EP1194605A1 - Acier austenitique a faible teneur en nickel - Google Patents

Acier austenitique a faible teneur en nickel

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Publication number
EP1194605A1
EP1194605A1 EP00935127A EP00935127A EP1194605A1 EP 1194605 A1 EP1194605 A1 EP 1194605A1 EP 00935127 A EP00935127 A EP 00935127A EP 00935127 A EP00935127 A EP 00935127A EP 1194605 A1 EP1194605 A1 EP 1194605A1
Authority
EP
European Patent Office
Prior art keywords
weight
steel
less
nitrogen
nickel
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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Application number
EP00935127A
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German (de)
English (en)
Inventor
Markus Speidel
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BASF SE
Original Assignee
BASF SE
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Filing date
Publication date
Application filed by BASF SE filed Critical BASF SE
Publication of EP1194605A1 publication Critical patent/EP1194605A1/fr
Withdrawn legal-status Critical Current

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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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • 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
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/10—Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
    • 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
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/10—Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
    • B22F1/103—Metallic powder containing lubricating or binding agents; Metallic powder containing organic material containing an organic binding agent comprising a mixture of, or obtained by reaction of, two or more components other than a solvent or a lubricating agent
    • 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
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/22—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip
    • B22F3/225—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip by injection molding
    • 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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
    • 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
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • 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
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
    • 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
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
    • B22F2998/10—Processes characterised by the sequence of their steps
    • 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 present invention relates to a low-nickel austenitic steel, in particular a low-nickel, molybdenum, manganese and copper-low austenitic steel and its use.
  • the invention further relates to methods for the production of articles made of such steels.
  • austenite here, as usual, denotes iron-containing alloys and includes carbon-containing iron.
  • austenite is a high-temperature modification of iron with a face-centered cubic crystal structure (" ⁇ -iron"), which is thermodynamically stable between 740 ° C and 1538 ° C 0 to a maximum of 2.1% by weight (at 1153 ° C.) of carbon in the form of a solid solution.
  • ⁇ -iron face-centered cubic crystal structure
  • austenitic steels or austenites all steels that have a face-centered cubic crystal lattice.
  • the cubic, face-centered austenite structure is necessary for many areas of application of steels or at least advantageous over other modifications (e.g.
  • Austenite for example, is not ferromagnetic, which makes austenitic steels usable for electrical or electronic components or other applications in which the occurrence of magnetic repulsive or attractive forces, for example clocks, is undesirable.
  • austenite is a high-temperature modification and thermodynamically unstable at lower temperatures, an austenitic steel must be stabilized against conversion into other modifications so that it retains its desired austenitic properties even at normal temperature. This can be done, for example, by adding alloying elements known as stabilizers of the austenite structure.
  • the most common alloying element used for this purpose is nickel, typically in an amount of 8 to 10% by weight.
  • alloy components are used to influence other properties of the steel (e.g. corrosion and wear resistance, hardness, strength or toughness) in the desired way.
  • certain alloy components often also leads to certain disadvantages - mostly dependent on the quantity - which can be counteracted to a certain extent by adjusting the alloy composition.
  • carbon and manganese generally help stabilize the austenite structure, but reduce it too much Amounts the corrosion resistance.
  • Silicon is a frequently unavoidable impurity, is also deliberately added as an oxygen scavenger, but promotes the formation of ⁇ -ferrite. Chromium, molybdenum and tungsten make a decisive contribution to corrosion resistance, but also favor the formation of ⁇ -ferrite.
  • Nitrogen in turn stabilizes the austenite structure and increases the corrosion stability, but excessively high nitrogen contents reduce the toughness of the steel.
  • One difficulty in optimizing steel compositions is that the properties of the steel do not change linearly with the content of certain alloy components, but that even small changes in the composition can lead to very large jumps in the material properties.
  • Another disadvantage of using non-ferrous metals as alloy components is usually their comparatively high price.
  • Austenitic steels low in nickel are sought-after materials for a number of application areas.
  • An increasingly important area of application for such steels are objects which, when used, are in contact with the human or animal body, since these steels naturally do not trigger any nickel allergy.
  • Nickel allergies are common causes of contact eczema or other allergic symptoms that occur when in contact with nickel-containing steels, for example when wearing
  • a number of low-nickel austenitic steels are known, including nickel-free ones.
  • the austenitic structure in such steels is stabilized by the element nitrogen.
  • AT-B-266 900 discloses the use of austenitic, unmagnetic steels for the production of moving, in particular vibratingly stressed machine parts, the steels to be used being used only in extremely wide ranges of possible combinations.
  • the following definitions are defined: 0 to 20% by weight of Mn, 0 to 30% by weight of Cr, 0 to 5% by weight of Mo and / or V, at least 0.5% by weight, preferably at least 1.4% by weight - N, 0.02 to 0.55% by weight C, 0 to 2% by weight Si, 0 to 25% by weight Ni, balance iron.
  • the broad areas mentioned cover different steels with completely different properties, criteria for the selection of certain steels are not given, nor are measures for the production of such steels taught.
  • EP-A-875 591 teaches the use of a corrosion-resistant largely nickel-free austenitic steel with the essential components 5-26% by weight Mn, 11-24% by weight Cr, 2.5
  • Ni 0.5% by weight of Ni, the rest of Fe, as a material for the production of objects which are in contact with living beings.
  • DE -A- 195 13 407 also teaches the use of a corrosion-resistant largely nickel-free austenitic steel as a material for the production of objects which are in contact with living beings.
  • This steel has the essential components 2-26% by weight Mn, 11-24% by weight Cr, 2.5-10% by weight Mo, 0.55-1.2% by weight N, below 0.3% by weight C, up to 0.5% by weight Ni, remainder Fe.
  • JP-A-07/150297 (Chemical Abstracts: Abstract No.
  • 123: 175994 discloses a steel of the composition 10-25% by weight Mn, 10-25% by weight Cr, 5-10% by weight Mo, 0.2-1% by weight N, 0.05-0.5% by weight C, up to 0.5% by weight Si, balance Fe, and its use in shipbuilding.
  • DE-A-196 07 828 teaches a steel of the composition 8-15% by weight Mn, 13-18% by weight Cr, 2.5-6% by weight Mo, 0.55-1.1% by weight. % N, up to 0.1% by weight C, up to 0.5% by weight Ni, balance Fe, and its use for various components, in particular generator cap rings.
  • the required high corrosion resistance is bought with a comparatively high amount of molybdenum, which is by far the most expensive among the common alloying elements.
  • DE-A-42 42 757 suggests the use of a steel with the essential components 21-35% by weight of Mn, 9-20% by weight of Cr, 0-
  • EP-A-422 360 discloses the use of a steel having the composition 17-20% by weight of Mn, 16-24% by weight of Cr, 0-3% by weight of Mo, 0.5-1.3% by weight. % N, up to 0.20% by weight C, balance Fe, for the production of components on rail vehicles.
  • EP-A-432 434 teaches a method for producing connecting elements from a steel of the composition 1 ⁇ , 5-20% by weight Mn, 17.5-20% by weight Cr, 0-5% by weight Mo, 0.8 - 1.2% by weight N, to 0.12% by weight C, 0.2-1% by weight Si, up to 0.05% by weight P, up to 0.015% by weight S, up to 3% by weight Ni, balance Fe.
  • DE-A-25 18 452 teaches a process for producing an austenitic steel with 21-45% by weight Mn, 10-30% by weight Cr, 0.85-3% by weight N, balance Fe, 5 Embroidery of a nitrogen-free or low-alloy master alloy at at least 925 ° C.
  • the steels taught in these documents contain a lower proportion of molybdenum, but a relatively high proportion of manganese, which has a negative effect on the corrosion properties.
  • DE-A-24 47 318 teaches an austenitic steel with 15 to 45% by weight Mn, 10 to 30% by weight Cr, 0.85 to 3% by weight N, up to 1% by weight C, 0 to 2% by weight of Si and at least one of the following three alloy constituents: 1 to 3% by weight of Cu, 1 to 5 4% by weight of Ni and 1 to 5% by weight of Mo, the content of the latter being different added to 5% by weight, remainder iron; the alloy composition must meet certain other conditions.
  • the alloy can be free of Cu and Ni if a comparatively high manganese content of at least 21% by weight is used. In this steel, too, nickel can only be dispensed with if a comparatively high molybdenum or manganese content is accepted and / or at least 1% by weight of copper is present.
  • EP-A-640 695 discloses a steel of the composition 11-25% by weight Mn, 10-20% by weight Cr, up to 1% by weight Mo, 0.05-0.55% by weight N , up to 0.01% by weight of C, up to 0.5% by weight of Ni, up to 1% by weight of Si, balance Fe, and its use for the production of articles of daily use which come into contact with the skin of living beings
  • JP-A-07/157847 teaches a steel of the composition 9-20% by weight Mn, 12-20% by weight Cr, 1-5% by weight Mo, 0.1-0.5% by weight N, 0.01-0.6% by weight C, 0.05-2.0% by weight Si, 0.05-4% by weight Cu, remainder Fe, and its use for the manufacture of watch cases.
  • JP-A-06/116 683 (Chemical Abstracts: Abstract No.
  • 35 121: 138554 discloses a steel with 5-23% by weight Mn, 13-22% by weight Cr, up to 5% by weight Mo, 0.2-0.6% by weight N, 0, 05 - 0.2% by weight C, up to 0.1% by weight In, up to 15% by weight Ni, balance Fe.
  • the steels disclosed in these documents contain - at least in parts of their possible compositions - comparatively
  • the task was to find a low-nickel, preferably nickel-free austenitic steel.
  • the steel should contain comparatively few other alloying elements - also for reasons of cost - in particular it should be low in molybdenum, manganese and copper, and still have excellent material properties - have ten, in particular be highly corrosion-resistant and have high strength.
  • Manganese less than 9.0% by weight; Chromium: at least 16 and at most 22% by weight; Nitrogen: more than 0.30 and at most 0.70% by weight; Carbon: more than 0.08 and at most 0.30% by weight; and silicon: less than 2.0% by weight.
  • Figures in% by weight relate to the composition of the finished steel.
  • the steel according to the invention is low in nickel and preferably nickel-free, austenitic, a material that can be easily manufactured and processed and is highly corrosion-resistant.
  • nickel-free, austenitic a material that can be easily manufactured and processed and is highly corrosion-resistant.
  • high strength and toughness which, together with its high resistance to corrosion, make it particularly suitable for applications in building or civil engineering, and especially for load-bearing components.
  • the steel according to the invention is low in nickel, ie nickel is added to it, if at all, only in comparatively small amounts, generally at most 2% by weight, for example at most 1% by weight.
  • the steel according to the invention is preferably nickel-free, ie free of intentionally added nickel. (Freedom from nickel is therefore a special case of poor nickel.) Nickel is mostly contained in small amounts or traces as an inevitable impurity, often due to the general use of steel scrap as a raw material for the production of iron or raw steel. In general, therefore, the steel according to the invention in its nickel-free embodiment contains less than 2.0% by weight of nickel, preferably less than 1% by weight of nickel and particularly preferably less than 0.5% by weight of nickel.
  • nickel in a particularly preferred manner, it contains less than 0.3% by weight of nickel.
  • a steel with such low nickel contents releases so little nickel even in constant contact with the human or animal body that there is no risk of sensitization or allergy.
  • nickel can also be added within the stated limits in order to set the desired material properties.
  • the steel according to the invention contains less than 9.0% by weight of manganese, preferably at most 8.5% by weight of manganese and in a particularly preferred manner at most 4.9% by weight of manganese. It also contains at least 16% by weight of chromium, preferably at least
  • chromium 21% by weight chromium. Its nitrogen content is more than 0.30, preferably at least 0.4, and at most 0.70 and preferably at most 0.55% by weight; and its carbon content is more than 0.08, preferably at least 0.12, for example 0.15, and at most 0.30% by weight. In a preferred embodiment, the sum of carbon and nitrogen is at least 0.55% by weight.
  • These alloying elements are essentially in solid solution, ie atomically finely distributed in the austenitic lattice, and not as carbides, nitrides or intermetallic phases.
  • a small addition of further alloying elements which are often used to improve certain properties for certain applications or as a common addition in steel production, does not generally impair the material properties of the steel according to the invention.
  • it can contain copper in an amount of less than 2.0, for example less than 1.0, preferably less than 0.5% by weight.
  • it can also contain tungsten in an amount of less than 2.0, preferably at most 1.0% by weight and silicon in an amount of less than 2.0, for example 0.2% by weight.
  • the steel according to the invention generally contains less than 2.0% by weight of molybdenum, preferably less than 1.0% by weight of molybdenum.
  • the steel according to the invention consists of iron, unavoidable impurities and the following components:
  • Chromium at least 16 and at most 22% by weight
  • Nickel less than 2.0% by weight
  • Nitrogen more than 0.30 and at most 0.70% by weight
  • Carbon more than 0.08 and at most 0.30% by weight; Silicon: less than 2.0% by weight;
  • Molybdenum less than 2.0% by weight
  • Copper less than 2.0% by weight
  • tungsten less than 2.0% by weight
  • the steel according to the invention consists of iron, unavoidable impurities and the following constituents:
  • Chromium at least 20 and at most 22% by weight; Nickel: less than 1.0% by weight;
  • Nitrogen more than 0.30 and at most 0.70% by weight, - carbon: more than 0.12 and at most 0.30% by weight; Silicon: less than 2.0% by weight - molybdenum: less than 1.0% by weight - copper: less than 1.0% by weight; and
  • Tungsten less than 1.0% by weight.
  • the steel according to the invention is extremely corrosion-resistant.
  • the corrosion resistance expressed as the critical crevice corrosion temperature, increases with the following effective amount of alloying elements in the steel:
  • Active sum Cr + 3.3 Mo + 20 C + 20 N - 0.5 Mn - 0.2 Ni,
  • the element symbol stands for the steel content of this element in% by weight.
  • the composition of the steel is therefore optimized to the highest possible effective amount within the limits that are specified by its other required material properties (strength, toughness, etc.). In these cases, a low manganese and nickel content and a high carbon and nitrogen content are preferred.
  • a typical area of use for the steel according to the invention is the production of objects which are in at least occasional contact with the human or animal body, for example glasses, watches, jewelry, implants, dental implants, metallic parts in clothing such as such as belt clasps, hooks and eyes, needles, safety pins, bed frames, railings, handles, scissors, cutlery, medical instruments such as injection needles, scalpels or other surgical instruments.
  • the surprisingly high corrosion resistance, strength and toughness of the steel according to the invention also opens up areas of application in which low nickel plays little or no role. It is used, for example, in civil engineering, for example for the production of reinforcing iron for reinforced concrete, fastening elements such as screws, bolts, rivets, nails, dowels or ropes, anchoring elements, hinges, rock anchors, load-bearing structures, facade elements, decorative elements or as prestressing steel, for example in the form of rods, wires or strands. It is also used as a material for the manufacture of technical apparatus, for example apparatus or pipelines in oil and gas exploration and production, in the associated marine engineering (ocean engineering) as well as in shipbuilding, or in petrochemicals.
  • the steel according to the invention is also used as a metallic binder phase of hard materials in hard material sintered parts.
  • the steel according to the invention is produced and / or shaped to the desired workpiece using known methods of steel production, for example by pressure-free melting, electro-slag remelting, pressure-electro-slag remelting, casting of the melt, forging, hot and / or cold working, powder metallurgy, for example pressing and sintering or powder - injection molding, both of which are possible with a powder of a uniform composition according to the invention or according to the known master-alloy technique, or, if appropriate, with subsequent embroidery of a nitrogen-free or low-nitrogen master alloy, provided that the melting and powder metallurgical processes mentioned were not carried out under sufficient nitrogen partial pressure.
  • known methods of steel production for example by pressure-free melting, electro-slag remelting, pressure-electro-slag remelting, casting of the melt, forging, hot and / or cold working, powder metallurgy, for example pressing and sintering or powder - injection molding, both of which are possible with a
  • a preferred method for producing objects made from the steel according to the invention is powder metallurgy.
  • a powder of the steel according to the invention or a nitrogen-free or nitrogen-poor master alloy is brought into a mold, for example by pressing, removed from the mold and sintered.
  • the required nitrogen content is adjusted by embroidery.
  • the constituents of the steel or its precursor can be in the form of a powdery mixture of the alloy elements or as a mixture of different alloys and / or pure elements, from which an alloy of the desired gross composition is formed by diffusion according to the “master alloy” technique during the sintering process
  • a mixture of pure iron powder and an alloy powder which contains the other alloy elements and optionally also iron can be used.
  • the steel powder, a nitrogen-free or nitrogen-poorer precursor is mixed with a thermoplastic, which is usually called "binder” in powder injection molding technology, and, if appropriate, other auxiliaries, so that a thermoplastic injection molding compound (“feedstock”) is formed overall.
  • thermoplastic injection molding compound is injection molded into a mold using the injection molding technology known from the processing of thermoplastic plastics, from which the injection molded body ⁇ tt H 1 1- »oooo
  • b2) 0 to 50% by weight of a polymer which is immiscible with b1) and which can be removed thermally without residue, or a mixture of such polymers
  • thermoplastic binder of powder a as thermoplastic binder of powder a
  • the polyoxymethylene mono- and copolymers and their preparation are known to the person skilled in the art and are described in the literature.
  • the homopolymers are usually prepared by polymerization (mostly catalyzed polymerization) of formaldehyde or trioxane.
  • a cyclic ether or a plurality of cyclic ethers is or are conveniently used as comonomer together with formaldehyde and / or trioxane in the polymerization, so that the polyoxymethylene chain with its sequence of (-OCH) units is interrupted by units in which more than one carbon atom is arranged between two oxygen atoms.
  • cyclic ethers suitable as comonomers are ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, 1,3-dioxane, 1,3-dioxolane, dioxepane, linear oligo- and polyformals such as polydioxolane or polydioxepane and oximeethylene terpolymers.
  • Suitable components b2) are in principle polymers which are not miscible with the polyoxymethylene homo- or polymer bl). Such polymers and their preparation are known to the person skilled in the art and are described in the literature.
  • Preferred polymers of this type are polyolefins, vinyl aromatic polymers, polymers of vinyl esters of aliphatic O - C 8 carboxylic acids, polymers of vinyl alkyl ethers with 1 to 8 C atoms in the alkyl group or polymers of methacrylic acid esters with at least 70% by weight of units which are derived from methacrylic acid esters or their mixtures.
  • Suitable polyolefins are, for example, polymers of olefins having 2 to 8 carbon atoms, in particular 2, 3 or 4 carbon atoms, and copolymers thereof. Polyethylene and polypropylene and their copolymers are particularly preferred. Polymers of this type are mass-produced products, widely used commercial goods and are therefore known to the person skilled in the art.
  • Suitable vinyl aromatic polymers are, for example, polystyrene and poly- ⁇ -methylstyrene and their copolymers with up to 30% by weight of comonomers from the group of acrylics. acid esters and acrylic or methacrylonitrile. Such polymers are also common commercial goods.
  • Suitable polymers of vinyl esters of aliphatic Ci-C ⁇ -carboxylic acids are, for example, polyvinyl acetate or polyvinyl propionate
  • suitable polymers of Ci-Cg-vinyl alkyl ethers are, for example, polyvinyl methyl ether or polyvinyl ethyl ether.
  • copolymers are, for example, at least 70 wt -.% Methacrylic acid esters of C 1 -C 1 4 alcohols, -methycrylat in particular methyl, and / or Ethyl methacrylate, used as monomer units.
  • Other comonomers which can be used are, for example, 0-30% by weight, preferably 0-20% by weight, of acrylic acid esters, preferably methyl acrylate and / or ethyl acrylate.
  • Component c) is a dispersing aid.
  • Dispersing aids are widespread and known to the person skilled in the art. In general, any dispersing aid can be used which leads to the improvement of the homogeneity of the injection molding compound.
  • Preferred dispersing agents are oligomeric polyethylene oxide with an average molecular weight of 200 to 400, stearic acid, hydroxystearic acid, fatty alcohols, fatty alcohol sulfonates and block copolymers of ethylene and propylene oxide. A mixture of different substances with dispersing properties can also be used as the dispersing aid.
  • the metal powder - in the powder injection molding process after prior mixing with the thermoplastic binder and possibly with the auxiliary materials - is brought into a mold with a shaping tool, for example a press, which comes as close as possible to its desired geometric final shape to avoid any time-consuming finishing of the finished sintered molded part.
  • a shaping tool for example a press
  • sintering causes the workpieces to shrink, which is usually compensated for by correspondingly larger dimensioning of the molded parts before sintering.
  • the powder injection molding feedstocks are shaped in a conventional manner using conventional injection molding machines.
  • the moldings are freed from the thermoplastic powder injection molding binder ("debinding") in the usual way, for example by pyrolysis.
  • the binder is preferably removed catalytically from the preferred injection molding composition according to the invention by the green compacts in a known manner with an atmosphere containing a gaseous acid This atmosphere is created by vaporizing an acid with sufficient vapor pressure, conveniently by passing a carrier gas, particularly nitrogen, through a storage vessel containing an acid. partially nitric acid, and then introducing the acidic gas into the debinding furnace.
  • the optimal acid concentration in the debinding furnace depends on the desired steel composition and the dimensions of the workpiece and is determined in individual cases through routine tests.
  • thermoplastic binder and / or auxiliary materials are pyrolyzed during heating to the sintering temperature and thereby completely removed.
  • the shaping is sintered in a sintering furnace to form the sintered molded part and, if a nitrogen-free or low-nitrogen precursor of the steel according to the invention was used, the desired nitrogen content is adjusted by nitriding.
  • the optimal composition of the furnace atmosphere for sintering and optionally nitriding and the optimal temperature control depend on the exact chemical composition of the steel used or to be produced or its precursor, in particular its nitrogen solubility, and on the grain size of the powder used. In general, both the increase in nitrogen partial pressure in the furnace atmosphere and the drop in temperature are directly correlated with higher nitrogen levels in the steel. However, since the lowering of the temperature not only slows down the sintering process itself, but also the diffusion rate of the nitrogen in the steel decreases, the sintering and / or nitridation process takes correspondingly longer at a lower temperature.
  • Nitrogen partial pressures in the furnace atmosphere of at least 0.1, preferably at least 0.25 bar are usually used. This nitrogen partial pressure is generally at most 2 bar, preferably at most 1 bar.
  • the furnace atmosphere can consist of pure nitrogen or inert gases such as argon and / or contain reactive gases such as hydrogen. It is usually advantageous to use a mixture of nitrogen and hydrogen as the furnace atmosphere in order to remove any interfering oxidic impurities in the metals.
  • the proportion of hydrogen, if present, is generally at least 5% by volume, preferably at least 15% by volume, and generally at most 50% by volume, preferably at most 30% by volume. If desired, this furnace atmosphere can also contain inert gases, for example argon.
  • the oven atmosphere should preferably be largely dry, generally a dew point of - 40 ° C is sufficient.
  • the (absolute) pressure in the sintering and / or nitridation furnace is usually at least 100 mbar, preferably at least 250 mbar. It is also generally at most 2.5 bar, preferably at most 2 bar. In a particularly preferred manner, work is carried out at normal pressure.
  • the sintering and / or nitriding temperature is generally at least 1000 ° C., preferably at least 1050 ° C. and in a particularly preferred manner at least 1100 ° C. Furthermore, it is generally at most 1450 ° C., preferably at most 1400 ° C. and in a particularly preferred manner at most 1350 ° C.
  • the temperature can be varied during the sintering and / or nitriding process, for example in order to completely or largely densely sinter the workpiece only at a higher temperature and then to set the desired nitrogen content at a lower temperature.
  • the optimal heating rates are easily determined by a few routine tests, usually they are at least 1 ° C. per minute, preferably at least 2 ° C. per minute and in a particularly preferred manner at least 3 ° C. per minute.
  • the highest possible heating rate is generally sought in order to avoid a negative influence on the quality of the sintering and / or nitridation, but a heating rate below 20 ° C. per minute will usually have to be set.
  • a waiting time at a temperature which is below the sintering and / or nitriding temperature during heating to the sintering and / or nitriding temperature, for example over a period of 30 minutes to two hours, for example one hour to maintain a temperature in the range of 500 ° C to 700 ° C, for example 600 ° C.
  • An austenitic steel consisting of 20% by weight chromium
  • An austenitic steel consisting of 21% by weight of chromium, 8.5% by weight of manganese, 0.55% by weight of nitrogen, 0.15% by weight of carbon, 0.2% by weight of silicon, the rest being iron and unavoidable impurities, was produced by melting in a vacuum induction furnace, pouring into molds, homogenizing, forging, solution annealing and quenching at 1100 ° C. Its yield strength was 610 MPa, its impact strength was 250 J, and its pitting potential in 22% sodium chloride solution at 23 ° C was 1260 mV.
  • the examples show that the steel according to the invention exceeds the corrosion resistance and strength of typical stainless steels and, with a much higher corrosion resistance, also the strength of low-alloy or unalloyed, non-stainless steels.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Manufacturing & Machinery (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Powder Metallurgy (AREA)

Abstract

L'invention concerne un acier austénitique à faible teneur en nickel, contenant du fer et les constituants suivants: moins de 9,0 % en poids de manganèse ; au minimum 16 % en poids et au maximum 22 % en poids de chrome ; plus de 0,30 % en poids et au maximum 0,70 % en poids d'azote ; plus de 0,08 % en poids et au maximum 0,30 % en poids de carbone ; et moins de 2,0 % en poids de silicium. L'invention concerne également la production et l'utilisation de cet acier.
EP00935127A 1999-06-24 2000-05-26 Acier austenitique a faible teneur en nickel Withdrawn EP1194605A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CH117299 1999-06-24
CH991172 1999-06-24
PCT/EP2000/004823 WO2001000897A1 (fr) 1999-06-24 2000-05-26 Acier austenitique a faible teneur en nickel

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EP1194605A1 true EP1194605A1 (fr) 2002-04-10

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US (1) US6682582B1 (fr)
EP (1) EP1194605A1 (fr)
JP (1) JP3798317B2 (fr)
CN (2) CN1495281A (fr)
AU (1) AU5072400A (fr)
WO (1) WO2001000897A1 (fr)

Families Citing this family (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2819526B1 (fr) * 2001-01-15 2003-09-26 Inst Francais Du Petrole Utilisation d'aciers inoxydables austenitiques dans des applications necessitant des proprietes anti-cokage
JP4538966B2 (ja) 2001-02-05 2010-09-08 大同特殊鋼株式会社 高強度高耐食非磁性ステンレス鋼
ITBS20020064A1 (it) * 2002-07-16 2004-01-16 Genesis S R L Metodo e sistema per il controllo remoto di apparecchiature
ATE413579T1 (de) * 2005-04-26 2008-11-15 Umarex Gmbh & Co Kg Verfahren zur herstellung eines verschlussschlittens einer schusswaffe
DE102005028099B3 (de) * 2005-06-16 2007-03-15 Hugo Kern Und Liebers Gmbh & Co. Kg Platinen- Und Federnfabrik Verfahren zum Herstellen von Nadeln für Textilmaschinen sowie danach hergestellte Nadeln
JP5223046B2 (ja) * 2005-11-02 2013-06-26 国立大学法人九州大学 生体用高窒素ニッケルフリーオーステナイト系ステンレス鋼の結晶粒微細化熱処理方法
JP4915202B2 (ja) * 2005-11-03 2012-04-11 大同特殊鋼株式会社 高窒素オーステナイト系ステンレス鋼
JP2007248397A (ja) * 2006-03-17 2007-09-27 Seiko Epson Corp 装飾品および時計
KR20080027171A (ko) * 2006-09-22 2008-03-26 세이코 엡슨 가부시키가이샤 소결체의 제조방법 및 소결체
JP5212602B2 (ja) * 2007-09-14 2013-06-19 セイコーエプソン株式会社 機器およびハウジング材の製造方法
US8182963B2 (en) * 2009-07-10 2012-05-22 GM Global Technology Operations LLC Low-cost manganese-stabilized austenitic stainless steel alloys, bipolar plates comprising the alloys, and fuel cell systems comprising the bipolar plates
US20110226391A1 (en) * 2009-07-13 2011-09-22 Korea Institute Of Machinery And Materials C+n austenitic stainless steel having high strength and excellent corrosion resistance, and fabrication method thereof
RU2553794C2 (ru) * 2009-10-16 2015-06-20 Хеганес Актиеболаг (Пабл) Азотсодержащая, низконикелевая спеченная нержавеющая сталь
CN102454688A (zh) * 2010-10-20 2012-05-16 新日兴股份有限公司 枢纽器以及具备该枢纽器的电子装置
JP5264867B2 (ja) * 2010-11-19 2013-08-14 新日興股▲分▼有限公司 ヒンジ素子及びそれを使った電子装置
JPWO2012070659A1 (ja) * 2010-11-26 2014-05-19 独立行政法人物質・材料研究機構 ニッケルフリーステンレス製ステント
EP2617839A1 (fr) * 2012-01-18 2013-07-24 MeKo Laserstrahl-Materialbearbeitungen e.K. Alliage de fer sans nickel pour stents
JP5789342B2 (ja) * 2012-01-31 2015-10-07 コリア インスティチュート オブ マシーナリー アンド マテリアルズ 優れた耐孔食性を有する高機能性高窒素２相ステンレス鋼
UA111115C2 (uk) 2012-04-02 2016-03-25 Ейкей Стіл Пропертіс, Інк. Рентабельна феритна нержавіюча сталь
EP2676685A1 (fr) * 2012-06-18 2013-12-25 Biotronik AG Stent en alliage de fer
CN103317125B (zh) * 2013-06-24 2016-03-30 上海大学 通过控制凝固过程制备亚稳相工程材料的方法
CH708231B1 (fr) 2013-06-27 2017-03-15 Nivarox Far Sa Ressort d'horlogerie en acier inoxydable austénitique.
EP2924514B1 (fr) 2014-03-24 2017-09-13 Nivarox-FAR S.A. Ressort d'horlogerie en acier inoxydable austénitique
CN104018083B (zh) * 2014-06-20 2016-01-06 重庆材料研究院有限公司 含氮不锈轴承钢及制备方法
CN112218528B (zh) 2018-03-16 2022-10-21 诺埃尔·埃尔曼 物质可控的释放的装置
CN110241380B (zh) * 2019-06-02 2021-06-29 深圳市百利鑫工业材料有限公司 一种医用无镍不锈钢的处理工艺
CN112281049A (zh) * 2020-11-23 2021-01-29 浙江宝武钢铁有限公司 一种无磁高氮不锈钢的制备方法

Family Cites Families (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE266900C (fr)
DE858568C (de) 1940-08-20 1952-12-08 Boehler & Co Ag Geb Gegen interkristalline Korrosion bestaendige Chrom-Mangan-Staehle und ihre Herstellung
US2764481A (en) 1954-09-20 1956-09-25 Allegheny Ludlum Steel Iron base austenitic alloys
US4116683A (en) * 1973-04-11 1978-09-26 Institute Po Metaloznanie I Technologia Na Metalite Nickel-free austenitic corrosion-resistant steel
US4217136A (en) 1974-05-01 1980-08-12 Allegheny Ludlum Steel Corporation Corrosion resistant austenitic stainless steel
US3943010A (en) 1974-06-12 1976-03-09 Allegheny Ludlum Industries, Inc. Process for producing austenitic ferrous alloys
JPH02156046A (ja) * 1988-12-07 1990-06-15 Nippon Steel Corp 高強度ステンレス鋼およびその製造方法
US4946644A (en) * 1989-03-03 1990-08-07 Baltimore Specialty Steels Corporation Austenitic stainless steel with improved castability
DE4023462C1 (fr) 1989-10-12 1991-07-04 Vereinigte Schmiedewerke Gmbh, 4630 Bochum, De
DE3940438C1 (fr) 1989-12-07 1991-05-23 Vereinigte Schmiedewerke Gmbh, 4630 Bochum, De
DE4007345A1 (de) 1990-03-08 1991-09-12 Basf Ag Thermoplastische massen fuer die herstellung metallischer formkoerper
DE4021739A1 (de) 1990-07-07 1992-01-09 Basf Ag Thermoplastische massen fuer die herstellung metallischer formkoerper
US5175900A (en) 1991-06-24 1993-01-05 Areway, Inc. Automatic index rotary buffing apparatus
AT397968B (de) 1992-07-07 1994-08-25 Boehler Ybbstalwerke Korrosionsbeständige legierung zur verwendung als werkstoff für in berührungskontakt mit lebewesen stehende teile
DE19513407C1 (de) 1995-04-08 1996-10-10 Vsg En & Schmiedetechnik Gmbh Verwendung einer austenitischen Stahllegierung für hautverträgliche Gegenstände
DE19607828C2 (de) 1995-04-15 2003-06-18 Vsg En Und Schmiedetechnik Gmb Verfahren zum Herstellen eines austenitischen Cv-Mn-Stahls
DE19614006A1 (de) 1996-04-09 1997-10-16 Basf Ag Verfahren zur Herstellung von Granulat und Formteilen aus Hartmetall- oder Cermet-Materialien
ES2150813T3 (es) 1997-04-29 2000-12-01 Bohler Edelstahl Gmbh & Co Kg Empleo de una aleacion biocompatible y tolerable por la piel.
FR2766843B1 (fr) * 1997-07-29 1999-09-03 Usinor Acier inoxydable austenitique comportant une tres faible teneur en nickel
US5848350A (en) * 1997-10-31 1998-12-08 Flomet, Inc. Nickel-free stainless steel alloy processible through metal injection molding techniques to produce articles intended for use in contact with the human body
EP0964071A1 (fr) * 1998-06-12 1999-12-15 Asulab S.A. Acier inoxydable ferritique et pièce extérieure d'habillement pour montre réalisée en un tel acier

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0100897A1 *

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Publication number Publication date
JP2003503595A (ja) 2003-01-28
US6682582B1 (en) 2004-01-27
CN1495281A (zh) 2004-05-12
CN1373815A (zh) 2002-10-09
CN1144894C (zh) 2004-04-07
WO2001000897A1 (fr) 2001-01-04
AU5072400A (en) 2001-01-31
JP3798317B2 (ja) 2006-07-19

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