EP1274872A1 - Method for the production of nitrogen alloyed steel, spray compacted steel - Google Patents

Method for the production of nitrogen alloyed steel, spray compacted steel

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Publication number
EP1274872A1
EP1274872A1 EP01933846A EP01933846A EP1274872A1 EP 1274872 A1 EP1274872 A1 EP 1274872A1 EP 01933846 A EP01933846 A EP 01933846A EP 01933846 A EP01933846 A EP 01933846A EP 1274872 A1 EP1274872 A1 EP 1274872A1
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EP
European Patent Office
Prior art keywords
steel
mass
content
spray
nitrogen
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.)
Granted
Application number
EP01933846A
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German (de)
French (fr)
Other versions
EP1274872B1 (en
Inventor
Claudia Ernst
Volker SCHÜLER
Bernd Gehricke
Ingolf Schruff
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Edelstahl Witten-Krefeld GmbH
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Edelstahl Witten-Krefeld GmbH
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/36—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.7% by weight of carbon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D23/00—Casting processes not provided for in groups B22D1/00 - B22D21/00
    • B22D23/003—Moulding by spraying metal on a surface
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/10—Alloys containing non-metals
    • C22C1/1036—Alloys containing non-metals starting from a melt
    • C22C1/1042—Alloys containing non-metals starting from a melt by atomising
    • 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%
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • 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
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/12—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the method of spraying
    • C23C4/123—Spraying molten metal
    • 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
    • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy

Definitions

  • the invention relates to a nitrogen-alloyed, ledeburitic steel with high wear resistance. Furthermore, the invention relates to a method for producing such a steel and a composite material which is produced using a steel according to the invention.
  • Ledeburitic chrome steels are often used for tools and components that require high wear resistance. Such steels are, for example, in the steel-iron list under the material numbers 1.2080 (X210Crl2), 1.2201 (X165CrV12), 1.2376 (X96CrMoV12), 1.2378 (X220CrVMol2-2), 1.2379 (X155CrVMol2-l), 1.2380 (Xol3CM) 1.2436 (X210CrW12), 1.2601 (Xl65CrMoV12), 1.2880 (X165CrCoMol2) and 1.2884 (X210CrCoWl2).
  • the steels in question each have carbon contents of more than 0.9% by mass, chromium contents of more than 10% by mass and various additions of the elements molybdenum, vanadium and tungsten. They are mainly used for the manufacture of tools and components that are used for the cutting or cold forming of metals or the processing of plastics.
  • the known steels of the type explained above are melted in an electric arc furnace under ambient pressure. After tapping the melt, it is treated further with ladle metallurgical processes, for example with a ladle furnace or a degassing plant, in order to reduce gases dissolved in the steel, such as the hydrogen, oxygen and nitrogen components contained in the respective steel.
  • the element silicon in particular is used in mass contents between 0.1 and 0.4% in order to bind the oxygen dissolved in the liquid melt to oxides. These are then separated with the refining slag.
  • the steels in question are additionally remelted according to an electroslag or arc vacuum remelting process. After pouring the melt into blocks or as a strand or after the additional remelting, the blocks become or the continuously cast bars are brought into the different delivery dimensions by hot forming, such as forging or rolling.
  • the known ledeburitic chromium steels have different degrees of wear resistance when hardened and tempered.
  • the carbides are cellular and unevenly distributed in the material structure due to the segregations that cannot be avoided in block or continuous casting. This applies even if the steels have been remelted after block or continuous casting.
  • the carbide distribution always leads to problems, for example, when a component, for example a tool, is to be produced from one of the known chromium steels which has good cutting edge stability. Problems have also been found in practice when finely contoured tool areas, such as threads in thread rolling dies, are to be produced. In such applications, the structure of the carbides present in each case entails the risk of crumbling and flaking, which as a result considerably reduce the service life of the respective tools.
  • the object of the invention is to provide a steel material which has a further improved wear resistance and shape retention.
  • a method for producing such a steel and a composite material produced using this steel are to be specified.
  • this problem is solved by a steel which is produced by spray compacting and has the following composition (in% by mass):
  • a wear factor S v corresponding to the sum of its weighted contents of Cr, Mo, V, Nb and W fulfills the following condition:
  • a Cr Cr content in mass%
  • Av V content in mass%
  • a N Nb content in mass%
  • a w W content in mass%
  • a S i Si content in mass%
  • a N N content in mass%.
  • An alloy steel according to the invention produced by spray compacting, is distinguished, in contrast to steels produced by melt metallurgy, by a high carbon and an increased nitrogen content with a high content of special carbide-forming and nitride-forming elements, as a result of which a high wear resistance is achieved.
  • steel according to the invention is due to the homogeneity of its structure despite the high alloy and hard phase contents good hot formability. These properties make steel according to the invention particularly suitable for the production of tools or components which are subject to great wear stresses, such as are generally given, for example, when cutting materials or in the plastics processing industry because of the filler contents of modern plastics.
  • nitrogen-alloyed steels according to the invention produced by spray compacting, have increased wear resistance and / or improved toughness compared to ledeburitic steels of the type discussed at the outset in relation to the respective application.
  • the improved properties of steels according to the invention lead to an increase in the service life of tools or components produced from these steels.
  • Cutting tools that are made from a steel according to the invention thus have improved cutting stability and improved cutting edge stability.
  • components made from steels according to the invention have an improved resistance to crack formation.
  • a steel according to the invention can be hardened to a hardness of up to 68 HRC by using a suitable heat treatment process.
  • the advantages of a steel according to the invention are achieved by its alloy components in combination with a special production method, known as spray compacting.
  • spray compacting When steel is spray compacted, a molten steel is melted in a protective gas stream in a gas atomizer spherical drops atomized. The gas quickly cools the metal drops to a temperature that lies between the liquidus and solidus, often even below solidus. The drops cooled in this way, moving at high speed and having a solid or pasty consistency, compact on the basis of their own kinetic energy on a substrate to form a dense material composite.
  • the structure of the sprayed block can be directly influenced by the rapid solidification from the liquid phase.
  • Spray compacting is described in detail in the articles "Near net-shape casting through metal spray deposition - The Osprey process", Otto H. Metelmann et al., Iron and Steel Engineer, November 1988, pp. 25-29, or "The Osprey Process: Principles and Applications ", Leatham et al., The International Journal of Powder Metallurgy, Vol. 29, No. 4, pp. 321-329.
  • spray compacting has proven to be an effective process for the desired nitrogen content in the ledeburitic steels mentioned. contribute.
  • spray compacting is characterized both by its effectiveness and its economy.
  • spray compacting enables the production of segregation- and pore-free products that have a homogeneous structure and a high density. With higher flexibility in terms of shape and fewer process steps, similar product properties can be achieved as in the powder metallurgical production of such products.
  • steels according to the invention with particularly outstanding properties have a C content of 1.0-1.9% by mass, an N content of 0.05-0.5% by mass, an Si content of 0, 15-1.5 mass%, a Cr content of 5.0-10.0 mass%, a Mo content of 0.5-5.5 mass%, a V content ⁇ 3.5 mass -%, an Nb content ⁇ 3.5% by mass and a W content ⁇ 3.0%.
  • Steels composed in this way have a particularly high wear resistance.
  • a carbon content of more than 1 mass% and a nitrogen content of more than 0.05 mass% is advantageous in order to achieve a hardness of more than 60 HRC.
  • the presence of carbon and nitrogen also has a favorable influence on the amount of hard phases contained and thus on the wear behavior.
  • spray compacting has a homogenizing effect on the microstructure and a limitation of the hard phase size. This has a positive impact on the
  • the silicon usually contained only in small amounts in steels for reasons of deoxidation is provided in a steel according to the invention with a mass content of 0.1% to preferably 1.5% by mass, since it remains dissolved in the basic matrix and increases the secondary hardness.
  • a mass content 0.1% to preferably 1.5% by mass
  • nitrogen contents As a "soft" structural component, this reduces wear resistance.
  • the contents of nitrogen and silicon contained in the steel according to the invention within the specified limits have an optimal effect on their hardness and wear resistance. The mutual effect of the nitrogen and silicon contents on the residual austenite content is shown in Fig.
  • Cobalt is not contained in a steel composed according to the invention, since this element can have negative effects on toughness and would increase the cost of materials.
  • the chromium content is limited to values ⁇ 11.5% by mass and is preferably in the specified, lower content range in order also to positively influence the toughness of the steel produced according to the invention.
  • the steel according to the invention contains further precipitation-hardening elements, such as, for example, up to 0.75% by mass of nitrogen, up to 0.05% by mass of boron, up to 0.5% by mass of titanium, up to Contains 0.5% by mass of zirconium and / or up to 0.25% by mass of aluminum.
  • additional alloy components can further increase the hardness and thus the wear resistance of a steel according to the invention.
  • a steel according to the invention has an optimized wear resistance if the sum of its weighted contents of the carbide-forming elements Cr, Mo, V, Nb and W corresponding wear factor S v is between 0.55 and 3.42.
  • an optimized silicon-nitrogen ratio V S iN must be set in order to influence the effect of the austenite-stabilizing element nitrogen by the ferrite-stabilizing effect of the element silicon and to further optimize the wear resistance in the steels according to the invention. It has been shown that if the range from 0.21 to 3.31 provided for the nitrogen-silicon ratio according to the invention is maintained, the residual austenite components which are harmful to the wear resistance can be reduced to values of ⁇ 25% after a single tempering process.
  • nitrogen-alloyed steel according to the invention contains additional hard materials, such as titanium carbide (TiC), silicon carbide (SiC), niobium carbide (NbC), chromium carbide (CrC), titanium nitride (TiN), tungsten carbide (WC), in its matrix, which have been injected into the spray as solid particles in the course of the spray compacting.
  • additional hard materials such as titanium carbide (TiC), silicon carbide (SiC), niobium carbide (NbC), chromium carbide (CrC), titanium nitride (TiN), tungsten carbide (WC), in its matrix, which have been injected into the spray as solid particles in the course of the spray compacting.
  • the above-mentioned object is achieved in that the steel is spray-compacted using nitrogen as the spray gas, in that the steel after the spray compacting at initial temperatures is hot worked up to 1150 ° C, the hot formed steel is cooled, the cooled steel is reheated to an austenitizing temperature of 1075 ° C to 1225 ° C, the reheated steel is quenched and the quenched steel at temperatures of 150 ° C - left at 625 ° C.
  • the tempering is preferably carried out at temperatures between 150 ° C. and 300 ° C. or between 500 ° C. and 625 ° C.
  • a steel according to the invention can be used particularly well to produce a composite material which has at least one first layer produced by a first steel and at least one second layer formed by a spray-compacted steel according to the invention, the steel of the first layer having a different composition than the spray-compacted steel.
  • the steel according to the invention can form a wear-resistant cover layer on a tough first layer.
  • Table 1 shows the chemical compositions of seven steels A - G in mass%.
  • the wear factor S v the silicon-nitrogen ratio V S i N and the abrasion determined in a wear test in grams are recorded for each of the steels.
  • Steels A - D are steels according to the invention, while steels E - G are listed for comparison.
  • melt For the production of spray-compacted, nitrogen-alloyed steels, a melt has been created from scrap and / or pure metals with the addition of the necessary alloy components. The melt was then atomized into spherical droplets in a nitrogen-containing protective gas stream.
  • the metal droplets were nitrided and rapidly cooled to a temperature between the liquidus and solidus, so that the droplets had a solid to pasty consistency after cooling in the gas stream.
  • the droplets thus created, moving at a high speed of 40 to 80 m / s, were directed onto a base plate on which the droplets compacted into a dense material composite due to their high kinetic energy.
  • the block produced in this way by spray compacting showed due to the rapid solidification of the metal droplets in the gas stream from the liquid phase and due to the introduced nitrogen content on a uniform distribution of hard phases and carbide or carbonitride sizes, which are significantly reduced compared to steel produced by melt metallurgy.
  • FIGS. 2 and 3 each show the micrograph of a nitrogen-alloy steel produced by spray compacting in the manner according to the invention in the annealed state, the respective microstructure in FIG. 1 with an enlargement of 100: 1 and in FIG. 3 with an enlargement of 500: 1 is shown.
  • FIGS. 4 and 5 show a corresponding representation of the microstructure of the same steel without the addition of nitrogen when this is produced in a conventional manner by melt metallurgy.
  • FIGS. 2 and 3 The high structural homogeneity which is readily apparent from FIGS. 2 and 3 enables the spray-compacted block to be easily formed by forging or rolling. Prior to the forming, a block or Diffusion annealing take place.
  • the improved formability of steels produced according to the invention makes it possible to carry out thermoforming at lower temperatures than the conventional procedure.
  • the hardness required in each case for the components or tools produced from the steels according to the invention can, after shaping, be hardened from an austenitizing temperature between 1075 ° C. and 1225 ° C. with subsequent tempering between Set 150 ° C and 625 ° C, whereby hardnesses of up to 68 HRC can be achieved.
  • Steels according to the invention have a balanced ratio between the carbide- or carbonitride-forming elements, which is characterized by the wear factor S v , which lies between 0.55 and 3.42 and is determined in the manner explained above.
  • This balanced ratio of carbide / carbonitride formers leads to a superior wear resistance of steels according to the invention, which has been confirmed in wear tests (FIG. 6).
  • a raw block with a diameter of 400 mm was produced from the nitrogen-alloyed steel C, the composition of which is given in Table 1, by spray compacting. Using a long forging machine, this block was deformed in a two-heat forging to a diameter of 115 mm, the starting temperature at 980 ° C and the end temperature at 969 ° C.
  • the forged ingot was then annealed.
  • the soft annealed material then became Threaded roller jaws produced, the dimensions of which were 85 mm x 50 mm x 24 mm and 95 mm x 50 mm x 24 mm.
  • These tools were subsequently heat treated to a hardness of 62 HRC.
  • the thread rolling jaws were used to produce screws from a stainless steel with the material number 1.4401 according to the steel-iron list.
  • the work results and the state of wear of the tools produced from the steel according to the invention were compared with the work results and the state of wear of thread rolling jaws which had been produced from a steel with an identical chemical composition, but without the addition of nitrogen, produced by melt-metallurgy. It was found that the service life of the threaded roller jaws produced from steel according to the invention was twice as long as the service life of the threaded roller jaws which had been produced from the conventionally produced steel of identical composition. Thus, 140,000 screws could be produced with the tools produced from steel according to the invention, while the tools made from conventionally produced steel were worn out after the production of 70,000 screws. Particularly noteworthy in this context is the excellent dimensional stability of the tools made from steel according to the invention in the area of the thread tips.
  • the nitrogen-alloyed steel C of table 1 produced by spray compacting was forged to a dimension of 160 mm ⁇ 160 mm and soft-annealed. From the forged steel, stamping tools were made from a micro-alloyed one Steel existing chain links manufactured, which were punched out of sheets with a thickness of 4 mm.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Heat Treatment Of Articles (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Coating By Spraying Or Casting (AREA)
  • Heat Treatment Of Steel (AREA)

Abstract

Nitrogen alloyed steel produced by spray compacting contains (in wt.%): 0.8-2.5 C, 0.03-0.75 N, 0.15-1.8 Mn, not more than 1.0 P, not more than 0.03 S, not more than 0.05 S, 5.0-11.5 Cr, 0.5-6.0 Mo, not more than 4.0 V, not more than 4.0 Nb, not more than 3.5 W, not more than 0.005 O2, and optionally further alloying components and a balance of iron and the usual impurities. Independent claims are also included for: (a) a process for the production of the steel comprising spray compacting the steel using nitrogen as the spray gas; heat treating at up to 1150[deg] C; cooling; heating to the austenitic temperature of 1075-1225[deg] C; quenching; and annealing at 150-625[deg] C; and (b) a composite material containing the steel.

Description

Stickstofflegierter, sprühkompaktierter Stahl, Verfahren zu seiner Herstellung und Verbundwerkstoff hergestellt aus dem Stahl Nitrogen-alloyed, spray-compacted steel, process for its production and composite material made from the steel
Die Erfindung betrifft einen stickstofflegierten, ledeburitischen Stahl mit hoher Verschleißbeständigkeit. Darüber hinaus betrifft die Erfindung ein Verfahren zur Herstellung eines solchen Stahls und einen Verbundwerkstoff, welcher unter Verwendung eines erfindungsgemäßen Stahls hergestellt ist.The invention relates to a nitrogen-alloyed, ledeburitic steel with high wear resistance. Furthermore, the invention relates to a method for producing such a steel and a composite material which is produced using a steel according to the invention.
Für Werkzeuge und Bauteile, die eine hohe Verschleißbeständigkeit erfordern, werden häufig ledeburitische Chromstähle eingesetzt. Derartige Stähle sind beispielsweise in der Stahl-Eisen-Liste unter den Werkstoffnummern 1.2080 (X210Crl2) , 1.2201 (X165CrV12), 1.2376 (X96CrMoV12) , 1.2378 (X220CrVMol2-2) , 1.2379 (X155CrVMol2-l) , 1.2380 (X220CrVMol3-4) , 1.2436 (X210CrW12), 1.2601 (Xl65CrMoV12) , 1.2880 (X165CrCoMol2) sowie 1.2884 (X210CrCoWl2) angegeben. Die betreffenden Stähle weisen jeweils Kohlenstoffgehalte von mehr als 0,9 Masse-%, Chromgehalte von mehr als 10 Masse-% und verschiedene Zusätze der Elemente Molybdän, Vanadium und Wolfram auf. Sie werden hauptsächlich zur Herstellung von Werkzeugen und Bauelementen verwendet, die für das Trennen oder Kaltumformen von Metallen oder die Verarbeitung von Kunststoffen eingesetzt werden. Die bekannten Stähle der vorstehend erläuterten Art werden in einem Elektrolichtbogenofen unter ümgebungsdruck erschmolzen. Nach dem Abstich der Schmelze wird diese mit pfannenmetallurgischen Verfahren, beispielsweise mit einem Pfannenofen oder einer Entgasungsanlage, weiter behandelt, um im Stahl gelöste Gase, wie die im jeweiligen Stahl enthaltenen Wasserstoff-, Sauerstoff- und Stickstoffanteile zu verringern. Zur Desoxidation wird dabei insbesondere das Element Silicium in Massengehalten zwischen 0,1 und 0,4 % verwendet, um den in der flüssigen Schmelze gelösten Sauerstoff zu Oxiden abzubinden. Diese werden dann mit der Raffinationsschlacke abgeschieden.Ledeburitic chrome steels are often used for tools and components that require high wear resistance. Such steels are, for example, in the steel-iron list under the material numbers 1.2080 (X210Crl2), 1.2201 (X165CrV12), 1.2376 (X96CrMoV12), 1.2378 (X220CrVMol2-2), 1.2379 (X155CrVMol2-l), 1.2380 (Xol3CM) 1.2436 (X210CrW12), 1.2601 (Xl65CrMoV12), 1.2880 (X165CrCoMol2) and 1.2884 (X210CrCoWl2). The steels in question each have carbon contents of more than 0.9% by mass, chromium contents of more than 10% by mass and various additions of the elements molybdenum, vanadium and tungsten. They are mainly used for the manufacture of tools and components that are used for the cutting or cold forming of metals or the processing of plastics. The known steels of the type explained above are melted in an electric arc furnace under ambient pressure. After tapping the melt, it is treated further with ladle metallurgical processes, for example with a ladle furnace or a degassing plant, in order to reduce gases dissolved in the steel, such as the hydrogen, oxygen and nitrogen components contained in the respective steel. For the deoxidation, the element silicon in particular is used in mass contents between 0.1 and 0.4% in order to bind the oxygen dissolved in the liquid melt to oxides. These are then separated with the refining slag.
Die Stickstofflöslichkeit bei der Herstellung im Elektroschlackofen unter Umgebungsdruck ist naturgemäß sehr gering. So erläutern beispielsweise H. Berns und J. Lueg in "Stickstofflegierte Werkzeugstähle", Neue Hütte 36 (1991) 1, S. 13 -18, daß in reinen Eisenschmelzen bei einer Temperatur von 1600 °C lediglich 0,04 % Stickstoff in Lösung gehen. Da diese Gehalte zudem im Zuge der erwähnten pfannenmetallurgischen Behandlungen weiter reduziert werden, enthalten auf diesem Wege hergestellte Stähle erfahrungsgemäß lediglich Stickstoffgehalte, die zwischen 0,005 und 0,025 Masse-% liegen.The nitrogen solubility when manufactured in an electric slag furnace under ambient pressure is naturally very low. For example, H. Berns and J. Lueg in "Nitrogen-alloyed tool steels", Neue Hütte 36 (1991) 1, pp. 13-18 explain that only 0.04% nitrogen dissolves in pure iron melts at a temperature of 1600 ° C , Since these contents are also further reduced in the course of the ladle metallurgical treatments mentioned, experience has shown that steels produced in this way only contain nitrogen contents which are between 0.005 and 0.025% by mass.
Sofern besondere Anforderungen an ihren Reinheits- und den Seigerungsgrad gestellt werden, werden in Rede stehende Stähle ergänzend gemäß einem Elektroschlacke- oder Lichtbogenvakuum-Umschmelzverfahren umgeschmolzen. Nach dem Gießen der Schmelze zu Blöcken oder als Strang bzw. nach dem ergänzenden Umschmelzen werden die Blöcke oder die stranggegossenen Riegel durch eine Warmformgebung, wie Schmieden oder Walzen, in die unterschiedlichen Lieferabmessungen gebracht.If special requirements are placed on their degree of purity and the degree of segregation, the steels in question are additionally remelted according to an electroslag or arc vacuum remelting process. After pouring the melt into blocks or as a strand or after the additional remelting, the blocks become or the continuously cast bars are brought into the different delivery dimensions by hot forming, such as forging or rolling.
Aufgrund ihrer unterschiedlichen Kohlenstoff- bzw. Carbidgehalte weisen die bekannten ledeburitischen Chromstähle im gehärteten und angelassenen Zustand eine unterschiedlich hohe Verschleißbeständigkeit auf. Dabei sind die Carbide wegen der beim Block- oder Stranggießen nicht vermeidbaren Seigerungen zellenförmig und ungleichmäßig im Werkstoffgefüge verteilt. Dies gilt selbst dann, wenn die Stähle nach dem Block- oder Stranggießen umgeschmolzen worden sind.Because of their different carbon and carbide contents, the known ledeburitic chromium steels have different degrees of wear resistance when hardened and tempered. The carbides are cellular and unevenly distributed in the material structure due to the segregations that cannot be avoided in block or continuous casting. This applies even if the steels have been remelted after block or continuous casting.
Die Carbidverteilung führt beispielsweise immer dann zu Problemen, wenn aus einem der bekannten Chromstähle ein Bauelement, beispielsweise ein Werkzeug, gefertigt werden soll, das eine gute Schneidkantenstabilität aufzuweisen hat. Ebenso sind in der Praxis Probleme festgestellt worden, wenn fein konturierte Werkzeugbereiche, wie beispielsweise Gewindegänge in Gewindewalzbacken, erzeugt werden sollen. Die jeweils vorhandene Struktur der Carbide bringt bei derartigen Anwendungen jeweils die Gefahr von Ausbröckelungen und Abplatzungen mit sich, welche im Ergebnis die Standzeit der jeweiligen Werkzeuge beträchtlich vermindern.The carbide distribution always leads to problems, for example, when a component, for example a tool, is to be produced from one of the known chromium steels which has good cutting edge stability. Problems have also been found in practice when finely contoured tool areas, such as threads in thread rolling dies, are to be produced. In such applications, the structure of the carbides present in each case entails the risk of crumbling and flaking, which as a result considerably reduce the service life of the respective tools.
Die Aufgabe der Erfindung besteht darin, einen Stahlwerkstoff zu schaffen, der eine weiter verbesserte Verschleißbeständigkeit und Formhaltigkeit aufweist. Darüber hinaus soll ein Verfahren zur Herstellung eines solchen Stahls und ein unter Verwendung dieses Stahls erzeugter Verbundwerkstoff angegeben werden. Diese Aufgabe wird hinsichtlich des Werkstoffs durch einen Stahl gelöst, welcher durch Sprühkompaktieren hergestellt ist und folgende Zusammensetzung aufweist (in Masse-%) :The object of the invention is to provide a steel material which has a further improved wear resistance and shape retention. In addition, a method for producing such a steel and a composite material produced using this steel are to be specified. With regard to the material, this problem is solved by a steel which is produced by spray compacting and has the following composition (in% by mass):
C: 0,8 - __ , ö "oC: 0.8 - __, ö "o
N: 0,03 - 0,75 %N: 0.03 - 0.75%
Si: 0,15 - 1,8 %Si: 0.15 - 1.8%
Mn: < 1,0 %Mn: <1.0%
P: < 0,03 %P: <0.03%
S: < 0,05 %S: <0.05%
Cr: 5,0 - 11,5 %Cr: 5.0 - 11.5%
Mo: 0,5 - 6,0 %Mo: 0.5 - 6.0%
V: < 4,0 %V: <4.0%
Nb: < 4,0 %Nb: <4.0%
W: < -3 f O "6W: <-3 f O "6
02: < 0,005 % gegebenenfalls weitere Legierungsbestandteile und als Rest Eisen und übliche Verunreinigungen,0 2 : <0.005%, if appropriate, further alloy constituents and the balance iron and customary impurities,
wobei ein der Summe seiner gewichteten Gehalte an Cr, Mo, V, Nb und W entsprechender Verschleißfaktor Sv folgende Bedingung erfüllt:a wear factor S v corresponding to the sum of its weighted contents of Cr, Mo, V, Nb and W fulfills the following condition:
0,55 < Sv < 3,420.55 <S v <3.42
mit: Sv = (ACr/9,33) + (AMo/17,22) + (Av/3,92) + (ANb/7,15) + (Aw/14,14),with: S v = (A Cr / 9.33) + (A Mo / 17.22) + (A v / 3.92) + (A Nb / 7.15) + (Aw / 14.14),
ACr : Cr-Gehalt in Masse-%, AMo '• Mo-Gehalt in Masse-%, Av : V-Gehalt in Masse-%, AN : Nb-Gehalt in Masse-% , Aw : W-Gehalt in Masse-% ,A Cr : Cr content in mass%, A Mo '• Mo content in mass%, Av: V content in mass%, A N : Nb content in mass%, A w : W content in mass%,
und wobei das Silicium-Stickstoff-Verhältnis VSj.N folgende Bedinungung erfüllt :and the silicon-nitrogen ratio V S j .N fulfills the following condition:
0 , 21 < VsiN < 3 , 310, 21 <V siN <3, 31
mit : VsiN = Asi + 2 AN with: VsiN = A si + 2 A N
ASi : Si-Gehalt in Masse-%, AN : N-Gehalt in Masse-%.A S i: Si content in mass%, A N : N content in mass%.
Ein erfindungsgemäßer, durch Sprühkompaktieren erzeugter legierter Stahl zeichnet sich, anders als schmelzmetallurgisch hergestellte Stähle, durch einen hohen Kohlenstoff- und einen erhöhten Stickstoffgehalt bei gleichzeitig hohem Gehalt an sondercarbidbildenden und nitridbildenden Elementen aus, wodurch eine hohe Verschleißbeständigkeit erzielt wird. Dabei sind die enthaltenen Hartphasen, die in Form von Carbidausscheidungen vorwiegend des Typs MC (mit M = V, Nb, W) und M7C3 (mit M = Cr, Mo) sowie in Form von Carbonitridauscheidungen vorwiegend in der Form der Phasen M(C,N) (mit M = V, Nb, W) und M7(C,N)3 (mit M = Cr, Mo) vorliegen, aufgrund des StickstoffZusatzes sowie des angewendeten Herstellverfahrens hinsichtlich ihrer Größe optimiert und homogen im Mikrogefüge verteilt. Dies führt einerseits dazu, daß aus erfindungsgemäßem Stahl hergestellte Werkstücke eine erhöhte Haltbarkeit auch bei abrasiver Belastung aufweisen. Andererseits ist erfindungsgemäßer Stahl aufgrund der Homogenität seines Gefüges trotz der hohen Legierungs- und Hartphasengehalte gut warmumformbar. Diese Eigenschaften machen erfindungsgemäßen Stahl insbesondere zur Herstellung von Werkzeugen oder Bauelementen geeignet, die großen Verschleißbeanspruchungen unterworfen sind, wie sie beispielsweise allgemein beim Trennen von Werkstoffen oder in der kunststoffverarbeitenden Industrie wegen der Füllstoffgehalte moderner Kunststoffe gegeben sind.An alloy steel according to the invention, produced by spray compacting, is distinguished, in contrast to steels produced by melt metallurgy, by a high carbon and an increased nitrogen content with a high content of special carbide-forming and nitride-forming elements, as a result of which a high wear resistance is achieved. The hard phases contained are predominantly in the form of carbide precipitates of the type MC (with M = V, Nb, W) and M 7 C 3 (with M = Cr, Mo) and in the form of carbonitride precipitates in the form of the phases M (C, N) (with M = V, Nb, W) and M 7 (C, N) 3 (with M = Cr, Mo) are present, due to the addition of nitrogen and the manufacturing process used, their size is optimized and homogeneously distributed in the microstructure , On the one hand, this leads to the fact that workpieces made from steel according to the invention have an increased durability even under abrasive loading. On the other hand, steel according to the invention is due to the homogeneity of its structure despite the high alloy and hard phase contents good hot formability. These properties make steel according to the invention particularly suitable for the production of tools or components which are subject to great wear stresses, such as are generally given, for example, when cutting materials or in the plastics processing industry because of the filler contents of modern plastics.
Es ist festgestellt worden, daß erfindungsgemäße, durch Sprühkompaktieren hergestellte stickstofflegierte Stähle verglichen mit ledeburitischen Stählen der eingangs erörterten Art bezogen auf den jeweiligen Anwendungsfall eine erhöhte Verschleißbeständigkeit und/oder eine verbesserte Zähigkeit besitzen. Im Ergebnis führen die verbesserten Eigenschaften erfindungsgemäßer Stähle zu einer Erhöhung der Standzeit von aus diesen Stählen hergestellten Werkzeugen oder Bauelementen. So weisen Schneidwerkzeuge, die aus einem erfindungsgemäßen Stahl hergestellt sind, eine verbesserte Schneidhaltigkeit und eine verbesserte Schneidkantenstabilität auf. Darüber hinaus besitzen aus erfindungsgemäßen Stählen hergestellte Bauelemente einen verbesserten Widerstand gegen Rißbildung. Des weiteren läßt sich ein erfindungsgemäßer Stahl durch Anwendung eines geeigneten Wärmebehandlungsverfahrens auf eine Härte von bis zu 68 HRC härten.It has been found that nitrogen-alloyed steels according to the invention, produced by spray compacting, have increased wear resistance and / or improved toughness compared to ledeburitic steels of the type discussed at the outset in relation to the respective application. As a result, the improved properties of steels according to the invention lead to an increase in the service life of tools or components produced from these steels. Cutting tools that are made from a steel according to the invention thus have improved cutting stability and improved cutting edge stability. In addition, components made from steels according to the invention have an improved resistance to crack formation. Furthermore, a steel according to the invention can be hardened to a hardness of up to 68 HRC by using a suitable heat treatment process.
Die Vorzüge eines erfindungsgemäßen Stahls werden, wie erwähnt, durch seine Legierungsbestandteile in Kombination mit einer besonderen Herstellungsweise, dem an sich bekannten Sprühkompaktieren, erreicht. Beim Sprühkompaktieren von Stahl wird in einem Gaszerstäuber eine Stahlschmelze in einem Schutzgasstrom in kugelförmige Tropfen zerstäubt. Durch das Gas werden die Metalltropfen schnell auf eine Temperatur abgekühlt, die zwischen Liquidus und Solidus liegt, häufig sogar unter Solidus. Die derart abgekühlten, sich mit hoher Geschwindigkeit bewegenden und eine feste oder teigige Konsistenz besitzenden Tropfen kompaktieren aufgrund der ihnen eigenen kinetischen Energie auf einem Substrat zu einem dichten Materialverbund. Über die schnelle Erstarrung aus der flüssigen Phase kann dabei der Aufbau des Gefüges des gesprühten Blocks direkt beeinflußt werden. Im einzelnen ist das Sprühkompaktieren in den Aufsätzen "Near net-shape casting through metal spray deposition - The Osprey process", Otto H. Metelmann et al., Iron and Steel Engineer, November 1988, S. 25 - 29, oder "The Osprey Process: Principles and Applications", A.G. Leatham et al., The International Journal of Powder Metallurgy, Vol. 29, No. 4, S. 321 - 329, beschrieben.As mentioned, the advantages of a steel according to the invention are achieved by its alloy components in combination with a special production method, known as spray compacting. When steel is spray compacted, a molten steel is melted in a protective gas stream in a gas atomizer spherical drops atomized. The gas quickly cools the metal drops to a temperature that lies between the liquidus and solidus, often even below solidus. The drops cooled in this way, moving at high speed and having a solid or pasty consistency, compact on the basis of their own kinetic energy on a substrate to form a dense material composite. The structure of the sprayed block can be directly influenced by the rapid solidification from the liquid phase. Spray compacting is described in detail in the articles "Near net-shape casting through metal spray deposition - The Osprey process", Otto H. Metelmann et al., Iron and Steel Engineer, November 1988, pp. 25-29, or "The Osprey Process: Principles and Applications ", Leatham et al., The International Journal of Powder Metallurgy, Vol. 29, No. 4, pp. 321-329.
Insbesondere hat sich das Sprühkompaktieren als wirkungsvolles Verfahren erwiesen, um den gewünschten Stickstoffgehalt in die genannten ledeburitischen Stähle . einzubringen. Anders als mit den üblicherweise zum Aufsticken von Stählen eingesetzten, kostenintensiven Verfahren, wie dem Druckelektroschlackeumschmelzverfahren unter Stickstoffpartialdrücken von bis zu 42 bar oder das pulvermetallurgische Aufsticken von Metallpulver durch Ammoniak, zeichnet sich das Sprühkompaktieren sowohl durch seine Effektivität als auch durch seine Wirtschaftlichkeit aus. Bei der Erprobung des erfindungsgemäßen Verfahrens gelang es, durch Versprühen mit einem Stickstoffgas im erstarrten Block Gehalte von bis zu 0,85 Masse-% Stickstoff einzustellen. Darüber hinaus besteht bei dieser Vorgehensweise die Möglichkeit, die Schmelze vor dem Versprühen durch Einsatzstoffe wie Chromstickstoff oder nitriertes Ferrochrom mit einer Grundmenge an gelöstem Stickstoff vorzulegieren und die Metalltröpfchen im Gasstrom weiter aufzusticken.In particular, spray compacting has proven to be an effective process for the desired nitrogen content in the ledeburitic steels mentioned. contribute. In contrast to the cost-intensive processes commonly used for embroidering steels, such as the pressure electroslag remelting process under nitrogen partial pressures of up to 42 bar or the powder-metallurgical embroidery of metal powder with ammonia, spray compacting is characterized both by its effectiveness and its economy. When testing the method according to the invention, it was possible to set contents of up to 0.85% by mass of nitrogen by spraying with a nitrogen gas in the solidified block. With this procedure, there is also the possibility pre-alloy the melt with a basic amount of dissolved nitrogen prior to spraying with feedstocks such as chromium nitrogen or nitrided ferrochrome and further embroider the metal droplets in the gas stream.
Im Unterschied zum Gießen ermöglicht das Sprühkompaktieren die Herstellung seigerungs- und porenfreier Produkte, die eine homogene Struktur und eine hohe Dichte aufweisen. Dabei können bei höherer Flexibilität hinsichtlich der Form und weniger Verfahrensschritten ähnliche Produkteigenschaften wie bei der pulvermetallurgischen Herstellung derartiger Produkte erzielt werden.In contrast to casting, spray compacting enables the production of segregation- and pore-free products that have a homogeneous structure and a high density. With higher flexibility in terms of shape and fewer process steps, similar product properties can be achieved as in the powder metallurgical production of such products.
Erfindungsgemäße Stähle mit besonders hervorragenden Eigenschaften weisen neben den übrigen Legierungsbestandteilen einen C-Gehalt von 1,0 - 1,9 Masse-%, einen N-Gehalt von 0,05 - 0,5 Masse-%, einen Si- Gehalt von 0,15 - 1,5 Masse-%, einen Cr-Gehalt von 5,0 - 10,0 Masse-%, einen Mo-Gehalt von 0,5 - 5,5 Masse-%, einen V-Gehalt < 3,5 Masse-%, einen Nb-Gehalt < 3,5 Masse-% und einen W-Gehalt < 3,0 % auf. Derart zusammengesetzte Stähle besitzen eine besonders hohe Verschleißbeständigkeit .In addition to the other alloy components, steels according to the invention with particularly outstanding properties have a C content of 1.0-1.9% by mass, an N content of 0.05-0.5% by mass, an Si content of 0, 15-1.5 mass%, a Cr content of 5.0-10.0 mass%, a Mo content of 0.5-5.5 mass%, a V content <3.5 mass -%, an Nb content <3.5% by mass and a W content <3.0%. Steels composed in this way have a particularly high wear resistance.
Ein Kohlenstoffanteil von mehr als 1 Masse-% und ein Stickstoffgehalt von mehr als 0,05 Masse-% ist vorteilhaft, um die eine Härte von mehr als 60 HRC zu erzielen. Gleichzeitig wird durch die Anwesenheit des Kohlenstoffs und des Stickstoffs auch die Menge der enthaltenen Hartphasen und somit das Verschleißverhalten günstig beeinflußt. Insbesondere durch das Legieren mit Stickstoff zeigt sich beim Sprühkompaktieren eine homogenisierende Wirkung auf das Mikrogefüge und eine Begrenzung der Hartphasengröße. Dies hat positive Auswirkungen auf dieA carbon content of more than 1 mass% and a nitrogen content of more than 0.05 mass% is advantageous in order to achieve a hardness of more than 60 HRC. At the same time, the presence of carbon and nitrogen also has a favorable influence on the amount of hard phases contained and thus on the wear behavior. In particular by alloying with nitrogen, spray compacting has a homogenizing effect on the microstructure and a limitation of the hard phase size. This has a positive impact on the
Zähigkeitseigenschaften erfindungsgemäßer Stähle. Gehalte des Elements Stickstoff, welche einen Wert von 0,75 Masse-% übersteigen, bewirken dagegen eine Verschlechterung des Verschleißverhaltens aufgrund hoher Restaustenitgehalte und stark verminderter Hartphasengrößen.Toughness properties of steels according to the invention. Levels of the element nitrogen, which exceed a value of 0.75 mass%, on the other hand, cause a deterioration in the wear behavior due to high levels of austenite and greatly reduced hard phase sizes.
Das in Stählen aus, Gründen der Desoxidation üblicherweise nur in geringen Mengen enthaltene Silicium ist bei einem erfindungsgemäßen Stahl mit einem Massengehalt von 0,1 % bis vorzugsweise 1,5 Masse-% vorgesehen, da es in der Grundmatrix gelöst bleibt und die Sekundärhärte erhöht. Zusätzlich ist festgestellt worden, daß mit zunehmendem Siliciumgehalt eine Abnahme des durch zunehmende Stickstoffgehalte verursachten Restaustenitgehaltes erreicht wird. Dieser vermindert als "weicher" Gefügebestandteil die Verschleißbeständigkeit. So ergänzen und beeinflussen sich die in den angegebenen Grenzen in erfindungsgemäßem Stahl enthaltenen Gehalte an Stickstoff und Silicium in ihrer Wirkung auf Härte und Verschleißbeständigkeit in optimaler Weise. Die gegenseitige Auswirkung der Stickstoff- und Siliciumgehalte auf den Restaustenitgehalt gehen aus Fig. 1 hervor, in welcher die röntgenographisch gemessenen Restaustenitgehalte in ledeburitischen Chromstählen erfindungsgemäßer Art in Abhängigkeit vom Silicium- und Stickstoffgehalt angegeben sind (Wärmebehandlung: 1075 °C / 15 min im Warmbad und 560 °C / lh an Luft) . Es ist festgestellt worden, daß die Anwesenheit von Wolfram für das Erreichen einer Härte in einem erfindungsgemäß erzeugten Stahl nicht zwingend notwendig ist, da die mindestens enthaltenen Sondercarbidbildner für die Bildung der erforderlichen Hartphasen ausreichen. Zur Vermeidung erhöhter Herstellkosten kann daher auf eine Zugabe von Wolfram zu dem erfindungsgemäß verwendeten Stahl verzichtet werden.The silicon usually contained only in small amounts in steels for reasons of deoxidation is provided in a steel according to the invention with a mass content of 0.1% to preferably 1.5% by mass, since it remains dissolved in the basic matrix and increases the secondary hardness. In addition, it has been found that with increasing silicon content a decrease in the residual austenite content caused by increasing nitrogen contents is achieved. As a "soft" structural component, this reduces wear resistance. The contents of nitrogen and silicon contained in the steel according to the invention within the specified limits have an optimal effect on their hardness and wear resistance. The mutual effect of the nitrogen and silicon contents on the residual austenite content is shown in Fig. 1, in which the X-ray-measured residual austenite contents in ledeburitic chromium steels of the type according to the invention are given as a function of the silicon and nitrogen content (heat treatment: 1075 ° C / 15 min in a hot bath and 560 ° C / lh in air). It has been found that the presence of tungsten is not absolutely necessary to achieve hardness in a steel produced according to the invention, since the at least contained special carbide formers are sufficient for the formation of the required hard phases. To avoid increased manufacturing costs, it is therefore not necessary to add tungsten to the steel used according to the invention.
Kobalt ist in einem erfindungsgemäß zusammengesetzten Stahl nicht enthalten, da dieses Element negative Auswirkungen auf die Zähigkeit haben kann und zu einer Verteuerung der Werkstoffkosten beitragen würde.Cobalt is not contained in a steel composed according to the invention, since this element can have negative effects on toughness and would increase the cost of materials.
Der Chrom-Gehalt ist auf Werte < 11,5 Masse-% beschränkt und liegt vorzugsweise in dem angegebenen, niedrigeren Gehaltsbereich, um ebenfalls die Zähigkeit des erfindungsgemäß erzeugten Stahls positiv zu beeinflussen.The chromium content is limited to values <11.5% by mass and is preferably in the specified, lower content range in order also to positively influence the toughness of the steel produced according to the invention.
Je nach Anwendungsfall kann es zudem günstig sein, wenn erfindungsgemäßer Stahl weitere ausscheidungshärtende Elemente, wie beispielsweise bis zu 0,75 Masse-% Stickstoff, bis zu 0,05 Masse-% Bor, bis zu 0,5 Masse-% Titan, bis zu 0,5 Masse-% Zirconium und / oder bis zu 0,25 Masse-% Aluminium, enthält. Durch diese zusätzlichen Legierungsbestandteile kann die Härte und damit die Verschleißbeständigkeit eines erfindungsgemäßen Stahls weiter gesteigert werden.Depending on the application, it may also be advantageous if the steel according to the invention contains further precipitation-hardening elements, such as, for example, up to 0.75% by mass of nitrogen, up to 0.05% by mass of boron, up to 0.5% by mass of titanium, up to Contains 0.5% by mass of zirconium and / or up to 0.25% by mass of aluminum. These additional alloy components can further increase the hardness and thus the wear resistance of a steel according to the invention.
Es ist festgestellt worden, daß ein erfindungsgemäßer Stahl eine optimierte Verschleißbeständigkeit aufweist, wenn der der Summe seiner gewichteten Gehalte an den carbidbildenden Elementen Cr, Mo, V, Nb und W entsprechender Verschleißfaktor Sv zwischen 0,55 und 3,42 beträgt.It has been found that a steel according to the invention has an optimized wear resistance if the sum of its weighted contents of the carbide-forming elements Cr, Mo, V, Nb and W corresponding wear factor S v is between 0.55 and 3.42.
Gleichzeitig ist ein optimiertes Silicium-Stickstoff- Verhältnis VSiN einzustellen, um die Wirkung des austenitstabilisierenden Elements Stickstoff durch die ferritstabilisierende Wirkung des Elements Silicium zu beeinflussen und die Verschleißbeständigkeit bei erfindungsgemäßen Stählen weiter zu optimieren. Es hat sich gezeigt, daß bei Einhaltung des erfindungsgemäß für das Stickstoff-Silicium-Verhältnis vorgesehenen Bereichs von 0,21 bis 3,31 die für die Verschleißbeständigkeit schädlichen Restaustenitbestandteile bereits nach einem einmaligen Anlaßvorgang auf Werte < 25 % vermindert werden können.At the same time, an optimized silicon-nitrogen ratio V S iN must be set in order to influence the effect of the austenite-stabilizing element nitrogen by the ferrite-stabilizing effect of the element silicon and to further optimize the wear resistance in the steels according to the invention. It has been shown that if the range from 0.21 to 3.31 provided for the nitrogen-silicon ratio according to the invention is maintained, the residual austenite components which are harmful to the wear resistance can be reduced to values of <25% after a single tempering process.
Gemäß einer weiteren vorteilhaften Ausgestaltung der Erfindung enthält erfindungsgemäßer, stickstofflegierter Stahl zusätzliche Hartstoffe, wie Titancarbid (TiC) , Siliciumcarbid (SiC) , Niobcarbid (NbC) , Chromcarbid (CrC) , Titannitrid (TiN) Wolframcarbid (WC) , in seiner Matrix, welche im Zuge des Sprühkompaktierens als feste Partikel in den Sprühstrahl injiziert worden sind. Diese Maßnahme bewirkt eine weitere Erhöhung der Verschleißbeständigkeit, wobei die guten Zähigkeitseigenschaften der stickstofflegierten Matrix erhalten bleiben.According to a further advantageous embodiment of the invention, nitrogen-alloyed steel according to the invention contains additional hard materials, such as titanium carbide (TiC), silicon carbide (SiC), niobium carbide (NbC), chromium carbide (CrC), titanium nitride (TiN), tungsten carbide (WC), in its matrix, which have been injected into the spray as solid particles in the course of the spray compacting. This measure brings about a further increase in wear resistance, while the good toughness properties of the nitrogen alloy matrix are retained.
Hinsichtlich des Verfahrens zur Herstellung eines erfindungsgemäßen Stahls wird die oben genannte Aufgabe dadurch gelöst, daß der Stahl unter Verwendung von Stickstoff als Sprühgas sprühkompaktiert wird, daß der Stahl nach dem Sprühkompaktieren bei Anfangstemperaturen von bis zu 1150 °C warmumgeformt wird, daß der warmumgeformte Stahl abgekühlt wird, daß der abgekühlte Stahl auf eine Austenitisierungstemperatur von 1075°C bis 1225 °C wiedererwärmt wird, daß der wiedererwärmte Stahl abgeschreckt wird und der abgeschreckte Stahl bei Temperaturen von 150 °C - 625 °C angelassen wird. Vorzugsweise erfolgt das Anlassen bei Temperaturen zwischen 150 °C und 300 °C oder zwischen 500 °C und 625 °C. Im Gegensatz zu druckaufgestickten Stählen ist aufgrund der optimalen Einstellung des Silicium- Stickstoff-Verhältnisses ein Tiefkühlen zur Restaustenitumwandlung nicht erforderlich. Bei. Einhaltung der erfindungsgemäßen Verfahrensparameter kann eine Härte bis zu 68 HRC selbst dann erzielt werden, wenn im Zuge der weiteren Verarbeitung ergänzende Umformschritte erforderlich sind. Die Warmumformung kann dabei durch Schmieden oder Walzen erfolgen.With regard to the method for producing a steel according to the invention, the above-mentioned object is achieved in that the steel is spray-compacted using nitrogen as the spray gas, in that the steel after the spray compacting at initial temperatures is hot worked up to 1150 ° C, the hot formed steel is cooled, the cooled steel is reheated to an austenitizing temperature of 1075 ° C to 1225 ° C, the reheated steel is quenched and the quenched steel at temperatures of 150 ° C - left at 625 ° C. The tempering is preferably carried out at temperatures between 150 ° C. and 300 ° C. or between 500 ° C. and 625 ° C. In contrast to pressure-embroidered steels, freezing to convert residual austenite is not necessary due to the optimal setting of the silicon-nitrogen ratio. In. Compliance with the process parameters according to the invention can achieve a hardness of up to 68 HRC even if additional forming steps are required in the course of further processing. The hot forming can be carried out by forging or rolling.
Schließlich kann ein erfindungsgemäßer Stahl besonders gut zur Erzeugung eines Verbundwerkstoffs genutzt werden, der mindestens eine durch einen ersten Stahl erzeugte erste Schicht und mindestens eine zweite, durch einen erfindungsgemäßen sprühkompaktierten Stahl gebildete zweite Schicht aufweist, wobei der Stahl der ersten Schicht eine andere Zusammensetzung aufweist als der sprühkompaktierte Stahl. Bei einem solchen Verbundwerkstoff können die unterschiedlichen Eigenschaften der einzelnen Schichten in optimaler Weise miteinander kombiniert werden. So kann der erfindungsgemäße Stahl beispielsweise auf einer zähfesten ersten Schicht eine verschleißbeständige Deckschicht bilden. Nachfolgend wird die Erfindung anhand von Ausführungsbeispielen näher erläutert.Finally, a steel according to the invention can be used particularly well to produce a composite material which has at least one first layer produced by a first steel and at least one second layer formed by a spray-compacted steel according to the invention, the steel of the first layer having a different composition than the spray-compacted steel. With such a composite material, the different properties of the individual layers can be optimally combined with one another. For example, the steel according to the invention can form a wear-resistant cover layer on a tough first layer. The invention is explained in more detail below on the basis of exemplary embodiments.
In Tabelle 1 sind die chemischen Zusammensetzungen von sieben Stählen A - G in Masse-% angegeben. Zudem sind für jeden der Stähle der Verschleißfaktor Sv, das Silicium- Stickstoffverhältnis VSiN und der in einem Verschleißversuch ermittelte Abrieb in Gramm verzeichnet.Table 1 shows the chemical compositions of seven steels A - G in mass%. In addition, the wear factor S v , the silicon-nitrogen ratio V S i N and the abrasion determined in a wear test in grams are recorded for each of the steels.
Bei den Stählen A - D handelt es sich um erfindungsgemäße Stähle, während die Stähle E - G zum Vergleich angeführt sind.Steels A - D are steels according to the invention, while steels E - G are listed for comparison.
Zur Herstellung sprühkompaktierter, stickstofflegierter Stähle ist aus Schrott und / oder reinen Metallen jeweils unter Zugabe der erforderlichen Legierungsbestandteile eine Schmelze erstellt worden. Anschließend ist die Schmelze in einem stickstoffhaltigen Schutzgasstrom in kugelförmige Tröpfchen zerstäubt worden.For the production of spray-compacted, nitrogen-alloyed steels, a melt has been created from scrap and / or pure metals with the addition of the necessary alloy components. The melt was then atomized into spherical droplets in a nitrogen-containing protective gas stream.
Im Zuge der Zerstäubung in dem stickstoffhaltigen Gasstrom erfolgte eine Aufstickung und schnelle Abkühlung der Metalltröpfchen auf eine Temperatur zwischen Liquidus und Solidus, so daß die Tröpfchen nach der Abkühlung im Gasstrom eine feste bis teigige Konsistenz aufwiesen. Dabei waren die so beschaffenen, sich mit einer hohen Geschwindigkeit von 40 bis 80 m/s bewegenden Tröpfchen auf eine Grundplatte gerichtet, auf welcher die Tröpfchen aufgrund der ihnen eigenen hohen kinetischen Energie zu einem dichten Materialverbund kompaktierten. Der auf diese Weise durch Sprühkompaktieren erzeugte Block wies aufgrund der im Gasstrom erfolgenden schnellen Erstarrung der Metalltröpfchen aus der Flüssigphase und aufgrund des eingebrachten Stickstoffgehaltes eine gleichmäßige Verteilung der Hartphasen und Carbid- bzw. Carbonitridgrößen auf, die im Vergleich zu schmelzmetallurgisch erzeugten Stählen deutlich vermindert sind.In the course of the atomization in the nitrogen-containing gas stream, the metal droplets were nitrided and rapidly cooled to a temperature between the liquidus and solidus, so that the droplets had a solid to pasty consistency after cooling in the gas stream. The droplets thus created, moving at a high speed of 40 to 80 m / s, were directed onto a base plate on which the droplets compacted into a dense material composite due to their high kinetic energy. The block produced in this way by spray compacting showed due to the rapid solidification of the metal droplets in the gas stream from the liquid phase and due to the introduced nitrogen content on a uniform distribution of hard phases and carbide or carbonitride sizes, which are significantly reduced compared to steel produced by melt metallurgy.
Die Figuren 2 und 3 zeigen jeweils das Schliffbild eines durch Sprühkompaktieren in erfindungsgemäßer Weise erzeugten, stickstofflegierten Stahls im geglühten Zustand, wobei in Fig. 1 das jeweilige Mikrogefüge bei einer Vergrößerung von 100:1 und in Fig. 3 bei einer Vergrößerung von 500:1 dargestellt ist.FIGS. 2 and 3 each show the micrograph of a nitrogen-alloy steel produced by spray compacting in the manner according to the invention in the annealed state, the respective microstructure in FIG. 1 with an enlargement of 100: 1 and in FIG. 3 with an enlargement of 500: 1 is shown.
Die Figuren 4 und 5 zeigen zum Vergleich eine entsprechende Darstellung des Mikrogefüges desselben Stahles ohne Stickstoffzusatz, wenn dieser in konventioneller Weise schmelzmetallurgisch erzeugt wird.For comparison, FIGS. 4 and 5 show a corresponding representation of the microstructure of the same steel without the addition of nitrogen when this is produced in a conventional manner by melt metallurgy.
Die aus den Figuren 2 und 3 ohne weiteres ersichtliche hohe Gefügehomogenität ermöglicht die problemlose Umformung des sprühkompaktierten Blocks durch Schmieden oder Walzen. Der Umformung vorausgehend kann eine Blockbzw. Diffusionsglühung erfolgen.The high structural homogeneity which is readily apparent from FIGS. 2 and 3 enables the spray-compacted block to be easily formed by forging or rolling. Prior to the forming, a block or Diffusion annealing take place.
Die verbesserte Umformbarkeit erfindungsgemäß erzeugter Stähle ermöglicht es, die Warmformung bei gegenüber der herkömmlichen Vorgehensweise niedrigeren Temperaturen durchzuführen. Die jeweils erforderliche Härte der aus den erfindungsgemäßen Stählen hergestellten Bauelemente oder Werkzeuge läßt sich nach der Formgebung durch ein Härten von einer Austenitisierungstemperatur zwischen 1075 °C und 1225 °C mit nachfolgendem Anlassen zwischen 150 °C und 625 °C einstellen, wobei Härten von bis zu 68 HRC erreicht werden können.The improved formability of steels produced according to the invention makes it possible to carry out thermoforming at lower temperatures than the conventional procedure. The hardness required in each case for the components or tools produced from the steels according to the invention can, after shaping, be hardened from an austenitizing temperature between 1075 ° C. and 1225 ° C. with subsequent tempering between Set 150 ° C and 625 ° C, whereby hardnesses of up to 68 HRC can be achieved.
Erfindungsgemäße Stähle weisen ein ausgewogenes Verhältnis zwischen den carbid- bzw. carbonitridbildenden Elementen auf, welches durch den zwischen 0,55 und 3,42 liegenden, in der voranstehend erläuterten Weise bestimmten Verschleißfaktor Sv gekennzeichnet ist. Dieses ausgewogene Verhältnis der Carbid-/Carbonitridbildner führt zu einer überlegenen Verschleißbeständigkeit erfindungsgemäßer Stähle, welche in Verschleißversuchen bestätigt wurde (Fig. 6) .Steels according to the invention have a balanced ratio between the carbide- or carbonitride-forming elements, which is characterized by the wear factor S v , which lies between 0.55 and 3.42 and is determined in the manner explained above. This balanced ratio of carbide / carbonitride formers leads to a superior wear resistance of steels according to the invention, which has been confirmed in wear tests (FIG. 6).
In diesen Versuchen wurde das Verschleißverhalten der Stähle A - G bei rollender Reibung bei einer Arbeit von 8,0 Nm x 10"6 überprüft, wobei die Gegenrolle jeweils aus dem Schnellarbeitsstahl mit der Werkstoffnummer 1.3207 gemäß Stahl-Eisen-Liste hergestellt war und eine Härte von 67 HRC aufwies.In these tests, the wear behavior of steels A - G with rolling friction at a work of 8.0 Nm x 10 "6 was checked, the counter roller being made from high-speed steel with the material number 1.3207 according to the steel-iron list and a hardness of 67 HRC.
Zur Überprüfung der Verschleiß- und Formhaltigkeit eines erfindungsgemäßen Stahls in der Praxis wurde in einer ersten Untersuchung durch Sprühkompaktieren ein Rohblock mit einem Durchmesser von 400 mm aus dem stickstofflegierten Stahl C gefertigt, dessen Zusammensetzung in Tabelle 1 angegeben ist. Mit einer Langschmiedemaschine wurde dieser Block in einer zweihitzigen Schmiedung auf einen Durchmesser von 115 mm verformt, wobei die Schmiedeanfangstemperatur bei 980 °C und die Schmiedeendtemperatur bei 969 °C lag.In order to check the wear and shape retention of a steel according to the invention in practice, a raw block with a diameter of 400 mm was produced from the nitrogen-alloyed steel C, the composition of which is given in Table 1, by spray compacting. Using a long forging machine, this block was deformed in a two-heat forging to a diameter of 115 mm, the starting temperature at 980 ° C and the end temperature at 969 ° C.
Der geschmiedete Block wurde anschließend weichgeglüht. Aus dem weichgeglühten Material wurden dann Gewindewalzenbacken hergestellt, deren Abmessungen 85 mm x 50 mm x 24 mm und 95 mm x 50 mm x 24 mm betrugen. Diese Werkzeuge wurden darauffolgend durch Wärmebehandlung auf eine Härte von 62 HRC gebracht.The forged ingot was then annealed. The soft annealed material then became Threaded roller jaws produced, the dimensions of which were 85 mm x 50 mm x 24 mm and 95 mm x 50 mm x 24 mm. These tools were subsequently heat treated to a hardness of 62 HRC.
Mit den Gewindewalzenbacken wurden Schrauben aus einem nicht-rostenden Stahl mit der Werkstoffnummer 1.4401 gemäß Stahl-Eisen-Liste hergestellt. Die Arbeitsergebnisse und der Verschleißzustand der aus dem erfindungsgemäßen Stahl hergestellten Werkzeuge wurden mit den Arbeitsergebnissen und dem Verschleißzustand von Gewindewalzenbacken verglichen, die aus einem schmelzmetallurgisch erzeugten Stahl identischer chemischer Zusammensetzung, jedoch ohne Stickstoffzusatz, hergestellt worden waren. Es zeigte sich, daß die Standzeit der aus erfindungsgemäßem Stahl hergestellten Gewindewalzenbacken doppelt so hoch war wie die Standzeit der Gewindewalzenbacken, die aus dem herkömmlich erzeugten Stahl identischer Zusammensetzung hergestellt worden waren. So ließen sich mit den aus erfindungsgemäßem Stahl erzeugten Werkzeugen 140.000 Schrauben fertigen, während die aus herkömmlich erzeugtem Stahl hergestellten Werkzeuge nach der Fertigung von 70.000 Schrauben verschlissen waren. Besonders hervorzuheben ist in diesem Zusammenhang die exzellente Formstabilität der aus erfindungsgemäßem Stahl hergestellten Werkzeuge im Bereich der Gewindespitzen.The thread rolling jaws were used to produce screws from a stainless steel with the material number 1.4401 according to the steel-iron list. The work results and the state of wear of the tools produced from the steel according to the invention were compared with the work results and the state of wear of thread rolling jaws which had been produced from a steel with an identical chemical composition, but without the addition of nitrogen, produced by melt-metallurgy. It was found that the service life of the threaded roller jaws produced from steel according to the invention was twice as long as the service life of the threaded roller jaws which had been produced from the conventionally produced steel of identical composition. Thus, 140,000 screws could be produced with the tools produced from steel according to the invention, while the tools made from conventionally produced steel were worn out after the production of 70,000 screws. Particularly noteworthy in this context is the excellent dimensional stability of the tools made from steel according to the invention in the area of the thread tips.
In einer zweiten Untersuchung wurde der durch Sprühkompaktieren hergestellte, stickstofflegierte Stahl C der Tabelle 1 auf eine Abmessung von 160 mm x 160 mm ausgeschmiedet und weichgeglüht. Aus dem geschmiedeten Stahl wurden Stanzwerkzeuge für aus einem mikrolegierten Stahl bestehende Kettenglieder hergestellt, die aus Blechen mit einer Dicke von 4 mm gestanzt wurden.In a second investigation, the nitrogen-alloyed steel C of table 1 produced by spray compacting was forged to a dimension of 160 mm × 160 mm and soft-annealed. From the forged steel, stamping tools were made from a micro-alloyed one Steel existing chain links manufactured, which were punched out of sheets with a thickness of 4 mm.
Die Arbeitsergebnisse und das Verschleißverhalten der aus dem erfindungsgemäßen Stahl hergestellten Stanzwerkzeuge wurden wiederum mit einem Stanzwerkzeug verglichen, welches aus einem schmelzmetallurgisch hergestellten Stahl derselben Zusammensetzung, jedoch ohne Stickstoff, erzeugt worden waren. Es zeigte sich auch in diesem Fall, daß das aus erfindungsgemäßem Stahl hergestellte Werkzeug eine deutlich verbesserte Standzeit aufwies als das Vergleichswerkzeug. So war das aus erfindungsgemäßem Stahl hergestellte Stanzwerkzeug nach der Fertigung von 290.000 Kettengliedern noch einsatzbereit, während das Vergleichswerkzeug nach der Stanzung von 200.000 Kettengliedern bereits verschlissen war. Hervorzuheben ist in diesem Zusammenhang die auch nach der Fertigung von 290.000 Kettengliedern noch vorhandene sehr gute Schneidkantenstabilität des aus dem erfindungsgemäßen Stahl hergestellten Stanzwerkzeugs. The results of the work and the wear behavior of the punching tools produced from the steel according to the invention were again compared with a punching tool which had been produced from a steel of the same composition, but without nitrogen, produced by melt metallurgy. It was also shown in this case that the tool made from steel according to the invention had a significantly improved service life than the comparison tool. The punching tool made from steel according to the invention was still ready for use after the production of 290,000 chain links, while the comparison tool was already worn out after the punching of 200,000 chain links. In this context, the very good cutting edge stability of the punching tool produced from the steel according to the invention is still present, even after the production of 290,000 chain links.
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Claims

PAT E N T AN S P RÜ C H E PAT E N T AN S P RÜ C H E
Stickstofflegierter Stahl mit hoherNitrogen alloy steel with high
Verschleißbeständigkeit, der durch Sprühkompaktieren hergestellt ist und folgende Zusammensetzung aufweist (in Masse-%) :Wear resistance, which is produced by spray compacting and has the following composition (in% by mass):
C: 0,8 - 2,5 %C: 0.8 - 2.5%
N: 0,03 - 0,75 %N: 0.03 - 0.75%
Si: 0,15 - 1,8 %Si: 0.15 - 1.8%
Mn: < 1,0 %Mn: <1.0%
P: < 0,03 %P: <0.03%
S: < 0,05 %S: <0.05%
Cr: 5,0 - 11,5 %Cr: 5.0 - 11.5%
Mo: 0,5 - 6,0 %Mo: 0.5 - 6.0%
V: < 4,0 %V: <4.0%
Nb: < 4,0 %Nb: <4.0%
W: < 3,5 %W: <3.5%
02: < 0,005 % gegebenenfalls weitere Legierungsbestandteile und als Rest Eisen und übliche Verunreinigungen,0 2 : <0.005%, if appropriate, further alloy constituents and the balance iron and customary impurities,
wobei ein der Summe seiner gewichteten Gehalte an Cr, Mo, V, Nb und W entsprechender Verschleißfaktor Sv folgende Bedingung erfüllt: 0,55 < Sv < 3,42a wear factor S v corresponding to the sum of its weighted contents of Cr, Mo, V, Nb and W fulfills the following condition: 0.55 <S v <3.42
mit: Sv = (Acr/9,33) + (AMo/17,22) + (Av/3,92) + (ANb/7,15) + (Aw/14,14),with: S v = (Acr / 9.33) + (A Mo / 17.22) + (A v / 3.92) + (A Nb / 7.15) + (A w / 14.14),
ACr : Cr-Gehalt in Masse-%, AMo : Mo-Gehalt in Masse-%, Av : V-Gehalt in Masse-%, ANb : Nb-Gehalt in Masse-%, Aw : W-Gehalt in Masse-%,A Cr : Cr content in mass%, A Mo : Mo content in mass%, A v : V content in mass%, A Nb : Nb content in mass%, A w : W content in mass%,
und wobei das Silicium-Stickstoff-Verhältnis VSiN folgende Bedinungung erfüllt:and the silicon-nitrogen ratio V S i N fulfills the following condition:
0,21 < VsiN < 3,310.21 <V siN <3.31
mit: VsiN = Asi + 2 AN with: VsiN = A si + 2 A N
ASi : Si-Gehalt in Masse-%, AN : N-Gehalt in Masse-%.A S i: Si content in mass%, A N : N content in mass%.
Stahl nach Anspruch 1, d a d u r c h g e k e n n z e i c h n e t, d a ß er einen C- Gehalt von 1,0 - 1,9 Masse-%, einen N-Gehalt von 0,05 - 0,5 Masse-%, einen Si-Gehalt 0,15 - 1,5 Masse-%, einen Cr-Gehalt von 5,0 - 10,0 Masse-%, einen Mo- Gehalt von 0,5 - 5,5 Masse-%, einen V-Gehalt < 3,5 Masse-%, einen Nb-Gehalt < 3,5 Masse-% und einen W-Gehalt < 3,0 Masse-% aufweist. Steel according to claim 1, characterized in that it has a C content of 1.0-1.9% by mass, an N content of 0.05-0.5% by mass, an Si content of 0.15%. 1.5 mass%, a Cr content of 5.0 - 10.0 mass%, a Mo content of 0.5 - 5.5 mass%, a V content <3.5 mass% , has an Nb content <3.5% by mass and a W content <3.0% by mass.
3. Stahl nach einem der voranstehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t, d a ß er bis zu 0,05 Masse-% Bor enthält.3. Steel according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t, that contains up to 0.05 mass% boron.
4. Stahl nach einem der voranstehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t, d a ß er bis zu 0,5 Masse-% Titan enthält.4. Steel according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t, that contains up to 0.5% by mass of titanium.
5. Stahl nach einem der voranstehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t, d a ß er bis zu 0,5 Masse-% Zirconium enthält.5. Steel according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t, that it contains up to 0.5% by mass of zirconium.
6. Stahl nach einem der voranstehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t, d a ß er bis zu 0,25 Masse-% Aluminium enthält.6. Steel according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t, that also contains up to 0.25% by mass of aluminum.
7. Stahl nach einem der voranstehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t, d a ß er zusätzliche Hartstoffe, wie Titancarbid, Siliciumcarbid, Niobcarbid, Chromcarbid, Titannitrid, Wolframcarbid, in seiner Matrix enthält, welche im Zuge des Sprühkompaktierens als feste Partikel in den Sprühstrahl injiziert worden sind.7. Steel according to one of the preceding claims, that contains additional hard materials, such as titanium carbide, silicon carbide, niobium carbide, chromium carbide, titanium nitride, tungsten carbide, in its matrix, which were injected as solid particles in the course of the spray compacting in the spray jet.
8. Verfahren zur Herstellung eines Stahls nach einem der voranstehenden Ansprüche, d a d u r c h g e k e n n z e i c h n e t,8. A method for producing a steel according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t,
- d a ß der Stahl unter Verwendung von Stickstoff als Sprühgas sprühkompaktiert wird, - d a ß der Stahl nach dem Sprühkompaktieren bei Anfangstemperaturen von bis zu 1150 °C warmumgeformt wird,since the steel is spray compacted using nitrogen as the spray gas, - that the steel is hot formed after spray compacting at initial temperatures of up to 1150 ° C,
- d a ß der warmumgeformte Stahl abgekühlt wird,- that the hot-formed steel is cooled,
- d a ß der abgekühlte Stahl auf eine- d a ß the cooled steel on a
Austenitisierungstemperatur von 1075°C bis 1225 °C wiedererwärmt wird,Austenitizing temperature of 1075 ° C to 1225 ° C is reheated,
- d a ß der wiedererwärmte Stahl abgeschreckt wird und- that the reheated steel is quenched and
- d a ß der abgeschreckte Stahl bei Temperaturen von 150 °C - 625 °C. angelassen wird.- d a ß the quenched steel at temperatures of 150 ° C - 625 ° C. is started.
9. Verfahren nach Anspruch 8, d a d u r c h g e k e n n z e i c h n e t, d a ß das Anlassen bei Temperaturen zwischen 150 °C und 300 °C erfolgt.9. The method of claim 8, d a d u r c h g e k e n n z e i c h n e t, that the tempering takes place at temperatures between 150 ° C and 300 ° C.
10. Verfahren nach Anspruch 8, d a d u r c h g e k e n n z e i c h n e t, d a ß das Anlassen bei Temperaturen zwischen 500 °C und 625 °C erfolgt.10. The method of claim 8, d a d u r c h g e k e n n z e i c h n e t, that the tempering takes place at temperatures between 500 ° C and 625 ° C.
11. Verbundwerkstoff mit mindestens einer durch einen ersten Stahl erzeugten ersten Schicht und mindestens einer zweiten Schicht, die durch einen stickstofflegierten, sprühkompaktierten Stahl nach einem der Ansprüche 1 bis 7 gebildet ist, wobei der Stahl der ersten Schicht eine andere Zusammensetzung aufweist als der sprühkompaktierte Stahl. 11. A composite material having at least one first layer produced by a first steel and at least one second layer formed by a nitrogen-alloyed, spray-compacted steel according to one of claims 1 to 7, wherein the steel of the first layer has a different composition than the spray-compacted steel ,
EP01933846A 2000-04-18 2001-04-18 Method for the production of nitrogen alloyed steel, spray compacted steel Expired - Lifetime EP1274872B1 (en)

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DE10019042 2000-04-18
DE10019042A DE10019042A1 (en) 2000-04-18 2000-04-18 Nitrogen alloyed steel produced by spray compacting used in the production of composite materials contains alloying additions of manganese and molybdenum
PCT/EP2001/004377 WO2001079575A1 (en) 2000-04-18 2001-04-18 Nitrogen alloyed steel, spray compacted steel, method for the production thereof and composite material produced from said steel

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EP1274872A1 true EP1274872A1 (en) 2003-01-15
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JP (1) JP2004501276A (en)
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ATE278816T1 (en) 2004-10-15
JP2004501276A (en) 2004-01-15
US20030156965A1 (en) 2003-08-21
EP1274872B1 (en) 2004-10-06
DE10019042A1 (en) 2001-11-08
WO2001079575A1 (en) 2001-10-25
DK1274872T3 (en) 2005-02-07
DE50103992D1 (en) 2004-11-11
ES2230308T3 (en) 2005-05-01

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