GB621890A - Method of nitriding ferrous metal alloys - Google Patents

Method of nitriding ferrous metal alloys

Info

Publication number
GB621890A
GB621890A GB3273046A GB3273046A GB621890A GB 621890 A GB621890 A GB 621890A GB 3273046 A GB3273046 A GB 3273046A GB 3273046 A GB3273046 A GB 3273046A GB 621890 A GB621890 A GB 621890A
Authority
GB
United Kingdom
Prior art keywords
per cent
dissociation
ammonia
white layer
alloy
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB3273046A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nitralloy Corp
Original Assignee
Nitralloy Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nitralloy Corp filed Critical Nitralloy Corp
Publication of GB621890A publication Critical patent/GB621890A/en
Expired legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/24—Nitriding
    • C23C8/26—Nitriding of ferrous surfaces

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Abstract

In a process of nitrogenizing ferrous metal alloy, the alloy, heated within the nitrogen hardening range, is treated with dry gaseous ammonia and its dissociation products showing an ammonium dissociation value which rapidly produces a white layer, continuing the treatment until a thin continuous white layer has been formed, then increasing the ammonium dissociation value so that the tendency to form a white layer is lessened and continuing the treatment until the necessary depth of case has been obtained. The alloy may be heated in a furnace at 925 DEG to 975 DEG C. for 5-15 hours during which ammonia is introduced to give a dissociation value of 15-65 per cent, preferably 30-40 per cent, and then for 10-90 hours when the dissociation value is 65-85 per cent. This dissociation value may be raised to 85-90 per cent for a final period and maintained till the white layer has been completely removed. The ammonia dissociation may be controlled by regulating the rate of flow of the ammonia into the chamber. The gaseous atmosphere should be kept rapidly agitated so that the dissociation is maintained constant throughout the chamber. A suitable alloy is one having an analysis C .34 per cent, Mn .55 per cent, Si .25 per cent, Cr 1.30 per cent, Al 1.24 per cent, Mo .17 per cent and the balance iron and unavoidable impurities.
GB3273046A 1943-11-05 1946-11-04 Method of nitriding ferrous metal alloys Expired GB621890A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US621890XA 1943-11-05 1943-11-05

Publications (1)

Publication Number Publication Date
GB621890A true GB621890A (en) 1949-04-21

Family

ID=22040780

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3273046A Expired GB621890A (en) 1943-11-05 1946-11-04 Method of nitriding ferrous metal alloys

Country Status (2)

Country Link
FR (1) FR916271A (en)
GB (1) GB621890A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2865791A (en) * 1954-03-05 1958-12-23 Metallgesellschaft Ag Metal nitride coating process
US4417927A (en) * 1982-03-29 1983-11-29 General Electric Company Steel nitriding method and apparatus
EP1163063A1 (en) * 1999-01-28 2001-12-19 AG Security Pty. Limited Hardened steel security materials

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2865791A (en) * 1954-03-05 1958-12-23 Metallgesellschaft Ag Metal nitride coating process
US4417927A (en) * 1982-03-29 1983-11-29 General Electric Company Steel nitriding method and apparatus
EP1163063A1 (en) * 1999-01-28 2001-12-19 AG Security Pty. Limited Hardened steel security materials
EP1163063A4 (en) * 1999-01-28 2002-09-04 Security Pty Ltd Ag Hardened steel security materials

Also Published As

Publication number Publication date
FR916271A (en) 1946-12-02

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