The present invention relates to a process for forming a metal component (20), the process comprising the steps of heating a metal blank (20) coated with a protective layer; cooling said metal blank (20) in a confined space (14), said cooling involving cooling by means of a gas, the gas being cooled by heat exchange with a cooling surface of a heat sink (22) inside said confined space (14), wherein a low frequency sound wave is provided into said confined space (14) in order to improve heat exchange both between the gas and a cooling surface of the at least one heat sink (22), and between the gas and the metal component (20), wherein the heated coated blank is cooled to a temperature below the melting point of the protective layer, and forming the coated blank to a component. The invention also relates to a production line for performing the process.

A surface treatment method includes: a first step of applying a plane wave-shaped shock wave to a workpiece to cause high-density transition to occur in a material structure of the workpiece; and a second step of applying a spherical wave-shaped shock wave or a pressure due to physical contact to the workpiece after the first step for plastic deformation of the workpiece.

The invention relates to a surface-hardened, rotationally symmetrical workpiece, to a hardening method and to a hardening apparatus. The proposed hardening apparatus comprises a machine frame on which two coaxially arranged rotary bearings designed to support a rotationally symmetrical workpiece are arranged, at least one rotary bearing being operatively connected to a drive device to generate rotation of the workpiece; and at lease one laser apparatus for generating focused, high-energy radiation is arranged on said rotary bearing, said laser apparatus being movable in the axial direction, and the radiation being directed toward the workpiece.

The invention relates to a surface-hardened, rotationally symmetrical workpiece, to a hardening method and to a hardening apparatus. The proposed hardening apparatus comprises a machine frame on which two coaxially arranged rotary bearings designed to support a rotationally symmetrical workpiece are arranged, at least one rotary bearing being operatively connected to a drive device to generate rotation of the workpiece; and at lease one laser apparatus for generating focused, high-energy radiation is arranged on said rotary bearing, said laser apparatus being movable in the axial direction, and the radiation being directed toward the workpiece.

A hardened portion in a vehicle structure has an almost hemispherical shape around a lower surface side of a bottom wall rear portion in a vehicle upper-lower direction, the lower surface side serving as a center of a curvature. As the hardened portion is formed, a direction of tensile stress generated in the hardened portion is a radial direction in which the center of the curvature serves as a center side. Thus, occurrence of tensile stress in directions opposite to each other by which a specific part within the hardened portion is pulled apart in a direction orthogonal to the thickness direction of the bottom wall rear portion is inhibited.

A hardened portion in a vehicle structure has an almost hemispherical shape around a lower surface side of a bottom wall rear portion in a vehicle upper-lower direction, the lower surface side serving as a center of a curvature. As the hardened portion is formed, a direction of tensile stress generated in the hardened portion is a radial direction in which the center of the curvature serves as a center side. Thus, occurrence of tensile stress in directions opposite to each other by which a specific part within the hardened portion is pulled apart in a direction orthogonal to the thickness direction of the bottom wall rear portion is inhibited.

A laser shock and supersonic vibration extrusion co-strengthening device and method. The device comprises a laser assembly, a vibration assembly, a hydraulic assembly and a connecting assembly. The method strengthens a hole (7) formed in a metal sheet (5) simultaneously by laser shock strengthening and supersonic vibration extrusion strengthening; a mandrel (1) is in clearance fit with the hole to constrain the hole, so as to avoid distortion of the hole and a hole angle when the laser shock is performed on an outer surface of a workpiece and to improve the strengthening effect of a hole wall; when the laser shock is performed on the outer surface of the metal sheet, supersonic vibration is applied by the mandrel in the hole; and a three-dimensional pressure stress distribution nearby the hole wall at a certain depth is formed under an interaction produced by power ultrasound and laser shock waves having a certain frequency, amplitude and modality, so that an inner surface having higher anti-fatigue performance and being smoother is provided to the hole. Defects of a traditional strengthening process are overcome, and the problem in strengthening the hole separately through the laser shock or supersonic vibration extrusion is solved.

A laser shock and supersonic vibration extrusion co-strengthening device and method. The device comprises a laser assembly, a vibration assembly, a hydraulic assembly and a connecting assembly. The method strengthens a hole (7) formed in a metal sheet (5) simultaneously by laser shock strengthening and supersonic vibration extrusion strengthening; a mandrel (1) is in clearance fit with the hole to constrain the hole, so as to avoid distortion of the hole and a hole angle when the laser shock is performed on an outer surface of a workpiece and to improve the strengthening effect of a hole wall; when the laser shock is performed on the outer surface of the metal sheet, supersonic vibration is applied by the mandrel in the hole; and a three-dimensional pressure stress distribution nearby the hole wall at a certain depth is formed under an interaction produced by power ultrasound and laser shock waves having a certain frequency, amplitude and modality, so that an inner surface having higher anti-fatigue performance and being smoother is provided to the hole. Defects of a traditional strengthening process are overcome, and the problem in strengthening the hole separately through the laser shock or supersonic vibration extrusion is solved.

The invention relates to a method and a device for strengthening the surface of workpieces, in particular of metal ones, by mechanical effects accompanying the impact of small projectiles or by mechanical effects accompanied by the impact of a shockwave induced by plasma created by electric evaporation of a metal foil. The device comprises a polymer strip with a metal foil on the surface of the side diverted from the surface of the workpiece in which foil bridges are formed to form projectiles, further comprising two electrodes and adjacent to the metal foil located on the polymer strip, wherein bridges are formed between the contact surface areas of the metal foil, and the electrodes and between which the plasma is formed, are mounted in a support body, through which flat conductors and are connected to a switch for switching large currents and high voltages with a high-voltage source. The polymer strip with the metal foil tightly abuts the support body with the electrodes and the electrodes and protrude above the upper surface of the support body to provide electric contact with the contact surface areas of the applied metal foil. The method of strengthening the surface of workpieces by means of the device according to the invention consists in that one cycle of strengthening the surface of workpieces involves the action of an electric current pulse supplied from a high voltage source after closing the switch by conductors to electrodes between which a high voltage is applied, thereby shorting the circuit on the metal foil at the location of the bridges to form a plasma expanding and by a compressive force acting on the polymer strip part of which hits as a projectile the surface of the workpiece. The plasma is generated by the electric current pulse, in addition to the expansion pressure, is also accelerated by the electromagnetic Lorentz force caused by the passage of electric current, through this plasma in the generated magnetic field.

The present invention provides a nitriding treatment method for forming a compound layer of ε phase (Fe.sub.2-3N) and γ′ phase (Fe.sub.4N) iron nitride excellent in wear durability in a steel material, from which a sliding member is formed, by short treatment, with a high thermal efficiency, with a reduced amount of used nitriding gas, and with a low environmental load. The nitriding treatment method of the present invention includes heating a sliding member made of a steel material at a temperature of 600° C. to 700° C. for a time of 1 to 25 minutes under an atmosphere of nitriding gas through high frequency induction heating or resistive heating, to form a compound layer of ε phase (Fe.sub.2-3N) and γ′ phase (Fe.sub.4N) iron nitride, the compound layer having a nitrogen content of higher than 4.5%, in a surface layer portion of the sliding member.