore than 0.15% by mass of P, 0.01-0.15% by mass of Al, and not more than 0.0050% by mass of N, where the surface layer further contains 0.01-0.08% by mass of C existing as a cementite and the inner layer further contains not more than 0.0050% by mass of C, and at least one of 0.02-0.10% by mass of Ti, 0.01-0.10% by mass of Nb, 0.02-0.10% by mass of V and 0.03-0.10% by mass of Zr, the carbon existing substantially as carbides of these elements, preferably both the surface layer and the inner layer further contain 0.0001-0.

Abstract: Energy, such as from one or more lasers, is directed at the surface of a substrate to mobilize and vaporize a constituent element (e.g., carbide) within the substrate (e.g., steel). The vaporized constituent element is reacted by the energy to alter its physical structure (e.g., from carbon to diamond) to that of a composite material which is diffused back into the substrate as a composite material. An additional secondary element, which can be the same as or different from the constituent element, may optionally be directed (e.g., sprayed) onto the substrate to augment, enhance and/or modify the formation of the composite material, as well as to supply sufficient or additional material for fabricating one or more coatings on the surface of the substrate. The process can be carried out in an ambient environment (e.g., without a vacuum), and without pre-heating or post-cooling of the substrate.

Abstract: Disclosed are alloying elements and microstructures suited for realizing a marked increase in strength of low-carbon or ultra-low-carbon steel plate using a high-density energy source such as a laser. Steel blanks satisfying both high formability and high strength requirements are provided which show sufficient press formability and yet can be markedly increased in strength by laser treatment or which have been markedly increased in strength by laser treatment in areas not to be subjected to severe forming.