A grain-oriented silicon steel with low iron loss, wherein the silicon steel is provided with a plurality of grooves on its surface, each of the grooves is 10-60 μm in width and 5-40 μm in depth, and the spacing between adjacent grooves is 1-10 mm. The manufacturing method therefor comprises: scoring the surface of the grain-oriented silicon steel with low iron loss by using a laser in order to form the grooves. The grain-oriented silicon steel with low iron loss can maintain the magnetic domain refining effect in a stress-relief annealing process, and avoid the introduction of more residual stress.

A process for obtaining a piston ring may include providing a piston ring of an internal combustion engine and submitting a surface of the piston ring to a laser surface heat treatment. The surface may be a sliding surface of the piston ring. The piston ring may be a one piece piston ring and/or a scrapper ring.

A process for obtaining a piston ring may include providing a piston ring of an internal combustion engine and submitting a surface of the piston ring to a laser surface heat treatment. The surface may be a sliding surface of the piston ring. The piston ring may be a one piece piston ring and/or a scrapper ring.

The invention relates to an apparatus (1) for cooling an automobile component (20) by means of a gas, the apparatus comprising a cooling box (11) with a re-closeable opening (12) for receiving an automobile component (20) to be cooled, wherein at least one heat sink (13) is provided inside the cooling box (11) for cooling of the gas, and wherein the apparatus (10) includes at least one infra sound pulsator (2, 3) arranged to provide an infra sound into said cooling box (11) to improve heat exchange of the gas both with a cooling surface of the at least one heat sink (13), and with the automobile component (20). The invention also relates to a process for cooling an automobile component in such an apparatus.

The invention relates to an apparatus (1) for cooling an automobile component (20) by means of a gas, the apparatus comprising a cooling box (11) with a re-closeable opening (12) for receiving an automobile component (20) to be cooled, wherein at least one heat sink (13) is provided inside the cooling box (11) for cooling of the gas, and wherein the apparatus (10) includes at least one infra sound pulsator (2, 3) arranged to provide an infra sound into said cooling box (11) to improve heat exchange of the gas both with a cooling surface of the at least one heat sink (13), and with the automobile component (20). The invention also relates to a process for cooling an automobile component in such an apparatus.

To provide a turbine rotor which enables mass production with a low-cost apparatus and which capable of suppressing leaning of the rotor shaft after welding to improve the yield, while a turbine blade rotor 12 and the rotor shaft 14 are fit to each other with concave and convex portions 12a and 14a and are permitted to be rotated, laser beam L from a laser beam generating device 30 is applied to a joint face 16 along the circumferential direction to weld the welding portion. Then, laser beam L is polarized to temper a region X on the rotor shaft side containing the welding portion with laser beam L. In contrast to residual stress R.sub.1 having a local angular distribution generated during the welding, residual stress R.sub.2 is permitted to be generated over the entire circumference by tempering. Leaning of the rotor shaft 14 after cooling is thereby be suppressed.

Methods for manufacturing hot-stamped components are described. The method includes providing a hot-stamped component by hot forming die quenching, and selecting a first and a second portion of the hot-stamped component, wherein the first portion has a different width than the second portion. A laser system, wherein the laser system c includes one or more optical elements and a laser source for generating a laser beam. The laser system is moved along a length of the component. Finally, the laser beam is applied in a single pass onto the selected first and second portions using the laser system, wherein a laser beam spot size is adjusted during the application of the laser beam and is adapted to the widths of the first and second portions, and wherein a power of the laser beam is regulated based on the temperature measured in the hot-stamped component. The disclosure further relates to components obtained using such methods.

Providing improved wear resistance to a metal material by hardening a surface layer and a surface layer hardening method. A base material is nitrided so that a metal material (40) has a surface layer hardened. The surface layer of the base material is formed with no nitrogen compound layer (40C), and the base material includes a region from a surface thereof to a depth of 78 μm, the region having a Vickers hardness higher than the base material by not less than 5%.

Providing improved wear resistance to a metal material by hardening a surface layer and a surface layer hardening method. A base material is nitrided so that a metal material (40) has a surface layer hardened. The surface layer of the base material is formed with no nitrogen compound layer (40C), and the base material includes a region from a surface thereof to a depth of 78 μm, the region having a Vickers hardness higher than the base material by not less than 5%.

Provided is a novel method for improving fatigue strength, which is applicable to any small portion that is covered with another member. A method for improving fatigue strength according to the present invention includes: disposing an aid (3, 15) to be opposed to an processing object (2A, 2B, 6) on which a fatigue strength improving process is performed, the aid being configured to assist the improving process; and generating sparks between the aid (3, 15) and the processing object (2A, 2B, 6).