Abstract: In quenching, where a heated steel pipe (2) is immersed in a water bath (3) in parallel with water surface for cooling a pipe outer surface, and cooling water is injected from an axial center nozzle (8) into one end of pipe for cooling a pipe inner surface, thereby rapidly cooling the entire pipe surface, reduction of strength difference along a length of the quenched pipe becomes possible by moving the nozzle (8) following the motion of the pipe axis (2), and starting injecting the water from the nozzle (8) so as for the water to reach the other pipe end at the time of the immersion of the entire circumference of the pipe outer surface. An opening (3a) preferably faces the nozzle (8) to remove the water, and the flow velocity is preferably set to 23 m/sec or more for better water flow inside the pipe (2).

Abstract: The method provides heat-resistant chromia- or alumina-forming Fe-, Fe(Ni), Ni(Fe), or Ni-based alloys having improved creep resistance. A precursor is provided containing preselected constituents of a chromia- or alumina-forming Fe-, Fe(Ni), Ni(Fe), or Ni-based alloy, at least one of the constituents for forming a nanoscale precipitate MaXb where M is Cr, Nb, Ti, V, Zr, or Hf, individually and in combination, and X is C, N, O, B, individually and in combination, a=1 to 23 and b=1 to 6. The precursor is annealed at a temperature of 1000-1500° C. for 1-48 h in the presence of a magnetic field of at least 5 Tesla to enhance supersaturation of the MaXb constituents in the annealed precursor. This forms nanoscale MaXb precipitates for improved creep resistance when the alloy is used at service temperatures of 500-1000° C. Alloys having improved creep resistance are also disclosed.

Abstract: A method of manufacturing high strength steel wire for cold forging containing 0.15-0.40 wt % of C, less than 1.5 wt % of Si, 0.30-2.0 wt % of Mn, less than 0.03 wt % of P, and less than 0.03 wt % of S. After initial cold-drawing, the wire rod is heated in a series of high frequency induction heating devices over the Ac3 transformation point for 30-90 seconds. The wire rod is then rapidly cooled and tempered at a temperature of from 500° C. to the A1 transformation point for 30-90 seconds. The wire rod is then cooled to achieve a tensile strength of 1,100-1, 400 MPa. The wire rod is then cold-drawn at an area reduction rate in excess of 25% and up to 40% to yield a tensile strength of 1,200-1,600 MPa, with improved service life of the mold.

Abstract: The present invention provides a method for manufacturing a grain oriented electrical steel sheet, including preparing as a material a steel slab having a predetermined composition and carrying out at least two cold rolling operations, characterized in that a thermal treatment is carried out, prior to any one of cold rolling operations other than final cold rolling, at temperature in the range of 500° C. to 750° C. for a period in the range of 10 minutes to 480 hours. The grain oriented electrical steel sheet of the present invention exhibits through utilization of austenite-ferrite transformation superior magnetic properties after secondary recrystallization.