A plunger member 3 used for a belt type continuously variable transmission is configured by cold press molding a blank material 32 according to deep-drawing molding, and closed forging, compression molding or a combined molding thereof, where during the cold press molding, a thickness of a bent corner portion 3f, which at least makes a sleeve portion 3c and a step-like formed portion (spring seating portion) 3d continuous to each other, is configured to be increased by 30% or more relative to a thickness of the blank material 32, and then a hardened surface layer 3B is configured to be formed on both of the entire front and back sides of the plunger member by performing a soft nitriding treatment.

The present disclosure relates to a steel forging process, in particular a hot steel forging process in horizontal press of a metal tube, preferably a cylindrical steel tube.

The present disclosure relates to a steel forging process, in particular a hot steel forging process in horizontal press of a metal tube, preferably a cylindrical steel tube.

A stabilizer having a tubular shape is provided so as to extend in a widthwise direction of a vehicle and coupled to a suspension arm at opposite end portions of the stabilizer. Each of the opposite end portions includes: a first large-diameter bar portion having an outside diameter greater than an outside diameter of an intermediate portion of the stabilizer; and a second large-diameter bar portion having an outside diameter greater than the outside diameter of the first large-diameter bar portion and having a wall thickness greater than a wall thickness of the intermediate portion.

A metal pipe having a thickened end portion, the metal pipe includes: when viewed in a longitudinal direction of the metal pipe, a thin portion which has a thickness t.sub.0; a first thickened portion which is provided on one end and has a thickness T which is larger than the thickness t.sub.0; and a first taper portion which is provided between the thin portion and the first thickened portion and has the thickness which gradually increases from t.sub.0 to T; when a hardness of an inner surface of the first thickened portion is measured in a circumferential direction and the hardness is plotted with respect to a position in the circumferential direction, in which a waveform representing a high hardness portion having a hardness which is 95% or more of a maximum hardness in the circumferential direction and a waveform representing a low hardness portion having a hardness which is less than 95% of the maximum hardness alternately appear, and a plurality of combinations of the waveform representing the high hardness portion and the waveform representing the low hardness portion appear.

A spinning device includes a flange forming section that, in a state where a base material having a tubular shape and including at least a large-diameter portion and a small-diameter portion is relatively rotated, forms a flange portion protruding in a direction away from a center axis by pressing the large-diameter portion in a center axis direction of the base material while contacting an outer peripheral portion of the small-diameter portion.

A spinning device includes a flange forming section that, in a state where a base material having a tubular shape and including at least a large-diameter portion and a small-diameter portion is relatively rotated, forms a flange portion protruding in a direction away from a center axis by pressing the large-diameter portion in a center axis direction of the base material while contacting an outer peripheral portion of the small-diameter portion.

The invention relates to a method for the production of hot-finished, particularly hot-rolled, seamless pipes having optimized fatigue properties in the welded state, having an outside diameter of up to 711 mm and a nominal wall thickness of up to 100 mm, made of metal, in particular steel. After hot or finish rolling, a defined pipe cross-section is produced on at least one pipe end across a predetermined length, having tight tolerances for inside and outside diameters, wherein the cross-section can then be welded to the pipe end of another pipe. According to the invention, in a region a wall thickness is created in a first step at the pipe end in question, the thickness being bigger than on the remaining pipe body, wherein the outside diameter is increased and/or the inside diameter is reduced. In a second step, the required pipe cross-section is produced in said region by mechanical treatment, and the transition from the treated to the untreated region of the pipe is produced with low surface roughness and almost notch-free, and the residual wall thickness remaining in the treatment region is within the required tolerances.

The invention relates to a method for the production of hot-finished, particularly hot-rolled, seamless pipes having optimized fatigue properties in the welded state, having an outside diameter of up to 711 mm and a nominal wall thickness of up to 100 mm, made of metal, in particular steel. After hot or finish rolling, a defined pipe cross-section is produced on at least one pipe end across a predetermined length, having tight tolerances for inside and outside diameters, wherein the cross-section can then be welded to the pipe end of another pipe. According to the invention, in a region a wall thickness is created in a first step at the pipe end in question, the thickness being bigger than on the remaining pipe body, wherein the outside diameter is increased and/or the inside diameter is reduced. In a second step, the required pipe cross-section is produced in said region by mechanical treatment, and the transition from the treated to the untreated region of the pipe is produced with low surface roughness and almost notch-free, and the residual wall thickness remaining in the treatment region is within the required tolerances.

A drive axle shaft and method for making the same are provided. The drive axle shaft includes an elongate tubular body and a wheel flange. The elongate tubular body has a longitudinal axis and comprises a first end portion and a second end. The second end is configured to be coupled to a side gear in a differential. The wheel flange is disposed at the first end portion and is configured to support a vehicle wheel. The elongate tubular body and the wheel flange are formed as a unitary body without any weld therebetween.