EP3801950A1 - Verfahren zum herstellen eines gegenstandes aus einem warmarbeitsstahl - Google Patents
Verfahren zum herstellen eines gegenstandes aus einem warmarbeitsstahlInfo
- Publication number
- EP3801950A1 EP3801950A1 EP19729227.9A EP19729227A EP3801950A1 EP 3801950 A1 EP3801950 A1 EP 3801950A1 EP 19729227 A EP19729227 A EP 19729227A EP 3801950 A1 EP3801950 A1 EP 3801950A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- powder
- article
- hot work
- steel
- preheating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
- B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
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- 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
- B22F1/14—Treatment of metallic powder
- B22F1/142—Thermal or thermo-mechanical treatment
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- 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
- B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
- B22F10/20—Direct sintering or melting
- B22F10/28—Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
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- 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
- B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
- B22F10/30—Process control
- B22F10/32—Process control of the atmosphere, e.g. composition or pressure in a building chamber
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- 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
- B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
- B22F10/30—Process control
- B22F10/36—Process control of energy beam parameters
- B22F10/368—Temperature or temperature gradient, e.g. temperature of the melt pool
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- 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
- B22F12/00—Apparatus or devices specially adapted for additive manufacturing; Auxiliary means for additive manufacturing; Combinations of additive manufacturing apparatus or devices with other processing apparatus or devices
- B22F12/10—Auxiliary heating means
- B22F12/17—Auxiliary heating means to heat the build chamber or platform
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y40/00—Auxiliary operations or equipment, e.g. for material handling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y40/00—Auxiliary operations or equipment, e.g. for material handling
- B33Y40/10—Pre-treatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y70/00—Materials specially adapted for additive manufacturing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y80/00—Products made by additive manufacturing
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- 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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- 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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- 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
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- 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
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- 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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
- B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
- B22F2009/0824—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid with a specific atomising fluid
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
- B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
- B22F2009/0848—Melting process before atomisation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
- B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
- B22F2009/086—Cooling after atomisation
- B22F2009/0876—Cooling after atomisation by gas
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- 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
- B22F2202/00—Treatment under specific physical conditions
- B22F2202/07—Treatment under specific physical conditions by induction
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- 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
Definitions
- the invention relates to a method for producing an article from a heat treated steel and the article, which is produced by the method.
- the invention relates to the manufacture of hot work tool articles made in additive manufacturing processes such as selective laser melting.
- the steels commonly used for this purpose are so-called maraging steels, where the hardening effect is not based on a carbidic hardening. This is partly because it is known that steels with a carbon content of more than 0.22% are thermally difficult to process and in particular are difficult to weld. In order to make available steel powder for such processes for broad applications and for broad user circles, corresponding maraging steels with a carbon content significantly below 0.22% have been sprayed so that they are easy to process.
- CEV carbon equivalent
- the carbon equivalent is a measure in material science for assessing the weldability of unalloyed and low-alloy steels.
- the carbon content and a variety of other alloying elements in the steel affect its behavior.
- a value of the carbon equivalent of less than 0.45% implies a ball-welding suitability, higher values require, in particular also depending on the thickness of the workpiece, the preheating of the material. From a value greater than 0.65%, the workpiece is suitable for welding only with increased effort, since it can lead to cold or hardening cracks due to martensite formation.
- CEV carbon equivalent
- the object of the invention is to provide a method with which even more reliable and predictable the properties of a verprintten hot-work steel can be achieved.
- the combination of the pressure parameters and the preheating temperature is decisive for a microcrack-free structure, the achievable porosity or density property and the number and size of the non-metallic inclusions (oxides) in the microstructure. These properties can no longer be influenced by the subsequent heat treatment. However, these properties are very important for the mechanical properties, such as strength, toughness and fatigue, which arise after the heat treatment.
- a product produced after preheating and suppression has a high residual austenite content and, secondly, a lack of tempering resistance. This makes the preheated and printed products unsuitable for use.
- the additively manufactured workpiece is hardened after being finished and subsequently tempered several times. It has been found that the additively produced articles have a shorter holding time during curing as well as during the tempering treatments. Thus, additively manufactured products also have an advantage over conventionally manufactured products.
- the tempering times are dependent on the dimensions, with the rule that one minute per millimeter of wall thickness is required for the heating times.
- a steel has proven, which has the following contents in wt.%:
- Si is a mixed crystal hardener and not a carbide-forming element, but it influences the carbide precipitation kinetics in the steel. It stabilizes the carbon so that it is only available at higher temperatures for the formation of carbides.
- Si serves as a deoxidizer and is therefore present in low concentrations in virtually all steels due to its production. It increases scaling resistance, yield strength and tensile strength without significantly reducing elongation.
- a decrease of the Si content leads to the reduction of the anisotropy of the mechanical properties.
- Low Si content enables the initial formation of metastable M3C carbides. These act like a C reservoir for the subsequent elimination of the desired MC carbides. It also suppresses the formation of unwanted M23C7 carbides at the grain boundaries.
- Mn expands and stabilizes the austenite region and thus suppresses the beginning of the bai- nitic transformation.
- the Bs temperature (bainite start temperature) is shifted to lower temperatures.
- the formation of martensite is thereby shifted to lower temperatures, which already causes a large amount of retained austenite when water quenched (Restaustent is uerwünscht). It promotes martensite formation at the grain boundaries, as it segregates intercellularly (in the grain) during solidification.
- Si it is a strong deoxidizer and one of the cheapest and most effective alloying elements in terms of hardenability and through-hardening.
- the critical cooling rate by adding Mn
- the hardening depth is increased. All- Higher concentrations lead to the reduction of thermal conductivity and, in interaction with sulfur [S] or oxygen (0), the formation of unwanted non-metallic inclusions (MnS - MnO).
- Mo forms special carbides and on the other hand with Fe mixed carbides. These are of the type M2C, M6C and MC. Addition of Mo increases the activation energy for C diffusion in the austenite and thus lowers the diffusion coefficient for C or C diffusion. This leads to lower Bs temperature and reduced bainite formation. On the other hand, addition of Mo results in refinement of the microstructure, ie, regardless of the cooling rate (1 ° C / s to 60 ° C / s), a fine texture is predominant. The grain coarsening remains low because of the low dissolution rate and the high solution temperature of the carbides (carbides counteract grain coarsening).
- austenitizing solution annealing
- improved tempering resistance can be achieved, as more carbide-forming elements can be precipitated and thereby more carbides are formed.
- the hard carbides also increase the hot-stretch limit and wear resistance.
- Mo improves the scale resistance of the steel. Too high contents will degrade the machinability and, in case it remains dissolved in the matrix, the thermal conductivity. It could also happen that embrittlement occurs when tempering due to the former austenitic grain being contaminated with carbides.
- Vanadium is one of the strongest carbide-forming elements besides Nb and Ti because of its high affinity to C. It forms fine and uniformly distributed precipitates of type MC during tempering. These are preferred because of their higher thermal resistance compared to other carbide grades. This leads to an increase in the heat resistance, increase of the yield strength, the wear resistance and improvement of the tempering resistance. However, at higher concentrations, a higher cure temperature is required to dissolve the thermally stable primary MC carbides. In hot working bars, only up to a maximum of 1% is added.
- the remelted electrodes are then forged or rolled in order to convert the cast structure into a deformation structure or to achieve the desired final dimensions.
- the steel is annealed to ensure the machinability of the customer.
- the steel is tempered after mechanical processing.
- the production of a powder which is suitable for additive manufacturing differs in that the steel material is atomized by inert gas atomization, in particular by the VIGA (Vacuum Induction Gas Automization) process.
- the melting of the feedstock takes place in the vacuum induction furnace, whereby due to the manganese content, the melting below Argon protective gas atmosphere takes place.
- the actual atomization process takes place with the aid of very high gas pressure.
- the crucible is tilted, in which the melt is, whereby the liquid melt flows into a Tundisch / distributor and from an opening at the bottom of this vessel, the liquid metal flows into a nozzle.
- the nozzle atomizes the molten metal into fine, small, about 1 to about 500 pm large metal particles, which undergo a sudden cooling and are present as Pu Iveragg lomerat after atomization.
- Argon or nitrogen can be used as the atomizing gas. Of particular importance here are the nozzle diameter, the pressure and the melting temperature.
- the inventive material when using the inventive material is advantageous that due to the high carbon content, the melting temperature is lower than in known steel used raw materials. As a result, the material is easier or better verdüsbar than, for example, a maraging steel.
- the resulting powder after atomization, will consist of particles of various sizes.
- the size of the powder particles or the particle size distribution of a particular fraction is adjusted.
- the desired particle size corresponds, for example, to 15-45 ⁇ m. This makes it necessary to screen or classify the powder in different powder fractions. This can be done, for example, by sifting or sifting.
- the powder thus obtained is placed in a preheated installation space and, if appropriate, also preheated, on the one hand the preheating temperature being high enough to produce a defect and, on the other hand, not being so high as to cause agglomeration and oxidation, because then the residual powder would not be usable after the creation of the component.
- Important print parameters are the laser power or the energy introduced per volume, the scan speed, the layer height, the line spacing, the focus diameter and the volume energy density during printing.
- the currently used tools which are manufactured additively, in particular for diecasting applications, are based on the material 1.2709, which can be printed very well due to the lack of carbon.
- the lack of carbon due to the lack of carbon, no carbon martensite is formed, but a nickel martensite, which is definitely worse than the carbon martensite at cyclic loads.
- According to the invention can by the Use of the carbon-richer, inventive material improved fatigue strength and longer life of die casting tools can be achieved.
- the material used in the invention is not melted in air and atomized in water, but melted under an argon atmosphere and preferably atomized with argon. This, as well as the exact tuning of the parameters already mentioned, and in particular the high carbon content, which ensures the good digestibility, create a superior product.
- Figure 1 shows the melt metallurgical production route of a hot work tool steel
- FIG. 2 shows the heat treatment route for printed material in contrast to melt-cast material
- FIG. 3 Hardness and impact energy
- Figure 5 is a porosity analysis in a light microscope
- FIG. 6 shows the porosity under the light microscope at different preheat temperatures
- FIG. 9 shows the scanning electron microscopic analysis of the microcracks in the microstructure in submerged preheaters.
- a hot-work steel material in particular having a chemical composition in% by weight of:
- Molybdenum 2.8 to 3.3
- Vanadium 0.41 to 0.69
- a steel material is used, which is sold by the company voestalpine Böhler Titan GmbH & Co. KG under the trade name W360.
- a material is used whose carbon content is 0.5% by weight, its silicon content is 0.2%, its manganese content is 0.25%, its chromium content is 4.5% and its molybdenum content is 3% and its vanadium content is 0.55%. equivalent.
- This material is conventionally melted, subjected to a secondary metallurgy and then cast in increasing block casting. Subsequently, the material is remelted as already described.
- the powder production or atomization of the material takes place, wherein the batch material is melted in the vacuum induction furnace and in this case is molten in a crucible.
- the melting takes place advantageously under a protective gas atmosphere and in particular under an argon atmosphere.
- the molten material is poured into a tundish / distributor which has an outlet at the bottom from which the liquid metal flows into a nozzle.
- the nozzle atomises the molten material into very fine metal particles, which undergo a sudden cooling and are then present as a powder agglomerate.
- Inert gases or noble gases and nitrogen can also be used as the atomizing gas.
- argon is used.
- the powder thus produced consists of particles of various sizes, with particulate matter in particular kel supportingnverotti of 15 to 45 miti is sought. To reach this fraction, the powder is either sieved or sifted.
- both the preheating temperature and the printing parameters and in particular the laser power or introduced energy, the scanning speed, the layer height of the powder bed, the line spacing, the focus diameter and the volume energy density are important parameters for the printing.
- the powder was printed on a system by the company Concept Laser, whereby the construction chamber was flooded with nitrogen.
- the preheating temperature be 230 ° C and 500 ° C, wherein the energy volume density of the laser EVD is 97.9 joules per mm 3.
- the powder is printed on a Renishaw plant, whereby the space chamber is flooded with argon and the preheating temperature is 400 ° C.
- the energy volume density EVD is 67.5 joules per mm 3 .
- microstructure is as microfine as possible with defined porosity or density properties and with the lowest possible number and size of non-metallic inclusions. These properties can no longer be influenced by the heat treatment, but are decisive for the mechanical properties that arise after the heat treatment.
- Figure 2 this corresponding heat treatment is shown.
- the heat treatment cycle of the printed material, but also for cast material, consists of hardening with subsequent repeated tempering,
- the holding time on the hardening temperature of the additive manufactured material in contrast to the holding time of potted material in half, so in about 15 instead of 30 minutes can be reduced.
- the printed material is also less sensitive during tempering, so that the holding time at tempering temperature can be reduced by 25% compared to cast material.
- the tempering times are basically dimension-dependent, whereby for the heating-up times, one minute of time must be invested per mm of wall thickness.
- Samples 1 and 2 were held at 1050 ° C for 15 minutes and then quenched in oil.
- Tempering was at 570 ° C for two and a half hours to the target hardness of 55-57 HRC.
- FIG. 4 shows the results of the tensile tests.
- the tensile strengths Rm and the yield strength Rp02 at about 2000 and 1600 MPa, respectively are at the same high level.
- the elongation at break (A5) and the fracture constriction (Z) are somewhat higher at a preheating temperature of 400 ° C than at 230 ° C.
- the tensile specimens at preheating temperatures of 230 and 400 ° C have a hardness of approx. 56 hrc, whereby no tensile tests were carried out at preheating temperatures of 500 ° C.
- FIG. 5 shows the results of the porosity analysis in a light microscope. This porosity measurement was carried out at three different magnifications and different numbers of measurement images on a light microscope. The lowest porosity level is achieved in all measurements with a preheat of 400 ° C. Here, a relative density of over 99.9% can be achieved. At a preheating temperature of 230 ° C, the difference between the construction directions XY (x50 relative density less than 99.7%) and X-Z (x50 relative density greater than 99.8%) is striking. In general, relative density values above 99.5% are good industry standards.
- the size and the shape of the pores are important for the achievable mechanical properties.
- evenly distributed small pores have advantages over unevenly distributed larger pores, in particular pores, which may not be ideally round or spherical.
- FIG. 6 shows the porosity in a light microscope. At a preheating temperature of 230 ° C shows that the pore shape and size are very different, which are also distributed unevenly. It comes to accumulations and binding errors.
- preheating temperature of 400 ° C small round pores and a homogeneous distribution and no binding errors are achieved.
- a preheating temperature of 500 ° C round pores are achieved, but they are very large and are not homogeneously distributed.
- preheating of about 400 ° C is advantageous.
- Figure 7 shows the electron microscopic analysis of the distribution of non-metallic inclusions.
- the summed pore area fraction as well as the oxide area fraction is lowest at 400 ° C preheat temperature.
- the non-metallic inclusions are predominantly silicon dioxide inclusions, with the highest oxide surface area generally present at the preheat temperature of 500 ° C. As the temperature rises, so does the tendency to oxidation.
- Both the pores and the oxides are defects that generally reduce the fatigue strength or mechanical cyclic properties of the material. In this respect, the size and distribution of the NME or oxides for the fatigue strength are significant.
- FIG. 8 shows the size, shape and distribution of the pores or energy in the scanning electron microscopic analysis on a defined surface.
- a preheating temperature of 230 ° C you can see many small round pores or large binding defects with different shape and pore accumulation.
- Many non-metallic inclusions have a wide broad distribution spectrum, resulting in an inhomogeneous error distribution pattern.
- 400 ° C there are many small round pores and only smaller, non-metallic inclusions that are evenly distributed. In total, this results in the most homogeneous error distribution image.
- the picture changes so much that the number of pores still decreases compared to 400 ° C, as well as the number of non-metallic inclusions, however, the frequency of large defects is high, so that the total surface area is highest.
- FIG. 9 shows the scanning electron microscopic microcrack analysis at the given preheating temperatures. It turns out that the microcracking frequency decreases with increasing preheating temperature, but microcracks are present at all temperatures.
- the W360 or related steels can only be printed with macrocracking pressure above a preheating temperature of more than 200 ° C. Im mistaken Condition, the material has a high content of retained austenite and on the other hand no tempering resistance, which makes a subsequent heat treatment favorable. Due to the very small cut-out area of the laser beam and the extremely fast quenching, the material after printing is in a state with a very fine microstructure, which means short diffusion paths for the subsequent thermal treatment. For this reason, the holding times can be shortened compared to molten material.
- preheating temperatures are usefully set from 200 ° C to 400 ° C.
- preheating temperatures 200 to 260 ° C can be sufficient.
- temperatures of 350 to 450 ° C., in particular 380 to 420 ° C. and in particular 390 to 410 ° C. are favorable.
- the introduced energy is preferably adjusted to 50 to 100 joules per mm 3 , wherein at temperatures of preheating of 400 ° C 50 to 70 Joule per mm 3 can be ben NEN and at lower preheating temperatures by 200 ° C 70 to 100 joules per mm 3 can be useful. In this respect, a higher laser energy is desired at a lower preheating temperature.
- Curing is carried out at temperatures above Ac 3 , the temperatures always being in the range from 990 to 1100 ° C. After achieving the soak, this temperature is not kept below 15 minutes and not over 25 minutes.
- Subsequent tempering takes place at least twice at a minimum of 500 ° C or a maximum of 630 ° C.
- tempering may also take place twice for two hours or three times for one hour. Otherwise it can also be started twice for 1.5 hours.
- the mechanical properties of printed hot-work tool steels can be set very well and comprehensibly and repeatedly, the thermal-cyclic properties being comparable to conventionally printed maraging steels with comparable impact energy and hardness significantly better in terms of cyclical loads.
- the printed materials manage as a comparatively cast material in a subsequent heat treatment.
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Abstract
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Applications Claiming Priority (2)
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DE102018113600.5A DE102018113600A1 (de) | 2018-06-07 | 2018-06-07 | Verfahren zum Herstellen eines Gegenstandes aus einem Warmarbeitsstahl |
PCT/EP2019/064381 WO2019233962A1 (de) | 2018-06-07 | 2019-06-03 | Verfahren zum herstellen eines gegenstandes aus einem warmarbeitsstahl |
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EP3801950A1 true EP3801950A1 (de) | 2021-04-14 |
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EP19729227.9A Pending EP3801950A1 (de) | 2018-06-07 | 2019-06-03 | Verfahren zum herstellen eines gegenstandes aus einem warmarbeitsstahl |
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EP (1) | EP3801950A1 (de) |
DE (1) | DE102018113600A1 (de) |
WO (1) | WO2019233962A1 (de) |
Families Citing this family (5)
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KR20210136966A (ko) * | 2019-03-14 | 2021-11-17 | 회가나에스 코오포레이션 | 프레스-및-소결 및 적층 제조를 위한 야금 조성물 |
DE102020115049A1 (de) * | 2020-06-05 | 2021-12-09 | Deutsche Edelstahlwerke Specialty Steel Gmbh & Co. Kg | Stahlmaterial zum Formen von Bauteilen durch additive Fertigung und Verwendung eines solchen Stahlmaterials |
EP4015102A1 (de) | 2020-12-16 | 2022-06-22 | voestalpine Edelstahl Deutschland GmbH | Entlüftungsvorrichtung für eine giessform zum giessen metallischer bauteile |
GB202100843D0 (en) * | 2021-01-22 | 2021-03-10 | Renishaw Plc | Laser powder bed fusion additive manufacturing methods |
CN115233101A (zh) * | 2022-07-22 | 2022-10-25 | 上海大学(浙江)高端装备基础件材料研究院 | 一种超高强度合金钢和一种18.8级螺纹紧固件及其制备方法 |
Family Cites Families (3)
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AT410447B (de) * | 2001-10-03 | 2003-04-25 | Boehler Edelstahl | Warmarbeitsstahlgegenstand |
WO2016013497A1 (ja) * | 2014-07-23 | 2016-01-28 | 株式会社日立製作所 | 合金構造体及び合金構造体の製造方法 |
CN106636977B (zh) * | 2017-02-11 | 2018-09-11 | 广州市嘉晟精密科技有限公司 | 一种免热处理预硬态塑料模具钢及其的3d打印方法 |
-
2018
- 2018-06-07 DE DE102018113600.5A patent/DE102018113600A1/de active Pending
-
2019
- 2019-06-03 EP EP19729227.9A patent/EP3801950A1/de active Pending
- 2019-06-03 WO PCT/EP2019/064381 patent/WO2019233962A1/de unknown
Also Published As
Publication number | Publication date |
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DE102018113600A1 (de) | 2019-12-12 |
WO2019233962A1 (de) | 2019-12-12 |
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