US3383203A - Non-magnetic steels - Google Patents

Non-magnetic steels Download PDF

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Publication number
US3383203A
US3383203A US610009A US61000967A US3383203A US 3383203 A US3383203 A US 3383203A US 610009 A US610009 A US 610009A US 61000967 A US61000967 A US 61000967A US 3383203 A US3383203 A US 3383203A
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Prior art keywords
steel
magnetic
steels
austenitic
impact strength
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Expired - Lifetime
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US610009A
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Baggstrom Karl Gote
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Saab Bofors AB
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Bofors AB
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese

Definitions

  • the present invention relates to a non-magnetic steel having desirable properties, particularly high impact strength, and to a method of producing said non-magnetic steel. Such steel is used for, among other things, the manufacture of retaining rings used in the electrical industry.
  • the steels consist essentially of carbon 0.50-0.80%, manganese 9.018.0%, silicon ODS-0.80%, chromium 20-60%, nickel 7.0-ll.0%, vanadium 0.60-1.0%, and the remainder iron.
  • austenitic steels having both high tensile strength and high impact strength.
  • the alloys have the following composition:
  • the austenitic steels of desired composition were solution treated and precipitation hardened by (l) annealing at a temperature of about 1150 C. for
  • the austenitic steels so treated were non-magnetic and had high tensile strengths and impact strengths greater than 5.5 kpm./crn.
  • the yield point, 0' has been defined as the load at which a non-proportional elongation corresponding to 0.2% of the original length of the test bar takes place. It is stated in kp./mm. and has been determined in an entirely conventional way, see ISO Recommendation R82.
  • the impact strength tests were carried out with so-called V test bars in Charpy equipment, in accordance with a procedure which conforms entirely to ISO Recommenda- TABLE II Type Composition, percent Yield point Impact of do strength steel 0 Si Mn Cr Ni V lip/mm. Kcv+20 0.,
  • Steels having compositions that do not meet the com position requirements of this invention (such as those disclosed in Belgian Patent 518,985 and US. Patent 2,865,740), when subjected to solution treatment and precipitation hardening, are not converted into steels having the high impact strengths as the non-magnetic austenitic steels of this invention.
  • a non-magnetic, austenitic steel having a high tensile strength and a high impact strength and having a composition consisting essentially of:
  • composition consisting essentially of:
  • a steel according to claim 2 which has an impact strength of at least 5.5 kpm./cm.
  • a steel according to claim 2 which has an impact strength of 8.0 kpm./cm. and consists essentially of:

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Hard Magnetic Materials (AREA)
  • Soft Magnetic Materials (AREA)

Description

United States Patent 3,383,203 NON-MAGNETIC STEELS Karl Giite Baggstriim, Karlskoga, Sweden, assignor to Aktiebolaget Bofors, Bofors, Sweden, a corporation of Sweden No Drawing. Continuation-impart of application Ser. No. 330,587, Dec. 16, 1963. This application Jan. 18, 1967, Ser. No. 610,009
Claims priority, application Sweden, Dec. 19, 1962, 13,711/62 6 Claims. (Cl. 75-128) ABSTRACT OF THE DISCLOSURE The present invention relates to a non-magnetic steel having desirable properties, particularly high impact strength, and to a method of producing said non-magnetic steel. Such steel is used for, among other things, the manufacture of retaining rings used in the electrical industry.
The steels consist essentially of carbon 0.50-0.80%, manganese 9.018.0%, silicon ODS-0.80%, chromium 20-60%, nickel 7.0-ll.0%, vanadium 0.60-1.0%, and the remainder iron.
The application is a continuation-in-part application based upon copending application Ser. No. 330,587 filed Dec. 16, 1963, now abandoned.
It is generally known that the non-magnetic, austenitic types of steel normally have a comparatively low tensile strength, and this, of course, limits the usefulness of such kinds of steel. When it has been desired to prepare a steel having both non-magnetic properties and a high tensile strength, austenitic types of steel were subjected to coldworking. However, such cold-Working requires much skill and experience, and there is still always some uncertainty in regard to the uniformity of the properties of the product. Moreover, if large units of steel are to be coldworked, special expensive machinery is required.
Studies in this field have therefore been directed toward eliminating cold-working, and through suitable heat treatment, consisting of solution treatment and precipitation hardening of certain alloys, considerable improvements have been obtained so as to obtain nonmagnetic steel of high tensile strength. However, all alloys hitherto known which have been subjected to this treatment have had poor impact strength.
In the following Table I, information is given about a number of alloys which, after solution treatment and precipitation hardening, have shown a high tensile strength, as measured by the yield point, but poor impact strength.
3,383,203 Patented May 14, 1968 tion R148. The impact strength was determined at +20 C. and the results are stated in kpm./cm.
It is accordingly an object of the present invention to provide a non-magnetic, austenitic steel having high tensile strength and high impact strength.
It is a further object of this invention to provide austenitic steels of specified composition which, when subjected to suitable treatment comprising solution and precipitation hardening will be changed into non-magnetic,
austenitic steels having both high tensile strength and high impact strength.
These and further objects of the invention will become apparent from the following description.
I have discovered that the objects of this invention can be achieved by subjecting alloys of the following composition:
Percent Carbon 0.50-0.80 Silicon 0.05-0.80 Manganese 9.0-l8.0 Chromium 2.0-6.0 Nickel 7.0-ll.0 Vanadium 0.60-l.0
and the remainder iron, together with the usual impurities in this type of steel, to solution treatment and precipitation hardening.
Preferably, the alloys have the following composition:
Percent Carbon 0.60-0.70 Silicon 0.05-0.50 Manganese 9.0-13.0 Chromium 4.0-5.0 Nickel 8.0l0.0 Vanadium 0.70-0.95
and the remainder iron, together with the usual impurities in this type of steel.
The austenitic steels of desired composition were solution treated and precipitation hardened by (l) annealing at a temperature of about 1150 C. for
about one hour,
(2) quenching in Water,
(3) annealing at a temperature of about 650 C. for
about 8 to 10 hours, and
(4) cooling in air.
The austenitic steels so treated were non-magnetic and had high tensile strengths and impact strengths greater than 5.5 kpm./crn.
Some examples of steel according to the present invention are shown in the following Table II.
The yield point, 0' has been defined as the load at which a non-proportional elongation corresponding to 0.2% of the original length of the test bar takes place. It is stated in kp./mm. and has been determined in an entirely conventional way, see ISO Recommendation R82. The impact strength tests were carried out with so-called V test bars in Charpy equipment, in accordance with a procedure which conforms entirely to ISO Recommenda- TABLE II Type Composition, percent Yield point Impact of do strength steel 0 Si Mn Cr Ni V lip/mm. Kcv+20 0.,
lrprn/cm.
H; 0.6 0.10 9.3 4.4 8.8 0.85 88.5 7.8 I 0.65 0.08 12.9 4.4 8.8 0.83 87.9 8.0 J 0.67 0.46 9.9 4.1 8.7 0.85 87.3 6.7 K 0. 69 0. 28 10. 4 4. 2 8. 7 0.86 92.2 5. 5
A comparison of the data in Tables I and II shows that non-magnetic, austenitic steels produced according to the invention, while having high tensile strength, also have greater impact strengths compared to the types of steels previously used in this connection.
Steels having compositions that do not meet the com position requirements of this invention (such as those disclosed in Belgian Patent 518,985 and US. Patent 2,865,740), when subjected to solution treatment and precipitation hardening, are not converted into steels having the high impact strengths as the non-magnetic austenitic steels of this invention.
What is claimed is:
1. A non-magnetic, austenitic steel having a high tensile strength and a high impact strength and having a composition consisting essentially of:
Percent Carbon 0.50-0.80
Silicon 0.05-0.80
Manganese 9.0-18.0 Chromium 2.0-6.0 Nickel 7.0-11.0 Vanadium 0.601.0
and the remainder iron.
2. A steel according to claim 1, wherein the composition consisting essentially of:
Percent Carbon 0.60-0.70 Silicon 0.05-0.50 Manganese 9.0-13.0 Chromium 4.0-5.0 Nickel 8.0-10.0 Vanadium 0.70-0.95
and the remainder iron.
. 4 3. A steel according to claim 2, which has an impact strength of at least 5.5 kpm./cm.
4. A steel according to claim 2, which has an impact strength of 8.0 kpm./cm. and consists essentially of:
Percent Carbon 0.65
Silicon 0.08
Manganese 12.9 Chromium 4.4
Nickel 8.8
Vanadium 0.83
Iron 72.3
5. A steel according to claim 1 which has been precipitation hardened.
6. A steel according to claim 2 which has been precipitation hardened.
References Cited UNITED STATES PATENTS HYLAND BIZOT, Primary Examiner. PAUL WEINSTEIN, Assistant Examiner.
US610009A 1962-12-19 1967-01-18 Non-magnetic steels Expired - Lifetime US3383203A (en)

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SE13711/62A SE303145B (en) 1962-12-19 1962-12-19

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SE (1) SE303145B (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4216816A (en) * 1977-11-16 1980-08-12 Thermit Welding GB Limited Aluminothermic welding of austenitic manganese steel
US4302248A (en) * 1978-07-04 1981-11-24 Kobe Steel, Limited High manganese non-magnetic steel with excellent weldability and machinability
US4342593A (en) * 1980-09-15 1982-08-03 Abex Corporation Castings
US4911884A (en) * 1989-01-30 1990-03-27 General Electric Company High strength non-magnetic alloy
US20100272148A1 (en) * 2009-04-23 2010-10-28 Medtronic, Inc. Multiple Use Temperature Monitor Adapter, System and Method of Using Same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USD824677S1 (en) * 2015-12-18 2018-08-07 Colgate-Palmolive Company Electric toothbrush

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE518985A (en) *
BE507473A (en) *
BE507591A (en) *
CH318247A (en) * 1952-08-22 1956-12-31 Hadfields Limited Austenitic steel
US2865740A (en) * 1954-06-23 1958-12-23 United States Steel Corp Precipitation-hardening nonmagneticferrous alloys

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE518985A (en) *
BE507473A (en) *
BE507591A (en) *
CH318247A (en) * 1952-08-22 1956-12-31 Hadfields Limited Austenitic steel
US2865740A (en) * 1954-06-23 1958-12-23 United States Steel Corp Precipitation-hardening nonmagneticferrous alloys

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4216816A (en) * 1977-11-16 1980-08-12 Thermit Welding GB Limited Aluminothermic welding of austenitic manganese steel
US4302248A (en) * 1978-07-04 1981-11-24 Kobe Steel, Limited High manganese non-magnetic steel with excellent weldability and machinability
US4342593A (en) * 1980-09-15 1982-08-03 Abex Corporation Castings
US4911884A (en) * 1989-01-30 1990-03-27 General Electric Company High strength non-magnetic alloy
US20100272148A1 (en) * 2009-04-23 2010-10-28 Medtronic, Inc. Multiple Use Temperature Monitor Adapter, System and Method of Using Same
US8926175B2 (en) 2009-04-23 2015-01-06 Medtronic, Inc. Multiple use temperature monitor adapter, system and method of using same

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Publication number Publication date
SE303145B (en) 1968-08-19
GB1060670A (en) 1967-03-08
CH442766A (en) 1967-08-31

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