GB426207A - Improvements in or relating to the case hardening of alloy steels by nitrogenisation - Google Patents

Improvements in or relating to the case hardening of alloy steels by nitrogenisation

Info

Publication number
GB426207A
GB426207A GB2672433A GB2672433A GB426207A GB 426207 A GB426207 A GB 426207A GB 2672433 A GB2672433 A GB 2672433A GB 2672433 A GB2672433 A GB 2672433A GB 426207 A GB426207 A GB 426207A
Authority
GB
United Kingdom
Prior art keywords
sodium
cyanamide
bath
salt bath
alloy steels
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
GB2672433A
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.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
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 EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Priority to GB2672433A priority Critical patent/GB426207A/en
Publication of GB426207A publication Critical patent/GB426207A/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
    • C23C8/40—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 liquids, e.g. salt baths, liquid suspensions
    • C23C8/42—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 liquids, e.g. salt baths, liquid suspensions only one element being applied
    • C23C8/48—Nitriding
    • C23C8/50—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)
  • Coating With Molten Metal (AREA)

Abstract

Alloy steels are nitrogenized by immersing them in a fused salt bath containing an alkali metal cyanamide such as sodium cyanamide, the bath being free from substantial amounts of alkaline earth compounds and having a temperature below 600 DEG C., preferably 500-550 DEG C. The salt bath contains also inorganic salts which do not react with the cyanamide and which lowers the melting point of the mixture such as sodium and/or potassium cyanide or a low melting mixture of lithium, sodium and potassium chloride. Access of air to the bath during the nitrogenization may be prevented by covering the bath with a layer of finely divided graphite or charcoal. In an example, an alloy steel containing 1,24 per cent of aluminium, 1,58 of chromium, 0,51 of manganese, 0,2 of molybdenum, 0,33 of carbon and 0,20 of silicon was immersed in a salt bath composed of about equal parts of potassium cyanide, sodium cyanide and sodium cyanamide at about 538 DEG C. Specification 314,423, [Class 72], is referred to.
GB2672433A 1933-09-28 1933-09-28 Improvements in or relating to the case hardening of alloy steels by nitrogenisation Expired GB426207A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2672433A GB426207A (en) 1933-09-28 1933-09-28 Improvements in or relating to the case hardening of alloy steels by nitrogenisation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2672433A GB426207A (en) 1933-09-28 1933-09-28 Improvements in or relating to the case hardening of alloy steels by nitrogenisation

Publications (1)

Publication Number Publication Date
GB426207A true GB426207A (en) 1935-03-28

Family

ID=10248242

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2672433A Expired GB426207A (en) 1933-09-28 1933-09-28 Improvements in or relating to the case hardening of alloy steels by nitrogenisation

Country Status (1)

Country Link
GB (1) GB426207A (en)

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