DE1919066C3 - Method of surface hardening by nitriding - Google Patents
Method of surface hardening by nitridingInfo
- Publication number
- DE1919066C3 DE1919066C3 DE19691919066 DE1919066A DE1919066C3 DE 1919066 C3 DE1919066 C3 DE 1919066C3 DE 19691919066 DE19691919066 DE 19691919066 DE 1919066 A DE1919066 A DE 1919066A DE 1919066 C3 DE1919066 C3 DE 1919066C3
- Authority
- DE
- Germany
- Prior art keywords
- nitriding
- surface hardening
- workpieces
- alkaline earth
- alkali
- 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
Links
- 238000000034 method Methods 0.000 title claims description 25
- 238000005121 nitriding Methods 0.000 title claims description 12
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 239000003513 alkali Substances 0.000 claims description 5
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 4
- 239000001257 hydrogen Substances 0.000 claims description 4
- 229910052739 hydrogen Inorganic materials 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 claims description 3
- 239000000956 alloy Substances 0.000 claims description 3
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 10
- 229910000831 Steel Inorganic materials 0.000 description 5
- 239000010959 steel Substances 0.000 description 5
- 229910021529 ammonia Inorganic materials 0.000 description 4
- 239000002609 medium Substances 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 239000000741 silica gel Substances 0.000 description 2
- 229910002027 silica gel Inorganic materials 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- XLJMAIOERFSOGZ-UHFFFAOYSA-M cyanate Chemical compound [O-]C#N XLJMAIOERFSOGZ-UHFFFAOYSA-M 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 1
- 235000013980 iron oxide Nutrition 0.000 description 1
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 230000009466 transformation Effects 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
- C23C8/06—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
-
- 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
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
Die Erfindung bezieht sich auf ein Verfahren zum Oberflächenhärten durch Nitrieren von Legierungen mit Elementen der Eisengruppe als Basis mit einem gasförmigen Arbeitsmedium, das Stickstoff und Wasserstoff enthältThe invention relates to a method for surface hardening by nitriding alloys with elements of the iron group as a basis with a gaseous working medium, nitrogen and hydrogen contains
Es ist bekannt, Gegenstände aus eisenhaltigen Legierungen in einem stickstoffhaltigen Medium bei hohen Temperaturen und längerer Einwirk2:eit an der Oberfläche durch Nitrieren zu härten.It is known objects made from ferrous alloys in a nitrogen-containing medium at high temperatures and prolonged exposure to the surface harden by nitriding.
Bei den bisher bekannten Nitrierverfahren unterscheidet man das Gasnitrieren und das Badnitrieren. Das Ziel beider Verfahren ist es, die Oberfläche von Stahl oder eisenhaltigen Werkstücken mit Stickstoff anzureichern und dadurch zu härten. Der Verschleiß an der Oberfläche dieser Werkstücke wird geringer, während der Kern dieser Werkstücke weich bleibt und seine erwünschte Zähigkeit beibehält.In the nitriding processes known up to now, a distinction is made between gas nitriding and bath nitriding. The aim of both processes is to clean the surface of steel or iron-containing workpieces with nitrogen to enrich and thereby harden. The wear on the surface of these workpieces is less while the core of these workpieces remains soft and maintains its desired toughness.
Beim Gasnitrieren wird als stickstoffabgebendes Mittel im allgemeinen Ammoniakgas verwendet und die zu behandelnden Werkstücke in einem gasdichten Ofen unter strömendem Ammoniakgas bei Temperaturen von 500 bis 5200C geglüht. Die Nitrierdauer beträgt bei diesem Verfahren bis zu 100 Stunden.When nitriding is used as a nitrogen-donating agent generally ammonia gas and the annealed workpieces to be treated in a gas-tight furnace under flowing ammonia gas at temperatures of 500-520 0 C. The nitriding time is up to 100 hours with this process.
Beim Badnitrieren werden flüssige Salzschmelzen verwendet,.die etwa 25 bis 50% Cyanid und bis zu 50% Cyanat enthalten. Die Badtemperatur beträgt bei diesem Verfahren zwischen 560 und 58O0C; die Behandlungsdauer liegt bei etwa 2 Stunden.In bath nitriding, liquid salt melts are used, which contain about 25 to 50% cyanide and up to 50% cyanate. The bath temperature in this process is between 560 and 58O 0 C; the treatment time is around 2 hours.
Die Nachteile der beiden genannten Verfahren liegen zunächst in der hohen Temperatur. Beim Abkühlen von diesen hohen Temperaturen entstehen oft Risse oder die Werkstücke verformen sich auf Grund innerer Spannungen. Weiterhin sind die beiden genannten Verfahren auf Grund der hohen Arbeitstemperaturen nicht für solche Werkstoffe oder Werkstücke geeignet, bei denen während des Aufheizens, während des Glühens oder während des Abkühlens für den Werkstoff schädliche Umwandlungsvorgänge oder für das Werkstück unzulässige Dimensionsänderungen auftreten. Weiterhin erfordern die beiden genannten Verfahren eine saubere, fettfreie und metallisch blanke Oberfläche. Die sogenannten nichtrostenden Stähle müssen vor und während des Nitrierprozesses durch geeignete Maßnahmen, z. B. durch HCl-Dämpfe, depassiviert werden. In der deutschen Patentschrift 9 50 916 wird vorgeschlagen, gesinterte oder nur gepreßte, poröse Eisenformlinge im Ammoniakstrom bei Temperaturen zwischen 150 und 450°C, vorzugsweise bei 350°C zu nitrieren. Als Nachteil dieses Verfahrens wird dort bereits angegeben, daß bei den zur Verwendung kommendenThe disadvantages of the two processes mentioned are first of all the high temperature. When cooling down These high temperatures often cause cracks or the workpieces to deform due to internal forces Tensions. Furthermore, the two processes mentioned are not due to the high working temperatures Suitable for such materials or workpieces that are being used during heating, during annealing or transformation processes that are detrimental to the material or to the workpiece during cooling impermissible dimensional changes occur. Furthermore, the two processes mentioned require a clean, grease-free and shiny metallic surface. The so-called stainless steels must be before and during the nitriding process by means of suitable measures, e.g. B. be depassivated by HCl vapors. In the German patent specification 9 50 916 it is proposed sintered or only pressed, porous iron moldings in a stream of ammonia at temperatures between To be nitrided at 150 and 450 ° C, preferably at 350 ° C. A disadvantage of this process is already indicated there that in the coming to use
ίο niedrigen Temperaturen das Ammoniak nicht mehr
oder nur in untergeordnetem Maße befähigt ist, Eisenoxyde zu reduzieren. Es sei daher meist vorteilhaft, das
zur Verwendung kommende Ammoniak von Sauerstoff und Wasserdampf zu befreien, dies könnte z. B. durch
Überleiten über einen Kontakt aus aktivem Kupfer, der bei seiner Arbeitstemperatur von etwa 180°C das Ammoniak
noch nicht zersetzt, den Sauerstoff plus Wasserstoff aber in Wasser überführt, und durch anschließendes
Trocknen, z. B. mit Silikagel, erfolgen. Das Überleiten einer größeren Gasmenge über einen Kontakt
aus aktivem Kupfer bei 180°C und das anschließende
Trocknen mit Silikagel ist sicher kein sehr wirtschaftliches Verfahren.
Aufgabe der vorliegenden Erfindung ist es, ein Verfahren zum Oberflächenhärten durch Nitrieren auch
von massiven Werkstücken aus Legierungen mit Elementen der Eisengruppe als Basis zu finden, das die
oben beschriebenen Nachteile der bisher bekannnten Verfahren vermeidet und bei niedrigeren Arbeitstemperaturen
durchführbar ist und eine oft mühsame Vorbehandlung oder Reinigung der Oberfläche der Werkstücke
vermeidet.ίο low temperatures the ammonia is no longer able to reduce iron oxides or only to a minor extent. It is therefore usually advantageous to free the ammonia used from oxygen and water vapor. B. by passing over a contact made of active copper, which at its working temperature of about 180 ° C does not yet decompose the ammonia, but converts the oxygen plus hydrogen into water, and then drying, e.g. B. with silica gel. Passing a larger amount of gas over a contact made of active copper at 180 ° C and then drying it with silica gel is certainly not a very economical process.
The object of the present invention is to find a method for surface hardening by nitriding also of solid workpieces made of alloys with elements of the iron group as a basis, which avoids the disadvantages of the previously known methods described above and can be carried out at lower working temperatures and often requires laborious pretreatment or Avoids cleaning the surface of the workpieces.
Zur Lösung dieser Aufgabe wird vorgeschlagen, daß ein gasförmiges Arbeitsmedium verwendet wird, das dampfförmige Alkali- und/oder Erdalkalimetalle enthält. Es hat sich gezeigt, daß bei diesem Verfahren schon bei Temperaturen von 350°C und bei wirtschaftlich vertretbaren Einwirkzeiten und ohne besondere Oberflächenvorbereitung eine Oberflächenhärtung erreichbar ist. Bei höheren Temperaturen wird die erforderliche Einwirkzeit kürzer. Die vorgeschlagenen Alkali- und/oder Erdalkalimetalle wirken vermutlich katalytisch, d. h. sie sind auf Grund ihrer hohen Sauerstoffaffinität in der Lage, die Stahloberfläche durch Oxydreduktion zu aktivieren.To solve this problem it is proposed that a gaseous working medium is used which Contains vaporous alkali and / or alkaline earth metals. It has been shown that in this process even at temperatures of 350 ° C and with economically justifiable exposure times and without special Surface preparation a surface hardening can be achieved. At higher temperatures the required Shorter exposure time. The proposed alkali and / or alkaline earth metals are believed to have a catalytic effect, d. H. Due to their high affinity for oxygen, they are able to penetrate the steel surface To activate oxide reduction.
Es hat sich gezeigt, daß das erfindungsgemäße Verfahren durchführbar ist bei einem geringeren Partialdruck des verwendeten Alkali- oder Erdalkalimetalls als dem der Prozeßtemperatur entsprechenden.It has been shown that the method according to the invention can be carried out at a lower partial pressure of the alkali or alkaline earth metal used than that corresponding to the process temperature.
Weiterhin ist das erfindungsgemäße Verfahren schon durchführbar bei einem Wasserstoffanteil im Arbeitsmedium von 0,01 Volumprozent oder mehr.Furthermore, the method according to the invention can already be carried out with a hydrogen content in the working medium of 0.01 volume percent or more.
Das vorgeschlagene Verfahren wurde erprobt mit einem austenitischen Cr-Ni-Stahl, z.B. 1.4301, und einem ferritischen warmfesten Cr-Mo-Stahl, z. B. 1.6770. Selbstverständlich sind auch zahlreiche andere austenitische und ferritische Stähle geeignet.The proposed method was tested with an austenitic Cr-Ni steel, e.g. 1.4301, and a ferritic creep-resistant Cr-Mo steel, e.g. B. 1.6770. Of course, there are also numerous others Austenitic and ferritic steels are suitable.
Mit diesem Verfahren können nicht nur poröse Eisenformlinge, sondern auch massive Werkstücke nitriert werden.With this process, not only porous iron moldings, but also solid workpieces can be nitrided will.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19691919066 DE1919066C3 (en) | 1969-04-15 | 1969-04-15 | Method of surface hardening by nitriding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19691919066 DE1919066C3 (en) | 1969-04-15 | 1969-04-15 | Method of surface hardening by nitriding |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| DE1919066A1 DE1919066A1 (en) | 1970-10-22 |
| DE1919066B2 DE1919066B2 (en) | 1975-04-30 |
| DE1919066C3 true DE1919066C3 (en) | 1975-12-11 |
Family
ID=5731257
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DE19691919066 Expired DE1919066C3 (en) | 1969-04-15 | 1969-04-15 | Method of surface hardening by nitriding |
Country Status (1)
| Country | Link |
|---|---|
| DE (1) | DE1919066C3 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5376936A (en) * | 1976-12-21 | 1978-07-07 | Pioneer Electronic Corp | Surface hardening method |
-
1969
- 1969-04-15 DE DE19691919066 patent/DE1919066C3/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE1919066A1 (en) | 1970-10-22 |
| DE1919066B2 (en) | 1975-04-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C3 | Grant after two publication steps (3rd publication) | ||
| E77 | Valid patent as to the heymanns-index 1977 | ||
| EF | Willingness to grant licences | ||
| 8339 | Ceased/non-payment of the annual fee |