Abstract:
A case hardening steel tube which has a hardness of 72-80 HRB and which gives a carburized layer with a high strength and high wear resistance and adequate resistance to impact fracture when it is formed into a final product by working and subsequent carburizing and quenching under relatively mild conditions is manufactured by forming a tube from a steel having a steel composition comprising, in mass percent, C: 0.1-0.25%, Si: 0.2-0.4%, Mn: 0.3-0.9%, P: at most 0.02%, S: 0.001-0.15%, Cr: 0.5-0.9%, Mo: 0.15-1%, Al: 0.01-0.1%, B: 0.0005-0.009%, N: less than 0.006%, and a remainder essentially of Fe, then subjecting the resulting steel tube to normalizing by soaking at a temperature of 880-980° C. followed by cooling at a cooling rate of at most 70° C. per minute, carrying out cold working of the normalized steel tube, and then annealing the cold worked steel tube at a temperature of 700-820° C.
Abstract:
A high-strength cold-rolled steel sheet having a tensile strength of 340 MPa or more, which can prevent galling, can be manufactured even if a large number of the steel sheets are continuously press-formed. This is because a surface texture thereof is con-trolled so that the surface texture includes flat areas in which a roughness profile has a deviation of ±2 μm or less from a filtered waviness curve and a dented portion having a maximum depth between 10 μm and 50 μm from the filtered waviness curve, wherein an average area of the dented portion is more than 0.01 mm2 and 0.2 mm2 or less, and an area fraction of the dented portion relative to the entire surface thereof is 5% or more and less than 20%.
Abstract:
A method and apparatus for surface hardening parts is disclosed. To harden a surface of a part, a relative movement, or advancing motion, is established between the part and at least one sonotrode-like tool which is excited in the ultrasonic frequency range. The tool is aligned during the surface hardening in such a way to the surface of the part to be hardened that a tool axis running in the effective direction of the tool runs at an angle to the surface of the part to be hardened.
Abstract:
The invention relates to foundry engineering, more specifically to producing an antifriction layer of a plain bearing by casting babbitt into a bearing shell or backing and is applicable to the manufacture and renewal of plain bearings.The invention is aimed at improving the quality of a plain bearing antifriction layer.A method for producing an antifriction layer of a plain bearing including: casting babbitt into a bearing shell or backing and forcedly cooling the babbitt at a speed providing structural uniformity of the antifriction layer, mainly by cooling babbitt on the cast-in layer side, characterized in that said casting of babbitt into a bearing shell or backing produces a semifinished antifriction layer which is subjected to plastic deformation by means of a punch under superplasticity conditions to produce an antifriction layer, the bearing shell or backing being used as a die.
Abstract:
A laser shock peening process for producing one or more compressive residual stress regions in a medical device is disclosed. A high-energy laser apparatus can be utilized to direct an intense laser beam through a confining medium and onto the target surface of a workpiece. An absorption overlay disposed on the target surface of the workpiece absorbs the laser beam, inducing a pressure shock wave that forms a compressive residual stress region deep within the workpiece. Medical devices such as stents, guidewires, catheters, and the like having one or more of these compressive residual stress regions are also disclosed.
Abstract:
Metallic workpieces of diverse shapes having work surfaces which are deformed at the surface and adjacent sub-surface layers by surface impact from ultrasonic transducers employing freely axially moving impacting elements propelled and energized by a transducer oscillating surface vibrating periodically at an ultrasonic frequency. The impacting elements are propelled in a random aperiodic and controlled impact mode at different phases of the periodic oscillation cycles. The transducer may be portable and provides a series of mechanically interconnected stages having mechanical resonances harmonically related as a multiple of the primary ultrasonic frequency and have matched stage resistances under instantaneous loading when the impact elements are driven by the transducer oscillating surface into the surface of the workpiece. This mode of operation produces Q-factor amplification of the input ultrasonic power oscillator energy at the impact needles and high propulsion velocities making it possible to machine metallic workpiece bodies to greater depths for compressing the metal to increase compressive strength of the workpiece work surfaces to substantially the ultimate material strength. The impact machining is done at ambient temperatures.
Abstract:
A method and surface treatment apparatus for preventing or arresting the development and propagation of cracks in the material surrounding a fastener. The method includes introducing compressive residual stresses in the material surrounding the fastener. The compressive residual stresses offset the high residual tensile and applied stresses which the material may be subjected to in operation and thereby prevent or arrest the development of cracks. The surface treatment apparatus comprises a compression tool, positioning device and at least one sensor for determining the location of a fastener on the surface being treated. Using the output of the sensor, the surface treatment apparatus is positioned relative to a fastener. The compression tool is impinged against the surface of the material adjacent to the fastener and rotated around the perimeter of the fastener thereby inducing a zone of compressive residual stress.
Abstract:
Methods are disclosed for increasing lift and decreasing drag on hydrofoils and swim fins. Methods are disclosed for providing a hydrofoil with a substantially longitudinal recess or venting system located substantially along the center axis of the hydrofoil. Methods also include providing the attacking surfaces of hydrofoils with an anhedral contour that forms a substantially lengthwise channel with the recess or venting means located along the center axis of this lengthwise channel. Methods are also disclosed for arranging a central recess or venting system to permit water to flow through it toward the lee surfaces in order to reduce the occurrence of outward directed spanwise flow conditions along the attacking surfaces and encourage inward directed spanwise flow conditions to occur along the attacking surfaces. Methods are disclosed for applying lift generating and drag reducing methods to both non-flexible and flexible hydrofoil blades that are used in reciprocating propulsion strokes through a fluid medium. Methods are also provided for controlling and reducing the build up of torsional stress forces within a flexible hydrofoil as it is encouraged to twist to a reduced angle of attack during use.
Abstract:
Devices including a magnetostrictive transducer, an oscillating system and a tool for ultrasonic impact treatment of constructions, construction units and components of machines and mechanisms are disclosed. The invention provides high reliability of magnetostrictive transducers, oscillating systems and their components, tools and their parts affected by simultaneous action of static, dynamic and impact load on a work surface, high stability of characteristics and interchangeability thereof under conditions of small-scale, full-scale and mass production. The invention also includes design solutions with the use of new methods of the realization and manufacturing technique of the above.
Abstract:
An improved gear including a plurality of teeth defining a surface, the teeth each having a substantially continuous first subsurface stress layer located below the surface, and a second subsurface stress layer located below the first subsurface stress layer, the first subsurface stress layer comprising a thickness of compressive residual stress.