US2920954A - Stainless steel alloy of high hardness - Google Patents

Stainless steel alloy of high hardness Download PDF

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US2920954A
US2920954A US728556A US72855658A US2920954A US 2920954 A US2920954 A US 2920954A US 728556 A US728556 A US 728556A US 72855658 A US72855658 A US 72855658A US 2920954 A US2920954 A US 2920954A
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stainless steel
alloy
hardness
columbium
bhn
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Norman S Mott
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Cooper Alloy Corp
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Cooper Alloy 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
    • C22C38/48Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum

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  • the new alloy is based on the simultaneous use of columbium and an increased amount of silicon. If desired, the nitrogen content also may be increased, as hereinafter explained, but this is optional and is unimportant compared to the use of columbium and increased silicon.
  • the broad range of my alloy includes the following chemical composition:
  • the balance would be iron, manganese, sulfur, phosphorus and other elements incidental to manufacture and normally found as residuals in stainless steel alloys.
  • BHN Brinell hardness number
  • WQ water quenched from 2000 F.
  • PH precipitation hardened by holding at 850-925 F. for eight hours, and then furnace cooling.
  • test number X-18DF is repeated from Table I.
  • Table II Test No. X-18 X-18DA X-l8DB X-18DF The elements other than columbium are substantially constant. This table shows that increasing the columbium percentage increases the hardness at a substantially constant level of the other elements.
  • a BHN of 600 is an upper limit of hardness, because above that cracks are produced. Accordingly, a range of 0.50 to 1.50% columbium is indicated, while a more preferred or narrower range would be 0.75 to 1.25% for the columbium. It may be noted that in these tests the silicon was approximately 3.50%.
  • test X-l8DB could have been included in Table I as showing a fifth example of my invention.
  • This table showsthe effect of increasing silicon on the BHN hardness values. Since a BHN of 400 minimum is my objective, it will be seen that a silicon content of about 3.5% is necessary at the lower columbium level of about 0.5%. A silicon content of about 3% is necessary at the higher columbium level of about 1.0%. Above 5% silicon, embrittlement and a tendency towards cracking sets in, and I have therefore set a maximum of 6%, with a preferred limit of 5%, for this element.
  • the iron content is not included, but it is understood that the balance is iron, subject to the presence of small amounts of impurities incidental to the usual melting practice when dealing with ferrous metals.
  • the maximum carbon content should be no higher than say 0.08%
  • the alloys are fully resistant to the usual corrosion tests, specifically 65% boiling nitric acid, 50% sulphuric acid at 80 F., and 5% hydrochloric acid at 80 F. These alloys are also fully resistant to salt spray. As previously indicated, in this respect the present alloys, despite their very high hardness, are comparable to the well-known AISI 316 and 317 types of stainless steel.
  • the alloys are weldable by using welding rods of the same general composition as the alloy being welded. These alloys are soft enough in the quench-annealed condition to be readily machinable, and they may be precipitation hardened by a comparatively low-temperature heattreatment to a very high degree of hardness.
  • columbium 1.5% columbium, and a carbon content not exceeding 0.08%, the remainder being essentially iron, with manganese, sulphur, phosphorus, and other elements incidental to manufacture and normally found as residuals in stainless steel alloys, and an optional nitrogen content of 0.04% to 0.25%.
  • a precipitation hardenable stainless steel alloy of Veryhigh hardness having a hardness exceeding 400 BHN in the precipitation hardened state said alloy having a range of 18% to 21% chromium, 8% to 12% nickel, 3.75% to 4.25% molybdenum, 3.5% to 5.0% silicon, 0.75% to 1.25% columbium, and a carbon content not exceeding 0.08%, the remainder being essentially iron, with manganese, sulphur, phosphorus, and other elements incidental to manufacture and normally found as residuals in stainless steel alloys, and an optional nitrogen content of 0.04% to 0.15%.
  • V precipitation hardenable stainless steel alloy of Veryhigh hardness having a hardness exceeding 400 BHN in the precipitation hardened state, said alloy having a range of 18% to 21% chromium, 8% to 12% nickel, 3.75% to 4.25% molybdenum, 3.5% to 5.0% silicon, 0.75% to 1.25% columbium, and a carbon content not exceeding 0.08%, the remainder being
  • a precipitation hardenable stainless steel alloy of very high hardness having a hardness exceeding 400 BHN in the precipitation hardened state said alloy having approximately 20.01% chromium, 8.69% nickel, 0.85% manganese, 3.82% molybdenum, 3.56% silicon, 1.23% columbium, 0.041% nitrogen, and 0.049% carbon, the remainder being essentially iron and other elements incidental to manufacture and normally found as residuals in stainless steel alloys.
  • a precipitation hardenable stainless steel alloy having a hardness exceeding 400 BHN in the precipitation hardened state, said alloy having approximately 20.10% chromium, 8.60% nickel, 0.89% manganese, 3.96% molybdenum, 3.55% silicon, 0.98% columbium, 0.04% nitrogen, and 0.052% carbon, the remainder being essentially iron and other elements incidental to manufacture and normally found as residuals in stainless steel alloys.

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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)

Description

United States Patent 2,920,954 STAINLESS STEEL ALLOY OF HIGH HARDNESS Norman S. Mott, Westfield, NJ., assignor to Cooper Al- }oy Corporation, Hillside, N.J., a corporation of New ersey No Drawing. Application April 15, 1958 Serial No. 728,556
9 Claims. (Cl. 75-128) excellent corrosion-resistance of the well-known A181 316 and 317 types of stainless steel.
The new alloy is based on the simultaneous use of columbium and an increased amount of silicon. If desired, the nitrogen content also may be increased, as hereinafter explained, but this is optional and is unimportant compared to the use of columbium and increased silicon.
The broad range of my alloy includes the following chemical composition:
Percent C .08 Cr 18-30 Ni 8-12 Mo 2-6 Si 3-6 Cb 0.50-1.50 N 2 0.04-0.25
1 Maximum. Optional.
In respect to nitrogen a normal minimum residual is considered to be 0.04%. Therefore, at the minimum there is no intentional addition of nitrogen.
A closer and more preferred range is as follows:
Percent C .08 Cr 18-21 Ni 8-12 M0 3.75-4.25 Si 3.5-5.0 Cb 0.75-1.25 N, 2 0.04-0.1s
1 Maximum. Optional.
In both of the chemical composition ranges given above, the balance would be iron, manganese, sulfur, phosphorus and other elements incidental to manufacture and normally found as residuals in stainless steel alloys.
Four specific examples of my alloy are given in the following table:
1 Not intentionally added.
In the above and in all following tables BHN means Brinell hardness number; WQ means water quenched from 2000 F.; and PH means precipitation hardened by holding at 850-925 F. for eight hours, and then furnace cooling.
It will be noted that the above specific examples of my alloy all have a remarkable hardness of over 500 BHN in the PH condition. I
To show the eifect of adding columbium, the following table may be referred to. The test number X-18DF is repeated from Table I.
Table II Test No. X-18 X-18DA X-l8DB X-18DF The elements other than columbium are substantially constant. This table shows that increasing the columbium percentage increases the hardness at a substantially constant level of the other elements. I consider a BHN of 400 in the PH condition the lowest hardness desirable for the present objective, and I consider a BHN of 500 preferable. A BHN of 600 is an upper limit of hardness, because above that cracks are produced. Accordingly, a range of 0.50 to 1.50% columbium is indicated, while a more preferred or narrower range would be 0.75 to 1.25% for the columbium. It may be noted that in these tests the silicon was approximately 3.50%. Incidentally, test X-l8DB could have been included in Table I as showing a fifth example of my invention.
The effect of increasing the nitrogen content is shown in the following table:
The eifect of increasing siliconis shown in the following table: 7
a Table IV Test No. X-ISDA x-rsno X-ISDB X-ISD .percent 049 056 052 058 or" d 20. 2s 20. 0s 20. 10 20. 35 Ni ..d0 8.34 8.56 8;60 s. 60 Mn. .81 .88 .89 .83 Mo. (1 3.89 a. 92 r 3.96 3.78 si 3. 51 4. s9 3. 55 4. 97 0b-- .51 .54 .98 .86 2 .039 .043 .040 041 BHN WQ 286 351 302 387 BHN PH 418 512 495 555 The first two tests are with a low level' of columbium, while the second two are with a high level of columbium. Otherwise, the elements are unchanged, except for silicon, which is changed from about 3.5 to 5.0%.
' This table showsthe effect of increasing silicon on the BHN hardness values. Since a BHN of 400 minimum is my objective, it will be seen that a silicon content of about 3.5% is necessary at the lower columbium level of about 0.5%. A silicon content of about 3% is necessary at the higher columbium level of about 1.0%. Above 5% silicon, embrittlement and a tendency towards cracking sets in, and I have therefore set a maximum of 6%, with a preferred limit of 5%, for this element.
In all of the foregoing analyses, the iron content is not included, but it is understood that the balance is iron, subject to the presence of small amounts of impurities incidental to the usual melting practice when dealing with ferrous metals. The maximum carbon content should be no higher than say 0.08%
It will be understood that the alloys are fully resistant to the usual corrosion tests, specifically 65% boiling nitric acid, 50% sulphuric acid at 80 F., and 5% hydrochloric acid at 80 F. These alloys are also fully resistant to salt spray. As previously indicated, in this respect the present alloys, despite their very high hardness, are comparable to the well-known AISI 316 and 317 types of stainless steel.
The alloys are weldable by using welding rods of the same general composition as the alloy being welded. These alloys are soft enough in the quench-annealed condition to be readily machinable, and they may be precipitation hardened by a comparatively low-temperature heattreatment to a very high degree of hardness.
It will be apparent that while I have set forth specific examples of my improved alloys, changes may be made without departing from the scope of the invention as sought to be defined in the following claims.
I claim:
i 1. A precipitation hardenable stainless steel alloy of very high hardness having a hardness exceeding 400 BHN in the precipitation hardened state, said alloy having 'a range of 18% to 30% chromium, 8% to 12% nickel, 2%
1.5% columbium, and a carbon content not exceeding 0.08%, the remainder being essentially iron, with manganese, sulphur, phosphorus, and other elements incidental to manufacture and normally found as residuals in stainless steel alloys, and an optional nitrogen content of 0.04% to 0.25%.
3. A precipitation hardenable stainless steel alloy of very high hardness having a hardness exceeding 400 BHN in the precipitation hardened state, said alloy having a range of 18% to 21% chromium, 8% to 12% nickel, 3.75% to 4.25% molybdenum, 3.5% to 5.0% silicon, 0.75% to 1.25% columbium, and a carbon content not exceeding 0.08%, the remainder being essentially iron,
4. A precipitation hardenable stainless steel alloy of Veryhigh hardness having a hardness exceeding 400 BHN in the precipitation hardened state, said alloy having a range of 18% to 21% chromium, 8% to 12% nickel, 3.75% to 4.25% molybdenum, 3.5% to 5.0% silicon, 0.75% to 1.25% columbium, and a carbon content not exceeding 0.08%, the remainder being essentially iron, with manganese, sulphur, phosphorus, and other elements incidental to manufacture and normally found as residuals in stainless steel alloys, and an optional nitrogen content of 0.04% to 0.15%. V
5. A precipitation hardenable stainless steel alloy of very high hardness having a hardness exceeding 400 BHN in the precipitation hardened state, said alloy having approximately 20.08% chromium, 8.56% nickel, 0.88% manganese, 3.92% molybdenum, 4.89% silicon, 0.54% columbium, 0.043% nitrogen, and 0.056% carbon, the remainder being essentially iron and other elements incidental tov manufacture and normally found as residuals in stainless steel alloys.
6. A precipitation hardenable stainless steel alloy of very high hardness having a hardness exceeding 400 BHN in the precipitation hardened state, said alloy having approximately 20.21% chromium, 8.81% nickel, 0.79% manganese, 3.76% molybdenum, 3.49% silicon, 0.96%
.columbium, 0.12% nitrogen, and 0.053% carbon, the
- very high hardness having a hardness exceeding 400 BHN in the precipitation hardened state, said alloy having approximately 20.35% chromium, 8.6% nickel, 0.83% manganese, 3.78% molybdenum, 4.97% silicon, 0.86% columbium, 0.041% nitrogen, and 0.058% carbon, the remainder being essentially iron and other elements incidental to manufacture and normally found as residuals in stainless steel alloys.
8. A precipitation hardenable stainless steel alloy of very high hardness having a hardness exceeding 400 BHN in the precipitation hardened state, said alloy having approximately 20.01% chromium, 8.69% nickel, 0.85% manganese, 3.82% molybdenum, 3.56% silicon, 1.23% columbium, 0.041% nitrogen, and 0.049% carbon, the remainder being essentially iron and other elements incidental to manufacture and normally found as residuals in stainless steel alloys.
9. A precipitation hardenable stainless steel alloy having a hardness exceeding 400 BHN in the precipitation hardened state, said alloy having approximately 20.10% chromium, 8.60% nickel, 0.89% manganese, 3.96% molybdenum, 3.55% silicon, 0.98% columbium, 0.04% nitrogen, and 0.052% carbon, the remainder being essentially iron and other elements incidental to manufacture and normally found as residuals in stainless steel alloys.
References Cited in the file of this patent UNITED. STATES PATENTS

Claims (1)

1. A PRECIPITATION HARDENABLE STAINLESS STELL ALLOY OF VERY HIGH HARDNESS HAVING A HARDNESS EXCEEDING 400 BHN IN THE PRECIPITATION HARDENED STATE, SAID ALLOY HAVING A RANGE OF 18% TO 30% CHROMIUM, 8% TO 12% NICKEL, 2% TO 6% MOLYBDENUM, 3% TO 6% SILICON, 0.5% TO 1.5% COLUMBIUM, AND A CARBON CONTENT NOT EXCEEDING 0.08% THE REMAINDER BEING ESSENTIALLY IRON.
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Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3029171A (en) * 1959-03-23 1962-04-10 Atlas Steels Ltd Age hardening of stainless steels with niobium silicides
US3073292A (en) * 1960-02-17 1963-01-15 Gen Motors Corp Composite valve lifter
US3093487A (en) * 1961-02-27 1963-06-11 Jones Eynon Egg products and processes for preparing same
US3337331A (en) * 1964-01-29 1967-08-22 Sandvikens Jernverks Ab Corrosion resistant steel alloy
US3854937A (en) * 1970-12-14 1974-12-17 Nippon Steel Corp Pitting corrosion resistant austenite stainless steel
US4000984A (en) * 1973-06-19 1977-01-04 Gebr. Bohler & Co. Ag High silicon-containing austenitic-iron-chromium-nickel alloys
USRE29313E (en) * 1970-12-14 1977-07-19 Nippon Steel Corporation Pitting corrosion resistant austenite stainless steel
US4171218A (en) * 1977-05-23 1979-10-16 Sumitomo Chemical Company, Limited Anticorrosive bellows
GB2122594A (en) * 1982-06-11 1984-01-18 Canadian Ind Apparatus and process for the manufacture of sulphuric acid(
FR2531945A1 (en) * 1982-06-11 1984-02-24 Cil Inc Apparatus and process for producing and concentrating sulphuric acid, and components of the apparatus
FR2541665A1 (en) * 1982-06-11 1984-08-31 Cil Inc Process for the concentration of sulphuric acid
FR2541591A1 (en) * 1982-06-11 1984-08-31 Cil Inc Acid distributor for dehydration or absorption for the production of sulphuric acid
FR2541664A1 (en) * 1982-06-11 1984-08-31 Cil Inc Apparatus for the production of sulphuric acid, and components of the apparatus
FR2541592A1 (en) * 1982-06-11 1984-08-31 Canadian Ind Sulphuric acid/gas contact unit for the production of sulphuric acid
FR2544061A1 (en) * 1982-06-11 1984-10-12 Cil Inc Heat exchanger for the production of sulphuric acid
FR2546871A1 (en) * 1982-06-11 1984-12-07 Cil Inc Apparatus for the concentration of sulphuric acid
EP0378998A1 (en) * 1989-01-14 1990-07-25 Bayer Ag Stainless wrought and cast alloys, and welding additives for parts contacted by concentrated hot sulfuric acid
US5028396A (en) * 1982-06-11 1991-07-02 Chemetics International Company, Ltd. Apparatus formed of high silicon chromium/nickel in steel in the manufacture of sulpheric acid
US5494537A (en) * 1994-02-21 1996-02-27 Nisshin Steel Co. Ltd. High strength and toughness stainless steel strip and process for the production of the same

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2403128A (en) * 1942-06-24 1946-07-02 Westinghouse Electric Corp Heat resistant alloys
US2822265A (en) * 1954-07-30 1958-02-04 Babcock & Wilcox Co Forgeable high strength austenitic alloy with molybdenum, tantalum, columbium-tantalum, and nitrogen additions

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2403128A (en) * 1942-06-24 1946-07-02 Westinghouse Electric Corp Heat resistant alloys
US2822265A (en) * 1954-07-30 1958-02-04 Babcock & Wilcox Co Forgeable high strength austenitic alloy with molybdenum, tantalum, columbium-tantalum, and nitrogen additions

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3029171A (en) * 1959-03-23 1962-04-10 Atlas Steels Ltd Age hardening of stainless steels with niobium silicides
US3073292A (en) * 1960-02-17 1963-01-15 Gen Motors Corp Composite valve lifter
US3093487A (en) * 1961-02-27 1963-06-11 Jones Eynon Egg products and processes for preparing same
US3337331A (en) * 1964-01-29 1967-08-22 Sandvikens Jernverks Ab Corrosion resistant steel alloy
US3854937A (en) * 1970-12-14 1974-12-17 Nippon Steel Corp Pitting corrosion resistant austenite stainless steel
USRE29313E (en) * 1970-12-14 1977-07-19 Nippon Steel Corporation Pitting corrosion resistant austenite stainless steel
US4000984A (en) * 1973-06-19 1977-01-04 Gebr. Bohler & Co. Ag High silicon-containing austenitic-iron-chromium-nickel alloys
US4171218A (en) * 1977-05-23 1979-10-16 Sumitomo Chemical Company, Limited Anticorrosive bellows
FR2541665A1 (en) * 1982-06-11 1984-08-31 Cil Inc Process for the concentration of sulphuric acid
FR2544061A1 (en) * 1982-06-11 1984-10-12 Cil Inc Heat exchanger for the production of sulphuric acid
GB2122594A (en) * 1982-06-11 1984-01-18 Canadian Ind Apparatus and process for the manufacture of sulphuric acid(
FR2541591A1 (en) * 1982-06-11 1984-08-31 Cil Inc Acid distributor for dehydration or absorption for the production of sulphuric acid
FR2541664A1 (en) * 1982-06-11 1984-08-31 Cil Inc Apparatus for the production of sulphuric acid, and components of the apparatus
FR2541592A1 (en) * 1982-06-11 1984-08-31 Canadian Ind Sulphuric acid/gas contact unit for the production of sulphuric acid
FR2543938A1 (en) * 1982-06-11 1984-10-12 Cil Inc PROCESS FOR PRODUCING SULFURIC ACID BY THE CONTACT METHOD
FR2531945A1 (en) * 1982-06-11 1984-02-24 Cil Inc Apparatus and process for producing and concentrating sulphuric acid, and components of the apparatus
FR2546871A1 (en) * 1982-06-11 1984-12-07 Cil Inc Apparatus for the concentration of sulphuric acid
US4543244A (en) * 1982-06-11 1985-09-24 C-I-L Inc. Use of high silicon Cr Ni steel in H2 SO4 manufacture
US5028396A (en) * 1982-06-11 1991-07-02 Chemetics International Company, Ltd. Apparatus formed of high silicon chromium/nickel in steel in the manufacture of sulpheric acid
EP0378998A1 (en) * 1989-01-14 1990-07-25 Bayer Ag Stainless wrought and cast alloys, and welding additives for parts contacted by concentrated hot sulfuric acid
US5051233A (en) * 1989-01-14 1991-09-24 Bayer Aktiengesellschaft Stainless wrought and cast materials and welding additives for structural units exposed to hot, concentrated sulfuric acid
US5494537A (en) * 1994-02-21 1996-02-27 Nisshin Steel Co. Ltd. High strength and toughness stainless steel strip and process for the production of the same

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