Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
  • B22F5/10—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of articles with cavities or holes, not otherwise provided for in the preceding subgroups
  • B22F5/106—Tube or ring forms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21H—MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS
  • B21H1/00—Making articles shaped as bodies of revolution
  • B21H1/06—Making articles shaped as bodies of revolution rings of restricted axial length
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
  • B22F5/10—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of articles with cavities or holes, not otherwise provided for in the preceding subgroups
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy

Definitions

• the invention relates to a method for producing large ring-shaped workpieces, in particular ring bandages for wear-resistant press rolls, by means of a hot isostatic pressing process.
• Such workpieces in particular ring bandages, which are applied to a roll body of a press roll, have already been produced in the prior art by hot isostatic pressing (HIP).
• HIP hot isostatic pressing
• the materials that can be used for the hot isostatic pressing process have very good wear properties, which is why ring bandages produced in this way should preferably be used.
• hot isostatic pressing takes place at high pressure and high temperature, which should be applied as evenly as possible to the entire workpiece, so that the size of the suitable devices (HIP systems) is very limited.
• HIP systems can currently produce band diameters of approx. I m, in exceptional cases up to approx. 1.2 m.
• the field of application of such bandages should, however, also be extended to briquetting, compacting, material bed crushing, grinders and numerous other processes. For economic reasons, however, larger drum diameters are often required for this.
• This object is achieved in that a ring blank is produced by the hot isostatic pressing process with dimensions specified by the HIP system, which is then brought to other, preferably larger, dimensions by a thermoforming process.
• a method for producing metal rings is known from US-A-3982904.
• a powdery material is filled into a hollow-walled sleeve.
• the powdery material can be encapsulated by, for example, a ring roller in the sleeve and heated there for hot compression and pressurized.
• the sleeve with the compacted powdery material is then radially expanded by the ring roller.
• a ring blank produced by the HIP process is processed further without a capsule, sleeve or the like.
• a compaction of the powder filled into the sleeve according to US-A-3982904 in a subsequent molding process is consequently in no way provided according to the invention, since a finished blank is used according to the HIP method.
• the ring blank After the hot isostatic pressing, the ring blank still has a very good plasticity, which can be used advantageously for a subsequent thermoforming process.
• other dimensions or profiles than those specified by the HIP system can be produced relatively inexpensively by the thermoforming process.
• the thermoforming process also leads to an improvement in the structure.
• the blank can have a diameter be enlarged, since this results in the corresponding cost advantages for ring bandages.
• the invention enables enlargements to be achieved which are in the range from greater than 1: 1 to 3: 1, preferably greater than 1: 1 to 2: 1. For example, for a HIP system that can produce bandages with a diameter of 1 m, this means that they can be expanded to a diameter of 2 m. Such a drastic enlargement of the blank increases the area of application of the ring bandages by a considerable amount.
• the blank is made essentially entirely of a HIP material.
• the blank provides enough material to achieve the dimensions of the ring bandage that are necessary after thermoforming.
• a further embodiment provides that the blank is produced from a HIP material applied to a suitable base material, the base material having properties which are matched to the HIP material with regard to the thermoforming process.
• Steel is particularly suitable as the base material. It is important that the material has properties that do not cause the HIP layer to detach from it during the thermoforming process. These circumstances can of course also be counteracted by appropriate thermoforming conditions. However, the properties of the materials are essentially decisive.
• the materials must also be matched to one another so that the bond is retained during the thermoforming process.
• the blank is made of different HIP composite materials, so that the later bandage has different materials in different areas, for example on the inner and outer circumference.
• a simple way of carrying out the thermoforming process is that the blank is enlarged during the thermoforming process by forging over a mandrel and / or expanding over a cone. This embodiment is particularly suitable for the production of smaller dimensions.
• thermoforming process can advantageously be carried out by ring rolling.
• Diameter ratio of main roll and roll mandrel the degree of rolling on the inner and outer circumference can be set. This is particularly advantageous if the blank is to be produced from several HIP composite materials that require different rolling conditions. For example, A larger roll is carried out on the inner circumference by means of a thinner roller mandrel.
• the ring rolling can also be used to produce a required profile of the ring-shaped workpiece. Such profiling depends on the particular application of the ring bandage.
• thermoforming process can be carried out by rolling the end faces of the blank, which has the particular advantage that there are also differences in the axial direction of the annular workpiece HIP or HIP and base materials can be connected to each other.
• the invention relates to a ring bandage for press rolls, which is produced by a method according to one of claims 1 to 11.
• the final diameter is larger than the largest diameter of a blank to be produced by the HIP system.
• the good wear properties of the HIP material, and the cohesion achieved through hot isostatic pressing are not adversely affected by the hot forming in the range of the usual forging temperatures (e.g. 1000 to 1200 ° C).
• the invention thus provides a very economical method for producing ring-shaped workpieces of larger dimensions.
• FIG. 1 shows a blank and a finished bandage of a first embodiment in a cross-sectional view
• FIG. 2 shows a schematic view of the thermoforming process for producing the bandage from FIG. 1,
• Fig. 3 shows a blank and a finished bandage of a second embodiment in a cross-sectional view
• Fig. 4 shows a further embodiment of a ring bandage in a cross-sectional view.
• FIG. 5 shows a blank and a finished bandage of a further embodiment of a cross-sectional view.
• 1 shows an annular blank 1 and an annular bandage 2 made from it.
• the blank 1 has an outer diameter D R and an inner diameter d R and consists of a single HIP material.
• the blank 1 is produced by hot isostatic pressing using high pressure and high temperatures in a HIP system (not shown).
• the currently The largest possible diameter D R of ring-shaped workpieces is approximately 1.2 m.
• the bandage 2 has an outer diameter D B and an inner diameter d B.
• the enlargement of the diameter from blank 1 to bandage 2 in this embodiment is approximately 1.7: 1.
• the blank 1 has correspondingly thicker wall thicknesses so that the correspondingly required wall thickness is achieved with the bandage 2.
• the amount of HIP material required essentially depends on the volume ratios.
• the schematic device for thermoforming shown in FIG. 2 comprises a driven main roll 3, which is seated on the outer periphery 4 of the blank and a roller mandrel 6 pressed onto the inner periphery 5 of the blank 1.
• axial rollers 7 are provided to maintain the axial dimensions of the blank 1.
• the main roll 3 has a diameter dn and the roll mandrel has a diameter d w .
• the degree of rolling on the inner and outer circumference 5.4 can be influenced by the selection of suitable diameters d H and d w , whereby the deformation on the outer and inner circumference 4.5 is optimized accordingly.
• the ratio of the diameter between the main roll 3 and the mandrel 6 also plays an important role here.
• the blank 1 is rolled continuously by the hot forming tool to the dimensions of the ring bandage 2. Due to the relatively plastic HIP material, which approximates in this forming process Forging temperature is a ring bandage 2 of good structure and accurate dimensions.
• FIG. 3 shows a blank 1 and a ring bandage 2, which is constructed from two different HIP materials 8 and 9, which are each arranged in a ring adjacent to one another.
• the materials 8, 9 have been brought into a dimensionally advantageous arrangement for further treatment by the hot isostatic pressing.
• the device shown in FIG. 2 is particularly suitable.
• both materials 8, 9 can be deformed with different degrees of rolling. This ensures that the two materials 8, 9 do not separate from one another during the thermoforming and the firm bond is retained even in the finished ring bandage 2.
• the final thicknesses of the layers of the materials 8, 9 must already be taken into account in the blank 1.
• FIG. 4 shows a further embodiment of a ring bandage 2, which has a profile.
• the blank 1 can have a corresponding preform, from which it is then thermoformed to the dimensions of the ring bandage 2.
• the main roller 3 and the mandrel 6 also have a corresponding profile.
• a wide variety of profiles can thus be produced on the outer and inner circumference 4, 5, which benefit a wide variety of applications.
• FIG. 5 shows a blank 1 and an annular bandage in which two materials are arranged axially one behind the other.
• the thermoforming process can therefore be carried out by mainly axial rolling along the end faces.
• bandages are e.g. used for briquetting presses, compacting machines, machines for material bed crushing, for mills and numerous other applications.
• the bandages 2 can be designed with special properties for the most varied of applications.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Forging (AREA)
• Powder Metallurgy (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7773699

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (5)

Citations (3)

• 1995
  • 1995-09-29 DE DE19536507A patent/DE19536507A1/de not_active Withdrawn
• 1996
  • 1996-09-27 AU AU72821/96A patent/AU7282196A/en not_active Abandoned
  • 1996-09-27 DE DE59604060T patent/DE59604060D1/de not_active Expired - Fee Related
  • 1996-09-27 JP JP51395897A patent/JP3150705B2/ja not_active Expired - Fee Related
  • 1996-09-27 WO PCT/EP1996/004237 patent/WO1997012710A1/de active IP Right Grant
  • 1996-09-27 EP EP96934481A patent/EP0852525B1/de not_active Expired - Lifetime

Patent Citations (3)

Non-Patent Citations (1)

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