GB2198749A - Method of manufacturing blocks or profiled sections by extrusion - Google Patents
Method of manufacturing blocks or profiled sections by extrusion Download PDFInfo
- Publication number
- GB2198749A GB2198749A GB08728325A GB8728325A GB2198749A GB 2198749 A GB2198749 A GB 2198749A GB 08728325 A GB08728325 A GB 08728325A GB 8728325 A GB8728325 A GB 8728325A GB 2198749 A GB2198749 A GB 2198749A
- Authority
- GB
- United Kingdom
- Prior art keywords
- preform
- powder
- compacts
- steel
- extrusion
- 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.)
- Granted
Links
- 238000001125 extrusion Methods 0.000 title claims description 8
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 239000000843 powder Substances 0.000 claims abstract description 31
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 27
- 239000010959 steel Substances 0.000 claims abstract description 27
- 239000002184 metal Substances 0.000 claims abstract description 8
- 229910052751 metal Inorganic materials 0.000 claims abstract description 8
- 238000000137 annealing Methods 0.000 claims abstract description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 9
- 230000002829 reductive effect Effects 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 4
- 229910052799 carbon Inorganic materials 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 claims description 3
- 239000000956 alloy Substances 0.000 claims description 3
- 239000003638 chemical reducing agent Substances 0.000 claims description 3
- 238000011049 filling Methods 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 3
- 238000003825 pressing Methods 0.000 claims description 2
- 238000007789 sealing Methods 0.000 claims description 2
- 230000001788 irregular Effects 0.000 abstract description 4
- 239000000463 material Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000000889 atomisation Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 238000000462 isostatic pressing Methods 0.000 description 2
- 238000005272 metallurgy Methods 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000011265 semifinished product Substances 0.000 description 2
- 239000003610 charcoal Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000009694 cold isostatic pressing Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 238000009692 water atomization Methods 0.000 description 1
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
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/20—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by extruding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
- B22F1/14—Treatment of metallic powder
- B22F1/145—Chemical treatment, e.g. passivation or decarburisation
-
- 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%
- C22C33/0285—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 Cr, Co, or Ni having a minimum content higher than 5%
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Powder Metallurgy (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
Abstract
A molten mass of steel is atomised by means of pressurised water; the irregular steel powder produced is subjected to a reduction annealing to remove the oxide skin surrounding the individual powder grains, plate-shaped compacts produced from the powder and a sheet-metal case is filled with these compacts to a desired level and the resulting preform extruded.
Description
"A METHOD OF MANUFACTURING BLOCKS OR PROFILED SECTIONS"
The present invention relates to a method of manufacturing blocks or profiled sections, in particular from special steel grades. In this connection, by "special steel grades" is meant alloy steels which, for example, on account of coarse primary-carbide precipitation, cannot be made even approximately with the same technological properties by melt-metallurgy as they. can be in a powder-metallurgical manner.
German Offenlegungsschrift No. 2,419,014 discloses a method of manufacturing tubes, bars or similar elongate sections from steel powder, in particular from stainless steel grades. In this method, a molten mass of steel is atomised by means of high-pressure gas to form a steel powder with spheroidal individual grains, an inert gas being used as atomising medium to avoid oxidation. This steel powder is then filled into a sheet-metal case which is evacuated and tightly sealed. The sheet-metal case with the powder filling is then brought to a relative density of at least 80% in a cold-isostatic pressing operation. The preform thus obtained is then heated and worked by extrusion to form the desired section, which is distinguished by a segregation-free structure.
A disadvantage in this method is, on the one hand, the necessity for the atomisation using inert gas, which compared with atomisation using water, because of the considerably poorer cooling conditions for the atomising particles, is substantially more complicated and thus more expensive. On the other hand, the isostatic pressing operation also requires appreciable expenditure in equipment, which makes the method expensive.
An object of the present invention is to provide a modification of this method in which the effort involved in carrying out the method is reduced.
According to the invention, there is provided a method of manufacturing a block or profiled section by extrusion of a preheated preform, which comprises the steps of:
atomising a molten mass of steel by means of pressurised water to produce steel powder;
subjecting the steel powder so formed to a reductive annealing in vacuum using solid carbon as reducing agent, whereby the oxide skin surrounding the individual powder grains is removed;
producing plate-shaped compacts from the reduced steel powder 3 having a substantially constant density of at least 6.0 g/cm by pressing in a powder press, said compacts having a cross-sectional shape corresponding to that of said preform;
filling a sheet-metal case with said compacts to a desired level, and evacuating and sealing said case, to form said preform; and
preheating and extruding the preform to form said block or profiled section.
Thus, in this method a steel powder which is of irregular configuration in its grain form is first produced by means of economic pressurised-water atomisation. Because of the means used, the particles of this steel powder are covered with an oxide skin which at first prevents further metallurgical processing of the powder. Reduction annealing is therefore provided for removing the oxide skin, which reduction annealing, according to the invention, is carried out in vacuum with solid carbon as a reducing agent. The result of this stage. is a practically oxygen-free steel powder with an oxygen content of expediently less than 1000 ppm, preferably less than 500 ppm, which, because of its irregular grain form, can be pressed very easily, so that it supplies without the need for special measures compacts with adequate green strength.The steel powder is therefore pressed on a normal metal-powder press to form plate-shaped compacts of, considered over the whole volume, approximately constant 3 density, the density being greater than 6.0 g/cm , preferably
3 greater than 6.4 g/cm . The cross-sectional shape of the plate-shaped compacts at the same time corresponds to the cross-sectional shape of the preform required for the final extrusion. To form the preform, a number of these compacts are filled into a sheet-metal case which is then evacuated and sealed.
In this way, a preform of any length can be manufactured whilst using only a single press tool for the plate-shaped compacts. The isostatic pressing operation, hitherto absolutely essential in the methods of the prior art for producing a preform with an approximately constant density, can therefore be dispensed with.
Because of this, however, the limitations on the size of the preform on account of the dimensions of an isostatic press chamber also no longer exist. The plate-shaped compacts can be produced with a constant density without difficulty and, by stacking one on another in the sheet-metal case, can be joined to form preforms with likewise virtually constant density and of any length. Surprisingly, the joint faces between the individual plate-shaped formed articles, after the extrusion of the preform heated to processing temperature, can no longer be detected in the extruded block or other profiled section.
The relative density of these products is 100 %; their structure is distinguished by uniformly finely distributed precipitation.
It is also possible in producing the compacts required for the preforms to use, instead of a particular steel powder, a mixture of several steel powders which are of different alloys or have been atomised differently, so that the technological properties of the products made can be influenced in a specific way.
The invention is illustrated by the following example:
To manufacture semi-finished products, a mass of molten steel of the material 1.3343 was atomised using water. The steel powder produced had an irregular particle shape and the following composition (% by weight):
0.12 % C
4.2 % Cr
5.1 % Mo
1.9 % V
6.5 % W
0.4 % Si
0.3 % Mn
0.98 % O (total).
This powder was reduced in vacuum using high-purity charcoal 0 for a period of about two hours at 1050 C. The final oxygen content was below 350 ppm. High-purity graphite was then added to the steel powder to adjust (for the purposes of better subsequent compressibility) the C-content to the desired value of 0.85%. This powder mix was pressed on a conventional powder press to form discs having a diamter of 140.5 mm and a thickness of 31 mm, these discs 3 having a density of 6.45 g/cm . Then, to obtain a preformed article, 15 of these discs were filled into a sleeve-shaped sheet-metal case made of the material St 37 and having a diameter of 145 mm and a wall thickness of 2 mm. The case was sealed, evacuated and welded air-tight. The case and the contents were then heated to a temperature of 12000C in a furnace, and the preform was hot extruded in an extrusion press to form a profiled bar of 51 mm diameter. The thin envelope (case material) of the profiled bar was removed by pickling in order to obtain the ready semi-finished product.
In a metallographic examination of the material, a structure appeared with an exceedingly fine carbide distribution, such as could not have been achieved with melt-metallurgy. The original joint faces between the discs of the preform could no longer be identified.
Claims (4)
1. A method of manufacturing a block or profiled section by extrusion of a preheated preform, which comprises the steps of:
atomising a molten mass of steel by means of pressurised water to produce steel powder;
subjecting the steel powder so formed to a reductive annealing in vacuum using solid carbon as reducing agent, whereby the oxide skin surrounding the individual powder grains is removed;
producing plate-shaped compacts from the reduced steel powder 3 having a substantially constant density of at least 6.0 g/cm by pressing in a powder press, said compacts having a cross-sectional shape corresponding to that of said preform;
filling a sheet-metal case with said compacts to a desired level, and evacuating and sealing said case, to form said preform; and
preheating and extruding the preform to form said block or profiled section.
2. A method as claimed in Claim 1, wherein said compacts are produced from a mixture of powders of different alloy steels.
3. A method of manufacturing a block or profiled section by extrusion of a preheated preform, substantially as hereinbefore described with reference to the example.
4. Blocks or profiled sections when manufactured by a method as claimed in any one of Claims 1 to 3.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3643016A DE3643016C1 (en) | 1986-12-12 | 1986-12-12 | Process for the production of blocks or profiles |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8728325D0 GB8728325D0 (en) | 1988-01-06 |
| GB2198749A true GB2198749A (en) | 1988-06-22 |
| GB2198749B GB2198749B (en) | 1990-07-25 |
Family
ID=6316349
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8728325A Expired - Fee Related GB2198749B (en) | 1986-12-12 | 1987-12-03 | A method of manufacturing blocks or profiled sections |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE3643016C1 (en) |
| GB (1) | GB2198749B (en) |
| SE (1) | SE500829C2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3928436C1 (en) * | 1989-08-24 | 1991-04-18 | Mannesmann Ag, 4000 Duesseldorf, De | |
| US6837915B2 (en) * | 2002-09-20 | 2005-01-04 | Scm Metal Products, Inc. | High density, metal-based materials having low coefficients of friction and wear rates |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB544974A (en) * | 1939-11-04 | 1942-05-06 | British Thomson Houston Co Ltd | Improved method of and apparatus for forming rods, tubes and like articles by extrusion |
| GB597638A (en) * | 1943-08-02 | 1948-01-30 | British Thomson Houston Co Ltd | Improvements relating to methods of and apparatus for extruding powdered materials |
| GB1069478A (en) * | 1964-04-06 | 1967-05-17 | Smith Corp A O | Method of making steel powder |
| GB1349452A (en) * | 1970-09-10 | 1974-04-03 | Ti Group Services Ltd | Production of an aluminium product |
| US3824097A (en) * | 1972-12-19 | 1974-07-16 | Federal Mogul Corp | Process for compacting metal powder |
| US3834004A (en) * | 1973-03-01 | 1974-09-10 | Metal Innovations Inc | Method of producing tool steel billets from water atomized metal powder |
| US3887402A (en) * | 1972-12-25 | 1975-06-03 | Yoshizaki Kozo | Method for producing high density steel powders |
| GB1425195A (en) * | 1972-06-29 | 1976-02-18 | Mannesmann Ag | Method of producing ferrous powder |
| GB2022001A (en) * | 1978-05-26 | 1979-12-12 | Glacier Gmbh Deva Werke | Sintering Non-Metallic Particles During Extrusion |
| GB1602581A (en) * | 1977-06-24 | 1981-11-11 | American Can Co | Production of steel strip by powder metallurgy |
| US4547336A (en) * | 1982-01-11 | 1985-10-15 | Meal Leve S.A. Industria E Comercio | Method for the manufacture of piston ring inserts by a powder metallurgy technique |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB732603A (en) * | 1953-05-11 | 1955-06-29 | Ici Ltd | Improvements in or relating to methods of and apparatus for the direct extrusion of a metal |
| US3766769A (en) * | 1972-06-22 | 1973-10-23 | Western Electric Co | Method of and means for commencing a deforming operation, e. g., hydrostatic extrusion of a billet |
| DE2310784B2 (en) * | 1973-03-03 | 1975-03-13 | Fa. Dr. Eugen Duerrwaechter Doduco, 7530 Pforzheim | Process for the production of a ductile silver-metal oxide semi-finished product |
| DE2419014C3 (en) * | 1974-04-19 | 1985-08-01 | Nyby Bruks AB, Nybybruk | Method of manufacturing stainless steel pipes and application of the method to the manufacture of composite pipes |
| DE3009916C2 (en) * | 1980-03-14 | 1985-10-10 | Nyby Uddeholm AB, Torshälla | Extruded billets for the powder metallurgical production of pipes and processes for their production |
-
1986
- 1986-12-12 DE DE3643016A patent/DE3643016C1/en not_active Expired
-
1987
- 1987-12-03 GB GB8728325A patent/GB2198749B/en not_active Expired - Fee Related
- 1987-12-11 SE SE8704958A patent/SE500829C2/en unknown
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB544974A (en) * | 1939-11-04 | 1942-05-06 | British Thomson Houston Co Ltd | Improved method of and apparatus for forming rods, tubes and like articles by extrusion |
| GB597638A (en) * | 1943-08-02 | 1948-01-30 | British Thomson Houston Co Ltd | Improvements relating to methods of and apparatus for extruding powdered materials |
| GB1069478A (en) * | 1964-04-06 | 1967-05-17 | Smith Corp A O | Method of making steel powder |
| GB1349452A (en) * | 1970-09-10 | 1974-04-03 | Ti Group Services Ltd | Production of an aluminium product |
| GB1425195A (en) * | 1972-06-29 | 1976-02-18 | Mannesmann Ag | Method of producing ferrous powder |
| US3824097A (en) * | 1972-12-19 | 1974-07-16 | Federal Mogul Corp | Process for compacting metal powder |
| US3887402A (en) * | 1972-12-25 | 1975-06-03 | Yoshizaki Kozo | Method for producing high density steel powders |
| US3834004A (en) * | 1973-03-01 | 1974-09-10 | Metal Innovations Inc | Method of producing tool steel billets from water atomized metal powder |
| GB1602581A (en) * | 1977-06-24 | 1981-11-11 | American Can Co | Production of steel strip by powder metallurgy |
| GB2022001A (en) * | 1978-05-26 | 1979-12-12 | Glacier Gmbh Deva Werke | Sintering Non-Metallic Particles During Extrusion |
| US4547336A (en) * | 1982-01-11 | 1985-10-15 | Meal Leve S.A. Industria E Comercio | Method for the manufacture of piston ring inserts by a powder metallurgy technique |
Also Published As
| Publication number | Publication date |
|---|---|
| SE8704958L (en) | 1988-06-13 |
| SE500829C2 (en) | 1994-09-12 |
| DE3643016C1 (en) | 1987-08-13 |
| SE8704958D0 (en) | 1987-12-11 |
| GB8728325D0 (en) | 1988-01-06 |
| GB2198749B (en) | 1990-07-25 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20001203 |