A processing die and a preparation method for a fastener are provided. The processing die includes a punch and a die. The top of the punch and the bottom of the die are configured for being connected with a hydraulic press, the die includes a first half die and a second half die which are clamped to form an inlet channel, an expansion corner channel and a torsion channel, and an extrusion channel is included in the forming sliding block, the inlet channel, the expansion corner channel, the torsion channel and the extrusion channel are sequentially assembled to form a die channel cavity, and a billet to be processed is successively subjected to upsetting, shearing, torsion and extrusion in a single die under the pressure of the punch.

A tungsten-base alloy material and a preparation method therefor. The preparation method comprises: 1) evenly grinding composite powder containing tungsten and zirconium oxide, and then performing annealing treatment at 700-1000° C. to obtain powder A; and 2) grinding and then compression moulding the powder A, and then performing liquid-phase sintering to obtain a tungsten-base alloy blank so as to obtain the tungsten-base alloy material.

The method consists of subjecting a coarse-grained titanium semi-product (1) with the pure titanium content of at least 99 wt % to a plastic deformation. In said plastic deformation the transverse cross-section surface area of the titanium semi-product is reduced by hydrostatic extrusion in which the titanium semi-product is the billet (1) extruded through the die (4). The reduction (R) of the transverse cross-section of the titanium billet (1) is realized in at least three but not more than five consecutive hydrostatic extrusion passes at the initial temperature of the billet (1) not above 50° C. and the extrusion velocity not above 50 cm/s. Prior to each hydrostatic extrusion pass, the titanium billet is covered with a friction-reducing agent. During the first hydrostatic extrusion pass, the reduction of the transverse cross-section surface area of the titanium semi-product is at least four, whereas during the second and third hydrostatic extrusion pass it is at least two and a half.

The present invention relates to a novel method for producing metallic semifinished products by extrusion, to the thus obtainable semifinished products and to contact pieces that can be produced therefrom.

A processing die and a preparation method for a fastener are provided. The processing die includes a punch and a die. The top of the punch and the bottom of the die are configured for being connected with a hydraulic press, the die includes a first half die and a second half die which are clamped to form an inlet channel, an expansion corner channel and a torsion channel, and an extrusion channel is included in the forming sliding block, the inlet channel, the expansion corner channel, the torsion channel and the extrusion channel are sequentially assembled to form a die channel cavity, and a billet to be processed is successively subjected to upsetting, shearing, torsion and extrusion in a single die under the pressure of the punch.

A system and method for producing a seamless pipe from a hollow billet with a smaller diameter than the seamless pipe, uses a pressure container configured to house the hollow billet. The hollow billet is surrounded by a fluid. A movable punch arranged to fit inside the hollow billet, wherein a hydraulic pressure is transferred from the fluid to the movable punch and to the hollow billet simultaneously, along at least a partial length of the hollow billet. A die opening is arranged serial to the pressure container, wherein the die opening is configured to house a fixed mandrel, the fixed mandrel having a diameter larger than an inner diameter of the hollow billet, so that a gap is formed between the die opening and the fixed mandrel, and the hydraulic pressure of the fluid is generated by an input force from an input punch to move the hollow billet towards the die opening and force the hollow billet material into the gap between the die opening and the fixed mandrel.

A method for manufacturing a tube includes continuously moving a tubular hollow blank through an expansion tool, and supplying fluid to a space delimited by the expansion tool and the tubular hollow blank the such that a hydraulic pressure is applied inside the tubular hollow blank. The magnitude of the hydraulic pressure is selected such that the tubular hollow blank is deformed plastically. The disclosure also relates to an arrangement for manufacturing a tube.

A method for manufacturing a tube includes continuously moving a tubular hollow blank through an expansion tool, and supplying fluid to a space delimited by the expansion tool and the tubular hollow blank the such that a hydraulic pressure is applied inside the tubular hollow blank. The magnitude of the hydraulic pressure is selected such that the tubular hollow blank is deformed plastically. The disclosure also relates to an arrangement for manufacturing a tube.

There are provided: a seamless steel pipe formed from a cylindrical steel material billet through a hot isostatic extrusion step, wherein a depth of a contiguous flaw formed on an inner periphery surface and an outer periphery surface of the steel pipe is 50 m or less; a hollow spring obtained by forming a hollow body in a shape of a coil or a bar or a bar with curved part from the seamless steel pipe made of spring steel and applying a surface treatment to the hollow body so that the hollow body has compressive residual stress; and a method for producing seamless steel pipe including: a billet molding step; a first heating step; a hot isostatic extrusion step; a second heating step; an extension step; a third heating step; and a pickling step.

Rods with the transverse cross-section surface area of at least 150 mm.sup.2 and tensile strength UTS above 1200 Mpa is produced using a plastic deformation that consisted of one-pass hydrostatic extrusion of the billet 1 made of austenitic steel, with the initial temperature of the billet being below 100 C. The reduction R of the transverse cross-section surface area of the biller (1), which takes place during the extrusion, is at least 2.