64 results about "Cold formed" patented technology

According to the NM450 wear-resistant steel suitable for the polar working condition and the production method thereof, low-cost component design is adopted, and the process steps comprise smelting, refining, continuous casting, heating, rolling and heat treatment; the steel-making process and harmful elements are strictly controlled to improve the purity of molten steel so as to improve the internal quality of the steel plate, and a strict rolling, quenching and low-temperature tempering heat treatment process is adopted. The NM450 wear-resistant steel plate which is high in toughness adaptability, high in wear resistance and excellent in cold forming performance comprehensive performance is developed, the thickness ranges from 6 mm to 30 mm, the surface hardness ranges from 450 HBW to 480 HBW, the core hardness ranges from 440 HBW to 465 HBW, and the core hardness reaches 95% or above of the surface hardness; the yield strength is not less than 1200 MPa, the tensile strength is not less than 1400 MPa, and the elongation is not less than 13%; the impact AKV at-50 DEG C is greater than or equal to 60J, and the impact AKV at-60 DEG C is greater than or equal to 40J; the bending angle is 90 degrees, the bending diameter D is 6a, and the cold bending result is intact.

This invention discloses a method and apparatus for preparing metal ingots based on melt flow-limited stacking casting and rapid cooling forming, relating to the field of metal forming technology. This method is based on continuous or intermittent advancement of melt flow-limited bottom casting, layer-by-layer reciprocating stacking, and layer-by-layer relay rapid cooling forming. It can achieve continuous rapid cooling forming of the molten metal, refining grains, and by limiting atomic diffusion, achieve layer-by-layer freezing-type rapid solidification forming with uniform atomic distribution in the molten metal, reducing component segregation. It can also simultaneously achieve the relay upward movement or reduction of casting defects such as shrinkage cavities and porosity layer by layer. The flow-limiting guide nozzle is equipped with a liquid outlet and a parallel and similarly shaped anti-oxidation coolant spray nozzle, located at the bottom of a crucible with a filter to reduce inclusions. This invention can simultaneously and rapidly reduce and coordinately control defects such as coarse grains, shrinkage cavities, porosity, component segregation, and inclusions during the solidification of the molten metal in a short process, achieving short-process, high-quality manufacturing of metal ingots, especially large metal ingots (including amorphous ingots).

The invention discloses a method for preparing a clad plate strip by adopting a hot continuous rolling process and the clad plate strip. The method sequentially comprises the steps of plate blank heating, rough rolling, clad blank preparation, clad rolling, controlled cooling and coiling, wherein a plate blank is subjected to surface polishing after being subjected to rough rolling and dephosphorization, then is subjected to preliminary covering and welding with a to-be-covered plate strip to form a covering blank, and then enters a finishing mill group to be subjected to covering rolling; the surface polishing of the plate blank, the preliminary covering of the to-be-covered coil and the welding are all carried out in an atmosphere protection cover, and N2, CO2 or a mixed gas of N2 and CO2 is introduced into the atmosphere protection cover; the plate blank is made of carbon steel; and the plate strip to be covered comprises titanium, copper or stainless steel. According to the invention, the hot continuous rolling process is adopted to produce the clad plate strip on line, the clad plate strip integrates the excellent characteristics of corrosion resistance, electric conduction, heat dissipation and beauty of the clad layer and high strength of the substrate, and the cost is lower and the application range is wider to the greatest extent; the product has the characteristics of corrosion resistance, good heat dissipation performance, easiness in cold forming processing, attractive appearance and no coating.

This invention discloses an electric field-assisted spline cold forming method and machine tool; this invention belongs to the technical field of machining and metal plastic forming equipment; it aims to solve the problems of high load, rapid mold wear and poor forming quality in the cold forming of splines of difficult-to-deform materials such as high-strength alloy steel and titanium alloy; the positive terminal of the pulse power supply forms a circuit with the workpiece through the center and the negative terminal through the brush, so that the high-frequency pulse current flows directly through the cold forming deformation zone, inducing the electroplastic effect, reducing the yield strength of the material and improving plasticity; on this basis, the symmetrically arranged cold forming tools apply radial force to the workpiece as the spindle rotates, and the spline teeth are formed by the axial feed and rotation of the workpiece; this method deeply couples electric field softening with mechanical forming, fundamentally reducing the forming load, extending the mold life and improving the spline dimensional accuracy and surface quality.

This invention discloses a method for producing easily formable ultra-high strength steel plates for engineering machinery, belonging to the field of metal material processing technology. This invention employs a medium-carbon + multi-element microalloying system, and through converter steelmaking + refining, continuous casting, billet heating, two-stage controlled rolling, and quenching + tempering heat treatment, produces ultra-high strength steel plates with a thickness of 5-20 mm. The resulting steel plate has a matrix structure of ultra-fine-grained lath martensite with an effective grain boundary size of 1.2-1.5 μm, a yield strength ≥1500 MPa, a tensile strength ≥1800 MPa, an elongation >10%, an impact energy >50 J at -40℃, and meets the requirements of D=6a and 180° bending without cracking. It possesses ultra-high strength, excellent low-temperature toughness, and cold formability, and can be directly used for forming key load-bearing structural components of engineering machinery. The process is simple and highly adaptable to industrial applications.

The invention discloses a corrosion-resistant and high-performance aluminum alloy cable material as well as a preparation method and application thereof, and relates to the technical field of aluminum alloy preparation. The component formula of the conductor is Al-xMg-ySi-zNi-mCe-nSc-qY, x is larger than or equal to 0.05 and smaller than or equal to 0.3, y is larger than or equal to 0.6 and smaller than or equal to 1.4, z is smaller than or equal to 0.35, m is larger than or equal to 0.01 and smaller than or equal to 0.2, n is larger than or equal to 0.03 and smaller than or equal to 0.2, q is larger than or equal to 0.04 and smaller than or equal to 0.1, iron is a main impurity element in the alloy, and the content of the iron is not larger than 0.1%. The aluminum alloy cable material with excellent mechanical properties (the tensile strength is larger than or equal to 122 MPa, and the elongation is larger than or equal to 14%), electrical properties (the conductivity is larger than or equal to 62% IACS) and corrosion resistance (the maximum IGC depth is smaller than 100 micrometers) is prepared by adopting the technological method of flame direct injection smelting, synchronous water quenching pull casting, cold forming machining and non-isothermal aging synchronous heat treatment, and the aluminum alloy cable material is suitable for aluminum alloy cables. The method is short in technological process, good in cable quality, high in corrosion resistance and wide in application prospect.

This invention provides an electroslag welding apparatus and a welding method thereof. The electroslag welding apparatus includes a workpiece body and a power source. A slag pool is disposed within the workpiece body, and a molten pool is disposed below the slag pool. Metal slag in the slag pool accumulates below the molten pool after passing through it, forming a weld. A liquid-cooled forming slider is disposed around the periphery of the molten pool. The height of the molten pool increases with the accumulation of the weld, and the height of the liquid-cooled forming slider also increases with the molten pool. Furthermore, a first conductive path is provided between the slag pool and the positive electrode of the power source, a second conductive path is provided between the weld and the negative electrode of the power source, and a third conductive path is provided between the liquid-cooled forming slider and the negative electrode. The electroslag welding apparatus provided by this invention can solve the problem of poor weld formation quality in the prior art.

Steel flat product for cold forming consisting of a steel substrate coated with a protective coating, wherein the protective coating consists of an inner Al-Si-containing and an outer alkaline earth oxide and / or transition metal oxide-containing layer, and wherein the steel substrate has a composition containing (in wt.%): - up to 0.09 carbon - up to 0.3 silicon - up to 0.9 manganese - up to 0.025 phosphorus - up to 0.02 sulfur - up to 0.1 aluminum - up to 0.14% titanium and / or niobium - up to 0.001 boron, and possibly - further alloying elements selected from the group up to 0.01 N, up to 0.15 Cu, up to 0.15 Cr, up to 0.15 Ni, up to 0.025 Mo, and / or up to 0.05 Sn, and - Residual iron and unavoidable impurities.

The object of this invention is to provide a high-strength hot-rolled flat steel product and a method for producing such a flat steel product, thus achieving a combination of high strength with high local cold formability and high economy in terms of steel. This is achieved through a high-strength hot-rolled flat steel product with high local cold formability, having a tensile strength Rm of at least 760 MPa, a yield strength ratio of at least 0.8, and a porosity of at least 30%, advantageously at least 40%, particularly advantageously at least 50%, at least 10%, preferably at least 16%, an elongation at break of at least 0.12, advantageously at least 0.17, and a ratio of local cold formability to overall cold formability of at least 5 and at most 13, and a microstructure consisting of more than 50% (by volume) bainite, no more than 10% (by volume), advantageously no more than 5% (by volume) carbon-rich microstructure such as martensite, retained austenite, pearlite, etc. The steel has a ferrite-based microstructure and the following chemical composition (wt%): C: 0.04–0.08; Si: 0.1–0.6; Mn: 1.0–2.0; P: maximum 0.06; S: ​​maximum 0.01; N: maximum 0.012; Al: not more than 0.06; Ti: not more than 0.18 and / or Nb: not more than 0.08; Mo: not more than 0.35; Ti+Nb greater than 0.06, wherein carbon and nitrogen exist in excess of stoichiometry according to the following formula: 1.0 < (C / 12 + N / 14) / (Ti / 48 + Nb / 93 + Mo / 96), the remainder being iron, including unavoidable steel-related elements.

The invention relates to a method (100) for producing a one-piece vehicle wheel (1), wherein the vehicle wheel (1) has a wheel disc segment (2) and a wheel rim segment (3), and wherein the method (100) comprises: providing (101) a one-piece preform (4) of a metal material, in particular a circular blank (4) of a metal material or a strip (4) of a metal material, wherein the metal material is specified by material quality and / or material thickness; forming a cylinder (5) from the provided one-piece preform (4) of a metal material, wherein the cylinder (5) comprises the wheel disc segment (2) and the wheel rim segment (3); profiling (103) the respective material thickness in different regions of the respective segment (2, 3) of the wheel disc segment (2) and / or the wheel rim segment (3) of the one-piece vehicle wheel (1) based on a cold forming method, in particular based on a spinning forming method.

The invention relates to a preparation method of an NS3103 thousand-degree-grade heat-resistant element, and belongs to the field of material forming and processing. The preparation of the heat-resistant element is completed by using a ceramic auxiliary basic part to perform investment casting molding, heating the basic part, inserting the basic part into a plate in a heating state, and performing integral slow cooling molding. The preparation method specifically comprises the following steps: step 1, molding; 2, making a shell; step 3, roasting; step 4, smelting and pouring; and 5, cleaning and hot press molding are conducted. By improving the dimensional precision of the basic part and combining the hot press molding process, the problem that a large gap exists after a plate is inserted into the basic part is solved, and after batch production, the NS3103 thousand-degree-grade heat-resistant element matching part is compact and stable in production quality.

The present invention relates to a structural base course coating composed of one or more base layers, each base layer comprising, by mass relative to its total mass: - 50% to 90% asphalt aggregates comprising, by mass relative to its total mass, a residual bituminous binder content ranging from 3% to 8%; - 0% to 48% sand; - 2% to 10% hydraulic binder, characterized in that each base layer, after compaction, has a thickness strictly less than 15 cm and is free of added bituminous binder. The present invention also relates to a cold-forming process for said base course coating, as well as to a road surface. Figure for the abstract: no figure

The utility model discloses a high-barrier sewing forming packaging bag which comprises an upper film body and a lower film body, and the end edges of the upper film body and the lower film body are heat-sealed and encircled to form a bag body; the upper film body comprises an upper outer layer, an upper barrier layer and an upper functional layer which are sequentially arranged from the outside of the bag body to the inside of the bag body; the lower die body comprises a lower outer layer, a lower blocking layer, a lower inner layer and a lower functional layer which are sequentially arranged from the outside of the bag body to the inside of the bag body; and the upper functional layer and the lower functional layer are polyethylene films containing drying agents. The drying agent particles are mixed into the PE to form the upper functional layer and the lower functional layer, so that the validity period of the absorption instrument can be prolonged; the barrier layer is made of cold forming aluminum, so that a plane bag can be replaced by three-dimensional packaging, and high-barrier water and oxygen resistance can be realized; and the outer layer of the bag body adopts the nylon NY design, so that the puncture-resistant and wear-resistant effects of the packaging bag are improved.

The invention discloses a preparation method of thin-gauge 780MPa-grade hot-rolled automobile structure steel with complex cold forming capacity. The preparation method comprises the following steps: a steelmaking process; a hot rolling process; the steel comprises the following chemical components in percentage by mass: 0.04 to 0.06 percent of C, 0.03 to 0.10 percent of Si, 1.55 to 1.65 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.005 percent of S, 0.020 to 0.040 percent of Alt, 0.105 to 0.120 percent of Ti, 0.13 to 0.20 percent of Mo, 0.0020 to 0.0060 percent of N and the balance of iron element and inevitable impurities. The invention aims to provide the preparation method of the 780MPa-grade hot-rolled steel for the automobile structure, wherein the thickness of the 780MPa-grade hot-rolled steel is 2.0-6.0 mm, and the 780MPa-grade hot-rolled steel has excellent cold forming capacity, so that the complex forming requirements of part of automobile structural parts are met.

The invention discloses a hot-rolled copper-clad plate strip and a production method, the hot-rolled copper-clad plate strip comprises a steel substrate and a copper layer on at least one surface of the steel substrate, and a copper-steel transition layer is formed on a contact interface of the steel substrate and the copper layer; the steel substrate comprises the following chemical components in percentage by weight: 0.04-0.09% of C, less than or equal to 0.10% of Si, 0.25-0.45% of Mn, less than or equal to 0.018% of P, less than or equal to 0.008% of S, 0.01-0.04% of Al, less than or equal to 0.005% of N, 0.01-0.028% of Ti and the balance of Fe. And the balance of Fe and inevitable impurity elements. The high-strength and wide-specification requirements are met, the yield strength is larger than or equal to 355 MPa, the tensile strength is larger than or equal to 490 MPa, the ductility is larger than or equal to 30%, the width can reach 700-1800 mm, the good copper-steel interface bonding strength, surface quality and cold-bending machining characteristics are achieved, the cold-bending forming performance meets the 180-degree cold-bending requirements of D = 0a, and the cold-forming machining requirements of high-strength structural parts in the fields of heat dissipation, electric conduction, corrosion resistance and decoration are met; moreover, steel and copper are compounded in the conventional steel hot continuous rolling production process, acid pickling, splitting and annealing processes after copper-clad rolling in an existing copper-clad process are omitted, the production efficiency is higher, and the cost is lower.

The invention discloses a production method for improving the cold forming performance of ultra-pure ferritic stainless steel, and belongs to the field of stainless steel production. The process sequentially comprises the steps of plate blank heating, rough rolling, finish rolling, coiling, thermal annealing and pickling, pre-rolling of a 20-roller mill, chrome steel wire shot blasting and pickling, rolling of the 20-roller mill, cold annealing and pickling, leveling of a temper mill, shearing and packaging. The method is characterized in that a composite rolling method of reciprocating rolling of the first two passes and the last two passes and one-way rolling of the middle pass is adopted in the cold rolling stage, and a roller sequence that a high-roughness F roller is used in the front section and a low-roughness H roller is used in the rear section is matched. By optimizing the hot rolling pass and the cold rolling process and cooperatively controlling the texture development, the strength of the favorable gamma fiber texture in the finished product is remarkably improved, the plastic strain ratio r value of the obtained 2D / 2B state cold-rolled steel coil is larger than 1.75, and the 2D / 2B state cold-rolled steel coil has excellent cold forming and deep drawing performance and can meet the high-end market requirement.

The invention discloses a 55Cr3 process method for a cold forming non-quenched and tempered automobile stabilizer bar. The 55Cr3 process method comprises the steps that a 55Cr3 blank produced through converter smelting, LF refining, RH vacuum treatment and a continuous casting route is sequentially subjected to heating, temperature control rolling and cooling. Aiming at the application requirements of the automobile stabilizer bar used in a cold forming and non-quenched and tempered state, the forming performance and the obdurability of the 55Cr3 are controlled, and the machining and application requirements of the stabilizer bar are met.

The utility model relates to a cold forming blister packaging machine which comprises a forming machine body, a movable mechanism is arranged on the inner wall of a mounting shell, first connecting rods are connected to the two sides of the movable mechanism, one ends of the first connecting rods are connected with two sets of first connecting rods, and one ends of the two sets of first connecting rods are connected with second connecting rods. A sliding groove is formed in the conveying belt, a second connecting rod is arranged in the sliding groove, one end of the second connecting rod is connected with a long plate, the long plate is movably clamped in the inner wall of the sliding groove, one end of the long plate is connected with a connecting pipe, one end of the connecting pipe is connected with a connecting column, and one end of the connecting column is movably provided with an adjusting roller. And production faults and product defects caused by loosening or tightening of the materials are effectively avoided. Due to the high-precision tension adjusting capacity, the forming machine can be suitable for various materials with different materials and thicknesses, and the flexibility and adaptability of equipment are enhanced.

The present invention relates to a steel sheet suitable as a material for vehicle body members and, more specifically, to: a plated steel sheet suitable not only for hot forming but also for cold forming; a manufacturing method thereof; and a hot press formed member obtained from the plated steel sheet.

The disclosure modalities relate to a blister pack having a laminated structure that is heat-sealed to a lacquer layer on cold-formed aluminum foil. The blister pack includes a lid layer comprising cold-formed aluminum foil, a lacquer layer on a sealing surface of the cold-formed aluminum foil, and a laminated structure sealed directly to the lacquer layer. The laminated structure includes a multilayer film and a plurality of cavities formed therethrough. The multilayer film includes a first conformable layer of a thermoplastic material and a sealing layer of a copolyester material. The sealing layer covers the first conformable layer and has an outer surface opposite the first conformable layer. The sealing layer has a crystallinity of 5 to 20% as measured by differential scanning calorimetry (DSC).The outer surface of the sealing layer is sealed directly against the lacquer layer.

The utility model discloses a range hood curved glass hot-bending quenching forming device which comprises a base, a lower die fixed to the base, a containing groove formed in the lower die, a top plate supported on the top of the base through stand columns, a telescopic air cylinder installed on the top plate, and a piston rod of the telescopic air cylinder penetrating through the top plate and then fixedly connected with an upper die. A protruding die head is arranged on the bottom face of the upper die, and the protruding die head is matched with the containing groove to form a containing die cavity. The upper mold and the lower mold are both provided with through holes penetrating front and back, and the through holes are arranged close to the placing mold cavity up and down; the heating element can be separated, when the mold and the glass are cooled through air cooling, the heating element cannot form interference, the heated mold can be rapidly cooled, and rapid cooling is facilitated; the through hole can be used as a heating cavity of a heating element and can also be used as a cooling cavity of an air cooling mechanism, so that the heating and cooling efficiency of the mold can be improved when the mold is arranged close to the cavity, and mutual interference is avoided.

The present disclosure relates to a vacuum forming method, apparatus, and resulting display that represent improvements in a variety of key areas. The method greatly improves manufacturing yield, for example, by reduced cure times. The method further facilitates improved control of glass shape to target shape and improved control of bondline thickness, which leads to, for example, improved survivability and long-term reliability.

The invention discloses a preparation method of a 1000MPa-grade high-strength plastic stainless steel plate, and belongs to the field of metal materials. In order to solve the technical problems that the strength and corrosion resistance of an existing stainless steel material are difficult to match in room-temperature and low-temperature environments and the like, the mechanical property, the corrosion resistance and the cold forming property of the stainless steel plate are well balanced through accurate control over the cold rolling reduction; and a low-cost solution can be provided for application of the stainless steel plate in the fields of ocean structures, aerospace, energy, chemical industry and the like.

The application discloses a kind of cold-formed steel-ALC plate combination floor and the combination structure of concrete beam, its connecting piece is pot-shaped connecting piece or channel steel connecting piece, be arranged in the both ends of cold-formed steel, for cold-formed steel is erected on concrete beam;Pot-shaped connecting piece includes rectangular steel strip and obliquely arranged prismatic steel strip, one end top of rectangular steel strip is attached to the upper flange of cold-formed steel, and the other end extends outward;The top of prismatic steel strip is connected with the bottom of rectangular steel strip, and the side wall is attached to the web of cold-formed steel;The web of channel steel connecting piece is attached to the web of cold-formed steel at one end, and extends outward at the other end.The application can be factory prefabricated, on-site assembly, reliable connection, clear force transmission path, fast construction speed, give full play to the advantages of cold-formed steel and concrete material, expand the application range of cold-formed steel structure, so that cold-formed steel-concrete composite structure becomes possible, applicable to high-rise building.

Method for manufacturing a fluid pump, in particular an oil pump, with a housing, wherein a chamber extends along a first direction from a first end of the housing to a second end of the housing, wherein a piston is movably arranged in a pumping section of the chamber, wherein at least annular sealing section of the piston abuts an inner wall of the pumping section of the piston chamber in a sealing manner, wherein a delivery line is formed in the piston, wherein the delivery line extends from a first end of the piston to a second end of the piston, wherein the first end of the piston is arranged outside the chamber, wherein the second end of the piston is arranged in the chamber, wherein the delivery line is designed to direct fluid from the first end of the piston into the chamber, wherein the piston and / or the housing are made of cold-formed metal.

The invention discloses an energy-saving and efficient method for preparing a high-performance aluminum alloy conductor, and relates to the technical field of metal material processing. The component formula of the lead is Al-xSi-yMg-zCu-mRE-nB, wherein x is larger than or equal to 0.6 and smaller than or equal to 1.4, y is larger than or equal to 0.05 and smaller than or equal to 0.3, z is smaller than or equal to 0.1, m is larger than or equal to 0.01 and smaller than or equal to 0.1, n is larger than or equal to 0.04 and smaller than or equal to 0.12, and the preparation technological process comprises the steps of burdening, flame direct injection smelting, refining, synchronous water quenching pull casting, cold forming machining and aging annealing synchronous heat treatment. By optimizing the formula and adopting the process matched with the formula, the wire with high mechanical strength (greater than or equal to 120 MPa), high conductivity (greater than or equal to 62% IACS) and good plasticity (greater than or equal to 14%) can be prepared, and the preparation method is short in process flow, easy to operate, low in preparation cost, low in energy consumption, convenient to industrialize and wide in application prospect.

The present invention relates to devices (10) and methods for producing a profile on a circumferential surface (16) of a (cylindrical) workpiece (14). The device (10) according to the invention comprises a test device (11) and a cold forming machine (12), wherein one or more characteristic hardness values ​​(17) of the workpiece (14) to be processed are determined and assigned to it in the test device (11). The feed position (26) of the at least one forming tool (21) of the cold forming machine (12) is determined and adjusted based on the characteristic hardness value (17) assigned to the workpiece (14). The characteristic hardness value (17) corresponds at least approximately to the actual hardness of the workpiece (14) to be processed. Based on this information, the feed position of the forming tool can be determined.the forming tools relative to the workpiece are selected in such a way that variations in the material hardness of the workpieces (14), which may occur from batch to batch as well as from workpiece (14) to workpiece (14) within a batch, can be compensated by the device and method according to the invention.

This invention discloses a hot-rolled steel strip for lightweight commercial vehicle body structures and its preparation method. The steel strip composition by weight percentage is: C≤0.06%, Si 0.15~0.30%, Mn 1.70~1.90%, Nb 0.05~0.09%, Ti 0.09~0.15%, Mo 0.20~0.30%, with the balance being Fe and impurities. The method includes: continuously casting into slabs and heating at 1230~1270℃ for 2.5~3.5h; two-stage controlled rolling, with a roughing pass reduction rate ≥30%, a finishing pass cumulative reduction rate ≥60%, and a final rolling temperature of 820~860℃; post-rolling cooling using UFC+ACC combined cooling at a cooling rate of 15~30℃ / s to 530~570℃; and coiling and then stacking cooling to below 200℃. The hot-rolled steel strip of this invention has a yield strength ≥700MPa, elongation after fracture ≥12%, impact energy at -40℃ ≥40J, and a microstructure of ferrite + bainite + a small amount of mafic elements. It has high strength, good cold formability and weldability, and can be delivered directly after hot rolling. It is suitable for lightweight commercial vehicle bodies.

A self-drilling, thread-forming screw made of stainless-steel has the following functional sections that merge into and / or are adjacent to one another: A screw tip, a truncated cone having a terminating dome, a cylindrical shank threaded at least in sections, and a head. A thread-like relief structure having longitudinally extended, arcuate ribs is arranged on the jacket of the truncated cone. These ribs, viewed in the longitudinal direction, are arranged one behind the other but spaced apart and follow a virtual helical curve. The screw is entirely manufactured of stainless-steel without post-manufacturing heat treatment to improve the material hardness by cold forming the screw head by upsetting. The screw tip is formed with the special thread-like relief structure consisting of the arcuate ribs, with this shape being achieved by a pinching movement transverse to the longitudinal axis between two opposing tool jaws. Protruding material is sheared off during subsequent thread rolling.