US3708353A - Processing for iron-base alloy - Google Patents

Processing for iron-base alloy Download PDF

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US3708353A
US3708353A US00169534A US3708353DA US3708353A US 3708353 A US3708353 A US 3708353A US 00169534 A US00169534 A US 00169534A US 3708353D A US3708353D A US 3708353DA US 3708353 A US3708353 A US 3708353A
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percent
iron
alloy
base alloy
nickel
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US00169534A
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R Athey
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RTX Corp
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United Aircraft Corp
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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
    • C22C38/50Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
    • 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
    • C22C38/54Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron

Definitions

  • percent vanadium, balance iron is provided to provide a grain size of ASTM 5 or finer when measured at 1,000X magnification (normal ASTM grain size readings are at lOOX magnification) with an ultimate tensile strength at room temperature of about 175,000
  • the present invention relates, in general, to the ironbase alloys and, more particularly, to novel processing therefor providing a significant increase in mechanical properties.
  • Aerospace Materials Specification AMS 5525 C describes an alloy of the nominal composition, by weight, of percent chromium, 26 percent nickel, 1.3 percent molybdenum, 2.1 percent titanium, 0.3 percent vanadium, balance substantially iron. As specified in AMS 5525 C, this alloy as currently processed has a maximum tensile strength of 105,000 p.s.i. after solutioning and a minimum tensile strength after full heat treatment of 140,000 p.s.i.
  • the present invention provides an iron-base alloy having physical properties equivalent to the AMS 5597 nickel-base alloy, particularly a minimum tensile strength at room temperature, in the fully heat treated condition, approaching 180,000 p.s.i.
  • processing is conducted at a temperature not exceeding 1,550F., preferably in the range of 1350F.-1,450F.
  • a low temperature stabilization thus replaces the high temperature solution heat treatment.
  • the alloy is then aged to provide maximum yield strength.
  • step 1 Present AMS 5525 AMS 5597 Invention Tensile Strength p.s.i., max. 120,000 105,000 140,000 Elongflw in 20 25 30 2 in. min. Rockwell Hardness (0.030 in.) B B90 TABLE III
  • step 3 Present AMS 5525 AMS 5597 Invention Tensile Strength p.s.i., min. 175,000 140,000 180,000 0.2% Strength 160,000 95,000 150,000 p.s.i., min. Elong.% in 2 in. min. 18 15 15
  • the following tables summarize the effect of the processing on a material of the appropriate chemistry.
  • Iron-base alloy sheet at a nominal composition, by weight, of about 15 percent chromium, 26 percent nickel, 1.3 percent molybdenum, 2.1 percent titanium and 0.3 percent vanadium, having at room temperature an ultimate tensile strength of about 175,000 p.s.i. or higher and an 0.2 percent yield strength of about 160,000 p.s.i. or higher.
  • the alloy after rolling being exposed to no sustained temperature in excess of about 1 ,5 50F.

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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

An iron-base alloy of the nominal composition, by weight, of 15 percent chromium, 26 percent nickel, 1.3 percent molybdenum, 2.1 percent titanium, 0.3 percent vanadium, balance iron, is provided to provide a grain size of ASTM 5 or finer when measured at 1,000X magnification (normal ASTM grain size readings are at 100X magnification) with an ultimate tensile strength at room temperature of about 175,000 p.s.i.

Description

United States Patent [191 Athey Jan.2,1973
[54] PROCESSING FOR IRON-BASE ALLOY [75] Inventor: Roy L. Athey, North Palm Beach,
Fla.
[73] Assignee: United Aircraft Corporation, East Hartford, Conn.
[22] Filed: Aug. 5, 1971 [2]] Appl. No.: 169,534
[52] US. Cl. ..148/l2.3, 148/37, 148/38 [51] Int. Cl. ..C22c 39/20, C22c 41/02, C21d 7/14 A [58] Field of Search ..l48/l2.3, 38, 37; 75/128 W, 75/128 T, 128 B [56] References Cited UNITED STATES PATENTS 2,909,426 10/1959 Richmond et al ..75/128 F 3,065,067 11/1962 Aggen ..75/128F Primary Examiner-W. W. Stallard AttorneyRichard N. James [5 7 ABSTRACT An iron-base alloy of the nominal composition, by weight, of 15 percent chromium, 26 percent nickel, 1.3 percent molybdenum, 2.1 percent titanium, 0.3
percent vanadium, balance iron, is provided to provide a grain size of ASTM 5 or finer when measured at 1,000X magnification (normal ASTM grain size readings are at lOOX magnification) with an ultimate tensile strength at room temperature of about 175,000
p.s.i.
3 Claims, No Drawings PROCESSING FOR IRON-BASE ALLOY BACKGROUND OF THE INVENTION The present invention relates, in general, to the ironbase alloys and, more particularly, to novel processing therefor providing a significant increase in mechanical properties.
Aerospace Materials Specification AMS 5525 C describes an alloy of the nominal composition, by weight, of percent chromium, 26 percent nickel, 1.3 percent molybdenum, 2.1 percent titanium, 0.3 percent vanadium, balance substantially iron. As specified in AMS 5525 C, this alloy as currently processed has a maximum tensile strength of 105,000 p.s.i. after solutioning and a minimum tensile strength after full heat treatment of 140,000 p.s.i.
There is an urgent demand in certain applications for a structural alloy having a strength of about 180,000 p.s.i. These strength requirements are satisfied by the nickel-base alloy specified in AMS 5597. However, for the particular application in mind, an iron-base alloy would be preferred to a nickel-base alloy because of an anticipated exposure of the alloy to a high pressure hydrogen environment. In such an environment hydrogen embrittlement is much more severe in the nickel-base alloys than those having basis in iron. Thus, it is extremely important, if not essential, to have available an iron-base alloy whose physical properties approach that of the AMS 5597 nickel-base alloy.
SUMMARY OF THE INVENTION The present invention provides an iron-base alloy having physical properties equivalent to the AMS 5597 nickel-base alloy, particularly a minimum tensile strength at room temperature, in the fully heat treated condition, approaching 180,000 p.s.i.
The detailed specification chemistry for this alloy, as compared to the AMS 5525 C alloy is set forth in the following table:
TABLE I Composition (percent by weight) This invention AMS 5525 C Min. Max. Min. Max. Carbon 0.08 0.08 Manganese 0.10 2 Silicon 0.25 1 Phosphorous 0.015 0.025 Sulfur 0.015 0.025 Chromium 13.5 16 13.5 16 Nickel 24 27 24 27 Molybdenum 1 1.5 l 1.5 Titanium 1.9 2.3 1.9 2.3 Boron 0.003 0.01 0.003 0.01 Vanadium 0.1 0.5 0.1 0.5 Aluminum 0.35 0.35 Iron Balance Balance Rolling into sheet or strip conducted at a starting temperature of about 1,800 F. with working down to about 1,550 F. produces a grain size too small to rate by ASTM charts at 100X magnification. Cold rolling with low temperature annealing may also be utilized to produce similar microstructures. Subsequent to the rolling operation, processing is conducted at a temperature not exceeding 1,550F., preferably in the range of 1350F.-1,450F. A low temperature stabilization thus replaces the high temperature solution heat treatment. The alloy is then aged to provide maximum yield strength.
DESCRIPTION OF THE PREFERRED EMBODIMENTS The conventional processing for the AMS 5525 alloy is as follows:
1. rolling between 2,000F. down to 1,800F.;
2. solution heat treatment at 1,800F.;
3. and precipitation heat treatment at 1,325F. for 16 hours.
The processing according to the comparative embodiment of the present invention involves the following parameters and sequence:
1. rolling at 1,800F. down to 1,550F.;
2. stabilization at about 1,400F.;
3. and aging at about 1,300F. for 16 hours. (optional) The comparative results of the respective processing are summarized in the following tables and compared, where appropriate, to the AMS 5597 nickel-base alloy goal:
TABLE 1] After step 1 Present AMS 5525 AMS 5597 Invention Tensile Strength p.s.i., max. 120,000 105,000 140,000 Elongflw in 20 25 30 2 in. min. Rockwell Hardness (0.030 in.) B B90 TABLE III After step 3 Present AMS 5525 AMS 5597 Invention Tensile Strength p.s.i., min. 175,000 140,000 180,000 0.2% Strength 160,000 95,000 150,000 p.s.i., min. Elong.% in 2 in. min. 18 15 15 The following tables summarize the effect of the processing on a material of the appropriate chemistry.
TABLE IV Heat No. 8461 Rolled at 2,000F.
Subsequent H.T. Yield Ultimate F./hr./cool k.s.i. k.s.i. EL R/A 1800/ l/0Q+ l300/l6/AC 98.4 158.2 27 44.7 (AMS 5525) 96.8 165.0 28 49.3 1700/l/OQ+ 100.8 168.3 28 47.1 1300/ 16/AC 1500/ I/OQ-l- 1300/16/AC 137.1 176.2 22 31.3 AC 138.8 176.3 20 36.5
TABLE V Heat No. 8461 Rolled at 1,800F.
Subsequent H.T. Yield Ultimate F.lhr./cool k.s.i. k.s.i. EL R/A Thus, it will be seen that the improved processing of the present invention provides an iron-base alloy having strength approaching that of the AMS 5597'nickelbase alloy, as desired.
Although the invention has been specifically described in detail in connection with specific examples and preferred embodiments, the invention in its broader aspects is not limited thereto, but departures may be made therefrom within the scope of the accompanying claims without departure from the principles of the invention and without sacrificing its chief advantages.
What is claimed is:
1. Alloy sheet at a composition of about, by weight, 13-16 percent chromium, 24-27 percent nickel, l-2 percent molybdenum, 1.5-2.5 percent titanium, 0.0030.0l percent boron, 0.1-0.5 percent vanadium, balance substantially iron, having at room temperature an ultimate tensile strength in excess of about 170,000 p.s.i. and an 0.2 percent yield strength in excess of about 150,000 p.s.i.
2. Iron-base alloy sheet at a nominal composition, by weight, of about 15 percent chromium, 26 percent nickel, 1.3 percent molybdenum, 2.1 percent titanium and 0.3 percent vanadium, having at room temperature an ultimate tensile strength of about 175,000 p.s.i. or higher and an 0.2 percent yield strength of about 160,000 p.s.i. or higher.
3. The method of producing sheet from an alloy of the nominal composition of about, by weight, 15 percent chromium, 26 percent nickel, 1.3 percent molybdenum, 2.1 percent titanium, 0.3 percent vanadium, balance substantially iron, which comprises:
rolling at a temperature not exceeding about and subsequently aging the alloy at a temperature of about 1,300F.,
the alloy after rolling being exposed to no sustained temperature in excess of about 1 ,5 50F.
4 I1! l I i

Claims (2)

  1. 2. Iron-base alloy sheet at a nominal composition, by weight, of about 15 percent chromium, 26 percent nickel, 1.3 percent molybdenum, 2.1 percent titanium and 0.3 percent vanadium, having at room temperature an ultimate tensile strength of about 175,000 p.s.i. or higher and an 0.2 percent yield strength of about 160, 000 p.s.i. or higher.
  2. 3. The method of producing sheet from an alloy of the nominal composition of about, by weight, 15 percent chromium, 26 percent nickel, 1.3 percent molybdenum, 2.1 percent titanium, 0.3 percent vanadium, balance substantially iron, which comprises: rolling at a temperature not exceeding about 1,800* F., and subsequently aging the alloy at a temperature of about 1, 300* F., the alloy after rolling being exposed to no sustained temperature in excess of about 1,550* F.
US00169534A 1971-08-05 1971-08-05 Processing for iron-base alloy Expired - Lifetime US3708353A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5223053A (en) * 1992-01-27 1993-06-29 United Technologies Corporation Warm work processing for iron base alloy
FR2727982A1 (en) * 1994-12-13 1996-06-14 Imphy Sa AUSTENITIC STAINLESS STEEL FOR HOT EMPLOYMENT
EP1262157A1 (en) * 2001-05-29 2002-12-04 Anton Meyer & Co.AG Scalpel for ophtalmology surgery

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2909426A (en) * 1958-03-27 1959-10-20 Universal Cyclops Steel Corp Ferrous base alloys
US3065067A (en) * 1959-01-21 1962-11-20 Allegheny Ludlum Steel Austenitic alloy
CA698600A (en) * 1964-11-24 The Carpenter Steel Company Age hardenable austenitic chromium-nickel-titanium steel
US3199978A (en) * 1963-01-31 1965-08-10 Westinghouse Electric Corp High-strength, precipitation hardening austenitic alloys
US3212884A (en) * 1963-07-03 1965-10-19 Marjorie O Soler Ferrous base alloys containing boron

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA698600A (en) * 1964-11-24 The Carpenter Steel Company Age hardenable austenitic chromium-nickel-titanium steel
US2909426A (en) * 1958-03-27 1959-10-20 Universal Cyclops Steel Corp Ferrous base alloys
US3065067A (en) * 1959-01-21 1962-11-20 Allegheny Ludlum Steel Austenitic alloy
US3199978A (en) * 1963-01-31 1965-08-10 Westinghouse Electric Corp High-strength, precipitation hardening austenitic alloys
US3212884A (en) * 1963-07-03 1965-10-19 Marjorie O Soler Ferrous base alloys containing boron

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5223053A (en) * 1992-01-27 1993-06-29 United Technologies Corporation Warm work processing for iron base alloy
FR2727982A1 (en) * 1994-12-13 1996-06-14 Imphy Sa AUSTENITIC STAINLESS STEEL FOR HOT EMPLOYMENT
WO1996018750A1 (en) * 1994-12-13 1996-06-20 Imphy S.A. Austenitic stainless steel to be used hot
EP1262157A1 (en) * 2001-05-29 2002-12-04 Anton Meyer & Co.AG Scalpel for ophtalmology surgery

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