EP1126042A1 - A steel - Google Patents

A steel Download PDF

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Publication number
EP1126042A1
EP1126042A1 EP01850029A EP01850029A EP1126042A1 EP 1126042 A1 EP1126042 A1 EP 1126042A1 EP 01850029 A EP01850029 A EP 01850029A EP 01850029 A EP01850029 A EP 01850029A EP 1126042 A1 EP1126042 A1 EP 1126042A1
Authority
EP
European Patent Office
Prior art keywords
steel
tempering
max
melt
tempered
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Withdrawn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
EP01850029A
Other languages
German (de)
English (en)
French (fr)
Inventor
Rainer Leppänen
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.)
Ovako Steel AB
Original Assignee
Ovako Steel AB
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 Ovako Steel AB filed Critical Ovako Steel AB
Publication of EP1126042A1 publication Critical patent/EP1126042A1/en
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • 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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C21D1/25—Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")

Definitions

  • the present invention relates to a steel, and more specifically a chain type steel, suitable for the production of bars with a diameter of up to about 160 mm, e.g. to be used for the manufacture of heavy anchor chains.
  • bars for the manufacture of heavy anchor chains primarily used for anchoring of oil riggs. Bar dimensions up to 155 mm diameter have been delivered. For the coarse dimensions a very low carbon steel type have been used which causes a number of difficulties in the steel plant, being very aggressive towards the melting equipment. The steel types used for smaller diameter anchor chains being low alloyd steels give unsatisfactory mechanical properties for bigger diameter anchor chains, that is for bar diameters above about 130 mm.
  • a steel for producing anchor chains having the following composition, in wt.%: C 0.03 - 0.07; Si 0.10 - 1; Mn 1.2 - 2.5; Cr 1.8 - 3; Ni 1.5- 3; Mo ⁇ 0.5; Nb,V,Ti total 0 - 0.10.
  • This steel is claimed to have a yield point of at least 600 Mpa, a rupture limit of at least 900 Mpa at room temperature and an impact toughness of at least 40 Joule at -20°C.
  • the restrictions of anchor steels for oil riggs in the ocean are becoming even stricter, and there is a demand for a steel with improved characteristics.
  • JP-61276956 is previously known a low alloy chain link steel including chromium and nickel being processed to obtain a tempered martensitic structure.
  • This steel comprises, in wt.%: C 0.20 - 0.30; Si 0.10 - 0.30; Mn 0.70 - 1.70; Cr 0.40 - 0.70; Ni 0.75 - 2.00; Al 0.01 - 0.05; P ⁇ 0.03; S ⁇ 0.030.
  • This steel is tempered after being quenched or case-hardened by means of carburising so that the microstructure is tempered martensite.
  • the weldability will deteriorate as well as the toughness, and there is a risk for hardening cracks.
  • the absence of Mo means there is a risk for temper embrittlement.
  • Ni is obviously used to compensate for a low Cr content, which will render this steel quite expensive.
  • JP-52006847B is previously known a high stregnth low alloy steel chain manufactured from steel bars containing, in wt.% C 0.1 - 0.2; Si 0.1 - 0.5; Mn 1.0 - 1.6; Cu 0.1 - 0.5; Ni 0.5 - 1.5; Cr 0.3 - 1.0; Mo 0.2 - 0.8, P ⁇ 0.02; S > 0.015, and acid.sol Al 0.02 - 0.1.
  • the starting steel bars have a high tensile strength, improved weldability and good workability, and the steel chain produced is tempered at 550 - 680°C.
  • the low Cr, and the low C content both affect the hardenability, which is deleterious for large diameter anchor chains.
  • the object of the invention is to provide a steel with improved mechanical properties and an improved behaviour in the steel plant.
  • Fig. 1 is a graph showing the hardness as a function of the tempering temperature for laboratory melt sample materials.
  • Fig. 2 is a graph showing the hardness as a function of the depth underneath the surface, for hardened and not tempered samples of said laboratory melt sample materials.
  • Fig. 3 is a graph showing the hardness as a function of the depth underneath the surface, for hardened and tempered samples of said laboratory melt sample materials.
  • Fig. 4 is a graph showing the jominy hardenability for said laboratory melt sample materials.
  • Fig. 5 is a graph showing the jominy hardenability for a full scale melt material.
  • the steel grade according to the invention is intended for manufacture of so called K4 chain with a diameter up to about 160 mm, and is not aggressive towards the melting equipment, and which steels result in very high qualities of the the finished chain.
  • sample material was manufactured as laboratory melts with ingot dimensions of 225x225 mms.
  • the respective ingots were forged into bars with a diameter of 140 mms. This gives a reduction rate of about 3, which is insufficient in normal production. This means that the results from normal production will be significantly better than the test results discussed in the following description.
  • Test samples were produced having two different analyses, MnCrNiMo variant, and MnCrNiMoV, respectively.
  • the steel according to the invention after through hardening gives a very small difference between surface hardness and hardness at the center.
  • Fig. 1 shows the hardness as a function of the tempering temperature, tempering time 1 hour. Hardening temperatures for the respective melts are 850°C for melt No. 129, and 890°C for melt No. 131. Sample size 25x25x25 mm.
  • melt No. 129 exhibits a flat curve without breaking points, which makes it less sensitive to variations in tempering temperature fluctuations.
  • the vanadium gives a strong tempering resistance up to 630°C, but at higher temperatures a steep curve is obtained with an increased sensitivity for temperature variations.
  • Fig. 2 shows the hardness as a function of the depth underneath the surface of a hardened not tempered sample with a diameter of 140 mm
  • Fig. 3 shows the hardness after tempering at 615°C for the melt No. 129 and at 645°C for melt No. 131.
  • the hardening temperature for the melt No. 129 was 850°C and for the melt No. 131, 890°C, all being quenched in water.
  • melt No. 129 exhibits the best result of the through hardening both for the not tempered and the tempered sample.
  • the difference in hardness between surface and center is very small.
  • Fig. 4 shows the result of the jominy test.
  • the austenitization temperature has been the same as with the through hardening test according to item 2 above.
  • the jominy test result corresponds well with the through hardening result according to item 2.
  • Melt No. 129 has the best hardenability.
  • Table II below shows the mechanical properties of hardened and tempered bar samples with a diameter of 140 mm. Heat treatment and taking of samples were made according to normal practice for testing of chain material. The melt No. 129 showing the best results in the hardenability testing and tempering tests has been examined at three different tempering temperatures.
  • Mechanical properties Melt Harden. temp °C Tempering. temp°C ReI Mpa Rm Mpa AS % Z % KV,J - 40°C - 20°C ⁇ 0°C 129 850 615 822 917 17 63 83 134 138 590 857 937 16 72 89 101 142 570 923 992 15 67 108 102 123 131 890 645 896 963 17 64 99 122 126 Demand acc. to DNV 580 860 12 50 50 70
  • the impact toughness at -20°C is close to the demand according to DNV, but only an area reduction rate of 3 is made with the melt sample, while castings in the production will have an area reduction rate of about 12, so this feature will be substantially improved.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)
EP01850029A 2000-02-14 2001-02-08 A steel Withdrawn EP1126042A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0000458 2000-02-14
SE0000458A SE515623C2 (sv) 2000-02-14 2000-02-14 Kättingstål

Publications (1)

Publication Number Publication Date
EP1126042A1 true EP1126042A1 (en) 2001-08-22

Family

ID=20278436

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01850029A Withdrawn EP1126042A1 (en) 2000-02-14 2001-02-08 A steel

Country Status (5)

Country Link
US (1) US20010024621A1 (zh)
EP (1) EP1126042A1 (zh)
JP (1) JP2001247933A (zh)
CN (1) CN1124360C (zh)
SE (1) SE515623C2 (zh)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004022792A2 (en) 2002-09-04 2004-03-18 Intermet Corporation Austempered cast iron article and a method of making the same
JP2007289979A (ja) * 2006-04-23 2007-11-08 Sanyo Special Steel Co Ltd Ｔｉ添加はだ焼鋼からなる鋳鋼片または鋼塊の製造方法およびその鋳鋼片または鋼塊並びにその鋳鋼片または鋼塊からなるはだ焼鋼鋼材
DE102013224851A1 (de) * 2013-12-04 2015-06-11 Schaeffler Technologies AG & Co. KG Kettenelement
CN106222574B (zh) * 2016-08-24 2017-09-19 宁波乾豪金属制品有限公司 一种耐腐蚀的弹簧悬架
WO2020041085A1 (en) 2018-08-21 2020-02-27 Exxonmobil Upstream Research Company Mooring chains comprising high manganese steels and associated methods

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2110239A (en) * 1981-11-24 1983-06-15 Uddeholms Ab Steel and chain made from the steel
JPH03115523A (ja) * 1989-09-28 1991-05-16 Kobe Steel Ltd 直接焼入型プレハードン鋼の製造方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS526847B2 (zh) * 1972-05-19 1977-02-25
JPS61276956A (ja) * 1985-05-31 1986-12-06 Kito Corp リンクチエ−ン

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2110239A (en) * 1981-11-24 1983-06-15 Uddeholms Ab Steel and chain made from the steel
JPH03115523A (ja) * 1989-09-28 1991-05-16 Kobe Steel Ltd 直接焼入型プレハードン鋼の製造方法

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
LLANOS J M: "NEW STEEL GRADE WITH AN OPTIMUM COMPROMISE BETWEEN HARDENABILITY AND TOUGHNESS", INTERNATIONAL CONGRESS ON HEAT TREATMENT AND SURFACE ENGINEERING,XX,XX, 26 September 1994 (1994-09-26), pages 111 - 119, XP000653532 *
PATENT ABSTRACTS OF JAPAN vol. 015, no. 313 (C - 0857) 9 August 1991 (1991-08-09) *

Also Published As

Publication number Publication date
SE0000458D0 (sv) 2000-02-14
SE0000458L (sv) 2001-08-15
US20010024621A1 (en) 2001-09-27
CN1309188A (zh) 2001-08-22
JP2001247933A (ja) 2001-09-14
CN1124360C (zh) 2003-10-15
SE515623C2 (sv) 2001-09-10

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