US20170333964A1 - Hot forming tool - Google Patents
Hot forming tool Download PDFInfo
- Publication number
- US20170333964A1 US20170333964A1 US15/519,988 US201515519988A US2017333964A1 US 20170333964 A1 US20170333964 A1 US 20170333964A1 US 201515519988 A US201515519988 A US 201515519988A US 2017333964 A1 US2017333964 A1 US 2017333964A1
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- US
- United States
- Prior art keywords
- tool
- relief
- base body
- raised
- metal
- 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.)
- Abandoned
Links
- 229910052751 metal Inorganic materials 0.000 claims abstract description 20
- 239000002184 metal Substances 0.000 claims abstract description 20
- 238000000576 coating method Methods 0.000 claims abstract description 14
- 239000011248 coating agent Substances 0.000 claims abstract description 13
- 239000011241 protective layer Substances 0.000 claims abstract description 13
- 230000036961 partial effect Effects 0.000 claims abstract description 4
- 239000010410 layer Substances 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 26
- 229910000831 Steel Inorganic materials 0.000 claims description 25
- 239000010959 steel Substances 0.000 claims description 25
- 239000000463 material Substances 0.000 claims description 20
- 238000005096 rolling process Methods 0.000 claims description 16
- 238000004519 manufacturing process Methods 0.000 claims description 15
- 239000004744 fabric Substances 0.000 claims description 13
- 238000006243 chemical reaction Methods 0.000 claims description 11
- 230000008569 process Effects 0.000 claims description 9
- 238000005242 forging Methods 0.000 claims description 8
- 244000287680 Garcinia dulcis Species 0.000 claims description 5
- 239000000126 substance Substances 0.000 claims description 5
- 238000010285 flame spraying Methods 0.000 claims description 3
- 238000007750 plasma spraying Methods 0.000 claims description 3
- 238000007751 thermal spraying Methods 0.000 claims description 2
- 238000001947 vapour-phase growth Methods 0.000 claims description 2
- 238000004804 winding Methods 0.000 claims 1
- 238000010618 wire wrap Methods 0.000 claims 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 12
- 239000007921 spray Substances 0.000 description 8
- 239000007789 gas Substances 0.000 description 7
- 239000002245 particle Substances 0.000 description 7
- 230000015572 biosynthetic process Effects 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 6
- 239000007787 solid Substances 0.000 description 5
- 238000005507 spraying Methods 0.000 description 5
- 239000002131 composite material Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 239000007858 starting material Substances 0.000 description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 238000005229 chemical vapour deposition Methods 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 238000005240 physical vapour deposition Methods 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 238000010891 electric arc Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000012447 hatching Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 235000013980 iron oxide Nutrition 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 230000035882 stress Effects 0.000 description 2
- 239000012808 vapor phase Substances 0.000 description 2
- 229910000669 Chrome steel Inorganic materials 0.000 description 1
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000005234 chemical deposition Methods 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
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- 230000006872 improvement Effects 0.000 description 1
- 230000004941 influx Effects 0.000 description 1
- 238000010849 ion bombardment Methods 0.000 description 1
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 239000002905 metal composite material Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
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- 238000004377 microelectronic Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229910052574 oxide ceramic Inorganic materials 0.000 description 1
- 238000005289 physical deposition Methods 0.000 description 1
- 230000002028 premature Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000004549 pulsed laser deposition Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 125000006850 spacer group Chemical group 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 238000002207 thermal evaporation Methods 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 239000011364 vaporized material Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B19/00—Tube-rolling by rollers arranged outside the work and having their axes not perpendicular to the axis of the work
- B21B19/02—Tube-rolling by rollers arranged outside the work and having their axes not perpendicular to the axis of the work the axes of the rollers being arranged essentially diagonally to the axis of the work, e.g. "cross" tube-rolling ; Diescher mills, Stiefel disc piercers or Stiefel rotary piercers
- B21B19/04—Rolling basic material of solid, i.e. non-hollow, structure; Piercing, e.g. rotary piercing mills
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B25/00—Mandrels for metal tube rolling mills, e.g. mandrels of the types used in the methods covered by group B21B17/00; Accessories or auxiliary means therefor ; Construction of, or alloys for, mandrels or plugs
Definitions
- the invention is in the field of manufacture of tubular metal workpieces and relates to forming tools, especially piercing plugs, forging mandrels and rolling mandrels with improved stability.
- Seamless steel tubes are generally made in three forming stages on respective rolling mills by hot forming.
- a solid steel block heated to about 1200° C. is pierced by means of an internal tool, the piercing plug, into the hollow bloom.
- the block is driven by means of inclined rolls over the piercing plug.
- the hollow bloom is reduced over the inner tool, a rolling mandrel, in diameter and wall thickness and stretched in the longitudinal direction.
- the rolling stock is converted to the required dimensions in diameter and wall thickness, where usually no internal tool is used.
- the inner tools in the first two forming stages are exposed in the production to high temperatures and mechanical pressures.
- the inner tools are made of heat resisting steel.
- a successive heating of the internal tool is often unavoidable. Due to heating the strength of the tool decreases and the tool can no longer withstand the mechanical stresses. The tool deforms and breaks.
- piercing plugs are provided with natural scale layers. These scale layers inhibit the flow of heat from the workpiece to be shaped into the tool and protect the tool from rapid heating and rapid loss of strength. When forming higher alloyed materials, the scale layer is removed, however, quickly and the thermal protection fails.
- the tool life could be improved if the thickness of the oxide layer could be enlarged. Then, the thermal insulation is better and during abrasive wear the protective layer would remain preserved longer.
- the protective layer is formed naturally from the base material by conversion to iron oxides, but does not have high stability. It is brittle and porous and therefore can be easily destroyed by mechanical and thermal stress. Therefore, these protective layers are limited in thickness. The limit of the layer is about 0.8 mm. The protective effect of such a layer is therefore limited accordingly. Heat penetrates therefore into the main body of the tool and reduces its strength, whereby it then comes to premature failure of the tool. With high-alloyed work-pieces abrasion leads relatively quickly, i.e. by a small length of the rolled material to the removal of the protective layer.
- the object of the present invention has therefore been to provide hot forming tools with improved stability, which are free from the above-stated disadvantages.
- these tools should have an oxide layer having a higher strength compared to the prior art, which can be also applied easily and without loss of material.
- a first aspect of the invention relates to a hot forming tool comprising a tool body having at least pro rata surface coating, which can be obtained, by that the basic body is provided with a raised metallic relief, which is subsequently completely or partially oxidized and converted into a protective layer.
- Another aspect of the invention includes a method for producing a hot forming tool comprising a tool body having at least pro rata surface coating, in which
- raised reliefs is the reverse case to a profiling of the tool.
- material is added and not removed.
- the relief formation is in contrast to the profiling not only much easier to realize, but by complete or partial conversion of the relief material, even a considerably harder and thus more stable oxide film is obtained, which leads to a significant improvement in tool life.
- the invention also provides the possibility of selecting the relief material to vary the quality of surface protection and adjust the process conditions.
- Hot forming tools of the present invention are preferably a piercing plug or a forging mandrel, which are typically made of steel.
- the invention includes under this preamble, however, in principle, any other metallic workpiece, in which the body is to be protected against heat influx.
- the term metal is not limited to iron and steel, but also includes other metallic materials including metal-composite materials that are to be supplied to a hot forming.
- the surface coating of the invention may be advantageously employed.
- the inner tools in the rolling mills with several successively arranged roll stands in the second forming stage is particularly important to ensure that the friction between tool and rolling stock is low. Therefore, the surface layer of the invention has to be grinded and polished for this application. Also, an additional layer can be applied, made of chrome on the protective layer according to the invention.
- the raised relief which is applied to the base body can be pronounced quite differently, the alternative embodiments are all suitable in principle to fulfill the task in full.
- it may be simply a wrapping of the body with a wire, preferably a steel wire at the raised relief.
- the raised relief can represent a metal fabric or metal mesh, which is applied to the base body.
- the metallic bodies applied to the surface of the tool are preferably made from a steel mesh, for example with a steel wire thickness of about 1 to about 5 mm and preferably about 1.5 mm and a mesh spacing of about 1 to 5 mm and in particular about 2.5 mm. Under the mesh spacing the distance of the center lines of two adjacent fabric elements is to be understood.
- the raised relief may be an irregular coating, as is achieved by chemical or physical deposition of metal from the vapor phase.
- the base body is simply wrapped with a wire, preferably a metal wire.
- a metal fabric or a metal mesh is used instead of the wire. This may be preformed, for example by forming the shape of the tool and then mounted on the base body. In order to increase the strength, it is advisable to weld the wire coil or the metal fabric to the base body.
- chemical vapor deposition is a group of coating methods which are used inter alia in the manufacture of microelectronic components and optical waveguides.
- a solid component is separated due to a chemical reaction from the gas phase.
- a prerequisite is that volatile compounds of the component layers exist, the entrained solid layer at a given reaction temperature.
- the method of the chemical vapor deposition is characterized by at least one reaction on the surface of the workpiece to be coated. This reaction must be at least a gaseous starting compound (starting material) and at least two reaction products—to be involved—of which at least one in the solid phase.
- starting material gaseous starting compound
- reaction products to be involved—of which at least one in the solid phase.
- the process is preferably carried out at reduced pressure.
- the starting material is converted into the gas phase using the preferred PVD.
- the gaseous material is then led to the substrate to be coated, where it condenses and forms the target layer.
- evaporation processes such as thermal evaporation, electron beam (electron beam evaporation) or laser beam evaporation (pulsed laser deposition).
- sputtering in which the starting material is sputtered by ion bombardment and transferred into the gas phase from which it can then be deposited on the basic body. All these processes have in common that the material to be deposited is in solid form in the mostly evacuated coating chamber.
- the target By bombardment with laser beams, magnetically deflected ions or electrons as well as by arc discharge, the target is evaporated.
- the proportion of atoms, ions or larger clusters in the vapor varies from procedure to procedure.
- the vaporized material moves either ballistically or performed by electric fields through the chamber and impinges on the parts to be coated, where it comes to the layer formation.
- Typical operating pressures are in the range of 10 ⁇ 4 Pa to 10 Pa. Since the vapor particles propagate straight, areas that are not visible seen from the steam source, are coated with a lower deposition rate. In order to produce a relief and no homogeneous coating a rotation of the substrate will be omitted different from the usual procedure.
- a fourth alternative embodiment of the relief formation comprises the so-called thermal spraying.
- the so-called spray additives are melted off, at or on inside or outside a spray burner, accelerated in a gas stream in the form of spray particles and thrown on the surface of the component to be coated.
- the component surface in this case (in contrast to the cladding) is not melted and thermally loaded only slightly.
- a layer formation takes place, as the spray particles are flattening more or less depending on process and material when impinging on the component surface, stick primarily by mechanical bonding and layer by layer to build the spray layer.
- Quality characteristics of spray coatings are low porosity, easy bonding to the component, avoidance of cracks and homogeneous microstructure.
- the layer properties obtained are significantly influenced by the temperature and the speed of the spray particles at the time of incidence to the surface to be coated.
- the surface state (purity, activation temperature) also exerts a significant influence on quality characteristics such as adhesion.
- electric arc arc spraying
- plasma jet plasma jet
- fuel-oxygen flame or fuel-oxygen high-speed flame conventional and high-velocity flame spraying
- fast, preheated gas cold gas spraying
- laser beam laser beam spraying
- the base body may be coated not only with metals but also oxide-ceramic materials and carbide materials (or in general composites).
- the coating takes place with a steel/ceramic mixture.
- the base body is preferably made of steel, it is valid for the material forming the raised relief, the requirement that it is at least capable rata for forming an oxide layer.
- this is iron or steel so that a layer of iron oxide, preferably scale is generated. It can be used as said, a mixture of iron/steel and ceramics for example in a weight ratio of about 20:80 to about 80:20.
- the relief may have different forms, ranging from regular (round, square, etc.) to any freeform. It can also be used composite materials, i.e. for example, a molybdenum fabric that is applied to the steel body.
- the fabric element can also consist of a composite of hard chrome steel (inside) and well oxidizable steel (outside). As the spacer, also combustible materials may be employed. It is also possible, for better heat insulation to embed ceramic.
- the complete or partial conversion of the metallic reliefs in an oxidic protective layer may be produced by known methods of the prior art, for example by flame spraying, plasma spraying, or is carried out by a thermochemical process.
- a part of the surface of the tool base body and a part of the relief deposited on the surface is converted into oxide.
- an additional oxide layer is formed on all surfaces, typically to about 3000 microns, and especially about 1.500 to about 2,500 microns.
- oxide is formed in the spaces between the bodies, for example, between the tool body and the applied steel fabric and within the meshes of the steel fabric.
- the result is a particularly thick protection layer which is reinforced by means of an internal body.
- the layer thickness is different than in the production of grooves not limited to a few millimeters. Layer thicknesses of 10 mm and more can be produced without difficulty and at low cost.
- Another object of the invention relates to the use of the new tool described in detail above, especially as a piercing plug, forging mandrel or rolling mandrel for the production of seamless tubes or hot-forging tubular workpieces of metal.
- a mesh preformed by forming the shape of the base steel was laid on with a steel wire thickness of 1.5 mm and a mesh width of 2.5 mm and welded. Successively, the composite has been exposed to a thermo-chemical oxidation. A coherent continuous oxide layer of 2500 microns thickness has been obtained.
- FIG. 1 shows a hot forming tool in the form of a piercing plug in a side view.
- the tool 1 has a tool body 2 having a work area 3 , which extends in the direction of an axis A over a certain length.
- the tool is provided with a coating 4 which protects the tool 1 against thermal and mechanical stress.
- FIGS. 2 and 3 show the detail “Z” in the horizontal section through the tool according to FIG. 1 once for the material body with raised relief before and after the production of the oxide protective layer (“scaling”).
- FIG. 2 a one recognizes the saw-shaped relief which is formed according to Example 1 by applying a wire mesh.
- the base body is characterized by the reference numeral 6 , the mesh by the numeral 7 .
- FIG. 2 b it is seen that a part of the surface of the relief has been converted to oxide, but also between the loops of the mesh, the surface of the base body has been oxidized (hatching with reference numeral 8 ).
- FIGS. 3 a and 3 b are analogue, however, the relief here has no square, but a round cross section. Again, one can see that the oxide layer (hatching) is developing in equal proportions above and beneath the original surface of the ferrous body.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
- Coating By Spraying Or Casting (AREA)
- Forging (AREA)
- Chemical Vapour Deposition (AREA)
Abstract
Disclosed is a hot forming tool (1) which consists of a main tool member (2) having an at least partial surface coating (4) and which can be obtained by providing the main tool member with a raised metal relief that is then entirely or partly oxidized and converted into a protective layer.
Description
- The invention is in the field of manufacture of tubular metal workpieces and relates to forming tools, especially piercing plugs, forging mandrels and rolling mandrels with improved stability.
- Seamless steel tubes are generally made in three forming stages on respective rolling mills by hot forming. In a first stage, on a so-called cross-roll piercing mill a solid steel block heated to about 1200° C. is pierced by means of an internal tool, the piercing plug, into the hollow bloom. Here, the block is driven by means of inclined rolls over the piercing plug. In the second forming stage, in a longitudinal rolling process the hollow bloom is reduced over the inner tool, a rolling mandrel, in diameter and wall thickness and stretched in the longitudinal direction. In the third forming stage, the rolling stock is converted to the required dimensions in diameter and wall thickness, where usually no internal tool is used.
- The inner tools in the first two forming stages are exposed in the production to high temperatures and mechanical pressures. In most cases, the inner tools are made of heat resisting steel. In the production, especially with larger rolling times a successive heating of the internal tool is often unavoidable. Due to heating the strength of the tool decreases and the tool can no longer withstand the mechanical stresses. The tool deforms and breaks.
- To achieve a long service life, piercing plugs are provided with natural scale layers. These scale layers inhibit the flow of heat from the workpiece to be shaped into the tool and protect the tool from rapid heating and rapid loss of strength. When forming higher alloyed materials, the scale layer is removed, however, quickly and the thermal protection fails.
- In rolling mandrels scaled tools or tools provided with a chromium layer are used depending on the forming process course. Corresponding piercing plugs are known from German Patent Application DE10 2008 056 988 A1 (SMS MEER). A disadvantage, however, is that the thermal insulation against the heat flow from the workpiece to be shaped into the tool is low. Thus, particularly with internal tools, which are used at reduced speed and length of contact, heating of the inner tool and its failure due to deformation and fracture occur.
- The tool life could be improved if the thickness of the oxide layer could be enlarged. Then, the thermal insulation is better and during abrasive wear the protective layer would remain preserved longer.
- The protective layer is formed naturally from the base material by conversion to iron oxides, but does not have high stability. It is brittle and porous and therefore can be easily destroyed by mechanical and thermal stress. Therefore, these protective layers are limited in thickness. The limit of the layer is about 0.8 mm. The protective effect of such a layer is therefore limited accordingly. Heat penetrates therefore into the main body of the tool and reduces its strength, whereby it then comes to premature failure of the tool. With high-alloyed work-pieces abrasion leads relatively quickly, i.e. by a small length of the rolled material to the removal of the protective layer.
- From the international patent application WO2011 107214 A1 (SMS MEER) piercing plugs or rolling mandrels are known for the production of seamless tubes or forging mandrels for hot forging of tubular workpieces of metal which have a surface profiling, in which the oxide layer is applied. In this way, better adhesion and longer service life to be achieved.
- Similar tools, in which the coating consists of molybdenum, are known from EP0385439A1 (NKK CORP.).
- Subject of the European patent application EP 2404680 A1 (SUMITOMO) is the manufacture of steel tubes according to the Mannesmann process. Claimed is a piercing plug the feature of which is, that it inhibits a channel, through which a lubricant is lead during piercing. According to [0053] the piercing plug can be coated by iron. For this an iron wire is lead to a spraying device where it is molten. The molted iron is then sprayed onto the piercing plug, i.e. a continuous coating is developing.
- In practice, the preparation of such profiled tools, however, proves to be expensive since the profiles have to be individually cut into the piercing plugs, and also lead to material losses. The manufacturing cost of a profile disproportionately increase with the size of the introduced grooves. An economic and feasibility limit is reached at just a few millimeters. Another disadvantage of the profile cut into the base body is the limitation of the material on good oxidizable steels. These have in particular a low chromium content and thus low hardness.
- The object of the present invention has therefore been to provide hot forming tools with improved stability, which are free from the above-stated disadvantages. In particular, these tools should have an oxide layer having a higher strength compared to the prior art, which can be also applied easily and without loss of material.
- A first aspect of the invention relates to a hot forming tool comprising a tool body having at least pro rata surface coating, which can be obtained, by that the basic body is provided with a raised metallic relief, which is subsequently completely or partially oxidized and converted into a protective layer.
- Under ‘raised’ has to be understood, that the relief is raising related to the surface of the tool (‘hill structure’) and thus is contradictory to a profiling where profile grooves are carved into the surface (‘valley structure’).
- Another aspect of the invention includes a method for producing a hot forming tool comprising a tool body having at least pro rata surface coating, in which
- (a) the body is provided with a raised metallic relief, and
- (b) successively the metallic relief is completely or partially oxidized and converted into a protective layer.
- The application of raised reliefs is the reverse case to a profiling of the tool. For the purposes of the invention, therefore, material is added and not removed. Surprisingly, it was found that the relief formation is in contrast to the profiling not only much easier to realize, but by complete or partial conversion of the relief material, even a considerably harder and thus more stable oxide film is obtained, which leads to a significant improvement in tool life. The invention also provides the possibility of selecting the relief material to vary the quality of surface protection and adjust the process conditions.
- The economic benefit of the invention is obvious and is in particular in the reduction of tool costs during the production of steel products, as well as the extension of the rolling time, which is usually associated with larger lengths of the rolling stock and reduced material waste.
- Tools
- Hot forming tools of the present invention are preferably a piercing plug or a forging mandrel, which are typically made of steel. The invention includes under this preamble, however, in principle, any other metallic workpiece, in which the body is to be protected against heat influx. The term metal is not limited to iron and steel, but also includes other metallic materials including metal-composite materials that are to be supplied to a hot forming.
- But not only in piercing plugs, the inner tools in piercing by cross rolling, with the other inner tools that are used in the production of seamless steel tubes, the surface coating of the invention may be advantageously employed. In the rolling mandrels, the inner tools in the rolling mills with several successively arranged roll stands in the second forming stage is particularly important to ensure that the friction between tool and rolling stock is low. Therefore, the surface layer of the invention has to be grinded and polished for this application. Also, an additional layer can be applied, made of chrome on the protective layer according to the invention.
- The raised relief, which is applied to the base body can be pronounced quite differently, the alternative embodiments are all suitable in principle to fulfill the task in full.
- In a first embodiment, it may be simply a wrapping of the body with a wire, preferably a steel wire at the raised relief.
- In a second embodiment, the raised relief can represent a metal fabric or metal mesh, which is applied to the base body.
- The metallic bodies applied to the surface of the tool are preferably made from a steel mesh, for example with a steel wire thickness of about 1 to about 5 mm and preferably about 1.5 mm and a mesh spacing of about 1 to 5 mm and in particular about 2.5 mm. Under the mesh spacing the distance of the center lines of two adjacent fabric elements is to be understood.
- In a third embodiment the raised relief may be an irregular coating, as is achieved by chemical or physical deposition of metal from the vapor phase.
- Relief Formation
- The application of the raised reliefs can by very different—simple and complex—procedures, which yet solve all the object of the invention to the full extent.
- In a first embodiment, the base body is simply wrapped with a wire, preferably a metal wire.
- In a second alternative embodiment, a metal fabric or a metal mesh is used instead of the wire. This may be preformed, for example by forming the shape of the tool and then mounted on the base body. In order to increase the strength, it is advisable to weld the wire coil or the metal fabric to the base body.
- In a third alternative embodiment, it is possible to produce the relief on the surface of the base body by chemical or physical vapor deposition (Chemical/Physical Vapor Phase Deposition, CVD/PVD).
- The term chemical vapor deposition is a group of coating methods which are used inter alia in the manufacture of microelectronic components and optical waveguides. At the heated surface of a substrate, a solid component is separated due to a chemical reaction from the gas phase. A prerequisite is that volatile compounds of the component layers exist, the entrained solid layer at a given reaction temperature. The method of the chemical vapor deposition is characterized by at least one reaction on the surface of the workpiece to be coated. This reaction must be at least a gaseous starting compound (starting material) and at least two reaction products—to be involved—of which at least one in the solid phase. To over competing vapor phase reactions to promote those reactions at the surface and thus to avoid the formation of solid particles, the process is preferably carried out at reduced pressure.
- Unlike the CVD, the starting material is converted into the gas phase using the preferred PVD. The gaseous material is then led to the substrate to be coated, where it condenses and forms the target layer. Examples are classical evaporation processes, such as thermal evaporation, electron beam (electron beam evaporation) or laser beam evaporation (pulsed laser deposition). For the purposes of the present invention, preferred is sputtering in which the starting material is sputtered by ion bombardment and transferred into the gas phase from which it can then be deposited on the basic body. All these processes have in common that the material to be deposited is in solid form in the mostly evacuated coating chamber. By bombardment with laser beams, magnetically deflected ions or electrons as well as by arc discharge, the target is evaporated. The proportion of atoms, ions or larger clusters in the vapor varies from procedure to procedure. The vaporized material moves either ballistically or performed by electric fields through the chamber and impinges on the parts to be coated, where it comes to the layer formation.
- For achieving that the vapor particles reach the components, and are not lost by scattering at the gas particles, the work must be done in vacuum. Typical operating pressures are in the range of 10 −4 Pa to 10 Pa. Since the vapor particles propagate straight, areas that are not visible seen from the steam source, are coated with a lower deposition rate. In order to produce a relief and no homogeneous coating a rotation of the substrate will be omitted different from the usual procedure.
- A fourth alternative embodiment of the relief formation comprises the so-called thermal spraying. Here additional materials, the so-called spray additives are melted off, at or on inside or outside a spray burner, accelerated in a gas stream in the form of spray particles and thrown on the surface of the component to be coated. The component surface in this case (in contrast to the cladding) is not melted and thermally loaded only slightly. A layer formation takes place, as the spray particles are flattening more or less depending on process and material when impinging on the component surface, stick primarily by mechanical bonding and layer by layer to build the spray layer. Quality characteristics of spray coatings are low porosity, easy bonding to the component, avoidance of cracks and homogeneous microstructure. The layer properties obtained are significantly influenced by the temperature and the speed of the spray particles at the time of incidence to the surface to be coated. The surface state (purity, activation temperature) also exerts a significant influence on quality characteristics such as adhesion.
- As energy carrier for the melting of the spray additive material are used electric arc (arc spraying), plasma jet (plasma spraying), fuel-oxygen flame or fuel-oxygen high-speed flame (conventional and high-velocity flame spraying), fast, preheated gas (cold gas spraying) and laser beam (laser beam spraying). According to EN 657 DIN standard spray methods are classified according to these criteria.
- Using this method, the base body may be coated not only with metals but also oxide-ceramic materials and carbide materials (or in general composites). Preferably in this embodiment the coating takes place with a steel/ceramic mixture.
- While the base body is preferably made of steel, it is valid for the material forming the raised relief, the requirement that it is at least capable rata for forming an oxide layer. Preferably, this is iron or steel so that a layer of iron oxide, preferably scale is generated. It can be used as said, a mixture of iron/steel and ceramics for example in a weight ratio of about 20:80 to about 80:20.
- It is understood that the relief may have different forms, ranging from regular (round, square, etc.) to any freeform. It can also be used composite materials, i.e. for example, a molybdenum fabric that is applied to the steel body. The fabric element can also consist of a composite of hard chrome steel (inside) and well oxidizable steel (outside). As the spacer, also combustible materials may be employed. It is also possible, for better heat insulation to embed ceramic.
- Oxidation
- The complete or partial conversion of the metallic reliefs in an oxidic protective layer may be produced by known methods of the prior art, for example by flame spraying, plasma spraying, or is carried out by a thermochemical process.
- In the oxidation of the tool with the metallic body applied on its surface, for example a steel fabric, a part of the surface of the tool base body and a part of the relief deposited on the surface is converted into oxide. At the same time, an additional oxide layer is formed on all surfaces, typically to about 3000 microns, and especially about 1.500 to about 2,500 microns. Thus, also oxide is formed in the spaces between the bodies, for example, between the tool body and the applied steel fabric and within the meshes of the steel fabric. The result is a particularly thick protection layer which is reinforced by means of an internal body. In particular, the layer thickness is different than in the production of grooves not limited to a few millimeters. Layer thicknesses of 10 mm and more can be produced without difficulty and at low cost.
- Another object of the invention relates to the use of the new tool described in detail above, especially as a piercing plug, forging mandrel or rolling mandrel for the production of seamless tubes or hot-forging tubular workpieces of metal.
- On the surface of a piercing plug a mesh preformed by forming the shape of the base steel was laid on with a steel wire thickness of 1.5 mm and a mesh width of 2.5 mm and welded. Successively, the composite has been exposed to a thermo-chemical oxidation. A coherent continuous oxide layer of 2500 microns thickness has been obtained.
-
FIG. 1 shows a hot forming tool in the form of a piercing plug in a side view. Thetool 1 has atool body 2 having awork area 3, which extends in the direction of an axis A over a certain length. In thework area 3, the tool is provided with acoating 4 which protects thetool 1 against thermal and mechanical stress. -
FIGS. 2 and 3 show the detail “Z” in the horizontal section through the tool according toFIG. 1 once for the material body with raised relief before and after the production of the oxide protective layer (“scaling”). - In
FIG. 2a one recognizes the saw-shaped relief which is formed according to Example 1 by applying a wire mesh. In this case, the base body is characterized by thereference numeral 6, the mesh by thenumeral 7. InFIG. 2b it is seen that a part of the surface of the relief has been converted to oxide, but also between the loops of the mesh, the surface of the base body has been oxidized (hatching with reference numeral 8). - The
FIGS. 3a and 3b are analogue, however, the relief here has no square, but a round cross section. Again, one can see that the oxide layer (hatching) is developing in equal proportions above and beneath the original surface of the ferrous body.
Claims (15)
1. A hot forming tool comprising a tool body having at least pro rata surface coating, obtainable in that the basic body is provided with a raised metallic relief, which is subsequently completely or partially oxidized and converted into a protective layer.
2. The tool according to claim 1 , wherein it is a piercing plug, a forging mandrel or a rolling mandrel.
3. The tool according to claim 1 , wherein the basic body is made of metal, preferably steel.
4. The tool according to claim 1 , wherein the raised relief on the base body is a wire wrapping.
5. The tool according to claim 1 , wherein the raised relief on the base body is a metal fabric.
6. A method for producing a hot forming tool comprising a tool body having at least pro rata surface coating, in which
(a) the body is provided with a raised metallic relief, and
(b) successively the metallic relief is completely or partially oxidized and converted into a protective layer.
7. The method according to claim 6 , wherein the raised relief is applied on the base body by winding a wire.
8. The method according to claim 6 , wherein the raised relief is applied on the base body by covering with a metal fabric.
9. The method according to claim 8 , wherein the metal fabric is preformed by deformation on the shape of the tool and then put onto the basic body.
10. The method according to claim 7 , wherein the wire or the metal fabric is welded to the base body.
11. The method of claim 6 , wherein the raised relief is applied on the base body by Chemical/Physical Vapor Phase Deposition.
12. The method according to claim 6 , wherein the raised relief is applied on the base body by thermal spraying.
13. The method according to claim 6 , wherein the base body consists of metal, preferably steel, and the material forming the raised relief, is capable of at least partly forming an oxide layer.
14. The method according to claim 6 , comprising complete or partial conversion of the metallic reliefs in an oxidic protective layer by flame spraying, plasma spraying, or Is carried out by a thermochemical process.
15. A method for the manufacture of seamless tubes or hot-forging tubular workpieces of metal, comprising using the tool according to claim 1 .
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102014016502.7A DE102014016502A1 (en) | 2014-11-07 | 2014-11-07 | Hot forming tool with reinforced oxide protective layer |
DE102014016502.7 | 2014-11-07 | ||
EP14197507.8 | 2014-12-11 | ||
EP14197507.8A EP3017888B1 (en) | 2014-11-07 | 2014-12-11 | Thermoforming tool |
PCT/EP2015/075758 WO2016071423A1 (en) | 2014-11-07 | 2015-11-04 | Hot forming tool |
Publications (1)
Publication Number | Publication Date |
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US20170333964A1 true US20170333964A1 (en) | 2017-11-23 |
Family
ID=52278347
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US15/519,988 Abandoned US20170333964A1 (en) | 2014-11-07 | 2015-11-04 | Hot forming tool |
Country Status (9)
Country | Link |
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US (1) | US20170333964A1 (en) |
EP (1) | EP3017888B1 (en) |
JP (1) | JP2017536237A (en) |
KR (1) | KR20170086519A (en) |
CN (1) | CN107206442B (en) |
BR (1) | BR112017007858A2 (en) |
DE (1) | DE102014016502A1 (en) |
RU (1) | RU2687321C2 (en) |
WO (1) | WO2016071423A1 (en) |
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DE102018116238A1 (en) * | 2018-07-04 | 2020-01-09 | Kme Germany Gmbh & Co. Kg | Hot forming tool and method for producing a hot forming tool |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130327107A1 (en) * | 2010-03-02 | 2013-12-12 | Kazim Serin | Hot work tool and method for producing same |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
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SU818684A1 (en) * | 1979-05-14 | 1981-04-07 | Челябинский Ордена Ленина Трубо-Прокатный Завод | Mandrel producing method |
JPS5913924B2 (en) | 1979-12-25 | 1984-04-02 | 日本鋼管株式会社 | Core metal for piercing rolling mill |
JPH02224806A (en) | 1989-02-28 | 1990-09-06 | Nkk Corp | Plug for producing seamless steel pipe |
JP3015389B2 (en) * | 1989-07-31 | 2000-03-06 | 株式会社東芝 | Superconducting coil manufacturing method |
SU1773525A1 (en) * | 1990-07-31 | 1992-11-07 | Dn Truboprokatnyj Z Im | Pipe drawing mandrel |
CN1041497C (en) * | 1992-08-06 | 1999-01-06 | 周春林 | Top head for metal tube rolling mill and its making method |
JP3772676B2 (en) | 2001-01-31 | 2006-05-10 | Jfeスチール株式会社 | Surface protective material for piercing and rolling tool and manufacturing method thereof |
DE102008056988A1 (en) | 2007-12-07 | 2009-06-10 | Sms Meer Gmbh | Seamless steel pipe producing method for rolling mill, involves providing inner tool in interior of pipe blank, where rotation movement opposite to rotary movement of pipe blank is imposed to piercer |
JP5169982B2 (en) * | 2009-03-03 | 2013-03-27 | 新日鐵住金株式会社 | Plug, piercing and rolling mill, and seamless pipe manufacturing method using the same |
CN102002710A (en) * | 2010-12-30 | 2011-04-06 | 两仪激光技术(天津)有限公司 | Cladding layer crack control method of laser surface cladding process |
JP5842772B2 (en) | 2012-09-11 | 2016-01-13 | Jfeスチール株式会社 | Seamless steel pipe rolling plug and method of manufacturing the same |
BR112015008558B1 (en) | 2013-01-11 | 2021-02-09 | Nippon Steel Corporation | buffer for hot tube production |
-
2014
- 2014-11-07 DE DE102014016502.7A patent/DE102014016502A1/en not_active Withdrawn
- 2014-12-11 EP EP14197507.8A patent/EP3017888B1/en not_active Revoked
-
2015
- 2015-11-04 RU RU2017118964A patent/RU2687321C2/en active
- 2015-11-04 US US15/519,988 patent/US20170333964A1/en not_active Abandoned
- 2015-11-04 CN CN201580060124.1A patent/CN107206442B/en active Active
- 2015-11-04 KR KR1020177013758A patent/KR20170086519A/en unknown
- 2015-11-04 WO PCT/EP2015/075758 patent/WO2016071423A1/en active Application Filing
- 2015-11-04 BR BR112017007858-9A patent/BR112017007858A2/en not_active Application Discontinuation
- 2015-11-04 JP JP2017522549A patent/JP2017536237A/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
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US20130327107A1 (en) * | 2010-03-02 | 2013-12-12 | Kazim Serin | Hot work tool and method for producing same |
Also Published As
Publication number | Publication date |
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WO2016071423A1 (en) | 2016-05-12 |
RU2017118964A3 (en) | 2018-12-07 |
RU2017118964A (en) | 2018-12-07 |
CN107206442B (en) | 2020-04-07 |
JP2017536237A (en) | 2017-12-07 |
EP3017888A1 (en) | 2016-05-11 |
BR112017007858A2 (en) | 2018-01-16 |
DE102014016502A1 (en) | 2016-05-12 |
KR20170086519A (en) | 2017-07-26 |
RU2687321C2 (en) | 2019-05-13 |
CN107206442A (en) | 2017-09-26 |
EP3017888B1 (en) | 2019-04-24 |
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