US3816111A - Chromium-base alloy for making a chill-mold and a process of making same - Google Patents

Chromium-base alloy for making a chill-mold and a process of making same Download PDF

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Publication number
US3816111A
US3816111A US00252256A US25225672A US3816111A US 3816111 A US3816111 A US 3816111A US 00252256 A US00252256 A US 00252256A US 25225672 A US25225672 A US 25225672A US 3816111 A US3816111 A US 3816111A
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United States
Prior art keywords
alloy
chromium
percent
chill
mold
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Expired - Lifetime
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US00252256A
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English (en)
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H Schneider
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Sulzer AG
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Individual
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Priority claimed from CH700271A external-priority patent/CH552426A/de
Priority claimed from CH609972A external-priority patent/CH568115A5/de
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
    • C22C27/06—Alloys based on chromium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/06—Permanent moulds for shaped castings
    • B22C9/061—Materials which make up the mould
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/20—Accessories: Details
    • B22D17/22—Dies; Die plates; Die supports; Cooling equipment for dies; Accessories for loosening and ejecting castings from dies
    • B22D17/2209—Selection of die materials

Definitions

  • the alloy contains 15 to Percent cobalt and/or 51 Int. (:1. c220 27/00, 82% 1/02 iron, 0 to 0.2 Percent nitrogen, stochiometric q [58] Field of Search /122, 123, 126, 124, ties relative to the nitrogen of a nitride-former 75 123 134 135 171 17 249/134 135 lected from titanium, hafnium and zirconium, and the remainder chromium up to 64 percent.
  • the alloy has 5 R f n Cited good heat conductivity, a small heat-expansion coeffi- UNTED STATES PATENTS cient, good resistance to corrosion and a sufficient heat resistance.
  • Chromium-based alloys have been known for use as the material for castturbine blades of gas turbines as well as for forged pieces.
  • the alloys contain up to 45 percent by weight of cobalt and/or iron and/or nickel as well as 0.01 to 0.5 percent by 'weight of nitrogen and stochiometric amounts of titanium, zirconium and/r hafnium as nitride-formers.
  • chill-molds for melts having temperatures of up to about 800C have been made of steels, this is, of iron-base alloys.
  • these steel chill-molds have not been suitable.
  • the chill molds for the higher temperature melts to be cast have been made of molybdenum-base alloys.
  • the molybdenum-base alloys have a drawback in that their ability to withstand oxidation is considerably decreased about 500C.
  • molybdenum-base alloys are less desireable as chill mold material because oftheir high cost.
  • the invention provides an alloy which contains, in weight percentages, a total of 15 to 35 percent of cobalt and/or iron, 0 to 0.2 percent of nitrogen, stochiometric quantities to the nitrogen of nitride-formers selected from the group consisting of titanium, hafnium, and/or zirconium, and the remainder being chromium, with the proportion of chromium amounting to at least 64 percent.
  • This chromium-base alloy is used as a material for chill molds for molten metals having temperatures of up to l550C.
  • the alloy has good heat-conductivity and a small heat-expansion coefficient which results in good ability to withstand temperature shocks.
  • the alloy also has a heat-resistance which suffices for the requirements made while, above all, the alloy has a good resistance to corrosion which gives it superiority in comparison with the aforesaid molybdenum-base alloys.
  • the chill molds of the invention practically never become cooled below 500C during their use, they practically never display low-temperature brittleness and relatively high transition temperature in going from the tough to the brittle state. When there are lengthy pauses in their use, damage to the chill mold during passage through the transition temperature can be avoided by suitably selected slow cooling or heatingup speeds.
  • ductility can be improved by the addition of yttrium or rare earth metals in an amount to constitute up to 1.5 percent of the weight of the alloy.
  • Other additives such as molybdenum, niobium, aluminum (in association with cobalt and nitrogen), and tantalum can be added in varying quantities to improve the ability to withstand heat. Tantalum, moreover, in combination with nitrogen, improves the ductility of the alloy.
  • a dense automatically building-up and automatically selfrepairing protective layer on the mold surface can be obtained by including a total of 3 to 7 percent of tantalum and niobium (with less than 4 percent of tantalum being present and with at least 1 percent of niobium) and 0.1 to 4 percent of aluminum. It has been found to be advantageous to subject this alloy, after solidifcation, to a heat treatment of the following kind: 2 hours of glowing in a protective gas atmosphere at l300 to 1600; cooling by compressed air to room temperature; 1 hour of glowing in air at 700C; and cooling in air to room temperature.
  • One process for the treatment of a chromium-base alloy for use as a chill mold is characterized in that the alloy is melted in a vacuum of approximately 10 to 10 torr and then cast into a block. The block is then machined out mechanically into the form of the desired chill-mold.
  • the purity of the block which is cast from the melt can be increased, in a simple way. That is, prior to being machined, the block is once more remelted in a vacuum, or else is solution heat treated at around 1600C in an argon atmosphere and then quenched in oil.
  • a grain-refining medium on the molten alloy, it is possible to obtain a finer grain by chemical techniques through an addition of a maximum of 0.1 percent by weight of boron and/or up to 1 percent by weight of silicon.
  • Physical techniques such as, among others, a vibratory treatment, e.g. by ultrasonic or mechanical means, can also be used. Further possibilities include means to obtain a rapid solidification of the cast chill mold material.
  • EXAMPLE 1 A vacuum induction furnace, lined with magnesium oxide (MgO) and in which a vacuum of approximately 10' to 10 torr is maintained, is charged with the individual components of the chromium-base alloy in the following sequence:
  • the mold for casting the chill mold may be made in such a way that the side with the negative of the chill mold hollow space consists of a ceramic mold-mass, which usually is of relatively poor heat conductivity while the other delirnitations of the mold for casting the chill mold consist of metal and/or graphite, which because of their good heat-conductivity promote'rapid solidification of the cast material of the chill mold.
  • the casting for the chill mold obtained from the chromium-base alloy is then solution heat treated at about 1500C in an argon atmosphere for about 2 hours, for the chief purpose of obtaining dissolution of chromium nitrides.
  • the casting is then cooled down from its temperature of the solution heat treatment by compressed air to room temperature and is once more held for about 1 hour at 700C in air, whereby a protective layer becomes formed on the chill mold surface and is cooled in air to room temperature.
  • the chill mold produced by the shaped-casting process is now ready to be put into use.
  • the superiority of the chromium-base alloys according to the invention as a material for chill molds is shown by so-called drop-impact test.
  • the materials that are to be compared with one another, and consisting of specimen plates of about 10 millimeters (mm) X 100 millimeters (mm) X 4 millimeters (mm) dimensions are subjected to drops falling down from a melting steel electrode, which always have a temperature of about 1580C, are of the same size, 7
  • thermoshock treatment in which they were alternately heated to 1200C and then quenched to 600C. During a test, about 3000 such shock-treatments were given to each specimen. In each case, after some 500 such treatments, the weightchange A G of the specimen was determined.
  • the plotted curves thus give the weight increment of various chromium-base alloys as a function of time.
  • the investigated alloys had the following compositions,
  • No. 2 As No. l, but with only percent Fe instead of 25 percent.
  • No. 3 As No. 1, but the melt contained only 2 percent Ta instead of 4 percent, but to make up for this contained also 3 percent Nb.
  • No. 4 As No. l, with an addition of 3 percent Nb.
  • alloy 4 appears to strive toward a saturation value for its increase of weight, this tendency is, however, far less apparent than that with alloy 3. In the case of alloy 4, therefore, saturation evidently occurs only after a substantially longer altematingtemperatures treatment, and, if it occurs at all, only after a substantially greater absorption of oxygen.
  • This invention thus provides a chromium-base alloy which is useful as a material in forming a chill mold for molten metals having temperatures of up to 1550C, e.g. for molten cobalt-base or nickel-base alloys, for cast irons and high-alloy austenitic steels.
  • the alloy is useful for a pressure-casting chill mold as well as for simple chill mold casting.
  • a chromium-base alloy chill mold for high temperature molten metal consisting essentially of by weight a total of 15 to 35 percent cobalt and/or iron of up to 0.2 percent nitrogen, stochiometric amounts relative to said nitrogen of a nitride former selected from the group consisting of titanium, hafnium and zirconium, a total of from 3 to 7 percent tantalum and niobium, said tantalum being present in an amount of less than 4 percent and said niobium being present in an amount of at least 1 percent, 0.1 to 4 percent aluminum for forming a dense self-forming and self-healing tightly-clinging protective layer with said tantalum on the surface of the alloy, and the remainder being essentially chromium, said chromium amounting to at least 64 percent.
  • a chromium-base alloy as set forth in claim 1 further comprising up to 1.5 percent yttrium and/or rare earth metals.
  • a chromium-base alloy as set forth in claim 1 further comprising by weight 5 to 10 percent molybdenum.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
US00252256A 1971-05-12 1972-05-11 Chromium-base alloy for making a chill-mold and a process of making same Expired - Lifetime US3816111A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH700271A CH552426A (de) 1971-05-12 1971-05-12 Verwendung einer chrom-basis-legierung als werkstoff fuer druckguss-kokillen.
CH609972A CH568115A5 (en) 1972-04-25 1972-04-25 Chromium alloy moulds-contg nitrides - for casting alloys of cobalt, nickel or steel

Publications (1)

Publication Number Publication Date
US3816111A true US3816111A (en) 1974-06-11

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US00252256A Expired - Lifetime US3816111A (en) 1971-05-12 1972-05-11 Chromium-base alloy for making a chill-mold and a process of making same

Country Status (7)

Country Link
US (1) US3816111A (OSRAM)
BE (1) BE783371A (OSRAM)
DE (1) DE2221220C3 (OSRAM)
FR (1) FR2137793B1 (OSRAM)
GB (1) GB1395051A (OSRAM)
IT (1) IT965053B (OSRAM)
SE (1) SE383902B (OSRAM)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5288228A (en) * 1989-11-17 1994-02-22 Kubota Corporation Heat-resistant materials
US5608174A (en) * 1992-05-14 1997-03-04 Eck; Ralf Chromium-based alloy
US6692586B2 (en) 2001-05-23 2004-02-17 Rolls-Royce Corporation High temperature melting braze materials for bonding niobium based alloys
US20050281703A1 (en) * 1999-05-27 2005-12-22 Japan Science And Technology Agency Cr-based alloy having an excellent strength-ductility balance at high temperature
US20090072430A1 (en) * 2007-09-17 2009-03-19 Kenneth Bosler Belt and systems for continuous vacuum forming
CN103205618A (zh) * 2012-01-16 2013-07-17 昆山允升吉光电科技有限公司 一种钴铬合金薄膜材料及其制备方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2607157B2 (ja) * 1989-11-17 1997-05-07 株式会社クボタ 加熱炉内の被加熱鋼材支持部材用耐熱合金

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2780545A (en) * 1954-02-03 1957-02-05 Battelle Development Corp High-temperature alloy
US2809139A (en) * 1952-10-24 1957-10-08 Research Corp Method for heat treating chromium base alloy
US2955937A (en) * 1958-01-21 1960-10-11 James A Mcgurty Oxidation resistant chromium alloy
US3017265A (en) * 1959-09-25 1962-01-16 Gen Electric Oxidation resistant iron-chromium alloy
US3174853A (en) * 1962-03-15 1965-03-23 Gen Electric Chromium base alloys
US3246980A (en) * 1964-03-23 1966-04-19 Union Carbide Corp Corrosion-resistant alloys
US3306740A (en) * 1964-11-23 1967-02-28 Wyman Le Roy High-temperature corrosionresistant alloys
US3347667A (en) * 1964-05-21 1967-10-17 Gen Electric Chromium base alloy

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1960125B2 (de) * 1969-11-17 1971-08-26 Sulzer Ag Bei vergleichsweise tiefen temperaturen duktile gut ver giessbare chromlegierung hoher festigkeit und hoher warm festigkeit

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2809139A (en) * 1952-10-24 1957-10-08 Research Corp Method for heat treating chromium base alloy
US2780545A (en) * 1954-02-03 1957-02-05 Battelle Development Corp High-temperature alloy
US2955937A (en) * 1958-01-21 1960-10-11 James A Mcgurty Oxidation resistant chromium alloy
US3017265A (en) * 1959-09-25 1962-01-16 Gen Electric Oxidation resistant iron-chromium alloy
US3174853A (en) * 1962-03-15 1965-03-23 Gen Electric Chromium base alloys
US3246980A (en) * 1964-03-23 1966-04-19 Union Carbide Corp Corrosion-resistant alloys
US3347667A (en) * 1964-05-21 1967-10-17 Gen Electric Chromium base alloy
US3306740A (en) * 1964-11-23 1967-02-28 Wyman Le Roy High-temperature corrosionresistant alloys

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5288228A (en) * 1989-11-17 1994-02-22 Kubota Corporation Heat-resistant materials
US5608174A (en) * 1992-05-14 1997-03-04 Eck; Ralf Chromium-based alloy
US20050281703A1 (en) * 1999-05-27 2005-12-22 Japan Science And Technology Agency Cr-based alloy having an excellent strength-ductility balance at high temperature
US8685315B2 (en) * 1999-05-27 2014-04-01 Japan Science And Technology Agency Cr-based alloy having an excellent strength-ductility balance at high temperature
US6692586B2 (en) 2001-05-23 2004-02-17 Rolls-Royce Corporation High temperature melting braze materials for bonding niobium based alloys
US20090072430A1 (en) * 2007-09-17 2009-03-19 Kenneth Bosler Belt and systems for continuous vacuum forming
CN103205618A (zh) * 2012-01-16 2013-07-17 昆山允升吉光电科技有限公司 一种钴铬合金薄膜材料及其制备方法
CN103205618B (zh) * 2012-01-16 2016-10-05 昆山允升吉光电科技有限公司 一种钴铬合金薄膜材料的制备方法

Also Published As

Publication number Publication date
GB1395051A (en) 1975-05-21
DE2221220A1 (de) 1972-11-23
FR2137793B1 (OSRAM) 1976-01-16
IT965053B (it) 1974-01-31
DE2221220B2 (de) 1973-06-20
FR2137793A1 (OSRAM) 1972-12-29
BE783371A (fr) 1972-09-01
SE383902B (sv) 1976-04-05
DE2221220C3 (de) 1974-01-17

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