Nippon Steel Sumitomo Metal Corporation

Hiroshi Shimanuki

Tetsuro Nose

A probability in which a stress amplitude &#x3c3;of an operating stress exceeds a stress amplitude &#x3c3;of a fatigue strength (a fatigue strength excess probability pof a virtual cell) at each virtual cell in which a region of a machine component is equally divided so that one inclusion is contained therein and having a virtual unit volume Vis derived on an assumption that a distribution function of an inclusion size &#x221a;{square root over ( )}area follows a generalized Pareto distribution. Then a probability in which the stress amplitude &#x3c3;of the operating stress exceeds the stress amplitude &#x3c3;of the fatigue strength (a fatigue strength excess probability pof the machine component) in at least one virtual cell is derived from the fatigue strength excess probability p.

Component fracture evaluation device, component fracture evaluation method and computer program

An impact treatment method for improving fatigue characteristics of a welded joint comprising pressing an impact pin against the surface of a base metal material near a toe of a weld bead and making it move relatively to the weld line direction to apply hammer peening treatment or ultrasonic impact treatment, characterized by using as the impact pin an impact pin having a tip curvature radius of &#xbd; or less of a thickness of the metal material and between 2 to 10 mm and, on a surface of a base metal material up to a range where a distance from the toe of the weld bead to the center of the impact treatment position is within 2.5 times the tip curvature radius of the impact pin and where the impact pin does not contact the weld metal during impact treatment, applying hammer peening or ultrasonic impact treatment so as to cause by the impact pin residual plastic deformation where an impact dent has a groove depth of 0.1 to 2 mm, the tip curvature radius of the impact pin or less, and 1/10th or less of the thickness of the metal material and where the impact dent has a width of 1.5 to 15 mm and five times or more the groove depth.

Impact treatment method for improving fatigue characteristics of welded joint, impact treatment device for improving fatigue characteristics for same, and welded structure superior in fatigue resistance characteristics

Growing community of inventors

Tokyo, Japan

Hiroshi Shimanuki