US3664830A - High tensile steel having high notch toughness - Google Patents

High tensile steel having high notch toughness Download PDF

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Publication number
US3664830A
US3664830A US46475A US3664830DA US3664830A US 3664830 A US3664830 A US 3664830A US 46475 A US46475 A US 46475A US 3664830D A US3664830D A US 3664830DA US 3664830 A US3664830 A US 3664830A
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Prior art keywords
steel
high tensile
aluminum
notch toughness
tensile steel
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US46475A
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Akira Kambayashi
Shun-Ichi Shimada
Takashi Ehara
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JFE Engineering Corp
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Nippon Kokan Ltd
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    • 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
    • C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
    • 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
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N

Definitions

  • the steel of the invention comprises 0.12-0.21% of carbon, 0.70l.00% of manganese, 0.20-0.35% of silicon, 0.400.65% of chromium, 0.l50.25% of molybdenum, 0.030.08% of vanadium, 0.01-0.03% of titanium, 0.00050.005% of boron, 0.020-0.060% of aluminum, ODDS-0.020% of nitrogen and the balance being iron and impurities. It is treated by hardening and tempering to provide a steel with a yield point of more than 70 kg./mrn. a tensile strength of more than 80 kg./mm. and an excellent notch toughness and weldability.
  • the present invention provides a steel which has both the high tensile strength and the notch toughness of the known steel containing expensive nickel, but at a lower cost and on an industrial scale.
  • the steel after nitrogen and aluminum addition, is hardened and tempered to precipitate nitrided aluminum.
  • the upper limit of the aluminum content is set at 0.060%. This is because more than 0.060% of aluminum is likely to harm the purity of steel.
  • the upper limit of the content of nitrogen is set at 0.020% to fix the same with respect to the above-mentioned upper limit of the aluminum content.
  • the lower limit of the aluminum content is set at 0.020%. This is because less than 0.020% of aluminum cannot be expected to achieve deoxidation of the steel and complete fixation of solidified nitrogen.
  • the lower limit of the nitrogen content is set at 0.008% bearing in mind the relationship between the amount of added aluminum and the required amount of nitrided aluminum.
  • Table 1 shows an example of the chemical composition of a steel of the present invention, the balance being iron and impurities
  • Table 2 shows the mechanical properties of a steel obtained by rolling the steel shown in Table 1 into a plate of gauge 25 mm. and by a heat-treatment comprising hardening and tempering.
  • the materials subjected to the impact test contained a. 2 mm. V-shaped notch.
  • the steel of this invention is superior to known high tensile steels both in yield point and tensile strength. In addition, it possesses a high notch toughness even at a temperature of 60 C. Consequently, the steel of this invention is comparable to known expensive high tensile steel containing nickel and is very useful for low-temperature service as a high tensile steel.
  • a high tensile steel comprising 0.l2-0.21% of carbon, 0.701.00% of manganese, 0.20-0.35% of silicon, 0.400.65% of chromium, 0.15-0.25 of molybdenum, 0.030.08% of vanadium, 0.01-0.03% of titanium, 0.00050.005% of boron, 0.020-0.060% of aluminum, 0.008-0.020% of nitrogen and the balance being iron and impurities, and treated by hardening and tempering.
  • a high tensile steel comprising 0.17% carbon, 0.93% manganese, 0.26% silicon, 0.63% chromium, 0.24% molybdenum, 0.04% vanadium, 0.01% titanium, 0.002% boron, 0.040% aluminum, 0.012% nitrogen, the balance being iron and impurities.

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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 Steel (AREA)

Abstract

A HIGH TENSILE STEEL COMPRISING 0.12-0.21% OF CARBON, 0.70-1.00% OF MANGANESE, 0.20-0.35% OF SILICON, 0.400.65% OF CHROMIUM, 0.15-0.25% OF MOLYBENUM, 0.030.08% OF VANADIUM 0.01-0.03% OF TITANIUM, 0.00050.0005% OF BORON, 0.020-0.60% OF ALUMINUM, 0.0080.020% OF NITROGEN AND THE BALANCE BEING IRON AND IMPURITIES, TREATED BY HARDENING AND TEMPERING TO PROVIDE THE STEEL WITH A YIELD POINT OF MORE THAN 70 KG./MM.2. A TENSILE STRENGTH OF MORE THAN 80 KG./MM.2. AND AN EXCELLENT NOTCH TOUGHNESS AND WELDABILITY.

Description

United States Patent 3,664,830 HIGH TENSILE STEEL HAVING HIGH N OTCH TOUGHNESS Akira Kambayashi and Shun-ichi Shimada, Kawasaki, and Takashi Ehara, Tokyo, Japan, assignors to Nippon Kokan Kabushiki Kaisha, Kawasaki-shi, Japan No Drawing. Filed June 15, 1970, Ser. No. 46,475 Claims priority, application Japan, June 21, 1969, Vi/48,794 Int. Cl. C22c 37/10, 39/14 US. Cl. 75-124 2 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to a high tensile steel.
SUMMARY OF THE INVENTION The steel of the invention comprises 0.12-0.21% of carbon, 0.70l.00% of manganese, 0.20-0.35% of silicon, 0.400.65% of chromium, 0.l50.25% of molybdenum, 0.030.08% of vanadium, 0.01-0.03% of titanium, 0.00050.005% of boron, 0.020-0.060% of aluminum, ODDS-0.020% of nitrogen and the balance being iron and impurities. It is treated by hardening and tempering to provide a steel with a yield point of more than 70 kg./mrn. a tensile strength of more than 80 kg./mm. and an excellent notch toughness and weldability.
BACKGROUND OF THE INVENTION ASTM A 517 GrB, USS T-1 Type A Steel is known in the art as a steel of this type. However, when such a high tensile strength steel was compared with steel containing nickel and having an equal high tensile strength, it was found to be lacking in notch toughness. Thus, such a known steel is not suitable as a high tensile strength steel for severe conditions of use.
The present invention provides a steel which has both the high tensile strength and the notch toughness of the known steel containing expensive nickel, but at a lower cost and on an industrial scale. The steel, after nitrogen and aluminum addition, is hardened and tempered to precipitate nitrided aluminum.
DESCRIPTION OF SPECIFIC EMBODIMENTS The upper limit of the aluminum content is set at 0.060%. This is because more than 0.060% of aluminum is likely to harm the purity of steel. The upper limit of the content of nitrogen is set at 0.020% to fix the same with respect to the above-mentioned upper limit of the aluminum content. The lower limit of the aluminum content is set at 0.020%. This is because less than 0.020% of aluminum cannot be expected to achieve deoxidation of the steel and complete fixation of solidified nitrogen. The lower limit of the nitrogen content is set at 0.008% bearing in mind the relationship between the amount of added aluminum and the required amount of nitrided aluminum.
3,664,830 Patented May 23, 1972 EXAMPLE Table 1 shows an example of the chemical composition of a steel of the present invention, the balance being iron and impurities, Table 2 shows the mechanical properties of a steel obtained by rolling the steel shown in Table 1 into a plate of gauge 25 mm. and by a heat-treatment comprising hardening and tempering.
TABLE 1 Percent C 0.17 Si 0.26
Mn 0.93 P 0.015 S 0.007 Cr 0.63 Mo 0.24 V 0.04 Ti 0.01 B 0.002 A1 0.040 N 0.012
TABLE 2 Tensile test Impact test Plato Tensile vEO vE-GO gauge Yield point strength Elongation (kgmJ (kgmJ vTs (mm.) (kg/mm?) (kg/nun!) (percent) cmfl) em?) C.)
Notes to Table 2 The materials subjected to the tensile test had a gauge length (G.L.) of two inches and a diameter of 14 mm.
The materials subjected to the impact test contained a. 2 mm. V-shaped notch.
From a study of the above example, it can be established that the steel of this invention is superior to known high tensile steels both in yield point and tensile strength. In addition, it possesses a high notch toughness even at a temperature of 60 C. Consequently, the steel of this invention is comparable to known expensive high tensile steel containing nickel and is very useful for low-temperature service as a high tensile steel.
We claim:
1. A high tensile steel comprising 0.l2-0.21% of carbon, 0.701.00% of manganese, 0.20-0.35% of silicon, 0.400.65% of chromium, 0.15-0.25 of molybdenum, 0.030.08% of vanadium, 0.01-0.03% of titanium, 0.00050.005% of boron, 0.020-0.060% of aluminum, 0.008-0.020% of nitrogen and the balance being iron and impurities, and treated by hardening and tempering.
2. A high tensile steel comprising 0.17% carbon, 0.93% manganese, 0.26% silicon, 0.63% chromium, 0.24% molybdenum, 0.04% vanadium, 0.01% titanium, 0.002% boron, 0.040% aluminum, 0.012% nitrogen, the balance being iron and impurities.
References Cited UNITED STATES PATENTS 2,858,206 10/1958 Boyce -126 D 3,291,655 12/1966 Gill 75--126 D 3,310,441 3/1967 Mandich 75124 HYLAN D BIZOT, Primary Examiner US. Cl. X.R.
75126 C, 126 D, 126 I, 126 J
US46475A 1969-06-21 1970-06-15 High tensile steel having high notch toughness Expired - Lifetime US3664830A (en)

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US (1) US3664830A (en)
AU (1) AU1649570A (en)
CH (1) CH510739A (en)
DE (1) DE2030400A1 (en)
FR (1) FR2052823A5 (en)
GB (1) GB1277996A (en)
NL (1) NL7009093A (en)
ZA (1) ZA704132B (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4025368A (en) * 1974-06-08 1977-05-24 Kawasaki Steel Corporation Weldable steel excellent in the toughness of the bond in a single layer welding with a large heat-input
US4062705A (en) * 1973-07-31 1977-12-13 Nippon Steel Corporation Method for heat treatment of high-toughness weld metals
US4537644A (en) * 1981-09-28 1985-08-27 Nippon Steel Corporation High-tension high-toughness steel having excellent resistance to delayed fracture and method for producing the same
US4561888A (en) * 1982-11-02 1985-12-31 Kabushiki Kaisha Kobe Seiko Sho Welding wire for use in submerged arc welding of Cr-Mo steels
US4634476A (en) * 1985-05-03 1987-01-06 Paccar Inc High-strength, low-alloy cast steel
US5525167A (en) * 1994-06-28 1996-06-11 Caterpillar Inc. Elevated nitrogen high toughness steel article
US6224825B1 (en) * 1997-04-29 2001-05-01 Ovako Steel Ab Case hardening steel
CN102618777A (en) * 2012-04-19 2012-08-01 浙江大学宁波理工学院 Method for improving high-speed machinability of cast iron

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2396805A2 (en) * 1977-07-06 1979-02-02 Ugine Aciers Quenched steels with optimum hardenability - obtd. by using specific amts. of boron, nitrogen, aluminium, and titanium and/or zirconium

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4062705A (en) * 1973-07-31 1977-12-13 Nippon Steel Corporation Method for heat treatment of high-toughness weld metals
US4025368A (en) * 1974-06-08 1977-05-24 Kawasaki Steel Corporation Weldable steel excellent in the toughness of the bond in a single layer welding with a large heat-input
US4537644A (en) * 1981-09-28 1985-08-27 Nippon Steel Corporation High-tension high-toughness steel having excellent resistance to delayed fracture and method for producing the same
US4561888A (en) * 1982-11-02 1985-12-31 Kabushiki Kaisha Kobe Seiko Sho Welding wire for use in submerged arc welding of Cr-Mo steels
US4634476A (en) * 1985-05-03 1987-01-06 Paccar Inc High-strength, low-alloy cast steel
US5525167A (en) * 1994-06-28 1996-06-11 Caterpillar Inc. Elevated nitrogen high toughness steel article
US6224825B1 (en) * 1997-04-29 2001-05-01 Ovako Steel Ab Case hardening steel
CN102618777A (en) * 2012-04-19 2012-08-01 浙江大学宁波理工学院 Method for improving high-speed machinability of cast iron
CN102618777B (en) * 2012-04-19 2013-05-01 浙江大学宁波理工学院 Method for improving high-speed machinability of cast iron

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CH510739A (en) 1971-07-31
ZA704132B (en) 1971-09-29
DE2030400A1 (en) 1971-04-29
FR2052823A5 (en) 1971-04-09
AU1649570A (en) 1972-06-01
NL7009093A (en) 1970-12-23
GB1277996A (en) 1972-06-14

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