EP0366900A1 - Sintered alloy containing carbide - Google Patents
Sintered alloy containing carbide Download PDFInfo
- Publication number
- EP0366900A1 EP0366900A1 EP89116290A EP89116290A EP0366900A1 EP 0366900 A1 EP0366900 A1 EP 0366900A1 EP 89116290 A EP89116290 A EP 89116290A EP 89116290 A EP89116290 A EP 89116290A EP 0366900 A1 EP0366900 A1 EP 0366900A1
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- EP
- European Patent Office
- Prior art keywords
- carbide
- phase
- mixed oxide
- powder
- carburization
- 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.)
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/02—Making ferrous alloys by powder metallurgy
- C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
- C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
- C22C33/0292—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5% with more than 5% preformed carbides, nitrides or borides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/16—Making metallic powder or suspensions thereof using chemical processes
- B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
- B22F9/20—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from solid metal compounds
- B22F9/22—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from solid metal compounds using gaseous reductors
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/02—Making ferrous alloys by powder metallurgy
- C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
- C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
- C22C33/0285—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5% with Cr, Co, or Ni having a minimum content higher than 5%
Definitions
- the invention relates to carbide materials as the starting material for highly wear-resistant tools, for example high-speed steels, and machine parts.
- the material according to the invention has the advantage of very good mechanical properties because of the small carbide grains with a narrow size range and because of its high density.
- the second step, the reduction / carburization of the mixed oxides, is carried out with carburizing gases or gas mixtures or carbon. They are particularly good for this Rotary tube ovens or fluidized bed reactors that prevent caking. This step can also be carried out in a bed.
- the third step (pressing and sintering) is carried out using methods known per se, although considerably larger temperature intervals are permitted during sintering than with the powders known hitherto.
- the carbide size in the powder agglomerates is determined both by the manufacturing process of the mixed oxide powders and by grain growth during carburizing.
- the crystallite size of the mixed oxide powder increases with increasing temperature in the RSV. This crystallite size significantly influences the carbide grain size after carburization.
- the carburization itself takes place at such low temperatures that there is no grain growth.
- Carburizing gases, gas mixtures or carbon are used as reducing and carburizing agents. CH4 / H2 mixtures with a carbon activity ⁇ 1 are suitable. Carbon acts both as a direct reducing / carburizing agent and indirectly through the formation of CO with the mixed oxide.
- the reaction is carried out in a time-controlled manner leads, that is, the carbon content is adjusted over the carburizing time.
- the relationship between carburizing time and carbon content must be determined empirically for the respective carburizing type.
- a solution with a metal concentration of 150 g / l is prepared from stoichiometrically equivalent amounts of chromium nitrate, cobalt nitrate, iron nitrate, vanadyl sulfate, ammonium metatungstate and ammonium heptamolybdate with the addition of water.
- the solution thus prepared is sprayed into a hot reactor at 10 l / h (reaction temperature 800 ° C.).
- the aerosol evaporates extremely quickly, the salts decompose, producing very fine-crystalline, homogeneous mixed oxide particles (FIG. 1). Gases and particles are separated in a separator, the powder is subjected to a reduction / carburization.
- the reduction / carburization takes place, for example, in one Fluid bed system, in which caking of the powder during the implementation can be excluded.
- the reaction is carried out at 950 ° C, the reaction gas is a mixture of 99% H2 and 1% CH4.
- FIG. 4 shows the structure of a sintered part in a magnification of 2500 times.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Powder Metallurgy (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
Abstract
Description
Die Erfindung betrifft Carbidwerkstoffe als Ausgangsmaterial für hochverschleißbeständige Werkzeuge, beispielsweise Schnellarbeitsstähle, und Maschinenteile.The invention relates to carbide materials as the starting material for highly wear-resistant tools, for example high-speed steels, and machine parts.
Bekannt ist die Herstellung von Schnellstahlpulver durch Wasserverdüsen fertiglegierter Schmelzen. Wasserverdüste Schnellstahlpulver weisen typischerweise Partikelgrößen von 40 µ bis 200 µ auf, welche nur in einem sehr engen Temperaturintervall (∼ 4° C) ohne starkes Kornwachstum gesintert werden können. Vollständige Dichte kann nur durch anschliessendes Heißisostatpressen erreicht werden.The production of high-speed steel powder by water atomizing of melted melts is known. Water atomized high-speed steel powders typically have particle sizes of 40 µ to 200 µ, which can only be sintered in a very narrow temperature interval (∼ 4 ° C) without strong grain growth. Complete density can only be achieved by subsequent hot isostatic pressing.
Der Erfindung liegt die Aufgabe zugrunde, einen gesinterten Schnellstahlwerkstoff zu schaffen, welcher gute mechanische Eigenschaften aufweist, wobei die Sinterung in einem großen Temperaturintervall durchgeführt werden kann.The invention has for its object to provide a sintered high-speed steel material which has good mechanical properties, wherein the sintering can be carried out in a large temperature interval.
Gelöst wird diese Aufgabe von einem Werkstoff mit den in Anspruch 1 genannten Merkmalen, Ausführungen der Erfindung, ein Legierungspulver und Herstellungsverfahren sind Gegenstände von Unteransprüchen.This object is achieved by a material with the features mentioned in claim 1, embodiments of the invention, an alloy powder and manufacturing processes are the subject of subclaims.
Der erfindungsgemäße Werkstoff hat den Vorteil sehr guter mechanischer Eigenschaften aufgrund der kleinen Carbidkörner mit engem Größenspektrum sowie aufgrund seiner hohen Dichte.The material according to the invention has the advantage of very good mechanical properties because of the small carbide grains with a narrow size range and because of its high density.
Das erfindungsgemäße Pulver hat folgende Vorteile:
- Bei der Sinterung kann ein breites Temperaturintervall (> 30°C) benutzt werden, was aufwendige Temperaturüberwachung und Regelung überflüssig macht und die Fertigungssicherheit erhöht (geringer Fertigungsausschuß).
- Vollständige Dichte (> 99,9 %) ist ohne starkes Kornwachstum möglich.
- Bei der Herstellung können einige Schritte, beispielsweise das Herstellen der individuellen Metalle, das Aufschmelzen und Legieren, und das aufwendige Verdüsen der Metallschmelze eingespart werden.
- Die Karburierung kann bei niedrigeren Temperaturen durchgeführt werden.The powder according to the invention has the following advantages:
- A wide temperature interval (> 30 ° C) can be used during sintering, which makes complex temperature monitoring and control superfluous and increases production reliability (low production scrap).
- Complete density (> 99.9%) is possible without strong grain growth.
- A few steps can be saved in the production, for example the production of the individual metals, the melting and alloying, and the complex atomizing of the metal melt.
- The carburizing can be carried out at lower temperatures.
Die günstigen Eigenschaften des Pulvers beruhen vor allem darauf, daß bereits im Legierungspulver, also vor der Sinterung kleine Carbidteilchen (< 3 µ) vorhanden sind, welche von der Binderphase umhüllt und benetzt werden. Die Struktur der Pulver ist nicht kompakt, sondern schwammig- oder korallenartig, woraus sich hohe Sinteraktivität ergibt.The favorable properties of the powder are based primarily on the fact that small carbide particles (<3 μ) are already present in the alloy powder, ie before sintering, which are enveloped and wetted by the binder phase. The structure of the powder is not compact, but rather spongy or coral-like, which results in high sintering activity.
Die Herstellung des Werkstoffs erfolgt in drei Schritten:
- 1. Herstellung von Mischoxidpartikeln
- 2. Reduktion/Karburierung zu Legierungspulvern
- 3. Sinterung
- 1. Production of mixed oxide particles
- 2. Reduction / carburization to alloy powders
- 3. Sintering
Der erste Schritt erfolgt bevorzugt mit einem Reaktionssprühverfahren (RSV), bei dem eine Metallsalzlösung der gewünschten Stöchiometrie in einem heißen Reaktor verdüst wird (T = 800° C bis 1200° C). Bei diesem Schritt bilden sich mikrokristalline Mischoxidpulver.
Der zweite Schritt, die Reduktion/Karburierung der Mischoxide wird mit karburierenden Gasen oder Gasmischungen oder Kohlenstoff durchgeführt. Dazu eignen sich besonders gut Drehrohröfen oder Wirbelschichtreaktoren, die ein Zusammenbacken verhindern. Dieser Schritt kann aber auch in einer Schüttung durchgeführt werden.The first step is preferably carried out using a reaction spray process (RSV), in which a metal salt solution of the desired stoichiometry is atomized in a hot reactor (T = 800 ° C. to 1200 ° C.). Microcrystalline mixed oxide powders are formed in this step.
The second step, the reduction / carburization of the mixed oxides, is carried out with carburizing gases or gas mixtures or carbon. They are particularly good for this Rotary tube ovens or fluidized bed reactors that prevent caking. This step can also be carried out in a bed.
Der dritte Schritt (Pressen und Sintern) erfolgt mit an sich bekannten Verfahren, wobei jedoch wesentlich größere Temperaturintervalle beim Sintern zulässig sind als bei den bisher bekannten Pulvern.The third step (pressing and sintering) is carried out using methods known per se, although considerably larger temperature intervals are permitted during sintering than with the powders known hitherto.
Die Erfindung wird anhand von Figuren näher erläutert.The invention is explained in more detail with reference to figures.
Es zeigt:
- Figur 1 Mischoxide aus dem RSV,
- Figur 2 und 3 Schnellstahlpulver,
- Figur 4 gesintertes Werkstoffteil (Gefüge).
- FIG. 1 mixed oxides from the RSV,
- 2 and 3 high-speed steel powder,
- Figure 4 sintered material part (structure).
Die im ersten Schritt hergestellten Mischoxidpulver werden im zweiten Schritt einer Reduktion/Karburierung unterworfen. Die Mischoxidpulver selbst zeichnen sich durch homogene Verteilung der Komponenten aus. Die Agglomeratgröße (3 bis 40µ) ist sowohl beeinflußbar über die Konzentration der eingesetzten Lösung, die Zerstäubungs- oder Verdüsungstechnik als auch über die Reaktortemperatur. Die Agglomerate setzen sich aus Primärkristalliten mit einer Größenverteilung zwischen 0,3 und 3 µ zusammen.The mixed oxide powders produced in the first step are subjected to a reduction / carburization in the second step. The mixed oxide powders themselves are characterized by a homogeneous distribution of the components. The agglomerate size (3 to 40µ) can be influenced both via the concentration of the solution used, the atomization or atomization technology and also via the reactor temperature. The agglomerates are composed of primary crystallites with a size distribution between 0.3 and 3 µ.
Die Homogenität und die feine Verteilung der einzelnen Komponenten bleibt bei der Karburierung erhalten. Aufgrund der schwamm- oder korallenartigen, also sehr oberflächenreichen und deswegen reaktiven Struktur des RSV-Mischoxids, kann die Reduktion/Karburierung bei Temperaturen zwischen 850° C und 1000° C durchgeführt werden. Im Gegensatz zu bekannten Verfahren für die Karburierung von Einzelmetallen, bei denen weit höhere Temperaturen die Regel sind (> 1200° C), bleibt die mikrokristalline Struktur des RSV-Pulvers dabei erhalten.The homogeneity and fine distribution of the individual components is retained during the carburization. Due to the sponge-like or coral-like, ie very surface-rich and therefore reactive structure of the RSV mixed oxide, the reduction / carburization can be carried out at temperatures between 850 ° C and 1000 ° C. In contrast to known processes for carburizing individual metals, in which far higher temperatures are the rule (> 1200 ° C), the microcrystalline structure of the RSV powder is retained.
Die Carbidgröße in den Pulveragglomeraten wird sowohl durch den Herstellungsprozess der Mischoxidpulver als auch durch Kornwachstum während des Karburierens bestimmt.
Die Kristallitgröße der Mischoxidpulver nimmt mit steigender Temperatur im RSV zu. Diese Kristallitgröße beeinflußt maßgeblich die Carbidkorngröße nach der Karburierung.
Die Karburierung selbst erfolgt bei so niedrigen Temperaturen, daß dabei kein Kornwachstum stattfindet.
Als Reduktions- und Karburierungsmittel werden karburierende Gase, Gasgemische oder Kohlenstoff eingesetzt. Geeignet sind CH₄/H₂-Mischungen mit einer Kohlenstoffaktivität < 1.
Kohlenstoff wirkt sowohl als direktes Reduktions-/Karburierungsmittel als auch indirekt über die Bildung von CO mit dem Mischoxid. Die Reaktion wird zeitkontrolliert durchge führt, das heißt der Kohlenstoffgehalt wird über die Karburierungszeit eingestellt. Der Zusammenhang zwischen Karburierungszeit und Kohlenstoffgehalt muß für die jeweilige Karburierungsart empirisch ermittelt werden.The carbide size in the powder agglomerates is determined both by the manufacturing process of the mixed oxide powders and by grain growth during carburizing.
The crystallite size of the mixed oxide powder increases with increasing temperature in the RSV. This crystallite size significantly influences the carbide grain size after carburization.
The carburization itself takes place at such low temperatures that there is no grain growth.
Carburizing gases, gas mixtures or carbon are used as reducing and carburizing agents. CH₄ / H₂ mixtures with a carbon activity <1 are suitable.
Carbon acts both as a direct reducing / carburizing agent and indirectly through the formation of CO with the mixed oxide. The reaction is carried out in a time-controlled manner leads, that is, the carbon content is adjusted over the carburizing time. The relationship between carburizing time and carbon content must be determined empirically for the respective carburizing type.
Eine Lösung mit einer Metallkonzentration von 150 g/l wird aus stöchiometrisch äquivalenten Mengen Chromnitrat, Kobaltnitrat, Eisennitrat, Vanadylsulfat, Ammoniummetawolframat und Ammoniumheptamolybdat unter Zugabe von Wasser hergestellt. Die so hergestellte Lösung wird mit 10 1/h in einen heißen Reaktor verdüst (Reaktionstemperatur 800° C). Das Aerosol verdampft extrem rasch, es erfolgt Zersetzung der Salze, wobei sehr feinkristalline, homogene Mischoxidpartikel entstehen (Figur 1). Gase und Partikel werden in einem Separator getrennt, das Pulver wird einer Reduktion/Karburierung unterzogen.A solution with a metal concentration of 150 g / l is prepared from stoichiometrically equivalent amounts of chromium nitrate, cobalt nitrate, iron nitrate, vanadyl sulfate, ammonium metatungstate and ammonium heptamolybdate with the addition of water. The solution thus prepared is sprayed into a hot reactor at 10 l / h (reaction temperature 800 ° C.). The aerosol evaporates extremely quickly, the salts decompose, producing very fine-crystalline, homogeneous mixed oxide particles (FIG. 1). Gases and particles are separated in a separator, the powder is subjected to a reduction / carburization.
Die Reduktion/Karburierung erfolgt beispielsweise in einer Wirbelschichtanlage, in der ein Verbacken der Pulver während der Umsetzung ausgeschlossen werden kann. Die Reaktion wird bei 950° C durchgeführt, als Reaktionsgas dient eine Mischung aus 99 % H₂ und 1 % CH₄.The reduction / carburization takes place, for example, in one Fluid bed system, in which caking of the powder during the implementation can be excluded. The reaction is carried out at 950 ° C, the reaction gas is a mixture of 99% H₂ and 1% CH₄.
Die genaue Einstellung des Kohlenstoffgehalts erfolgt zeitkontrolliert und beträgt für 5 kg-Chargen größenordnungsmäßig 40 Stunden. Die Figuren 2 und 3 zeigen karburiertes Pulver.The exact setting of the carbon content is time-controlled and is on the order of 40 hours for 5 kg batches. Figures 2 and 3 show carburized powder.
Die so hergestellten Pulver lassen sich ohne Zugabe weiterer Preßhilfsmittel zu Grünlingen mit etwa 6,3 g/cm³ verdichten. Die Sinterung erfolgt im Vakuum, bei Temperaturen zwischen 1235° C und 1265° C. In diesem Intervall stellt sich vollständige Dichte ohne Kornwachstum ein (sonst nur möglich durch Sintern bis 97 % der theoretischen Dichte mit anschließendem Heißisostatpressen). Figur 4 zeigt in 2500-facher Vergrößerung das Gefüge eines gesinterten Teils.The powders thus produced can be compacted into green compacts with about 6.3 g / cm³ without the addition of further pressing aids. Sintering takes place in a vacuum, at temperatures between 1235 ° C and 1265 ° C. In this interval, complete density is achieved without grain growth (otherwise only possible by sintering up to 97% of the theoretical density with subsequent hot isostatic pressing). FIG. 4 shows the structure of a sintered part in a magnification of 2500 times.
Claims (10)
- einer ersten Phase aus Hartstoffpartikeln wie Wolframcarbid und/oder Molybdäncarbid und/oder Chromcarbid und/oder Vanadiumcarbid und/oder Niobcarbid und/oder Tantalcarbid und/oder Mischcarbiden der genannten Metalle mit einer Korngrösse zwischen 2 µ und 7 µ und
- einer zweiten Phase, bestehend aus einer Eisenbasislegierung, welche die Partikel der ersten Phase umhüllt (Binderphase) und
- einer Dichte oberhalb von 99,9 % der theoretischen Dichte.1. Sintered, metal-bonded carbides, used as a material for high-speed steels
- A first phase made of hard material particles such as tungsten carbide and / or molybdenum carbide and / or chromium carbide and / or vanadium carbide and / or niobium carbide and / or tantalum carbide and / or mixed carbides of the metals mentioned with a grain size between 2 μ and 7 μ and
- A second phase, consisting of an iron-based alloy, which envelops the particles of the first phase (binder phase) and
- A density above 99.9% of the theoretical density.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19883830112 DE3830112A1 (en) | 1988-09-05 | 1988-09-05 | METHOD FOR PRODUCING SINTED, METAL-BOND CARBIDES FOR HIGH-SPEED WORK STEELS |
DE3830112 | 1988-09-05 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0366900A1 true EP0366900A1 (en) | 1990-05-09 |
Family
ID=6362309
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP89116290A Withdrawn EP0366900A1 (en) | 1988-09-05 | 1989-09-04 | Sintered alloy containing carbide |
Country Status (2)
Country | Link |
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EP (1) | EP0366900A1 (en) |
DE (1) | DE3830112A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5835842A (en) * | 1993-05-20 | 1998-11-10 | Toshiba Kikai Kabushiki Kaisha | Alloy having excellent corrosion resistance and abrasion resistance, method for producing the same and material for use in production of the same |
CN113260473A (en) * | 2019-01-18 | 2021-08-13 | Vbn组件有限公司 | 3D printed high-carbon-content steel and preparation method thereof |
US11123801B2 (en) * | 2015-05-13 | 2021-09-21 | Kennametal Inc. | Cutting tool made by additive manufacturing |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2256106A1 (en) * | 1973-12-28 | 1975-07-25 | Union Carbide Corp | |
US3901689A (en) * | 1973-08-15 | 1975-08-26 | Union Carbide Corp | Method for producing chromium-chromium carbide powder |
US4032302A (en) * | 1974-12-23 | 1977-06-28 | Hitachi Metals, Ltd. | Carbide enriched high speed tool steel |
EP0076326A1 (en) * | 1981-04-08 | 1983-04-13 | The Furukawa Electric Co., Ltd. | Sintered, high-v, high-speed steel and process for its production |
US4487627A (en) * | 1982-11-01 | 1984-12-11 | Fuji Photo Film Co., Ltd. | Method for preparing ferromagnetic metal particles |
EP0234099A2 (en) * | 1986-02-25 | 1987-09-02 | Crucible Materials Corporation | Powder metallurgy high speed tool steel article and method of manufacture |
-
1988
- 1988-09-05 DE DE19883830112 patent/DE3830112A1/en active Granted
-
1989
- 1989-09-04 EP EP89116290A patent/EP0366900A1/en not_active Withdrawn
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3901689A (en) * | 1973-08-15 | 1975-08-26 | Union Carbide Corp | Method for producing chromium-chromium carbide powder |
FR2256106A1 (en) * | 1973-12-28 | 1975-07-25 | Union Carbide Corp | |
US4032302A (en) * | 1974-12-23 | 1977-06-28 | Hitachi Metals, Ltd. | Carbide enriched high speed tool steel |
EP0076326A1 (en) * | 1981-04-08 | 1983-04-13 | The Furukawa Electric Co., Ltd. | Sintered, high-v, high-speed steel and process for its production |
US4487627A (en) * | 1982-11-01 | 1984-12-11 | Fuji Photo Film Co., Ltd. | Method for preparing ferromagnetic metal particles |
EP0234099A2 (en) * | 1986-02-25 | 1987-09-02 | Crucible Materials Corporation | Powder metallurgy high speed tool steel article and method of manufacture |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5835842A (en) * | 1993-05-20 | 1998-11-10 | Toshiba Kikai Kabushiki Kaisha | Alloy having excellent corrosion resistance and abrasion resistance, method for producing the same and material for use in production of the same |
US11123801B2 (en) * | 2015-05-13 | 2021-09-21 | Kennametal Inc. | Cutting tool made by additive manufacturing |
CN113260473A (en) * | 2019-01-18 | 2021-08-13 | Vbn组件有限公司 | 3D printed high-carbon-content steel and preparation method thereof |
CN113260473B (en) * | 2019-01-18 | 2023-09-19 | Vbn组件有限公司 | 3D printed high-carbon-content steel and preparation method thereof |
Also Published As
Publication number | Publication date |
---|---|
DE3830112C2 (en) | 1990-06-07 |
DE3830112A1 (en) | 1990-03-15 |
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