Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
  • B21C37/00—Manufacture of metal sheets, rods, wire, tubes, profiles or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
  • B21C37/06—Manufacture of metal sheets, rods, wire, tubes, profiles or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B19/00—Tube-rolling by rollers arranged outside the work and having their axes not perpendicular to the axis of the work
  • B21B19/02—Tube-rolling by rollers arranged outside the work and having their axes not perpendicular to the axis of the work the axes of the rollers being arranged essentially diagonally to the axis of the work, e.g. "cross" tube-rolling ; Diescher mills, Stiefel disc piercers or Stiefel rotary piercers
  • B21B19/04—Rolling basic material of solid, i.e. non-hollow, structure; Piercing, e.g. rotary piercing mills
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
  • B21J5/00—Methods for forging, hammering, or pressing; Special equipment or accessories therefor
  • B21J5/06—Methods for forging, hammering, or pressing; Special equipment or accessories therefor for performing particular operations
  • B21J5/10—Piercing billets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
  • B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
  • B21B1/466—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a non-continuous process, i.e. the cast being cut before rolling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B23/00—Tube-rolling not restricted to methods provided for in only one of groups B21B17/00, B21B19/00, B21B21/00, e.g. combined processes planetary tube rolling, auxiliary arrangements, e.g. lubricating, special tube blanks, continuous casting combined with tube rolling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
  • B21B3/02—Rolling special iron alloys, e.g. stainless steel
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21H—MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
  • B21H1/00—Making articles shaped as bodies of revolution
  • B21H1/06—Making articles shaped as bodies of revolution rings of restricted axial length
  • B21H1/12—Making articles shaped as bodies of revolution rings of restricted axial length rings for ball or roller bearings

Definitions

• the invention relates to a method for producing a hot-formed tube high-carbon especially hypereutectoid steel according to the generic term of Main claim.
• a block is cast, which turns into a tube round on a roughing mill is rolled.
• This round tube is preferably closed using the Assel method formed into a hot-finished pipe (see steel pipe manual 10th edition, Vulkan-Verlag, Essen, 1986, pages 141-143).
• Assel Street usually points a rotary hearth furnace as a heating system, one as a cross rolling mill trained perforator for producing a hollow body follows.
• This hollow body an Assel mill consisting of three is evenly distributed over the circumference arranged cross rollers supplied with a shoulder calibration are. After pulling out the rod that serves as the inner tool, this becomes Intermediate pipe reheated and over a multi-stand reducing mill and over a downstream sizing mill produces the hot-finished pipe.
• a disadvantage of this method is that the tube round used close to the dimension must be hot-made pipe and to cover the delivery program A large number of rolled or forged tubular round material is required.
• Assel Street is the preferred facility for the production of roller bearing tubes, but also other tube production systems, such as push bench systems or Pipe continuous lines are always used using preformed and diffusion annealed feed.
• the object of the invention is a method for producing a hot-finished Specify tube from high-carbon, in particular hypereutectoid steel, which in Compared to the known method is cheaper and with a higher Material utilization and a shorter material throughput time can be achieved.
• the essence of the invention is the use of undeformed continuous casting from steel, in particular from the material group of rolling bearing steels of any cross-section on a tube production system, eliminating the previously required upstream rolling or forging process and dispensing with the diffusion annealing required by the prior art considerable cost and time.
• the material is used better because it does not have to be divided and scooped as often.
• care must be taken to ensure that during the hole process as part of the overall process of the tube production plant, a stress state is built up in the length of use to be formed, which has the highest possible negative mean stress value s m while minimizing shear stresses.
• the method according to the invention can be used for all types of continuous casting, such as vertical continuous casting or curved continuous casting, and regardless of the cross section, ie whether square, octagonal, polygonal or round.
• the continuous casting block produced is divided into insert lengths without pre-deformation, ie in the as-cast state, heated to the forming temperature and then fed to the tube production system.
• the push bench and the drawing press method have proven to be particularly advantageous.
• the heated insert length for the punching process is inserted into a round die and, as already mentioned, a negative mean stress value s m is built up during the punching process in the workpiece to be formed. This prevents the material from tearing open.
• modified metallurgy and special measures for casting the continuous casting are provided as measures according to the invention.
• This also includes an adapted casting speed in the range of preferably 1.8-1.2 m / min. for the dimension range 170 - 240 mm ⁇ .
• the casting speed ranges given above make it easier for the bubbles and inclusions to rise in the sense of a high degree of purity, but are selected so that the desired fine grain size is not impaired.
• the rapid solidification of the relatively small cross sections leads to a structure with a high degree of fine grain even in the as-cast state and at the same time prevents the precipitation of coarse carbides.
• the special immersion nozzle is characterized in that the diameter is ⁇ 25 mm with a corresponding height. This has a favorable effect on the ferrostatic pressure and the flow behavior during casting.
• a minimum content of aluminum is often required. Since a generally customary calcium treatment in the sense of the formation of liquid calcium aluminates to improve the degree of purity for the rolling bearing steel is not permitted, the aluminum content must be chosen so that the amount of Al 2 O 3 formed in the cast continuous casting is small. For this reason, no aluminum is added in the process according to the invention without the oxygen content assuming undesirable values. Dispensing with the addition of Al does not mean that no traces of Al are present in the melt, either because of the low Al content of the alloy components or because of the lining.
• the method according to the invention is based on an arbitrarily chosen example - Use of undeformed and non-diffusion-annealed continuous casting preferably hypereutectoid steel for the production of seamless roller bearing tubes a tube production plant with a punch press, in which the choice of Forming conditions a compressive stress state arises during punching - closer explained.
• a hot-rolled pipe is to be manufactured Dimension 60.3 ⁇ with 8.0 mm wall made of bearing steel 100Cr6.
• Starting from A pig iron produced in the blast furnace is in a first step desulfurized, to a range less than 0.010 percent by mass. over The pig iron is turned into an LD converter with a capacity of up to 250 t Blown steel.
• the casting is then carried out in a round format on a multi-core continuous casting machine to a diameter of 220 mm.
• the casting speed is approx. 1.4 m / min.
• the distributor is provided with partitions for better flow control and the immersion nozzle preferably has a diameter of ⁇ 25 mm with a longer one Pouring funnel that always remains filled.
• the entire casting room is made with argon sealed and when pouring the melt is not flushed with argon, so that no perm plug is required.
• special starting heads are used for casting. After When they are cut into long rods, they are marked and visually for defects checked and then transported to the push bench system.
• the first forming of the takes place in the punch press heated ingot to a hollow body with the dimensions 223.0 x 51.0 mm instead. This corresponds to an extension of 1.39.
• the hollow body is in the elongator stretched further to a dimension of 192.0 x 40.0 mm. This corresponds to one Elongation of 1.43.
• the elongated hollow body having a bottom becomes inserted into the push bench.
• the hollow body is inserted by means of an inserted rod pushed through several scaffolds, thereby measuring 127.5 x 8.25 mm lengthened.
• the aspect ratio is 6.18.
• the rod is pulled out and the Separated floor area.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Forging (AREA)
• Heat Treatment Of Steel (AREA)
• Rolls And Other Rotary Bodies (AREA)
• Shaping Of Tube Ends By Bending Or Straightening (AREA)
• Metal Rolling (AREA)
• Treatment Of Steel In Its Molten State (AREA)
• Continuous Casting (AREA)
• Heat Treatment Of Articles (AREA)
• Extrusion Of Metal (AREA)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)

Applications Claiming Priority (5)

Publications (2)

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ID=25937667

Family Applications (1)

Country Status (11)

Cited By (1)

Families Citing this family (6)

Family Cites Families (4)

• 1995
  • 1995-06-13 CA CA002192970A patent/CA2192970A1/en not_active Abandoned
  • 1995-06-13 SK SK1597-96A patent/SK282573B6/sk unknown
  • 1995-06-13 EP EP95921715A patent/EP0764063B1/de not_active Expired - Lifetime
  • 1995-06-13 PL PL95317837A patent/PL178838B1/pl unknown
  • 1995-06-13 JP JP8501479A patent/JPH10505789A/ja active Pending
  • 1995-06-13 CZ CZ963644A patent/CZ364496A3/cs unknown
  • 1995-06-13 BR BR9508017A patent/BR9508017A/pt not_active IP Right Cessation
  • 1995-06-13 ES ES95921715T patent/ES2128736T3/es not_active Expired - Lifetime
  • 1995-06-13 CN CN95193596A patent/CN1062785C/zh not_active Expired - Fee Related
  • 1995-06-13 AT AT95921715T patent/ATE176411T1/de not_active IP Right Cessation
  • 1995-06-13 WO PCT/DE1995/000800 patent/WO1995034387A1/de not_active Ceased

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