EP0169587A1 - Hoch beanspruchbarer Kohlenstoffstahldraht - Google Patents

Hoch beanspruchbarer Kohlenstoffstahldraht Download PDF

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Publication number
EP0169587A1
EP0169587A1 EP85200924A EP85200924A EP0169587A1 EP 0169587 A1 EP0169587 A1 EP 0169587A1 EP 85200924 A EP85200924 A EP 85200924A EP 85200924 A EP85200924 A EP 85200924A EP 0169587 A1 EP0169587 A1 EP 0169587A1
Authority
EP
European Patent Office
Prior art keywords
steel
wire
wires
strength
boron
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP85200924A
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English (en)
French (fr)
Inventor
Martin Bombeke
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bekaert NV SA
Original Assignee
Bekaert NV SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bekaert NV SA filed Critical Bekaert NV SA
Publication of EP0169587A1 publication Critical patent/EP0169587A1/de
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60

Definitions

  • the present invention pertains to the field of drawn carbon steel wire and applications thereof. More in particular the invention relates to a high-strength pearlitic steel wire having a specified composition allowing an improved capacity for effecting large drawing reductions and for obtaining higher than normal levels of useful tensile strength exceeding 2000 Newton per square millimetre.
  • the wire of this invention is suited for demanding applications, such as high-duty ropes cables and springs and more specifically it is intended for reinforcing rubber articles, e.g. steel cord and bead wire for tires, belt cord for rubber belts, hose wire for high-pressure hoses, etc...
  • plain carbon steel wires of sufficient carbon content, inclusive low-alloyed variants thereof, are employed for high-strength applications up to about 2000 N/mm l .
  • said wires are subjected either to a martensitic quench and tempering treatment or to the combined operation of metallurgical patenting and subsequent cold drawing, the latter being the case of this invention.
  • drawn pearlitic wires are usually made of plain high-carbon steel having the following general composition (by weight) : the remainder being Fe and unavoidable impurities related to steelmaking practice.
  • alloyed compositions of said plain carbon steels are sometimes used.
  • These variants may contain a member or members selected from a group consisting of Cr, Ni, Cu, Mo, Co, W, Nb, V, Ti, Al and other elements which can be present in varying amounts depending on the selected member and the alloying purpose for a given application.
  • alloying elements For alloyed carbon steels the price supplementover plain carbon grades, which may widely vary according to type and amount of alloying addition, can be acceptable.
  • alloying elements often have undesirable side effects (e.g. prolongement of heat treatment cycles, slower pearlite transformation, more difficult solution of stable carbide formers, etc.) which may seriously affect productivity, especially in the production of fine wires (e.g. for tire cord) necessitating a number of intermediate patenting operations.
  • the solution offered by the present invention does not possess the disadvantages as explained above, and yet enables to achieve definite and unexcepted improvements over the prior wiremaking art. It thereby fulfils the important object of providing a higher than hitherto achievable useful wire strength (largely exceeding 2000 N/mmi) in a most efficient and economical way.
  • Another object of the present invention is to decrease incidence of wire breaks and to suppress the appearance of undesirable brittleness encountered when drawing usual steel wires to high-tensile levels.
  • Still another important object is to provide a wire having an enhanced deformation capacity, allowing larger than normal total drawing reductions as compared to conventional carbon steel wires.
  • a drawn steel wire (generally less than 5 mm diameter) having a deformed microstructure consisting of essentially pearlite (obtained by lead patenting or by a similar isothermal transformation process to pearlite and subjected thereafter to a required drawing reduction) and having a useful strength of more than 2000 N/mm l , which wire is made from a specified plain carbon steel composition characterized by a micro-alloying addition of boron and containing (in percentage of weight) 0.6 to 1.2 % C, 0 to 1.0 % Mn, 0 to 1.0 % Si, max. 0.035 % P, max. 0.035 % S, 0.0005 to 0.015 % B, the remainder Fe and inevitable impurities.
  • a drawn pearlitic carbon steel wire having a steel composition as defined above and an elevated tensile strength of not less than following values related to final wire diameter :
  • said wires are provided with a rubber adherent coating.
  • a drawn carbon steel wire with a tensile stress in excess of 2200 N/mmt having a specified composition containing 0.6 to 1.2 % C, 0 to 0.35 % Si, less than 0.60 % Mn, max. 0.008 % N, max. 0.025 % S, max. 0.025 % P and 0.001 to 0.01 % B, the balance Fe and incidental impurities.
  • the present invention also provides a carbon steel wire of 0.1 to 0.5 mm diameter having said preferred specified composition and imparted with a tensile strength of at least 2700 N/mm 2 , preferably at least 3000 N/mm for diameters of 0.3 mm and below, which wire further contains a rubber adherent brass coating on its surface for the purpose of adequate rubber reinforcement.
  • Also comprised of the present invention are articles made of pearlitic wires possessing the specified steel composition of this invention and drawn to a high-tensile strength as specified above.
  • a particular embodiment therein are wire elements and structures for rubber reinforcement, which elements are fabricated from steel wire of the present invention and are covered with a rubber adherent coating, for example brass plated bead wire and steel cord for tires, brassed hose wire, belt cord from brassed or galvanized wires for rubber belts and the like.
  • the steel wires of this invention allow larger total drawing reductions without causing a normally encountered increase in wire breaks and without enhanced risk of overdrawing.
  • the latter phenomenon usually gives rise to wire of inconsistent ductility, poor plasticity in torsion and to a significant increase in rejected wire, which deficiencies are largely overcome by the wires of this invention.
  • An important advantage of the wires produced according to the present invention is their improved residual ductility, which remains satisfactory and reliable even after large total drawing strains. This permits to raise the already elevated useful strength level above the practical safety limits of conventional steel wire.
  • the shaded bands (3) and (4) refer to cold work hardening by drawing of patented conventional carbon steel wire of resp. 0.65 - 0.70 % C and 0.80 - 0.85 % C.
  • Reference numeral (5) indicates the onset of brittle behaviour when drawing conventional wires.
  • the comparative curves of Fig. 1 clearly demonstrate that the steel wires of this invention are superior in ultimate drawing capacity and in attainable useful tensile strength.
  • Curve 2 further shows that the novel steel wire composition use is apt to enhanced strain-hardening after proper patenting. This additional capacity is not observed in conventional wire processing (owing to less controllable bainite formation when patenting usual steel wire grades to a finest possible pearlite structure).
  • Prior art experience related to wire applications of boron steel include for example U.K. Patent Specification 1.203.779, describing an alloyed carbon steel containing boron as an extra element of a multi-alloying addition of Cr-Ti-Zr + Sn, Sb or As, said alloyed steel resulting in a strength of at least 1000 N/mm in tempered martensite with improved resistance to delayed rupture.
  • a German application DE 3312205 describes a boron-treated low-alloyed carbon steel specifying a desired amount of acid soluble boron combined with a small content of Al and Ti, effective in increasing continuous casting yield (steelmaking), whereby said steel composition is intended for prestressed wire of tempered martensitic structure (T.S. of 1500 N/mm t ).
  • U.S. patent 2.527.731 describes a spring wire drawn from air patented carbon steel wherein the boron addition is intended to allow air patenting of rather thick wires to be substituted for (more expensive) lead patenting without sacrifice of usually obtained mechanical properties (T.S. of about 1800 N/mm 1 ).
  • An additional surprisingly advantageous effect of boron in steel wire according to the present invention is the capacity to control the patenting heat treatment of said wire in such a way that the as patented tensile strength (P.T.S.) of pearlite can be raised substantially above the maximum level attainable with conventional steel wires of similar carbon content (without risk of forming hard constituents in the pearlite structure).
  • P.T.S. tensile strength
  • Said maximum strength of undeformed pearlitic steel wire is given by the well-known rule of thumb
  • the steel wires according to the present invention may be shaped in any appropriate cross-section ranging from a rectangular strip-form (obtainable by flat rolling) to a polygonal shape.
  • a substantially circular cross-section is generally preferred in a majority of end uses. They may be used with advantage in a variety of heavy-duty wire-containing products such as, for example, strands, traction cables, ropes, steel cords and springs.
  • a particular embodiment of the present invention relates to wire elements formed from steel wires of this invention for use as a rubber reinforcement (such as bead wire and tire beads, steel tire cord, steel belt cord, etc.) and to rubber articles reinforced therewith.
  • the wires are provided with a rubber adherable coating, more often a thin brass alloy coating of 0.1 to 0.4 ⁇ m thickness, which alloy comprises at least 55 % of copper and preferably 60 to 75 % of copper, the remainder zinc (and sometimes lesser amounts of a ternary alloying element such as cobalt or nickel).
  • the brassed wires for stranding or twisting into cord will generally have a diameter of from 0.10 to 0.40 mm and a tensile class of 2500 - 2800 N/mm t and preferably more than 2800 N/mm 2 .
  • the improved residual plasticity of the high tensile wires according to the invention after wire drawing has proved to be particularly beneficial with regard to the cord making operation and to the mechanical properties of rubberized cord in tyre service.
  • useful tensile strength of said cord wire can be raised above 3000 N/mm l without the otherwise occurring difficulties of overdrawing, stranding fractures and inconsistent or unsatisfactory cord properties (e.g. poor cord fatigue life, increased tendency to brittle and stress corrosion cracking).
  • ff means the wire diamter
  • T.S. means the tensile strength (stress at rupture in tensile testing)
  • El. means the percent of total elongation
  • X means the percentage of reduction in area (striction) at tensile rupture
  • Nb means the number of reverse bends until rupture in the bend test
  • Nt the number of torsions in the simple torsion test where a length of 100 times the wire diameter is twisted around its axis until it breaks or splits longitudinally.
  • Table 1 shows the chemical composition of a steel wire according to the invention as compared to a normal carbon steel wire.
  • Table 2 shows the mechanical properties of the manufactured wires, in the as hot rolled, resp. as patented condition and after cold drawing.
  • boron steel is deformable to very high total reductions and gives ultra-high tensile strength levels without complete loss of ductility. Moreover boron steel possesses an unexpected capacity to refine the pearlite microstructure (regulable in combination with an optimum transformation temperature) with virtual absence of undesirable constituents (bainite, divorced pearlite ...) which are unavoidable in conventional steel wire patented at too low a temperature.
  • Table 6 shows the fatigue limit obtained with hard drawn carbon steel wire of the invention (compare with table 5).
  • the steel wires in accordance with the invention attain a high fatigue limit and its ratio to the ultimate tensile strength being still more than 0.30 in spite of the elevated strength level, is indicative of the superiority of boron steel wires in very demanding applications.
  • cabling loss has been determined on steel cords made of 0.25 mm filaments, resp. from a boron steel with 0.73 % C and from a high-grade usual carbon steel with 0.70 % C and 0.85 % C, of a chemical composition given below.
  • Wires 0.25 mm of said steel qualities were cold drawn to a tensile strength class of 3000 to 3200 N/mm l .
  • the steel wires of the invention possess a much lesser propensity to strength loss as a result of cord manufacturing, which means that the boron steel wires are more resistant to structural damage given their higher residual ductility in comparison with conventional carbon steel wires.
  • the boron steel wire compositions in accordance with the invention exhibit improved drawing performance and later onset of embrittlement.
  • the wires of the invention can attain a remarkable degree of strain hardening and can be drawn to exceptional strength levels owing to the unexpected beneficial effects of boron on microstructure and ductility.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Ropes Or Cables (AREA)
  • Metal Extraction Processes (AREA)
EP85200924A 1984-07-09 1985-06-12 Hoch beanspruchbarer Kohlenstoffstahldraht Withdrawn EP0169587A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB848417468A GB8417468D0 (en) 1984-07-09 1984-07-09 Carbon steel wire
GB8417468 1984-07-09

Publications (1)

Publication Number Publication Date
EP0169587A1 true EP0169587A1 (de) 1986-01-29

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP85200924A Withdrawn EP0169587A1 (de) 1984-07-09 1985-06-12 Hoch beanspruchbarer Kohlenstoffstahldraht

Country Status (4)

Country Link
EP (1) EP0169587A1 (de)
JP (1) JPS6152348A (de)
BR (1) BR8503246A (de)
GB (1) GB8417468D0 (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991019014A1 (fr) * 1990-06-07 1991-12-12 Sodetal S.A.R.L. Procede pour l'obtention d'un fil d'acier ecroui a resistance elevee
EP0620284A2 (de) * 1993-04-12 1994-10-19 The Goodyear Tire & Rubber Company Verfahren zum Herstellen von patentiertes Stahldraht
EP1897964A1 (de) * 2005-06-29 2008-03-12 Nippon Steel Corporation Hochfester walzdraht mit hervorragender drahtziehleistungsfähigkeit und herstellungsverfahren dafür
EP1900837A1 (de) * 2005-06-29 2008-03-19 Nippon Steel Corporation Hochfester walzdraht mit hervorragender drahtziehleistungsfähigkeit und herstellungsverfahren dafür
EP2034036A3 (de) * 2007-09-05 2010-10-06 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Walzdraht mit hervorragender Drahtziehfähigkeit und Herstellungsverfahren dafür
JP2016056438A (ja) * 2014-09-12 2016-04-21 新日鐵住金株式会社 鋼線材及び鋼線材の製造方法
EP3020844A1 (de) * 2013-07-09 2016-05-18 National Institute for Materials Science Martensitischer stahl und verfahren zur herstellung davon
CN113474575A (zh) * 2019-02-26 2021-10-01 贝卡尔特公司 用于打开和关闭汽车的车门或尾门的致动器

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2995250B1 (fr) * 2012-09-07 2016-04-01 Michelin & Cie Fil d'acier a haute trefilabilite comprenant un taux de carbone en masse compris entre 0,6 % et 0,74 % bornes incluses

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2527731A (en) * 1949-03-04 1950-10-31 American Steel & Wire Co Fatigue resistant steel wire and method of making the same
GB1203779A (en) * 1966-12-16 1970-09-03 Yawata Iron & Steel Co High tensile strength tough steel having resistance to delayed rupture
FR2058914A5 (de) * 1969-08-20 1971-05-28 Caterpillar Tractor Co
FR2173628A5 (de) * 1972-02-25 1973-10-05 Monsanto Co
DE3312205A1 (de) * 1982-04-03 1983-10-20 Sumitomo Electric Industries, Ltd., Osaka Borhaltiger stahl und verfahren zu dessen herstellung

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2527731A (en) * 1949-03-04 1950-10-31 American Steel & Wire Co Fatigue resistant steel wire and method of making the same
GB1203779A (en) * 1966-12-16 1970-09-03 Yawata Iron & Steel Co High tensile strength tough steel having resistance to delayed rupture
FR2058914A5 (de) * 1969-08-20 1971-05-28 Caterpillar Tractor Co
FR2173628A5 (de) * 1972-02-25 1973-10-05 Monsanto Co
DE3312205A1 (de) * 1982-04-03 1983-10-20 Sumitomo Electric Industries, Ltd., Osaka Borhaltiger stahl und verfahren zu dessen herstellung

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENTS ABSTRACTS OF JAPAN, vol. 7, no. 155 (C-175)[1300], 7th July 1983; & JP - A - 58 67 828 (SHIN NIPPON SEITETSU K.K.) 22-04-1983 *

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1991019014A1 (fr) * 1990-06-07 1991-12-12 Sodetal S.A.R.L. Procede pour l'obtention d'un fil d'acier ecroui a resistance elevee
FR2663041A1 (fr) * 1990-06-07 1991-12-13 Sodetal Fil d'acier ecroui a resistance elevee.
EP0620284A2 (de) * 1993-04-12 1994-10-19 The Goodyear Tire & Rubber Company Verfahren zum Herstellen von patentiertes Stahldraht
EP0620284A3 (de) * 1993-04-12 1995-05-17 Goodyear Tire & Rubber Verfahren zum Herstellen von patentiertes Stahldraht.
TR27825A (tr) * 1993-04-12 1995-08-29 Goodyear Tire & Rubber Dönüstürülmüs celik tel üretimi icin bir islem.
EP1897964A4 (de) * 2005-06-29 2009-04-08 Nippon Steel Corp Hochfester walzdraht mit hervorragender drahtziehleistungsfähigkeit und herstellungsverfahren dafür
EP1900837A1 (de) * 2005-06-29 2008-03-19 Nippon Steel Corporation Hochfester walzdraht mit hervorragender drahtziehleistungsfähigkeit und herstellungsverfahren dafür
EP1900837A4 (de) * 2005-06-29 2009-04-01 Nippon Steel Corp Hochfester walzdraht mit hervorragender drahtziehleistungsfähigkeit und herstellungsverfahren dafür
EP1897964A1 (de) * 2005-06-29 2008-03-12 Nippon Steel Corporation Hochfester walzdraht mit hervorragender drahtziehleistungsfähigkeit und herstellungsverfahren dafür
US8142577B2 (en) 2005-06-29 2012-03-27 Nippon Steel Corporation High strength wire rod excellent in drawability and method of producing same
US8864920B2 (en) 2005-06-29 2014-10-21 Nippon Steel & Sumitomo Metal Corporation High strength wire rod excellent in drawability and method of producing same
EP2034036A3 (de) * 2007-09-05 2010-10-06 Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) Walzdraht mit hervorragender Drahtziehfähigkeit und Herstellungsverfahren dafür
EP3020844A1 (de) * 2013-07-09 2016-05-18 National Institute for Materials Science Martensitischer stahl und verfahren zur herstellung davon
EP3020844A4 (de) * 2013-07-09 2017-03-29 National Institute for Materials Science Martensitischer stahl und verfahren zur herstellung davon
JP2016056438A (ja) * 2014-09-12 2016-04-21 新日鐵住金株式会社 鋼線材及び鋼線材の製造方法
CN113474575A (zh) * 2019-02-26 2021-10-01 贝卡尔特公司 用于打开和关闭汽车的车门或尾门的致动器
CN113474575B (zh) * 2019-02-26 2023-07-25 贝卡尔特公司 用于打开和关闭汽车的车门或尾门的致动器

Also Published As

Publication number Publication date
GB8417468D0 (en) 1984-08-15
BR8503246A (pt) 1986-03-25
JPS6152348A (ja) 1986-03-15

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Inventor name: BOMBEKE, MARTIN