SE533988C2 - Steel material and process for making them - Google Patents

Description

25 30 35 533 988 2 longitudinal and transverse. Furthermore, high-alloy steels cannot be manufactured with good yield within the entire desired dimensional range due to manufacturing-related reasons.

The spray-formed cold working steels have smaller and rounder carbides than the conventionally manufactured ones, normally between 1 and 20 μm, which are evenly distributed in the matrix of the steel.

This manufacturing technique provides the opportunity to manufacture very high-alloy steels, such as high-speed steels, e.g. T15 and sleeve higher alloy high-speed steels, and tool steels, e.g. Weartec, with up to 15% Vanadium seen softer MqCg type chromium carbides are replaced by harder MX carbides. In this way, it has been possible to produce steel with extremely good abrasion resistance, such as the steel called Weartec mentioned above.

The spray-molded steels also show better dulctility and more homogeneous properties regardless of direction than the conventionally manufactured steels. As the solidification rate for spray-shaped materials varies between surface and center, a size gradient for the carbides is obtained from surface to center where the next carbides are found in the surface as the solidification rate there is slightly higher. There are also defects in the material caused by heat cavities and heat cracks that do not always allow themselves to swell during hot processing. The reason is that spray molding has proven to be a process that is relatively difficult to control due to many process parameters.

The powder-metallurgically manufactured steels have, thanks to the sophisticated manufacturing technology, an industrial structure that is completely homogeneous in all directions. Thanks to this and the fact that the steels receive very kar carbide particles, normally between 1 and 3 μm, an optimal combination of relatively good abrasion resistance, hardness and ductility is obtained.

By balancing the alloy compound, primarily by adding even higher levels of vanadium and possibly niobium, one can promote the formation of very hard carbides at the expense of less hard carbides. As a result, the powder metallurgical materials can also obtain extremely good abrasion resistance despite relatively relatively small carbides.

Among the conventionally produced materials, we find the standard steels AISI D2, D6 and D7, which are today used for cold working style grooves with a more or less element of abrasive wear. The nominal compositions of its known steels are given in Table 1. 20 25 533 988 3 Table 1 Conventional cold working steels - nominal compositions,% by weight C Si Mn Cr Mo WV AISID2 1.5 0.3 0.3 12.0 1.0 - 1.0 AISID6 2.1 0.3 0.8 12.5 - 1.1 - AISI D7 2.35 0.3 0.5 12.0 1.0 _ 4.0 U.S. Patent No. 6,348,109 describes a steel material that can be manufactured via spray molding. The material has been shown to have a better combination of abrasion resistance and toughness than conventional ledburitic cold working steels of type AISI D2, D6 AND D7.

Furthermore, in the US patent application publication US 2004/0094239 A1 a spray-formed steel material is described with excellent wear resistance, good corrosion resistance, hardenability and tempering resistance and adequate toughness. The steel material is primarily intended for use in plastic molding equipment, and is used there as a construction element for feeding and guiding plastic masses in machines for the manufacture of plastic components and further in mold tools and tool parts for injection molding of plastics. However, the known steel material is not limited to these application areas but can also be used for a number of other applications, where said properties are necessary or desirable, e.g. for details in pumps for feeding abrasive media and wear parts in machines and other equipment.

Among the powder metallurgically produced materials, we find the steels known under the product ranges Vanadis 4 and Vanadis 10. The nominal compositions of these steels are shown in Table 2.

Table 2 Powder metallurgically produced cold working steels - nominal compositions,% by weight, residual Fe and impurities C Si Mn Cr Mo V vanaais®4 1.5 1.0 0.4 8.0 1.5 4.0 vanadis fi io 2.9 1, 0 0.5 8.0 1.5 9.8 The above powder metallurgically manufactured steels offer extremely good combinations of nut resistance and toughness, but the powder metallurgical process is very time consuming and advanced. The document WO 03/069004 A1 describes another powder metallurgically manufactured steel material for primarily the manufacture of tools for casting electronic components in plastic. The steel material has good corrosion resistance, including good resistance to spot corrosion during spark machining and very good wear resistance. It can be hardened and tempered to a hardness of 61-64 HRC, preferably 62-63 HRC, and has very high compressive strength in hardened and tempered condition as well as good polishability and good durability stability even during prolonged use of the tool made of steel . This known steel material contains in weight% 2.2-3.3% (C + N), however at least 0.3% C and at least 0.06% N, O, 1-2.0% Si, 0.1 -2.0% Mn, 19-23% Cr, max 2.0% Ni, max 2.0% Co, 0.5-3.0% (Mo + W / 2), however max. 1.0% W, 4.2-7.5% (V + Nb / 2), however max. 0.1% Nb, max. 0.2% S, leaving essentially only iron and impurities.

The production of powder for powder metallurgy should be distinguished from the production of metal granules, where as described in e.g. US 3,888,956 and US 5,017,218 a steel melt are allowed to fall on a plate and bounce to the side to fall into a water bath, where the granules with a size of 2-25 mm are rapidly cooled. Granules produced in this way have hitherto been used as refrigerated scrap, ie. the granulate has been added to cool the melt during the steelmaking process. Furthermore, granules with different chemical compositions are produced which are then used in one-piece production of cast tools, so-called metallic molding tools, ie a small amount of the granulate is remelted and poured into a tool.

However, it has been shown that there is a desire and opportunity to further improve some of the known steel materials. Furthermore, it has been found that there is a desire for a more rational, more robust, simpler, more reliable and / or cheaper process for the production of steel materials than the currently known techniques of spray molding and powder metallurgical production. Above all, there is a desire to be able to mass-produce large volumes of steel materials which can be used in mass production of larger parts for which the advanced manufacturing methods with spray molding and powder metallurgy do not constitute a possible alternative for cost reasons.

BRIEF SUMMARY OF THE INVENTION An object of the present invention is to provide a process for producing a new family of steel materials with a more homogeneous hard phase distribution alternatively with a more homogeneous distribution of scalability-enhanced particles, than the hot casting material and , more robust, simpler, more reliable and / or cheaper than the currently potential technology of spray formation or powder metallurgical fi-anist setting. This object is achieved in that the method according to the present invention comprises the following steps: 'producing a steel malt, granulating the melt by allowing a jet of the melt to hit an impact element and splitting into droplets which may fall into a tank containing a kyhnedium, so that they are rapidly cooled to granules with a till shaped to round shape and a size of from 0.5 mm to 30 mm, preferably a size of from 1 mm to 10 mm, filling a capsule with formed rapidly cooled granules, and hetisostatic compaction or heat extrusion of the capsule with the granulate into an at least near completely dense body.

It is also an object of the invention to provide a durable steel material with a more homogeneous hard phase distribution than the cast and hot machined material, which can be produced with a more rational, robust, simpler, more reliable and / or cheaper process than is possible with today's potential the technique of spray molding or powder metallurgical production.

This object is achieved in that the durable steel material according to the present invention has a composition comprising the following alloying elements in% by weight: C: 0.1-5% C + N: 0.1-8% Si: 0.01-4% Mn: 0.01-15% Cr: 0.01-40% Mo: 0.01-1.5% V: 0.01-20%, and possibly any additional or some of the following accessory alloying elements: N1 <40% W: < 15% Nb. <15% Co: <20% Ti: <5% Zr: <5% Cu: <5% A1 <1% S: <1% residual essentially only Fe and any impurities, it is genom prepared by hetisostatic compaction or heat extrusion of granules with a size of 0.5-30 mm, preferably 1-10 mm, obtained by rapid cooling of a decomposed melt with the specified composition, and - that the steel contains the hetisostatic compaction or heat extrusion an even distribution of up to 50 [mu] m in size, preferably up to 10 [mu] m, of different but also round carbides, nitrides and / or carbonitrides of at least one of the type MX, M1C3, and M5C carbides, where the majority of these carbides, nitrides and / or carbonitrides have a size greater than 0.1 μm, preferably greater than 0.2 μm.

The tin “MX-carbides” here refers to carbides, nitrides and carbonitrides where M is mainly vanadium and X is carbon and / or nitrogen. As a rule, a smaller proportion of the vanadium content can be replaced by a double proportion of niobium. The tin "MX-carbides" also includes carbides, nitrides and carbonitrides where M is mainly titanium and / or zirconium. The term "MyCg carbides" here refers to carbides, M is mainly chromium and C is carbon. The term “MgC carbides” here refers to carbides where M is mainly molybdenum and C is carbon. The tin "accessory elements" refers to deliberately added elements that can be added to the steel melt without adversely affecting the properties of the steel.

In the description there are a number of designations whose meaning is shown below: HRC = hardness according to Rockwell RA = Proportion of residual austenite in the matrix after curing and tempering, vol-% tg-5 = cooling rate expressed in seconds for cooling from 800 ° C to 500 ° C TA = austenitization temperature, ° C h = hour M7C3 (larnel1eutektiktun) = eutectic precipitation of M7C3 carbides in austenite with the carbides substantially lamellarly formed the technique of spray molding or powder metallurgical production. The above steel material obtains a more homogeneous hard phase distribution in case a durable steel material is manufactured than the cast and hot machined material and thus obtains a very good abrasion resistance which makes the material suitable for use in tools for forming and cutting various work materials such as sheet steel, aluminum, textile, paper, ceramic-coated work material, etc., ie. conventional cold work applications. Furthermore as a tool for forming / cutting plastic granules or in mold inserts, screws, nozzles, pipes in plastic production according to e.g. the principle of extrusion, injection molding, compression molding. High abrasion resistance is also required for construction details such as pump parts, 10 15 20 25 30 35 533 988 7 valve parts, strokes, abutments, fragmentation levers for tires, paper, wood, metal, etc., wear parts or knives in the packaging industry, the food industry, the pulp industry, the mining and mineral industry or other process industries, and abrasive parts in transmissions and engines in the automotive industry. In addition, it is an advantage if the durable steel material according to the invention also meets one or more of the following conditions: 0 Adequate purity. High fi action, 3-40% by volume of larger approx. 0.1-100 μm round to irregular hardening phase particles formed during the solidification reaction during granulation, The size is less affected in the subsequent hetisostatic compaction process. 0 Good heat treatment properties; tempering temperature TA = 950-1150 ° C. 0 Good hardenability. 0 Form stable during heat treatment. 0 Found stable under dri fi conditions - little prone to aging; low residual austenitic RA after high temperature annealing. 0 Secondary hardening with a hardness of 50-66 HRC. 0 Good surface coating properties with PVD / CVD / nitriding. 0 Good sparking properties. 0 Abrasive abrasion resistance better than or equivalent to powder metallurgically manufactured steel materials, 0 Toughness preferably equal to or better than AISI D2. 0 High compressive strength. 0 Relatively good fatigue properties. Acceptable machinability. 0 Acceptable sandability. 0 Good corrosion resistance for selected alloys.

The rapid cooling and granulation of a melt with the indicated composition gives a high fraction, 3-40% by volume, of larger, up to 50 μm, preferably up to 10 μm, round to irregular hard phase particles, where most of these carbides, nitrides and / or or carbonitrides have a size greater than 0.1 μm, preferably greater than 0.2 μm, which are formed in the solidification reaction during the granulation. The indicated alloy composition is balanced so as to obtain an even distribution of the above-mentioned hard phase particles, usually consisting of MX, M1C3 and / or M6C in a matrix.

During the granulation, which most easily takes place in water, surface oxides may form on the granulate. It is convenient that these optional surface oxides be reduced prior to the hetisostatic compaction to give the produced steel material an adequate purity, so that the hetisostatically compacted steel material becomes free of oxidic inclusions. This can be done by grazing the granulate or by reducing the granulate in a reducing atmosphere, e.g. hydrogen. Of course, other methods known to the person skilled in the art can also be used.

A preferred temperature in carrying out the hetisostatic compaction is 1000-150 ° C, preferably 1150 ° C.

The particle size is only slightly affected by the subsequent hetisostatic compaction (HIP) and provides good abrasion resistance. If it is desired to increase the particle size, this can be achieved at least to some extent by extending the holding time up to 10 or 20 hours and / or increasing the temperature slightly for certain alloys.

It is conceivable that the steel material can be used in HIPat design, but otherwise the completely tight body is hot-worked by rolling or forging into bars with dimensions up to 01000 mm or slightly more. These can then be soft annealed to a hardness of approx. 150 - 3050 HB. There, the full-body is machined into one or more steel products, which are hardened and tempered to obtain preferably martensite, which provides a property profile suitable for abrasion-prone applications even in a corrosive environment. In addition, an adequate ductility / toughness is obtained.

An alternative to the hetisostatic compaction is a compaction of the granules by a heat extrusion. The capsule filled with granules and evacuated on gas is heat-extruded in one or more steps, the granules being compressed into an at least almost completely tight body. A preferred temperature in carrying out the heat extrusion is 1000-135 ° C, preferably 1150 ° C. It is also possible to proceed directly after the heat extrusion directly to a hot working in the form of forging or hot rolling to obtain a finished blank with the desired dimension. With regard to the sulphide sizes described in the present application, sizes after compaction are meant for an at least close to completely dense body, i.e. before any further hot working.

During curing, the material is austenitized at a temperature between 950 - 1150 ° C, after which the material is rapidly cooled to room temperature. Coolant is adapted depending on dimension and alloy content. In rapid cooling to room temperature, the austenite is converted to martensite, but in some cases a certain proportion of residual austenite may occur at room temperature, so a deep cooling down to -40 ° C or in liquid nitrogen at about -196 ° C may be required.

Tempering can take place once or twice at a temperature of 150-650 ° C. Typical of the steel material according to the invention is because after hardening and tempering it has a microstructure which at room temperature consists of a matrix, which mainly consists of martensite, and in this matrix an even distribution of different but also round hard phase particles. of the kind mentioned above, in addition there may be secondary separated hard phase particles of submicroscopic size.

Furthermore, it is an object of the present invention to provide a machinability-improved steel material with improved density which has a more even distribution of machinability-improving particles, which can be produced with a more rational, robust, simpler, more reliable and / or cheaper process than possible with the currently potential technology of spray forming or powder metallurgical production. This object is achieved in that the machinability-improved steel material according to the present invention has the following composition in% by weight: C: 0.1-2.0% C + N: 0.1-2.2% Si: 0.01-2% Mn: 0.01-15% Cr: 0.01-18% Mo: 0.01-5% V: 0.01-2% S: 0.01-1%, and optionally any additional or some of the following accessory alloying element: Ni <10% W: <4% Nb. <1% Co: <5% Ti: <0.5% Zr: <0.5% Cu: <2% Al <1% Ca 5-75 ppm O 50-100 ppm residues essentially only Fe and any impurities, - that it is produced by hetisostatic compaction or heat extrusion of granules with a size of 0,5-30 mm obtained by rapid cooling of a decomposed needle with the specified composition, and - that the steel after the hetisostatic compaction or heat extrusion has a microslose structure containing an iron distribution of 0.1 to 30 μm large, odd, but also substantially rounded manganese salts, MnS, and / or calcium manganese salts, where the majority of these sulfides preferably have a size of 0.1-10 μm, than more preferably no more than 0.1-3 μm.

By producing granules according to the method described above, a steel material which instead of a very good abrasive abrasion resistance can exhibit a very good machinability and substantially improved cross-ductility ironed with conventionally manufactured machinability-improved steel materials known on the market today. These improvements are achieved by the steel material obtaining a more homogeneous distribution of cutability-improving salt particles than conventionally manufactured steel materials. More specifically, the steel contains a microscopic structure whose compaction contains an iron distribution of 0.1-50 μm large, substantially rounded manganese salts, MnS, and / or calcium manganese oxides.

Most of these solids preferably have a size of at most 10 μm, even more preferably at most 1-3 μm.

Among today's known steel materials, which are conventionally manufactured with up to 0.15% sulfur addition, we find e.g. H13, which is an example of a hot working steel, and AISI 420, which is an example of a corrosion-resistant plastic mold steel. The cutability-enhanced steel material according to the invention normally has a hardness in hardened and tempered state of max 55 HRC, preferably max 45 HRC and even more preferably the hardness is in the range 30-40 HRC to be machined with cutting tools to final shape at tool manufacturers.

Additional features that characterize the inventory and what is achieved thereby will be apparent from the detailed description below.

BRIEF DESCRIPTION OF THE DRAWINGS In the following, the invention will be described in more detail with reference to preferred embodiments and the accompanying drawings. shows the microstructure of a cast-in-place steel material in hot-worked, hardened and tempered.

Figure 1 Figure 2 shows the microstructure of a powder metallurgical steel material in a hot-worked, hardened and tempered state. shows the microstructure of a spray-formed steel material in a hot-worked, hardened and tempered state.

Figure 3 203 30 533 988 11 Figure 4 shows the structure of a steel material manufactured according to a method according to the invention in hot-worked, hardened and tempered condition.

Figures 5 and 6 show the microstructure of a steel material made according to an inventive method in the machined, hardened and tempered state.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS According to the present invention, a steel melt having the following composition in% by weight is first prepared: C C + N Si Mn Cr Mo V min 0.05 0.05 0.01 0.01 0.01 0.01 0.01 01 max 5 8 4 15 40 15 20 and possibly any of the following accessory elements: Ni W Nb Co Ti Zr Cu Al S Ca (ppm) O (ppm) min 3 10 max 40 15 15 20 5 5 5 1 1 75 100 remains essentially only Fe sarnt any contaminants.

For granulating the steel melt, a preferably vertical jet of the melt is allowed to fall on an abutment element located above a water surface in a container in a granulating device, so that the jet of the impact force is broken into droplets, which spread radially from the abutment element and fall into the water. , where they are subjected to rapid cooling, so that the granules formed by the time they reach the bottom of the vessel have solidified at least on the surface. The drop height of the melt is adjusted so that the formed granules obtain a typical size of 0.5-30 mm, preferably 1-10 mm, and fl ikig to round shape. After discharge from the granulating device, the granulate is dried, which may be partly due to the heat not completely cooled in the granules.

The rapid cooling of a melt with the indicated composition gives a high fraction, 3-40% by volume, of larger, up to 50 μm, preferably up to 10 μm, round to irregular hard phase particles, where most of these carbides, nitrides and / or carbonitrides have a size greater than 0.1 μm, preferably greater than 0.2 μm, which are formed in the solidification reaction during the granulation. By adding a high content of vanadium and the corresponding stoichiometric content of carbon to an alloy system where Fe-C and at least one carbide-forming element are included in the alloy system, C-Cr-Mo-WV-Ti-Nb-Zr-Co-Ni Fe, due to the rapid cooling during solidification, a precipitation of carbides in the melt and in the residual melting ranges is obtained, or a primary precipitation of more sparingly soluble carbides, nitrides and carbonitrides, such as e.g. V (C, N) and Nb (C, N), Ti (C, N) and Zr (C, N) occur directly in the melt. This precipitation sequence is also found again in granulated steel fragments with a size of 1-30 mm, which is illustrated by fi g. 4 as a typical case for the first described case and of Fig. 5 for the latter case.

After surface oxides on the dry quenched granules may have been reduced, the granules are filled into capsules, which are then compressed hetistostatically, alternatively heat-extruded, into an at least approximately completely dense body. The hetisostatic compaction is conveniently carried out at a temperature of 1000-1350 ° C, preferably 150 ° C.

The reduction of surface oxides gives the produced steel material an adequate purity, so that the hetistostatically compressed steel material has a low content or is more or less free of oxidic inclusions. In this way, the presence of surface oxides in the granule boundaries can be avoided while any oxidic entrapment within the granules themselves is not affected by such a reduction process. Any presence of such oxides can be avoided or minimized by other methods known to those skilled in the art, e.g. by melting and refining the steel melt in vacuum and using pure raw materials as input material. In some applications with high demands on abrasive abrasion resistance, however, it is not necessary to reduce the oxides as these may instead contribute to the abrasion resistance of the steel material. Through hot working of the hetisostatic body, a decomposition of any surface oxides also takes place, which is why their possible negative effects on the ductility of the material can be reduced.

The hot isostatically compacted capsule is then hot-worked, first to obtain a completely tight body if necessary, and then further hot-worked to a finished rod with a dimension up to 01000 mm or slightly more, or to other products. The product is then soft annealed to a hardness between about 150-350 HB, after which it is processed to the desired shape by cutting processing.

The heat treatment is performed as follows. The steel material is cured by austenitization at 950 - 150 ° C where the material, after heating to the specified temperature, is kept at the current temperature for about 30 minutes to 2 hours, after which it is rapidly cooled to room temperature. During austenitization, a structural conversion of the matrix to austenite is obtained and a certain proportion of the carbides can be dissolved in whole or in part while the alloying elements contained therein precipitate into the austenite. Upon rapid cooling, the austenite is converted to martensite. A certain proportion of residual austenite may occur after high temperature run in some of the preferred embodiments, so it may be appropriate for them to deep cool the material. The tempering of the steel material can take place once or twice at a temperature of 150-650 ° C, typically for a holding time of 2 hours at a time. In the upper range of the temperature range, typically from 500-65 ° C, a characteristic secondary hardening of the material is obtained by obtaining a certain precipitation of secondary hard phase particles of submicroscopic size. Typical of the steel material according to the invention is thus that its hardening and tempering has a microstructure which at room temperature consists of a matrix consisting mainly of martensite, and in this matrix in melt phase separated out hardwoods of MX type, which have typically rounded to round shape. , iron ore may be secondarily separated hardwoods of submicroscopic size, mainly in the form of MX, M7C3 and M6C carbides, nitrides and / or carbonitrides.

Preferably, the completely dense body is machined into one or more steel products, which are hardened and tempered to obtain predominantly martensite as well as an adequate ductility / toughness.

By the above-mentioned process for producing the above-mentioned steel material comprising the stated features, the process becomes more rational, more robust, simpler, more reliable and cheaper than the current potential technology of spray forming or powder metallurgical production, and a new family of steel materials is obtained.

The effect of the alloying elements on the properties of the steel Carbon and, where applicable, nitrogen are included in the steel's matrix and contribute to the steel being given the required hardness. Together with vanadium or other carbide-forming elements such as titanium, niobium and zirconium, carbon and nitrogen are included in primary and secondary precipitated MX carbides, which in a very effective way contribute to the steel obtaining a very good abrasive abrasion resistance. Carbon also combines with chromium and molybdenum to form M7C3 and MóC carbides which also contribute to abrasion resistance.

Silicon can be used for deoxidation of the steel. Silicon also contributes to making the steel slow-running steel in order to achieve higher strength.

Manganese is added in connection with the deoxidation of the steel to make the slag slag more easily separated. Manganese is also added because it contributes to the hardenability of the steel and can in some cases be the only constituent element responsible for this effect. Manganese can also contribute to the steel being given good machinability properties by forming manganese welds together with sulfur. By also adding calcium and oxygen, calcium manganese oxides are formed, which in addition to contributing to good machinability, results in the steel obtaining a better ductility than if pure manganese salts are formed. 20 25 30 533 988 14 Chromium contributes to the steel having good hardenability and contributes to the steel's abrasion resistance and hardness by precipitation of MyCg carbides. At high levels, chromium also contributes to the steel gaining increased corrosion resistance. Molybdenum also contributes to the hardenability of the steel. Molybdenum can be at least partially replaced by twice the amount of tungsten. Preferably, however, the steel does not contain more tungsten than in the content of impurities.

In addition to the above elements, the steel can also contain other elements that in various ways contribute to giving the desired properties.

Nickel is an element that increases the hardenability and toughness in concentrations above about 1%. Since nickel is an austenite stabilizer, in many cases it is desired to limit the nickel content in the material.

Nickel also has a solution-curing effect.

Cobalt is added primarily to increase the heat hardness of the material but also provides a certain solution-curing effect.

Copper is an element that provides a certain solution-curing effect. At concentrations above 0.6%, a certain precipitation-cured effect can also be obtained during tempering.

The following is a more detailed description of various embodiments of the invention.

According to a preferred embodiment of the invention, the steel melt has a composition comprising the following alloying elements, in% by weight: C C + N Si Mn Cr Mo V Min 0.1 0.1 0.01 0.01 0.01 12 0.01 0.01 max 5 8 4 15 21 15 20 In addition to the elements listed above, the steel melt may also contain one or more of the accessory elements listed in Table 3 earlier in the description, leaving essentially only Fe and any impurities.

In this embodiment, carbon and any nitrogen present must be present in sufficient quantity for the steel to undergo the hetisostatic compaction or heat extrusion and hot working in the hardened and annealed state of the steel, and together with vanadium to form up to 15% by volume of MX carbides, where M is mainly vanadium, partly with chromium being able to form up to 30% by volume of M-γCg carbides, where M consists mainly of chromium, whereby the total content of MX carbides and MyCg carbides should amount to 3 -40% by volume, partly included in a solid solution in the martensitic matrix of the steel in the hardened state in order to thus contribute to the hardness of the steel.

The steel material according to this first preferred embodiment is primarily intended for use in plastic-forming equipment, and is used there as construction elements, e.g. screws and barrels, for feeding and guiding plastic masses in machines for the manufacture of plastic components, e.g. elements in injection molding and extrusion assemblies, and further in molds and tool parts for injection molding of plastics. Furthermore, the steel material is suitable for the manufacture of tools for casting electronic components in plastic.

In addition, the steel material has good corrosion resistance, including good resistance to spot corrosion during spark machining, very good wear resistance. It can be cured and tempered to a hardness of 58-64 HRC, preferably 59-62 HRC. However, the steel material is not limited to these application areas but can also be used for a number of other applications, where said properties are necessary or desirable, e.g. for parts in pumps for feeding abrasive media, wear parts in machines and other equipment as well as knives used in more or less corrosive environments, e.g. in the food industry and the plastics industry.

Preferably, the steel melt according to this first preferred embodiment has the following composition in% by weight: C C + N Si Mn Cr Ni Mo WV Nb Co Ti Zr Cu S Min 0.5 0.6 0.1 0.1 13 0.01 3 max 2.5 5 2.0 3.0 20 2.5 4 3 12 5 5 0.5 0.5 1 0.2 residue essentially only Fe and any impurities. In a first possible variant, the steel melt according to the first preferred embodiment has the following composition in% by weight: C C + NSiMnCrNiMoW V NbCoTiZrCuS Min 0.65 0.75 0.1 0.1 0.1 0.10 max 1.20 1.5 1.0 1.0 19 1.2 1 1.5 1.5 0.5 0.5 2 0.1 0.1 0.5 0.1 Residue essentially only Fe and any impurities, In a second conceivable variant, the steel melt according to the first preferred embodiment has the following composition in% by weight : 20 533 988 16 C C + N Si Mn Cr Ni Mo WV Nb Co Ti Zr Cu S Min 1.2 1.3 0.1 0.1 16 0.01 0.01 3 max 2.0 2.1 1 , 0 1,0 21 1,5 2,5 2,5 9 2 2 0,1 0,1 0,5 0,1 residual essentially only Fe and any impurities, According to a second preferred embodiment of the invention, the steel melt has the following composition in weight%: C C + NSiMn Cr NiMoW V NbCoTiZrCuS Min 0.01 0.02 0.01 0.01 0.01 0.01 max58451310l0l020l510555l left essentially only Fe sarnt any impurities, E fi the hetisostatic compaction or heat extrusion and heat treatment have the durable steel material has a microstructure which contains up to 30% by volume evenly distributed 1-50 μm large, preferably 1-10 μm, non-uniform, but also round MX, M7C3 and / or M fi C carbides.

In the context of this second preferred embodiment of the invention, it is conceivable that a third variant of the steel mantle has the following composition in% by weight: C C + N Si Mn Cr Ni Mo WV Nb Co Ti Zr Cu S Min 0.5 0.6 0 .1 0.1 4 0.01 0.01 0.01 max 3 3.2 1.0 1.0 13 1.5 4.5 2.5 4 1.0 3 0.1 0.1 0.5 0.1 essentially only Fe and any impurities.

After the hetisostatic compaction or heat extrusion and hot working to finished material, the durable steel material has a microstructure containing 5-20% by volume evenly distributed 1-50 μm large, preferably 1-10 μm, non-uniform, but also round MX-, M7C3 and / or M fi C carbides.

Preferably, this third variant has the following composition in% by weight: C C + N Si Mn Cr Ni Mo WV Nb Co Ti Zr Cu S Min 1.0 1.1 0.1 0.1 ll 0.01 0.01 max 2.0 2.2 1.0 1.0 13 1.5 1.5 1.5 1.5 0.5 2 0.1 0.1 0.5 0.1 residue essentially only Fe and any impurities.

In the case of the hetisostatic compaction or heat extrusion and hot working to the finished material, the durable steel material has a microsulture which contains 10-15 volumes. -iCg carbides, but with a certain element of MX carbides.

Furthermore, it is conceivable that, within the framework of this second preferred embodiment, a fourth variant of the steel melt has the following composition in% by weight: C C + N Si Mn Cr Ni Mo WV Nb Co Ti Zr Cu S Min 1.5 1, 6 0.1 0.1 4 0.01 6 max 4 4.5 2.0 3.0 12 1.5 5 2.5 12 1.0 2 0.1 0.1 0.5 0.1 residue essentially only Fe and any contaminants.

After the hetisostatic compaction or heat extrusion and hot working to finished material, the durable steel material has a microstructure containing 10-30% by volume evenly distributed 1-50 μm large, preferably 1-10 μm, non-uniform, but also said MX-, M7C3 and / or MáC carbides.

The area of use of the steel material according to this second embodiment of the invention can be anything from wear and tear, e.g. in the mining industry and other process industries, to tools in the conventional cold working area for the production of tools for cutting and punching, cold extrusion, powder pressing, deep drawing, etc., ie. details exposed to strong abrasive abrasion.

Vanadium, carbon and nitrogen must be present in a sufficient content so that the material after the hetisostatic compaction or heat extrusion and hot working in the hardened and annealed state can contain 10-30 vol% MX and MyCg carbides in the matrix, of which up to 8 vol -% consists of MyCg carbides. Preferably, the steel contains 1.5 - 4% carbon and 0.1 - 3% nitrogen so that the total content of C + N amounts to 1.6 - 7%. The vanadium content must be at least 3% and a maximum of 12%, whereby vanadium can be replaced at least in part by double the amount of niobium up to a maximum of 1.0% Nb.

Preferably, this fourth variant has the following composition in% by weight: C C + N Si Mn Cr Ni Mo WV Nb Co Ti Zr Cu S Min 1.9 2.0 0.1 0.1 5 0.01 6 max 3.3 3.4 2.0 2.0 10 1.5 4.0 1.0 ll 1.0 2 0.1 0.1 0.5 0.1 residue essentially only Fe and any impurities, After the hetisostatic compaction or heat extrusion and hot working to finished material, the durable steel material has a nicotrostructure containing 15-25% by volume, evenly distributed 1-50 μm large, preferably 1-10 μm, non-uniform, but also round MX-, M1C3 and / or M5C- carbides. Even more preferably, this fourth variant has the following composition in% by weight: C C + N Si Mn Cr Ni M0 WV Nb Co Ti Zr Cu S Min 2.5 2.6 0.1 0.1 4 0.01 8 max 3 .0 3.5 2.0 2.0 8 1.5 2.5 1.0 10 1.0 2 0.1 0.1 0.5 0.1 residue essentially only Fe and any impurities, After the hetisostatic compaction or the heat extrusion and hot working to finished material, the durable steel material has a microstructure containing 16-24 vol% evenly distributed 1-50 μm large, preferably 1-10 μm, oily, but also round MX and M1C3 carbides, of which up to 8% evenly distributed 1-50 μm large, preferably 1-10 μm, non-uniform, but also nmda, M7C3 carbides.

According to a third embodiment of the invention, the steel melt instead has a composition that is balanced in order to obtain a machinability-improved material with good ductility, toughness and / or heat hardness. In this third embodiment, the steel melt has the following composition in% by weight: C C + N Si MnCrNiMoW V NbCoTiZrCuAl Min 0.05 0.05 0.05 0.05 0.01 0.01 0.01 max 2.0 2.2 2 15 18 10 5 4 2 1 5 0,5 0,5 2 l and possibly also 3-75 ppm calcium and 10-100 ppm oxygen, essentially only Fe remaining and any impurities.

After the hetisostatic compaction or heat extrusion, the steel material has a microstructure containing an iron distribution of 0.1-SO μm large, non-uniform, but also substantially rounded manganese solids, MnS, where most of these solids preferably have a size of 0.1-10 μm. , even more preferably 0.1-S pm. By also adding 3-75 ppm calcium and 10-100 ppm oxygen, manganese salts can be modified as stated earlier so that the manganese salts will be completely or partially replaced by calcium manganese oxides. A certain presence of carbides may also be present in the steel material according to this third embodiment. In analogy with the idea of invention, these have a distribution, shape and size according to what has been previously described. Within the scope of this third embodiment of the invention, it is conceivable that a fifth variant of the steel melt has the following composition in% by weight: C C + N Si Mn Cr Ni Mo V A1 S Min 0.08 0, 16 0.05 0.05 13.0 0.01 0.01 0.01 0.01 0.01 max 0.19 0.28 1.5 2.0 15.4 1.8 1.3 0.7 1 1 and preferably 3-75 ppm calcium and 10-100 ppm oxygen, leaving essentially only Fe and any impurities.

In this case, the steel primarily obtains a very good machinability in combination with good toughness and ductility. The microstructure in the toughened state consists of a martensitic matrix with up to 30% by volume of ferrite and the steel material has a hardness between 290 - 360 I-IB. The good cutability is achieved by alloying with 0.01-1% sulfur, preferably 0.03-0.5%, and even more preferably 0.1-0.2%, whereby manganese combines with sulfur and forms the above-mentioned manganese salts . Preferably, calcium and oxygen are also added which bring about a globulation of the manganese sulphides and a formation of calcium manganese oxyuldes instead. If calcium and oxygen are also added, the sulfur content can be reduced to 0.035 - 0.25% S in combination with 3 - 100 ppm Ca, preferably 5 - 75 ppm Ca, suitably max. 40 ppm Ca, and 10 - 100 ppm O. These calcium margarine oxysuldes are not as elongated as manganese sulphides and thus an improvement in ductility can be obtained. Manganese can also completely or partially replace chromium as a hardening-enhancing element.

The steel material according to this third embodiment must be able to be delivered in a toughened condition to enable the manufacture of holders for plastic forming tools and the plastic forming tool itself in very large dimensions. Despite the fact that the content of the hardenability-increasing elements nickel and molybdenum has been reduced, the steel has a hardenability that enables hardening in air, even in very coarse dimensions. Lu fi curing is an advantage as it is possible to avoid residual stresses that can give rise to deformations in connection with the cutting machining to a finished shape. The curing is carried out by austenitization at a temperature of 900 - 1100 ° C, preferably at 950 - 1025 ° C, or about 1000 ° C, followed by quenching in oil, polymer bath, in gas in a vacuum oven or most preferably in air. The annealing is carried out as hard temperature annealing at 510 - 650 ° C, preferably at 540 - 620 ° C, for at least one hour, preferably by double annealing twice for two hours each.

In addition to the above-mentioned elements, the steel according to this third embodiment can also contain up to 2%, copper, preferably a maximum of 0.40% and even more preferably a maximum of 0.25% copper in order to increase the corrosion resistance and / or the hardness. . However, copper has a negative effect on hot ductility even at low concentrations. In addition, copper cannot be extracted from the steel, which makes scrap handling and recycling of the material more difficult.

Strong carbide formers such as niobium, titanium and zirconia should not normally be present in the material of this third embodiment as any carbides would adversely affect toughness and ductility.

In a sixth variant according to the third embodiment of the invention, the steel melt has the following composition in% by weight: C C + N Si Mn Cr Ni Mo V Al S 0.30 0.30 0.05 0.05 0.05 0.01 0.01 .3 0.4 0.50 0.15 1.5 1.8 5.5 1.8 1.5 1.3 1 1 residual iron and unavoidable impurities.

Min max This steel material also shows a very good cutability in combination with good toughness and ductility. The good cutability is achieved by alloying with 0.01-1% sulfur, preferably 0.03-0.5%, and even more preferably 0.1-0.2%, whereby manganese combines with sulfur and forms the above-mentioned manganese salts . Preferably, calcium and oxygen are also added, which effect a globulation of the manganese salts and a formation of calcium manganese oxides instead. If calcium and oxygen are also added, the sulfur content can be reduced to 0.035 - 0.25% S in combination with 3 - 100 ppm Ca, preferably 5 - 75 ppm Ca, suitably max. 40 ppm Ca, and 10 - 100 ppm O. These calcium manganese oxysuldes are not as elongated as manganese sulphides and thus an improvement in ductility can be obtained. In addition, this steel material exhibits a high heat wear resistance and a good combination of other properties, such as tempering resistance, thermal conductivity, hardenability and strength.

The steel material is intended to be used for machining work material in the hot state.

Typical examples of the use of steel are tools for extrusion and die casting of light metals, mainly aluminum. Another type of use is forging tools. Vanadium must be included in the steel in a content of at least 0.4% and a maximum of 1.3%. Vanadium helps to give the steel good tempering resistance, good abrasion resistance and contributes to good strength by forming vanadium carbides which help to create a relatively st n crystal structure. 20 533 988 21 ACCOUNT OF EXECUTIONS PERFORMED With reference to the accompanying drawings, the experiments performed will now be described.

Table 4 below shows the compositions of a number of test alloys. Steels 1-3 constitute comparative materials, while steels 4 and 5 are examples of steel materials produced according to the inventive process. Steel 1 is a commercial steel material that is produced in a conventional way via casting. Steel 2 is a commercial steel material produced via powder metallurgical production. Steel 3 is a commercial steel material that is via made via spray molding. Steel 4 and steel 5 are both commercial compositions with which experiments have been carried out with manufacturing according to the inventive method. Steel 5 is a steel material with essentially the same composition as steel 3. The reference materials steel 1 and steel 2 have not been analyzed for all constituent elements, but it should be understood that the steel in addition to the specified elements contains unavoidable impurities at normal levels derived from steel production.

Table 4, Chemical composition of the test tubes Steel nrC SiMn PS Cr Ni MoW Set 1.5 0.3 0.3 12.0 1.0 Steel2 2.9 0.5 0.5 8.0 1.5 Steel3 2, 80 0.78 0.64 0.030 0.016 6.91 0.16 2.23 0.15 Steel4 1.42 0.32 0.32 0.022 0.0032 12.0 0.23 0.89 0.019 Steel5 2.71 0 .70 0.65 0.028 0.019 6.97 0.15 2.18 0.44 Steel no. Co V Ti Cu A1 NO Steel 1.0 Ar (ppm) Steel 2 9.8 Steel3 0.02 9.20 0.003 0.08 0.001 0.09 Steel4 0.031 0.97 0.008 0.055 0.009 0.051 0.0650 Steel5 0.020 8.44 0.007 0.062 0.001 0.12 left essentially only iron.

Granules were prepared from two steel melts of 4 tonnes each with a composition according to Table 4 below according to the method initially described. Capsules were filled with 25 kg of granules each, after which the capsules were sealed, evacuated on lu fi and compacted by hetisostatic pressing. The forged ends were cured by austenitization at 1025 ° C for 30 minutes in vacuum oven before being cooled at a cooling rate tg.5 of about 100s. Thereafter, the substances were annealed by heating twice to 525 ° C for 2 hours with intermediate cooling to room temperature.

Microstructure and hardness The microstructure and hardness of the obtained substances were analyzed and compared with the reference material in the hardened and tempered state. The recoverable steels 4 and 5 were cured in a vacuum oven with a cooling rate, tg.5, of about 100s. Friend treatment data and measured hardness are shown in Table 5.

Table 5, Heat treatment data and hardness in hardened and tempered state Steel Austenitiseriß (° C / 3 Omin) Tempering (° C / 2x2h) Hardness (HRC) Steel l 1025 525 60 Steel 2 1020 200 60 Steel 3 1025 525 63 Steel 4 1025 525 58 Steel 5 1025 525 62 The microstructure of steel 1 can be seen from the light-optical photo in Figure 1. The steel has the inhomogeneous microstructure typical of ingot cast materials with relatively coarse, forging-extending carbides which form longitudinal streaks in the material. Most of the carbides are between 10 and 20 μm, but the steel also contains carbides with a length of up to 50 μm. The steel contains about 13% MyCg carbides in a martensite matrix.

The microstructure of steel 2 is shown in Figure 2. In a matrix of martensite, an even distribution of relatively round MX and M7C3 carbides with a size of 1-3 μm is seen to its longest extent. The carbide content amounts to about 15 vol% MX carbides and 7 vol% MvCg carbides. As is the case with fi guren, the MX carbides are slightly fi closer than MyCg carbides, which are fewer in number but in return slightly larger.

Figure 3 shows the microsulcture of steel 3 which is a spray-shaped steel material. In a matrix of martensite, an even distribution of relatively round, 1-7 μm MX and MyCg carbides is seen. A relatively large proportion of the MX carbides have sizes around 5 μm, while the majority of MqCg carbides have sizes smaller than 5 μm. The abundant presence of larger MX carbides is one reason why this steel exhibits very good abrasive abrasion resistance, which is reported below. Figure 4 shows the microstructure of steel 4 which is manufactured according to an inventive method in hot machined, hardened and tempered condition. In a matrix of martensite there is an even distribution of relatively round, very fine, about 1-2 μm to its longest extent, chromium-rich MyCg carbides which are separated out in residual melting areas in the matrix during the solidification of the melt droplets during granulation. The microstructure is very reminiscent of the microstructure obtained in powder-metallurgically manufactured materials, which may be considered a surprise given the relatively much simpler manufacturing process. The amount of carbides amounts to about 13% by volume and by hetisostatic compaction, hot working and subsequent hardening and tempering, most of the carbides are found as discrete particles or as smaller carbide aggregates.

Coherent major carbide networks are lacking. A certain presence of very small, rounded surface oxides can also be seen.

Figures 5 and 6 show the microstructure of steel 5 which is manufactured according to an inventive method in hot machined, hardened and tempered condition. Figure 5 shows an even distribution of slightly irregular but relatively rounded MX and MvCg carbides with a size of 1-10 μm in a martensite matrix. The total carbide content in steel 5 amounts to 21% by volume, of which 16% by volume are NIX carbides and 5% by volume are MqCg carbides. In comparison with steel 3, which has essentially the same composition as steel 5 but which is manufactured by spray-forming technology, steel 5 shows a more dispersed distribution of the carbides, more similar to the carbide structure found in powder metallurgically manufactured materials, e.g. steel 2. Some presence of larger, irregular, up to 10 pm large MIX carbides is found in the matrix. These larger carbides can in a very positive way contribute to the steel obtaining a very good abrasive abrasion resistance. The figure also shows a certain presence of broken surface oxides.

Figure 6 shows another example of the nickel structure of steel 5. It is seen that the steel has a similar carbide distribution with, if possible, slightly more rounded carbides than what was shown in figure 5.

Abrasive abrasion resistance The abrasion resistance of the refractory steels was compared with that of the reference material by stick against disc test with A120; as an abrasive. The results are shown in Table 6 below, where the steel's abrasive abrasion resistance is reported as the amount of worn material per unit time (mg / min). Steel 3 exhibits the best abrasion resistance while steel 5 made according to an inventive process exhibits a relatively very good abrasion resistance, considerably much better than steel 2 which is a powder metallurgically manufactured material. Steel 4, which has been manufactured by an inventive method, has an abrasion resistance which is on a par with the conventionally manufactured steel 1.

For the result, the hardness also plays a role in the fact that harder materials have a better abrasion resistance, which is a contributing factor to the slightly lower result for steel 4. The type of carbides and the size of them in the material affect the result. Due to a higher content of vanadium in the steel material, a larger proportion of hard MX carbides is obtained at the expense of a smaller proportion of less hard M7C3 or MóC carbides, which gives an increased nut resistance. Steel 1 and steel 4 with about 13% by volume of M7C3 carbides have relatively low abrasion resistance compared to e.g. steel 5 which contains about 21 vol% carbides divided into 16 vol% MX carbides and 5 vol% M / Cg carbides. In the case of steels 2, it is primarily the smaller size of the carbides which results in the abrasive abrasion resistance not being as good as in steels 3 and 5.

Table 6, Abrasive abrasion resistance, mgjniin) Steel Steel Steel2 Steel4 Steel13 Steel5 60 I-IRC 60 HRC 58 HRC 63 HRC 63 HRC A120; 69 17 74 3.5 8.7 800 mesh INDUSTRIAL APPLICATION The method according to the invention is intended for use where powder metallurgical production or spray molding cannot be done for cost reasons. The process results in a process that is also more rational, simpler and more reliable than the currently potential technology of spray molding. The steel material according to the invention is intended for use in applications where high demands are placed on abrasion resistance of components forming and cutting of various working materials such as sheet steel, aluminum, textiles, paper, ceramic coated working material, etc., ie. conventional cold work applications. Furthermore when forming or cutting plastic granules or in mold inserts, screws, nozzles, pipes in plastic production according to e.g. the principle of extrusion, injection molding, pressure forming. High abrasion resistance is also required for construction details such as. pump parts, valve parts, strokes, abutments, fragmentation knives for tires, paper, wood, metal, etc., wear parts or knives in the dry packing industry, the food industry, the pulp industry, the mining and mineral industry or other process industries, and abrasive parts in transmissions and engines in the automotive industry. 20 25 30 35 533 988 25 DISCUSSION Through the inventive process, where the process threads are more rational, more robust, simpler, more reliable and cheaper than the current potential technology of spray forming or powder metallurgical production, steel material can be produced with a more homogeneous hard phase distribution than in hot cast iron distribution. material. With the inventive method it is possible to produce steel materials, even high-alloy, which after HIP and hot working have a nikrostruct structure which has an iron distribution of about 1-50 μm large, preferably 1-10 μm large, non-uniform, but also round MX-, M7C3 and M fi C carbides.

Due to the rapid cooling, a much smaller dendritic size is obtained for granulated steel, a carbide size is obtained which is not too good to give good abrasion resistance, as is the case in powder metallurgically manufactured material, nor is it victorious, as in conventional cast or electroslag graphs. manufactured material. With this new process, even for materials without partially primarily separated carbides containing V 'or Nb, an even predilection of adequately large carbides of the M1C3 or MGC type is obtained. In addition to an equal or better abrasive abrasion resistance, products from this new setting method have a possible lower ductility than powder metallurgically manufactured material. Heat treatment response is otherwise the same, as are other properties. Even in comparison with powder metallurgically manufactured materials, an improved abrasive abrasion resistance is noticeable, while the ductility is better in PM steels.

Thanks to the inventive process, steel materials cast today, which are not sufficiently sophisticated to be manufactured by spray molding or powder metallurgy due to being too expensive, can be given significantly improved properties at a reasonable cost.

Furthermore, the typical lamellar solidification structure of M7C3 which occurs in conventionally or by electroslagging alloys of type AISI D2 can be avoided, which in hot working gives a smoothness which gives anisotropic properties in the longitudinal and transverse directions. For conventionally cast steel, the inventive method thus offers an opportunity to manufacture a steel material with improved and considerably more homogeneous properties in the longitudinal and transverse direction.

ALTERNATIVE EMBODIMENTS It is conceivable to have steel materials manufactured where granules with different compositions are mixed in order to combine the different properties of the materials. It can conveniently be done in such a way that granules with a certain fraction size are mixed with granules with a different, smaller fraction size. By a suitable procedure in connection with the placement of the granules in the container for HIPning, it can be ensured that the smaller granules are distributed in the spaces between the larger granules and by choosing suitable fraction sizes it becomes possible in this way to evenly distribute in a certain way out a certain amount of the smaller granules among the larger ones. In a similar way, it is also conceivable to mix granules and powdered metal powder in the same container for HIPning. Those skilled in the art will appreciate that the technique can also be used to produce HIPs where certain areas have been given a mixture of granules / powder of a second material while other areas consist only of granules of the first material. It is further appreciated that more than two materials may be mixed together in this manner.

It will be appreciated that refrigerants other than water may be used in the granulation process.

For example, it is conceivable to use a hydrocarbon such as kerosene or oil. Furthermore, it is conceivable to use surface nitrogen, which by adjusting the pressure in the container could be allowed to form a strongly cooling gas above the cooling bath. Furthermore, it is conceivable to spray in a mist of refrigerant which cools the granules and that in such a solution no cooling bath is used. Another possible way is to arrange the cooling tank with an unidentified bed at the bottom with a forced supply of cooling gas. It will be appreciated that the use of a medium other than water and oxygen-containing gas such as lu fi causes the granules not to oxidize. This would eliminate the need for the oxide reduction that now exists in some cases. Furthermore, it will be appreciated that different cooling materials cool the granules at different speeds, whereby it becomes possible to influence the carbide structure and the size of the carbides by suitable choice of cooling medium.

Claims (1)

1. 0 15 20 25 30 533 988 27 PATENT REQUIREMENTS 6.. Process for the production of a steel material, characterized by the following steps: - production of a steel melt, - granulation of the melt by allowing a jet of the melt to hit an impact element and split into droplets, which may fall into a tank containing a coolant, so that they are rapidly cooled to granules with a fl to nmd shape and a size of fi of 0.5 mm to 30 mm, preferably a size of from 1 mm to 10 mm, - filling a capsule with formed rapidly cooled granules, and - heat isostatic compaction or heat extrusion of the capsule with the granulate to an at least almost completely dense body. Process according to Claim 1, characterized in that surface oxides on the granulate are reduced before the hetisostatic compaction or heat extraction. Method according to claim 1 or 2, characterized in that the hot isostatically compacted capsule is hot-worked to obtain a completely tight body. Process according to any one of claims 1-3, characterized in that the hetisostatic compaction is carried out at a temperature of 1000-1350 ° C, preferably 1150 ° C, for a holding time of 2-10 hours. Process according to any one of claims 1-4, characterized by processing the completely dense body into one or fl your steel products, which are hardened and tempered to obtain predominantly martensite and an adequate ductility / toughness. Process according to Claim 1, characterized in that the steel melt has a composition comprising the following alloying elements in contents as follows,% by weight: CC + NSiMnCrMoV min 0.05 0.05 0.01 0.01 0.01 0.01 0.01 0.01 max 5 8 4 15 40 15 20 and possibly any one or more of the following accessory elements: Ni W Nb Co Ti Zr Cu Al S Ca (ppm) O (ppm) min 3 10 IIIBX 40l51520555ll 75 100 residue essentially only Fe and any impurities . Process according to Claim 6, characterized in that the steel melt has a composition comprising the following alloying elements in contents of different concentrations,% by weight: CC + N Si MnCrMo V Min 0.1 0.1 0.01 0.01 12 0.01 0.01 max 5 8 4 15 21 15 20 residual essentially only Fe and any contaminants and accessory elements. Process according to Claim 7, characterized in that the steel melt has the following composition in vi1ct-%: 'c_c + N si MacrNi, Mawvnbco Ti zrcuAi s Min 0.5 0.6' 0.1 0.1 131 0.01 '3 max 2.5 5 2.0 3.0 20 2.5 4 3 12 5 5 0.5 0.5 1 1 0.2 residue essentially only Fe and any impurities. Process according to Claim 8, characterized in that the steel melt has the following composition in% by weight: C C + NSiMnCrNi MoW VNbCoTiZrCuAl Min 0.65 0.75 0.1 0.1 0.01 0.01 max 1.20 1 .5 1.0 1.0 19 1.2 1.5 1.5 1.5 0.5 2 0.1 0.1 0.5 1 residue essentially only Fe and any impurities. Process according to Claim 8, characterized in that the steel melt has the following composition in% by weight: CC + NSiMnCrNi Mo WVNbCoTi ZrCuAlS Min 1.2 1.3 0.1 0.1 16 0.01 0.01 3 residue essentially only Fairy and any contaminants. Method according to claim 6, characterized in that the steel malt has a composition comprising the following alloying elements in contents as follows, weight%: CC + N SiMnCrNiMoWVCo Min 0.01 0.02 0.01 0.01 0.01 0, 01 0.01 max5 8 4 5131010102010 essentially only Fe remaining and any contaminants and accessory elements. max 2.0 2.1 1.0 1.0 21 1.5 2.5 2.5 9 2 2 0.1 0.1 0.5 1 0.1 20 533 988 29 11. A method according to claim 10, characterized in that the stem melt has the following composition weight%: C C + N Si Mn Cr Ni Mo WV Nb Co Ti Zr Cu S Min 0.5 0.6 0.1 0.1 4 0.01 0.01 max 3 3 .2 1.0 1.0 13 1.5 4.5 2.5 4 1.0 3 0.1 0.1 0.5 0.1 residue essentially only Fe and any impurities. Process according to Claim 11, characterized in that the steel melt has the following composition in% by weight: C C + N Si Mn Cr Ni Mo W '.V Nb Co Ti Zr Cu S Min 1.0 1.1 0.1 0, 1 ll 0.01 0.01 max 2.0 2.2 1.0 1.0 13 1.5 1.5 1.5 1.5 0.5 2 0.1 0.1 0.5 0.1 essentially only Fe and any impurities. Process according to Claim 10, characterized in that the steel melt has the following composition in% by weight: C C + N Si Mn Cr Ni Mo WV Nb Co Ti Zr Cu Al S Min 1.5 1.6 0.1 0.1 40 .01 6 max 4 4,5 2,0 3,0 12 1,5 5 2,5 12 1,0 2 0,1 0,1 0,5 0,1 residual essentially only Fe and any impurities. Process according to Claim 13, characterized in that the steel melt has the following composition in% by weight: C C + N Si Mn Cr Ni Mo WV Nb Co Ti Zr Cu Al S Min 1.9 2.0 0.1 0.1 .01 6 max 3.3 3.4 2.0 2.0 10 1.5 4.0 1.0 ll 1.0 2 0.1 0.1 0.5 0.1 residue essentially only Fe and any ßroreningar . Process according to Claim 14, characterized in that the steel melt has the following composition in% by weight: C C + N Si Mn Cr Ni Mo WV Nb Co Ti Zr Cu S Min 2.5 2.6 0.1 0.1 40 01 8 max 3.0 3.5 2.0 2.0 8 1.5 2.5 1.0 101.0 2 0.1 0.1 0.5 0.1 residue essentially only Fe and any impurities. Process according to claim 1, characterized in that the steel melt has the following composition in% by weight: C C + N Si Mn Cr Ni Mo WV Co Ti Zr Cu Min 0.05 0.05 0.05 0, 05 0.01 0.01 0.01 maX 2.0 2.2 2 15 18 10 5 4 2 0.5 0.5 and possibly 3-75 ppm calcium and 10-100 ppm oxygen, residual essentially only Fe and any pollutants. Steel material, characterized in that it has a composition comprising the following learning elements in contents according to,% by weight: C C + N S1 Mn Cr Mo V min 0.1 0.1 0.01 0.01 0.01 0.01 0.01 0.01 mâX 5 8 4 15 40 15 20 lighting elements: Ni W NbCo T1 Zr Cu and possibly some or more of the Al S Ca (ppm) O (ppm) min 3 10 maX 40 15 15 20 5 5 5 1 l 75 100 residues essentially only Fe and any impurities. - that it is fi made by hetisostatic compaction or heat extrusion of 18. granules with a size of 0,5-SO mm obtained by rapid cooling of a decomposed melt with the specified composition, and that the steel after the hetisostatic compaction or heat extrusion and hot working into finished material has a nncrostrulture containing 3-40% by volume evenly distributed up to 50 μm large, preferably up to 10 μm, oily, but also round MX, M7C3, and MóC carbides, where most of these carbides, nitrides and / or carbonitrides have a size greater than 0.1 μm, preferably greater than 0.2. Cutability-enhanced steel material according to claim 17, characterized in that it has a composition comprising the following alloying elements in contents as below, weight%: um. C C + N Si Mn Cr Ni Mo WV Nb Co Ti Zr Cu Min 0.05 0.05 0.05 0.05 0.01 0.01 0.01 maX 2.0 2.2 2 15 18 10 5 4 0.5 0.5 and preferably 3-75 ppm calcium and 10-100 ppm oxygen, residual essentially only F e and any impurities, 533 988 31 - that it is produced by hetisostatic compaction or heat exudation of granules with a size of 0.5-30 mm obtained by rapid cooling of a decomposed melt with the specified composition, and - that the steel after the hetisostatic compaction or heat extraction has a nail structure containing an even distribution of 0.1-30 μm large, non-uniform, but also substantially rounded manganese solids, MnS, and / or calcium manganese oxides where the majority of these solids preferably have a size of at most 10 μm, even more preferably no more than 0.1-3 μm in order to obtain a cutability-enhanced material with good ductility, toughness and warmth . Use of a steel material according to claim 17 for the manufacture of cold working tools and wear goods, i.e. products which are subjected to strong abrasive wear. Use of a steel material according to claim 18 for the manufacture of plastic forming tools, holders and holder details for plastic forming tools, ie products that are subjected to advanced machining at high cutting speeds in the hardened and tempered state, hot work tools such as tools for heat extrusion, die casting and extrusion of light metals, forging tools and cutting tool holders.