WO1992011941A1 - Refining element and method of manufacturing the same - Google Patents
Refining element and method of manufacturing the same Download PDFInfo
- Publication number
- WO1992011941A1 WO1992011941A1 PCT/SE1991/000840 SE9100840W WO9211941A1 WO 1992011941 A1 WO1992011941 A1 WO 1992011941A1 SE 9100840 W SE9100840 W SE 9100840W WO 9211941 A1 WO9211941 A1 WO 9211941A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- refining
- refining element
- grains
- front side
- layer
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/02—Making ferrous alloys by powder metallurgy
- C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
- C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
- C22C33/0292—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5% with more than 5% preformed carbides, nitrides or borides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C7/00—Crushing or disintegrating by disc mills
- B02C7/11—Details
- B02C7/12—Shape or construction of discs
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/12—Metallic powder containing non-metallic particles
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
- C22C32/001—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides
- C22C32/0015—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with only oxides with only single oxides as main non-metallic constituents
- C22C32/0026—Matrix based on Ni, Co, Cr or alloys thereof
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
- D21D1/00—Methods of beating or refining; Beaters of the Hollander type
- D21D1/20—Methods of refining
- D21D1/30—Disc mills
- D21D1/306—Discs
Definitions
- This invention relates to a refining element for the refining of material, such as fibre material, and to the manufacture of this element.
- a refining element is provided on its front side with a pattern of refining members in the form of elevations or irregularities, for example a pattern of bars and intermediate grooves, and is intended for a disc refiner comprising two opposed refining discs, which are rotatable relative one another.
- the refining elements are so arranged on the refining discs, that a refining gap is formed between opposed ref ⁇ ining elements, through which gap the fibre material is intended to pass.
- the refining discs, and thus. ' also the refining elements can be designed so as to define one or several plane and/or conic refining gaps.
- the refining elements At the passage of the fibre material through the refining gaps, the refining elements expose and work the fibres combined with a large heat development. At the same time, the refining elements proper unavoidably are subjected to wear. Owing to this wear, the shape of the refining members of the refining elements gradually changes. The intensity and type of treatment of the fibre material is affected not only by the size of the refining gaps, but also by the shape of the front side of the refining element, and, therefore, the refining elements must be replaced after a certain time of operation. It is, therefore, desired to avoid wear to the greatest possible extent.
- the aforesaid problem can be reduced, and a refining element be obtained, which has a surface layer with high wear resistance.
- This result is achieved according to the invention, in that the refin ⁇ ing element- is provided with a surface structure, which comprises grains of extreme hardness embedded in a matrix of a softer material.
- the invention implies, that the refining element, or at least a layer on its front side, is manufactured by cold- isostatic pressing of a mechanical mixture of grains of a hard phase and a powder of a softer steel alloy. Thereby, a " structure is obtained which cannot be achieved in another way. The grains remain in their place in the structure during the manufacture. Thus, the distribution of grains in the element can be determined and controlled. This im ⁇ plies also, that the desired surface structure can be maint ⁇ ained in spite of the wear, which unavoidably takes place.
- the layer on the front side of the refining element thus, must have a thickness corresponding at least to the wear of the pattern of the refining element which can be accept ⁇ ed with a view to the quality of the refined material.
- grains of hard phase are carbides andnitrides of chromium, vanadium, molybdenum, tungsten and titanium as well as aluminium oxide. Diamonds can also be used, but probably are much too expensive for this application.
- the hardness of the grains shall exceed 1000 HV (Vickers) and the grain size preferably should be 0.05-0.8 mm.
- the grain size must be adapted to the geometry of the refining element in question.
- the grains should have a rounded, preferably spherical shape. Other shapes, however, cannot be exclud ⁇ ed.
- the steel alloy constituting the matrix, in which thegrains are embedded, shall have a hardness lower than that of the grains.
- the hardness should be 250-800 HV, i.e. steel used conventionally for the manufacture of refining elements.
- Such steel material should be an alloy containin 0.05-1.7% C, 16-19% Cr, 0-1.0% Mo and 0-2.0% Ni.
- the harder grains shall constitute 10-50% by weight.
- the refining element is manufactured, in that the hard grai are mixed mechanically with the steel alloy in powder state and placed in a mould, the appearance of which corresponds to the pattern of the refining element.
- This;:mixture is thereafter subjected to coldisostatic pressing with a comp ⁇ acting pressure of 2500-7000 bar.y preferably 4000-7000 bar, so that grains and powderr are compacted to a uni orm.
- Layer Coldisostatic pressing which is known per se, implies that the pressing takes place without preheating, and that' the compacting pressure is distributed uniformly over all surf ⁇ aces of the object.
- This can be carried out, for example, in that the pressure is executed by a liquid, which surr ⁇ ounds the mould formed of a resilient material. Preferably, several moulds can be pressed simultaneously. After press ⁇ ing, the material is sintered and possibly heat treated.
- the layer manufactured in this way can constitute the entir refining element or a part thereof.
- the front side of the refining element which is subjected to wear, it may be suitable to combine the pressed layer with a rear side, which has been cast in a conventional manner, to a complete refining element.
- the front side then has the structure desired for the refining while the rear side can be worked in usual manner and be provided with means for attachment in the refiner.
- the front side and rear side preferably are joined togeth ⁇ er in such a way, that the cast rear side is placed in the mould together with the mixture of powder and grains which is to constitute the front side of the refining element, and the joining takes place simultaneously with the powder pressing.
- a weight loss in average of 320 mg was measured for the conventional sample, and of 170 mg for the sample according to the invention.
Abstract
A refining element for disc refiners, where the refining element on the front side is provided with a pattern of refining members, and a method of manufacturing the same. At least a layer on the front side of the element comprises grains with a size of 0.05-0.8 mm and a hardness exceeding 1000 HV (Vickers), which grains by cold isostatic pressing are included in a matrix of a softer material, such as a steel alloy. The grains constitute 10-15 % by weight. According to the manufacturing method, the grains are mixed with a powder of the softer material, the mixture is placed in a mould and subjected to cold isostatic pressing with a compacting pressure of 2500-7000 bar, whereafter the resulting layer is sintered. This layer can constitute the entire refining segment or at least the front side thereof.
Description
Refining element and method of manufacturing the same
This invention relates to a refining element for the refining of material, such as fibre material, and to the manufacture of this element. Such a refining element is provided on its front side with a pattern of refining members in the form of elevations or irregularities, for example a pattern of bars and intermediate grooves, and is intended for a disc refiner comprising two opposed refining discs, which are rotatable relative one another.
The refining elements are so arranged on the refining discs, that a refining gap is formed between opposed ref¬ ining elements, through which gap the fibre material is intended to pass. The refining discs, and thus.'also the refining elements, can be designed so as to define one or several plane and/or conic refining gaps.
At the passage of the fibre material through the refining gaps, the refining elements expose and work the fibres combined with a large heat development. At the same time, the refining elements proper unavoidably are subjected to wear. Owing to this wear, the shape of the refining members of the refining elements gradually changes. The intensity and type of treatment of the fibre material is affected not only by the size of the refining gaps, but also by the shape of the front side of the refining element, and, therefore, the refining elements must be replaced after a certain time of operation. It is, therefore, desired to avoid wear to the greatest possible extent.
By using material of greater hardness, such as various alloys of steel or ceramic material, wear has been reduced and thereby the refining elements were given a longer life. The refining surface, however, is subjected, besides mechan¬ ical wear, also to, for example, corrosion, cavitation,
fatigue and smoothing, which affect the quality of the pulp.
According to the present invention, the aforesaid problem can be reduced, and a refining element be obtained, which has a surface layer with high wear resistance. This result is achieved according to the invention, in that the refin¬ ing element- is provided with a surface structure, which comprises grains of extreme hardness embedded in a matrix of a softer material. The characterizing features of the invention are defined in detail in the attached claims.
The invention implies, that the refining element, or at least a layer on its front side, is manufactured by cold- isostatic pressing of a mechanical mixture of grains of a hard phase and a powder of a softer steel alloy. Thereby, a "structure is obtained which cannot be achieved in another way. The grains remain in their place in the structure during the manufacture. Thus, the distribution of grains in the element can be determined and controlled. This im¬ plies also, that the desired surface structure can be maint¬ ained in spite of the wear, which unavoidably takes place. The layer on the front side of the refining element, thus, must have a thickness corresponding at least to the wear of the pattern of the refining element which can be accept¬ ed with a view to the quality of the refined material. Examples of grains of hard phase are carbides andnitrides of chromium, vanadium, molybdenum, tungsten and titanium as well as aluminium oxide. Diamonds can also be used, but probably are much too expensive for this application.
The hardness of the grains shall exceed 1000 HV (Vickers) and the grain size preferably should be 0.05-0.8 mm. The hardness of the grains, thus, shall exceed the hardness of the impurities, for=-example sand, which can follow along with the material to be refined. The grain size, however,
must be adapted to the geometry of the refining element in question. The grains should have a rounded, preferably spherical shape. Other shapes, however, cannot be exclud¬ ed.
The steel alloy constituting the matrix, in which thegrains are embedded, shall have a hardness lower than that of the grains. The hardness should be 250-800 HV, i.e. steel used conventionally for the manufacture of refining elements. Such steel material should be an alloy containin 0.05-1.7% C, 16-19% Cr, 0-1.0% Mo and 0-2.0% Ni. The harder grains shall constitute 10-50% by weight.
The refining element is manufactured, in that the hard grai are mixed mechanically with the steel alloy in powder state and placed in a mould, the appearance of which corresponds to the pattern of the refining element. This;:mixture is thereafter subjected to coldisostatic pressing with a comp¬ acting pressure of 2500-7000 bar.y preferably 4000-7000 bar, so that grains and powderr are compacted to a uni orm. Layer Coldisostatic pressing, which is known per se, implies that the pressing takes place without preheating, and that' the compacting pressure is distributed uniformly over all surf¬ aces of the object. This can be carried out, for example, in that the pressure is executed by a liquid, which surr¬ ounds the mould formed of a resilient material. Preferably, several moulds can be pressed simultaneously. After press¬ ing, the material is sintered and possibly heat treated.
The layer manufactured in this way can constitute the entir refining element or a part thereof. As it is the front side of the refining element, which is subjected to wear, it may be suitable to combine the pressed layer with a rear side, which has been cast in a conventional manner, to a complete refining element. The front side then has the structure
desired for the refining while the rear side can be worked in usual manner and be provided with means for attachment in the refiner.
The front side and rear side preferably are joined togeth¬ er in such a way, that the cast rear side is placed in the mould together with the mixture of powder and grains which is to constitute the front side of the refining element, and the joining takes place simultaneously with the powder pressing.
In order to compare the wear resistance of an element accord¬ ing to the invention and a conventional element, tests were carried out as follows.
A sample manufactured according to the invention, for which grains of aluminium oxide were used, was compared with a sample in the form of a cast conventional steel alloy. When applying a standard wear resistance test method, at which the weight loss of the sample constitutes the measure, of wear, a weight loss in average of 320 mg was measured for the conventional sample, and of 170 mg for the sample according to the invention.
The invention, of course, is not restricted to the embodim¬ ents described above, but can be varied within the scope of the invention idea.
Claims
1. A refining element for disc refiners for refining fibre material, where the refining element on the front side is provided with a pattern of refining members in the form of elevations or irregularities, werein at least a layer on the front side of the element comprises grains,
10-50% by weight, with a size of 0.05-0.8 mm and a hardness exceeding 1000 HV (Vickers) , c h a r a c t e r i z e d i n that the grains in said layer are embedded by coldisostatic pressing and subsequent sintering in a matrix of a steel alloy containing 0.05-1.7% C, 16-19% Cr,
0-1.0% Mo and 0-2.0% Ni and with a hardness of 250-800 HV.
2. A refining element as defined in claim 1, c h a r a c t e r i z e d i n that said layer constitutes the entire refining element.
3. A refining element as defined in claim 1, c h a r a c t e r i z e d i n that said layer constitutes the front side of the refining element, while its rear side consists of a conventionally cast steel alloy.
4. A method of manufacturing a refining element, which on the front side is provided with a pattern of refining members in the form..of elevations or irregularities and is intended for disc refiners for refining of fibre material, c h a r a c t e r i z e d i n that grains with a size of 0.5-0.8 mm and a hardness exceeding 1000 HV (Vickers) and powder of a steel alloy, containing 0.05-1.7% C, 16-19% Cr, 0-1.0% Mo and 0-2.0% Ni, are mixed and placed in a mould, the appearance of which corresponds to the pattern of the refining element, that said mixture is subjected to coldisostatic pressing with a compacting pressure of 2500-7000 bar, so that grains and powder are joined together to a layer, which thereafter is sintered, and which layer constitutes the entire refining element or the front side thereof, which is combined with a rear side to a complete refining element.
5. A method as defined in claim 4, c h a r a c t e r i z e d i n that a conventionally cast steel alloy intended to constitute the rear side of the refining element is placed in the mould together with the powder-grain mixture, which is intended to constitute the front side of the refining element, and that front and rear side are joined together by the pressing.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE9100042A SE467563B (en) | 1991-01-08 | 1991-01-08 | PAINTING ELEMENTS FOR DISC REFINERS FOR PAINTING FIBER MATERIALS AS WELL AS PREPARING A PREPARATION OF A PAINTING ELEMENT |
| SE9100042-2 | 1991-01-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1992011941A1 true WO1992011941A1 (en) | 1992-07-23 |
Family
ID=20381549
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/SE1991/000840 WO1992011941A1 (en) | 1991-01-08 | 1991-12-06 | Refining element and method of manufacturing the same |
Country Status (2)
| Country | Link |
|---|---|
| SE (1) | SE467563B (en) |
| WO (1) | WO1992011941A1 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0634522A1 (en) * | 1993-07-13 | 1995-01-18 | Technogenia S.A. | Defibrating- or refining disk for paper pulp and process for making the same |
| WO1997040204A1 (en) * | 1996-04-24 | 1997-10-30 | J&L Fiber Services, Inc. | Stainless steel alloy for pulp refiner plate |
| EP0773304A3 (en) * | 1995-11-06 | 1997-12-10 | Hitachi, Ltd. | Wear resisting sintered alloy and control rod driving apparatus of a nuclear reactor using it |
| EP0995810A1 (en) * | 1998-10-20 | 2000-04-26 | J&L Fiber Services, Inc. | Stainless steel alloy for pulp refiner plate |
| WO2006091063A1 (en) * | 2005-02-22 | 2006-08-31 | Trevino Morales Julio Antonio | Refining sector and production method thereof |
| CN105986500A (en) * | 2015-02-06 | 2016-10-05 | 上海东冠纸业有限公司 | Treatment method for pulp of paper for daily use |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE402019B (en) * | 1975-04-09 | 1978-06-12 | Uddeholms Ab | GRINDING SHEET FOR DISC MILLS AND KIT FOR MAKING THE GRINDING SHEET |
| US4704251A (en) * | 1985-07-18 | 1987-11-03 | Teknologisk Institut | Method for the production of a wear resistant part of a soil working tool |
-
1991
- 1991-01-08 SE SE9100042A patent/SE467563B/en not_active IP Right Cessation
- 1991-12-06 WO PCT/SE1991/000840 patent/WO1992011941A1/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE402019B (en) * | 1975-04-09 | 1978-06-12 | Uddeholms Ab | GRINDING SHEET FOR DISC MILLS AND KIT FOR MAKING THE GRINDING SHEET |
| US4704251A (en) * | 1985-07-18 | 1987-11-03 | Teknologisk Institut | Method for the production of a wear resistant part of a soil working tool |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0634522A1 (en) * | 1993-07-13 | 1995-01-18 | Technogenia S.A. | Defibrating- or refining disk for paper pulp and process for making the same |
| FR2707677A1 (en) * | 1993-07-13 | 1995-01-20 | Technogenia | Plate for defibering or refining paper pulp, and process for its production. |
| US5580472A (en) * | 1993-07-13 | 1996-12-03 | Technogenia S.A. | Paper pulp defibering or refining plate and method of manufacturing it |
| US5836531A (en) * | 1993-07-13 | 1998-11-17 | Technogenia S.A. | Paper pulp defibering or refining plate and method of manufacturing it |
| EP0773304A3 (en) * | 1995-11-06 | 1997-12-10 | Hitachi, Ltd. | Wear resisting sintered alloy and control rod driving apparatus of a nuclear reactor using it |
| WO1997040204A1 (en) * | 1996-04-24 | 1997-10-30 | J&L Fiber Services, Inc. | Stainless steel alloy for pulp refiner plate |
| US5824265A (en) * | 1996-04-24 | 1998-10-20 | J & L Fiber Services, Inc. | Stainless steel alloy for pulp refiner plate |
| US6245289B1 (en) | 1996-04-24 | 2001-06-12 | J & L Fiber Services, Inc. | Stainless steel alloy for pulp refiner plate |
| EP0995810A1 (en) * | 1998-10-20 | 2000-04-26 | J&L Fiber Services, Inc. | Stainless steel alloy for pulp refiner plate |
| WO2006091063A1 (en) * | 2005-02-22 | 2006-08-31 | Trevino Morales Julio Antonio | Refining sector and production method thereof |
| CN105986500A (en) * | 2015-02-06 | 2016-10-05 | 上海东冠纸业有限公司 | Treatment method for pulp of paper for daily use |
Also Published As
| Publication number | Publication date |
|---|---|
| SE9100042L (en) | 1992-07-09 |
| SE9100042D0 (en) | 1991-01-08 |
| SE467563B (en) | 1992-08-10 |
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