To provide a grain-oriented electrical steel sheet that can achieve both sufficiently low transformer core loss and sufficiently low noise. Disclosed is a grain-oriented electrical steel sheet having a tension coating on a surface thereof and subjected to magnetic domain refining treatment by generating linear closure domains extending in a direction within 30° of a transverse direction, in which an average interval L between adjacent closure domains is 15 mm or less, a depth ratio r.sub.d of a depth of the closure domains to a sheet thickness, calculated by a predetermined formula, is 35% or more, and a volume fraction r.sub.v of the closure domains, calculated by a predetermined formula, is 0.30% or more and 3.0% or less, and an area ratio r.sub.s of the closure domains, calculated by a predetermined formula, is 0.50% or more and 4.0% or less.

A method for reducing and homogenizing residual stress of a metal frame based on elastic acoustic waves that includes determining an injection scheme of elastic acoustic waves based on residual stress distribution and material characteristics of a metal frame, where the injection scheme comprises at least one of the number of injection directions and corresponding injection direction(s), an excitation scheme and working parameters of the elastic acoustic waves; placing the metal frame in a substrate and fixing the inner and outer frames of the metal frame; assembling an excitation device for the elastic acoustic waves based on the determined excitation scheme of the elastic acoustic waves; injecting the acoustic waves into the metal frame from at least one direction; and performing the reduction and homogenization for multiple rounds if the reduction and homogenization of the residual stress of the metal frame in a single round does not meet the requirement.

A method for reducing and homogenizing residual stress of a metal frame based on elastic acoustic waves that includes determining an injection scheme of elastic acoustic waves based on residual stress distribution and material characteristics of a metal frame, where the injection scheme comprises at least one of the number of injection directions and corresponding injection direction(s), an excitation scheme and working parameters of the elastic acoustic waves; placing the metal frame in a substrate and fixing the inner and outer frames of the metal frame; assembling an excitation device for the elastic acoustic waves based on the determined excitation scheme of the elastic acoustic waves; injecting the acoustic waves into the metal frame from at least one direction; and performing the reduction and homogenization for multiple rounds if the reduction and homogenization of the residual stress of the metal frame in a single round does not meet the requirement.

A device for reducing and homogenizing residual stress of a metal frame including a substrate, a frame fixing device and ultrasonic vibrators. A groove with an upward opening is provided in the middle of the substrate, and a shape enclosed by vertical side walls of the groove matches a shape of an outer frame of a metal frame to be processed. A plurality of through holes that are horizontally diverged are arranged around the side walls of the groove, and the through holes are vertically intersected with the groove. The ultrasonic vibrators are provided on the substrate and front ends of the ultrasonic vibrators extend into respective through holes to abut against the metal frame in the groove. The frame fixing device is also arranged in the groove where the metal frame is located, after the metal frame to be processed is placed in the groove.

A laser shock strengthening method for small-hole components (4) with different thicknesses. In the method, different technological parameters are used for laser shock strengthening of the small-hole components (4) with different thicknesses, statistical analysis is conducted after a large number of tests to obtain an empirical formula; the empirical formula is a relational expression AA of the power density and the thicknesses of the small-hole component (4). The power density of laser shock strengthening of the small-hole components (4) with different thicknesses can be determined according to the relational expression; and a method for selecting and determining related technological parameters is provided. According to the method, after the small-hole components (4) with different thicknesses are subjected to laser shock strengthening by using a proper technology, reasonable residual compressive stress distribution can be obtained, a good strengthening effect can be achieved, effective shock quality control can be conducted on the components, and workpiece deformation is controlled while guaranteeing the fatigue life of the small-hole components (4).

A method includes producing a functional structure on an aluminum surface with a local laser treatment of an aluminum surface. The local laser treatment is carried out with a pulsed laser system having a pulse duration of from 10 ns to 100 ns. The average power of the pulsed laser system is less than 5 kW.

Systems and methods resolve stresses in additive manufacturing. A stress resolution profile including frequency and amplitude parameters of an ultrasonic input are determined based on physical properties of the product. Successive layers of a material are added and energy is applied to incorporate the material of each layer into the product. An ultrasonic input is applied with the determined parameters to resolve stress as the product is built up. The ultrasonic input is varied as a depth of the material incorporated into the product increases.

A multi-track laser beam process for surface hardening a low-carbon and low manganese steel. The process includes providing cold rolled close annealed (CRCA) steel sheets having in weight percentage, C: 0.03-0.07, Mn: 0.15-0.25 or 1.4, S: 0.005-0.009, P: 0.009-0.014, Si: 0.005-0.02, Al: 0.04, V: 0.001, Nb: 0.001, and Ti: 0.002 and heating the surface of the steel sheet to an austenizing temperature using a multi-track laser beam, where, upon cooling, phase transformation of the initial microstructure to a harder dual phase structure occurs. The surface temperature of the steel sheet may be controlled based on a comparison of the on-line surface temperature effect with pre-stored data representing the desired surface temperature effect to eliminate any possibility of melting the sheet. The development of the desired microstructure of the sheet, including measurement of the hardness level and the fraction of different phases, may be periodically reviewed.

The production method of the novel austenitic stainless steel kitchen knives and the low-carbon high-chromium martensitic alloy powder of the present invention include providing an austenitic stainless steel knife body. It cladding low-carbon high-chromium martensitic alloy powder on the austenitic stainless steel cutter body through high-frequency density laser pulse cladding process, tempering treatment, cutter face grinding, end face grinding, and edge processing; The invention adopts an austenitic stainless steel cutter body, and then adopts a high-frequency density laser pulsation cladding process to make a low-carbon high-chromium martensitic stainless steel at the cutting edge by plasma electrofusion.

A grain-oriented electrical steel sheet incudes a groove formed on a surface and a solidified alloy layer formed under the groove, wherein the solidified alloy layer includes particles of a certain average diameter.