BE347973A - - Google Patents
Info
- Publication number
- BE347973A BE347973A BE347973DA BE347973A BE 347973 A BE347973 A BE 347973A BE 347973D A BE347973D A BE 347973DA BE 347973 A BE347973 A BE 347973A
- Authority
- BE
- Belgium
- Prior art keywords
- parts
- layer
- tin
- nitriding
- nitrogen
- Prior art date
Links
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 20
- 238000005121 nitriding Methods 0.000 claims description 12
- ATJFFYVFTNAWJD-UHFFFAOYSA-N tin hydride Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 12
- 229910052718 tin Inorganic materials 0.000 claims description 11
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 6
- 229910001128 Sn alloy Inorganic materials 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- FGIUAXJPYTZDNR-UHFFFAOYSA-N Potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 claims description 3
- VWDWKYIASSYTQR-UHFFFAOYSA-N Sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 claims description 3
- 239000004115 Sodium Silicate Substances 0.000 claims description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N Sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminum Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 239000011248 coating agent Substances 0.000 claims description 2
- 238000000576 coating method Methods 0.000 claims description 2
- 150000003839 salts Chemical class 0.000 claims description 2
- 239000011780 sodium chloride Substances 0.000 claims description 2
- 229910052911 sodium silicate Inorganic materials 0.000 claims description 2
- 229910001092 metal group alloy Inorganic materials 0.000 claims 2
- 239000007788 liquid Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- REDXJYDRNCIFBQ-UHFFFAOYSA-N aluminium(3+) Chemical class [Al+3] REDXJYDRNCIFBQ-UHFFFAOYSA-N 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000002349 favourable Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- 239000004323 potassium nitrate Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
- 239000004317 sodium nitrate Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
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
- C23C8/04—Treatment of selected surface areas, e.g. using masks
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)
Description
<Desc/Clms Page number 1>
Procédé pour protéger contre l'action durcissante de l'azote certaines parties d'une pièce destinée ! être durcie par nitruration.
La présente invention a pour objet un procédé pour protéger contre l'action durcissante de l'azote certaines parties d'un objet destiné à être durci par nitruration. Ce procédé peut, par exemple, être mis en oeuvre de la façon suivante.
Les objets en fer ou acier destinés à être durcis par nitruration sont recouverts, aux emplacements qui doivent être protégés contre l'action durcissante de l'azote, d'une couche d'un métal ou alliage qui lors du durcissement de la pice protège les emplacements en question contre la péné- tration de l'azote. Un procédé tout particulièrement appro- @
<Desc/Clms Page number 2>
prié consiste à recouvrir les emplacements à protéger d'une couche d'étain ou d'un alliage d'étain, soit par les pro- cédés habituels d'étamage, soit en trempant quelques mi- nutes les parties à protéger dans un bain d'étain liquide.
Lorsqu'on enlevé du bain les parties étamées, la pièce pré- sente aux parties en question une couche d'étain d'épaisseur variable, parfois importante.
La protection ainsi obtenue contre l'action durcissante de l'azote résiste-- des essais l'ont montré - à plusieurs durcissements successifs par nitruration ; pourpouvoir de nouveau durcir un emplacement étamé, il est nécessaire d'en- lever préalablement la couche d'étain sur une certaine profondeur.
Comme la température de fusion de l'étain ou de l'al- liage d'étain employé est inférieure à la température habituelle de nitruration, l'étain ou l'alliage d'étain viennent à fondre pendant la nitruration et pourraient se répandre sur les parties de la pièce traitée qui doivent prendre le durcissement par l'azote. Pour éviter cet in- convénient, on recouvre les parties étamées avec un en- duit résistant à 500 et ayant pour but de retenir l'étain ou l'alliage d'étain à l'état liquide et de l'empêcher de couler: les compositions ayant une adhérence suffisante et ne se criquant pas à la température de nitruration per- mettent d'obtenir un résultat favorable.
On peut, en particulier, utiliser dans ce but une couche de silicate de soude et de poudre d'aluminium que l'on fait sécher avec soin.
On peut aussi, pour éviter cet inconvénient tremper les parties étamées où la pièce tout entière dans un bain salin (par exemple nitrate de soude ou de potasse) chauffé @
<Desc/Clms Page number 3>
400 C environ. Dans le bain l'étain devient liquide et cou- le au fond, sans pouvoir adhérer aux parties qui n'avaient pas été préalablement étamées. La raison en est que les parties non préalablement étamées, lorsqu'on les plonge dans un bain, s'oxydent légèrement; en outre les gouttes d'étain se recouvrent également d'une légère couche d'oxy'- de, de sorte qu'elles ne conviennent pas 1 l'étamage. (Cette légère oxydation des parties non étamées ne présente pas le moindre inconvénient pour la nitruration proprement dite).
Une fois les pièces préparées de la manière ci- dessus indiquée, elles sont soumises à la nitruration pro- prement dite ; parties non étamées prennent par nitru- ration la dureté bien connue, tandis que les parties préa- lablement étamées restent douces et pavent être usinées sans difficulté.
<Desc / Clms Page number 1>
Process for protecting parts of a intended part against the hardening action of nitrogen! be hardened by nitriding.
The present invention relates to a method for protecting against the hardening action of nitrogen certain parts of an object intended to be hardened by nitriding. This method can, for example, be implemented as follows.
The iron or steel articles intended to be hardened by nitriding are covered, at the locations which must be protected against the hardening action of nitrogen, with a layer of a metal or alloy which, when the part hardens, protects the parts. locations in question against the penetration of nitrogen. A particularly suitable process.
<Desc / Clms Page number 2>
required consists in covering the places to be protected with a layer of tin or a tin alloy, either by the usual tinning processes, or by soaking the parts to be protected for a few minutes in a bath of liquid tin.
When the tin parts are removed from the bath, the part presents to the parts in question a layer of tin of varying, sometimes significant, thickness.
The protection thus obtained against the hardening action of nitrogen resists - tests have shown - several successive hardening operations by nitriding; in order to be able to harden again a tinned spot, it is necessary to first remove the tin layer to a certain depth.
As the melting temperature of the tin or tin alloy used is lower than the usual nitriding temperature, the tin or the tin alloy will melt during nitriding and could spread over it. the parts of the treated part which are to take nitrogen hardening. To avoid this inconvenience, the tinned parts are covered with a coating resistant to 500 and intended to retain the tin or the tin alloy in the liquid state and prevent it from flowing: compositions having sufficient adhesion and not cracking at the nitriding temperature make it possible to obtain a favorable result.
One can, in particular, use for this purpose a layer of sodium silicate and aluminum powder which is carefully dried.
To avoid this drawback, it is also possible to soak the tinned parts or the entire part in a heated salt bath (for example sodium or potassium nitrate) @
<Desc / Clms Page number 3>
Approximately 400 C. In the bath, the tin becomes liquid and sinks to the bottom, without being able to adhere to the parts which had not been previously tinned. The reason is that the parts not previously tinned, when immersed in a bath, oxidize slightly; furthermore, the tin drops are also covered with a light layer of oxide, so that they are not suitable for tinning. (This slight oxidation of the non-tinned parts does not present the slightest drawback for the nitriding proper).
Once the parts have been prepared in the manner indicated above, they are subjected to the actual nitriding; parts not tinned take by nitru- tion the well-known hardness, while the previously tinned parts remain soft and can be machined without difficulty.
Claims (1)
Publications (1)
Publication Number | Publication Date |
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BE347973A true BE347973A (en) |
Family
ID=23547
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
BE347973D BE347973A (en) |
Country Status (1)
Country | Link |
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BE (1) | BE347973A (en) |
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0
- BE BE347973D patent/BE347973A/fr unknown
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