DE1019671B - Method of treating rock drill bits and drill rods for rock drill bits - Google Patents
Method of treating rock drill bits and drill rods for rock drill bitsInfo
- Publication number
- DE1019671B DE1019671B DEA25028A DEA0025028A DE1019671B DE 1019671 B DE1019671 B DE 1019671B DE A25028 A DEA25028 A DE A25028A DE A0025028 A DEA0025028 A DE A0025028A DE 1019671 B DE1019671 B DE 1019671B
- Authority
- DE
- Germany
- Prior art keywords
- nitriding
- drill
- rock
- hardness
- drill bits
- 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.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 12
- 239000011435 rock Substances 0.000 title claims description 12
- 238000005121 nitriding Methods 0.000 claims description 25
- 238000011282 treatment Methods 0.000 claims description 9
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 7
- 239000010959 steel Substances 0.000 claims description 7
- 229910021529 ammonia Inorganic materials 0.000 claims description 4
- 238000005520 cutting process Methods 0.000 claims description 4
- 238000000137 annealing Methods 0.000 claims description 3
- 238000009792 diffusion process Methods 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 239000007789 gas Substances 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 230000007935 neutral effect Effects 0.000 claims description 2
- 241000589614 Pseudomonas stutzeri Species 0.000 claims 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 238000006396 nitration reaction Methods 0.000 description 2
- 241000580063 Ipomopsis rubra Species 0.000 description 1
- VNTLIPZTSJSULJ-UHFFFAOYSA-N chromium molybdenum Chemical compound [Cr].[Mo] VNTLIPZTSJSULJ-UHFFFAOYSA-N 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000005480 shot peening Methods 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
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)
- Earth Drilling (AREA)
- Drilling Tools (AREA)
Description
DEUTSCHESGERMAN
Die Lebensdauer von Bohrstangen für Gesteinsbohrer wird dadurch begrenzt, daß die Bohrstange im Laufe der Anwendung infolge von Ermüdungsrissen, die entweder an der Oberfläche der Bohrstange oder an der Fläche des in der Mitte gelegenen Spülloches entstehen, bricht. Es ist bekannt, daß durch Druckspannungen in der Oberfläche des Materials das Aufkommen von Rissen erschwert und dadurch die Lebensdauer der Bohrstange verlängert wird. Es ist daher bereits- vorgeschlagen, solche "Druckspannungen z. B. durch Kugelstrahlen oder durch besondere Wärmebehandlungen zu erzeugen. Ein anderes bekanntes Verfahren, Druckspannungen1 an der Oberfläche des Materials zu erzeugen, ist, der Oberfläche durch geeignete Behandlung fremde Elemente, z. B. Kohle oder Stickstoff, zuzuführen.The life of drill rods for rock drill bits is limited by the fact that the drill rod breaks in the course of use due to fatigue cracks either on the surface of the drill rod or on the surface of the central flush hole. It is known that compressive stresses in the surface of the material make the occurrence of cracks more difficult and thereby extend the life of the drill rod. It is therefore bereits- proposed to generate such "compressive stresses z. B. by shot peening or by special heat treatments. Another known process, compressive stress 1 to produce the material at the surface is the surface of foreign by suitable treatment elements, z. B. coal or nitrogen to supply.
Die Nitrierung ist an und für sich bekannt und wird verwendet, um sehr harte und gegen Verschleiß widerstandsfähige Flächen zu bekommen. Diese werden jedoch sehr spröde, was die Ursache dafür sein dürfte, daß Versuche, die mit Nitrierung von Gesteinsbohrstahl gemacht wurden, mißglückten. Die Bohrstangen wurden so spröde, daß sie leicht zerbrachen. The nitriding is known in and of itself and is used to be very tough and against wear and tear to get resistant surfaces. However, these become very brittle, which is the cause It is likely that attempts made with nitriding rock drill steel failed. the Boring bars became so brittle that they were easily broken.
Die Erfindung betrifft ein Verfahren zur Behandlung von Gesteinsbohrern und Bohrstangen für Gesteinsbohrer, bei dem die Bohrstange in bekannter Weise ausgewalzt wird und danach einer Nitrierbehandlung unterworfen wird, und ist im wesentlichen dadurch gekennzeichnet, daß die Nitrierbehandlung abgebrochen wird, bevor die Härte der Außenschicht der Bohrstange sprunghaft zu dem auf dem Kurvenblatt dargestellten höheren Härteniveau, das bei längeren Härtezeiten erhalten wird, übergeht.The invention relates to a method for treating rock drills and drill rods for rock drills, in which the boring bar is rolled out in a known manner and then a nitriding treatment is subjected, and is essentially characterized in that the nitriding treatment is canceled before the hardness of the outer layer of the drill rod skyrockets to that on the The higher hardness level shown in the curve sheet, which is obtained with longer hardening times, passes over.
Untersuchungen über die Härte des Werkstoffes in der Nähe der Oberfläche als Funktion der Zeit bei Nitrierung von Stahl mit der für Bohrstangen üblichen Analyse haben gezeigt, daß zuerst nur eine mäßige Härtesteigerung erfolgt. In diesem Bereich entstehen Druckspannungen in der Außenschicht, ohne daß diese zu spröde wird. Nach einer gewissen Zeit, die von den Nitrierbedingungen abhängig ist, tritt eine beinahe sprunghafte Steigerung der Oberflächenhärte ein, die innerhalb verhältnismäßig kurzer Zeit hohe Werte erreicht. Gleichzeitig konnte im Mikroskop beobachtet werden, daß der Stahl, wenn der Stickstoffgehalt einen gewissen kritischen Wert erreicht hat, eine neue besonders harte und spröde Phase bildet. Dieser Wert ist sowohl von den Nitrierbedingungen als auch von der Zusammensetzung des Stahls abhängig. Als Beispiel kann angeführt werden, daß beim Nitrieren von Bohrstahl des Chrom-Molybdän-Typs in reinem Ammoniak bei 540° C die sprunghafte Härtesteigerung nach 16 bis 20 Stunden Verfahren zur BehandlungInvestigations into the hardness of the material near the surface as a function of time Nitriding of steel with the usual analysis for boring bars have shown that initially only one moderate increase in hardness takes place. In this area compressive stresses arise in the outer layer, without this becoming too brittle. After a certain time, which depends on the nitriding conditions, there is an almost sudden increase in surface hardness, which is within a relatively short period of time Time reached high values. At the same time it could be observed in the microscope that the steel, if the nitrogen content has reached a certain critical value, a new one that is particularly hard and brittle Phase forms. This value depends both on the nitriding conditions and on the composition of the Steel dependent. As an example it can be cited that when nitriding drill steel of the chromium-molybdenum type in pure ammonia at 540 ° C the sudden increase in hardness after 16 to 20 hours Method of treatment
von Gesteinsbohrern und Bohrstangenof rock drills and drill rods
für Gesteinsbohrerfor rock drill
Anmelder:Applicant:
Aktiebolaget Svenska Kullagerfabriken,
Göteborg (Schweden)Aktiebolaget Svenska Kullagerfabriken,
Gothenburg (Sweden)
Vertreter: Dipl.-Ing. E. Jourdan, Patentanwalt,
Frankfurt/M., Kronberger Str. 46Representative: Dipl.-Ing. E. Jourdan, patent attorney,
Frankfurt / M., Kronberger Str. 46
Beanspruchte Priorität:
Schweden vom 9. Juni 1955Claimed priority:
Sweden 9 June 1955
Sven Anders Baeckström, Hofors (Schweden),
ist als Erfinder genannt wordenSven Anders Baeckström, Hofors (Sweden),
has been named as the inventor
eintritt, wie aus dem Diagramm hervorgeht, in dem die senkrechte Achse die Vickershärte (Hv) beim Bohrstahl und die waagerechte Achse die Nitrierzeit in Stunden (h) bezeichnet. Kurve 1 zeigt die Veränderung der Härte 0,01mm und Kurve 2 die entsprechende Veränderung 0,12 mm unter der Oberfläche. Bei der herkömmlichen Nitrierung wird eine größere Härte erstrebt, weshalb die Nitrierzeit erheblieh länger ist, nach der einschlägigen Literatur nicht selten bis zu 96 Stunden. Nach der vorliegenden Erfindung soll dagegen die Nitrierung abgebrochen werden, bevor die sprunghafte Steigerung der Härte eintritt. occurs, as can be seen from the diagram in which the vertical axis denotes the Vickers hardness (H v ) for drill steel and the horizontal axis denotes the nitriding time in hours (h). Curve 1 shows the change in hardness 0.01 mm and curve 2 the corresponding change 0.12 mm below the surface. In conventional nitriding, a greater hardness is sought, which is why the nitriding time is considerably longer, according to the relevant literature not infrequently up to 96 hours. According to the present invention, on the other hand, the nitration should be terminated before the sudden increase in hardness occurs.
Dadurch, daß die Nitrierung vor der sprunghaften Härtesteigerung abgebrochen wird, wird eine die Lebensdauer verlängernde Spannung in der Außenschicht erhalten, ohne daß die Lebensdauer durch die bei längerer Nitrierzeit entstehende Sprödigkeit gefährdet wird.Because the nitriding is terminated before the sudden increase in hardness, a die Life-prolonging stress in the outer layer is obtained without affecting the life-time through the brittleness resulting from prolonged nitriding is at risk.
Um sicher zu sein, daß der Härtegradient senkrecht zur Oberfläche keine zu hohen Werte annimmt, muß jedoch auf die Nitrierbehandlung ein Diffusionsglühen folgen, was am besten bei einer Temperatur von 500 bis 590° C, beispielsweise 8 Stunden lang, erfolgt.To be sure that the hardness gradient perpendicular to the surface does not assume too high values, however, the nitriding treatment must be followed by diffusion annealing, which is best done at one temperature from 500 to 590 ° C, for example for 8 hours.
In gewissen Fällen kann das zum Nitrieren verwendete Ammoniak mit einem neutralen Gas verdünnt werden, z. B. mit Stickstoff in beispielsweiseIn certain cases the ammonia used for nitriding can be diluted with a neutral gas be e.g. B. with nitrogen in for example
- - 709 80:6/242- - 709 80: 6/242
gleichen Teilen, wodurch die Konzentration von Stickstoff in der Oberfläche vermindert werden kann und sich der Verlauf der Nitrierung leichter beherrschen läßt.equal parts, whereby the concentration of nitrogen in the surface can be reduced and the course of the nitration can be controlled more easily.
Wenn die Bohrstange mit einer Krone und/oder mit geschmiedetem Kragen versehen werden soll, muß dies erfolgen, bevor die Bohrstange der Nitrierbehandlung unterzogen wird. Ferner soll bei Herstellung von Gesteinsbohrern mit Hartmetallschneide das Nitrieren vorgenommen werden, bevor die Schneide am Bohrstahl angebracht worden ist.If the boring bar is to be provided with a crown and / or a forged collar, this must be done before the boring bar is subjected to the nitriding treatment. Furthermore, in production of rock drills with hard metal cutting edges, the nitriding must be carried out before the Cutting edge has been attached to the drill steel.
Claims (8)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE1019671X | 1955-06-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| DE1019671B true DE1019671B (en) | 1957-11-21 |
Family
ID=20418707
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DEA25028A Pending DE1019671B (en) | 1955-06-09 | 1956-06-02 | Method of treating rock drill bits and drill rods for rock drill bits |
Country Status (1)
| Country | Link |
|---|---|
| DE (1) | DE1019671B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2507212A1 (en) * | 1981-06-08 | 1982-12-10 | Usui Kokusai Sangyo Kk | STEEL TUBE HAVING A LAYER CURED ON AT LEAST ONE OF ITS SURFACES |
-
1956
- 1956-06-02 DE DEA25028A patent/DE1019671B/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2507212A1 (en) * | 1981-06-08 | 1982-12-10 | Usui Kokusai Sangyo Kk | STEEL TUBE HAVING A LAYER CURED ON AT LEAST ONE OF ITS SURFACES |
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