CA1228707A - Method of making pipes by powder metallurgy and pipe blanks made in accordance therewith - Google Patents
Method of making pipes by powder metallurgy and pipe blanks made in accordance therewithInfo
- Publication number
- CA1228707A CA1228707A CA000466063A CA466063A CA1228707A CA 1228707 A CA1228707 A CA 1228707A CA 000466063 A CA000466063 A CA 000466063A CA 466063 A CA466063 A CA 466063A CA 1228707 A CA1228707 A CA 1228707A
- Authority
- CA
- Canada
- Prior art keywords
- bulge
- wall
- inner pipe
- pipe
- pipe wall
- 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.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25C—HAND-HELD NAILING OR STAPLING TOOLS; MANUALLY OPERATED PORTABLE STAPLING TOOLS
- B25C1/00—Hand-held nailing tools; Nail feeding devices
- B25C1/06—Hand-held nailing tools; Nail feeding devices operated by electric power
-
- 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
- B22F3/12—Both compacting and sintering
- B22F3/1208—Containers or coating used therefor
- B22F3/1258—Container manufacturing
-
- 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
- B22F3/02—Compacting only
- B22F3/04—Compacting only by applying fluid pressure, e.g. by cold isostatic pressing [CIP]
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Powder Metallurgy (AREA)
- Shaping Metal By Deep-Drawing, Or The Like (AREA)
- Drilling And Boring (AREA)
Abstract
Abstract of the Invention A method of making pipes by powder metallurgy, in which powder of metal and/or metal alloys is filled into a thin-walled casing consisting of inner pipe wall outer pipe wall and a bottom , subsequently the casing is closed on its side remote from the bottom by an annular cover and is subjected to a cold-isostatic pressure whereby the powder is compacted within the casing to produce a solid or dimensionally stable pipe blank or compact , which is then hot-worked, e.g.
extruded. In order to prevent thermal cracks on the inner pipe or inner pipe wall , especially in the region of the ends thereof, the inner pipe or inner pipe wall is provided prior to hot-working on at least one end region thereof with at least one circumferentially extending bulge
extruded. In order to prevent thermal cracks on the inner pipe or inner pipe wall , especially in the region of the ends thereof, the inner pipe or inner pipe wall is provided prior to hot-working on at least one end region thereof with at least one circumferentially extending bulge
Description
~870~
A METHOD OF MAKING PIPES BY POWDER METALLURGY AND PIPE
BLANKS SEMIFINISHED PRODUCTS) MADE IN ACCORDANCE
THEREWITH
Specification The invention is directed to a method of making pipes by powder metallurgy, in which powder of metal and/or metal alloys is filled into a thin-walled casing consisting of an inner casing wall, an outer casing wall and a bottom, whereupon the casing is closed by an annular cover on the side remote from the bottom and is subjected to a cold isostatic pressure, whereby compacting the power within the casing so as to produce a solid or dimensionally stable pipe blank which is then hot-worked, viz., extruded while being heated Such a method has been known generally. However, it has been found that cracks due to thermal stresses frequently occur chiefly on the inner pipe or inner pipe wall, respectively, particularly on the two end regions, i.e., near the casing bottom and/or the casing cover. The cracks may extend either across the entire circumference of the inner pipe or inner pipe wall, respectively, or only across part thereof, depending on the magnitude of the thermal stresses.
It has been found that the cause of such crack formation is non-uniform heating of the pipe casing to the hot working temperature. Such non-uniform heating occurs especially when large furnaces and relatively large pipe blanks or compacts are employed. For instance, it has been found that the thermal stresses may result in elongations especially of the inner pipe or inner pipe wall, respectively, amounting to 0.5 to 1% ox the length of the pipe blank or compact.
The present invention is based on the object of preventing such crack formation during heating of the pipe blank to the hot-working temperature.
In accordance with the invention this object is solved in a surprisingly simple way by the characterizing measures of patent claim 1, wherein the features described in the sub claims, which relate to engineering and shaping measures, have been found to be especially advantageous.
Due to the bulge according to the invention it is possible to compensate or neutralize thermal stresses, wherein the bulge or bulges are provided at locations of maximum thermal stress, i.e., preferably in the end regions of the inner pipe or inner pipe wall, respectively.
The size of the bulges) according to the invention depends on the dimensions of the pipe blank and also, of course, on the hot-wor~ing temperature. The bulge(s) should be dimensioned such that the inner pipe or inner pipe wall, respectively, is practically completely smoothed out upon heating of the pipe blank or compact to the hot-working temperature. The expansion or elongation of the inner pipe caused by the differences in temperature may be calculated from the start on the basis of the following equation:
-`` 1Zæ~7 IT tic) x Pipe (mm) x where T temperature difference expressed in C, L length of the pipe blank or compact expressed in (mm), and coefficient of thermal expansion.
Preferably, the bulges extend radially outwardly and are formed by means of rollers or rolls or the like, wherein both male and female mounds may be employed.
It is highly significant that the bulges should have a "gentle or shallow curved shape", especially in the tray-sessional regions between bulge and inner pipe or inner pipe wall, respectively. Thus the bulge cross-section is somewhat trough-shaped, the radii of transition being approximately in the range of the radius of the inner pipe wall. The formation of folds should be prevented at all costs.
As explained above, the bulges according to the invention permit stretching or elongation of the inner pipe or inner pipe wall upon heating of the pipe blank or compact to the hot-working temperature without any problems, so that the inner pipe wall will be smoothed out.
With especially large pipe blanks it will be appropriate prior to the formation of the bulges to anneal the cores-pounding locations, e.g. the end regions of the inner pipe and to remove the oxide layer formed thereby.
A METHOD OF MAKING PIPES BY POWDER METALLURGY AND PIPE
BLANKS SEMIFINISHED PRODUCTS) MADE IN ACCORDANCE
THEREWITH
Specification The invention is directed to a method of making pipes by powder metallurgy, in which powder of metal and/or metal alloys is filled into a thin-walled casing consisting of an inner casing wall, an outer casing wall and a bottom, whereupon the casing is closed by an annular cover on the side remote from the bottom and is subjected to a cold isostatic pressure, whereby compacting the power within the casing so as to produce a solid or dimensionally stable pipe blank which is then hot-worked, viz., extruded while being heated Such a method has been known generally. However, it has been found that cracks due to thermal stresses frequently occur chiefly on the inner pipe or inner pipe wall, respectively, particularly on the two end regions, i.e., near the casing bottom and/or the casing cover. The cracks may extend either across the entire circumference of the inner pipe or inner pipe wall, respectively, or only across part thereof, depending on the magnitude of the thermal stresses.
It has been found that the cause of such crack formation is non-uniform heating of the pipe casing to the hot working temperature. Such non-uniform heating occurs especially when large furnaces and relatively large pipe blanks or compacts are employed. For instance, it has been found that the thermal stresses may result in elongations especially of the inner pipe or inner pipe wall, respectively, amounting to 0.5 to 1% ox the length of the pipe blank or compact.
The present invention is based on the object of preventing such crack formation during heating of the pipe blank to the hot-working temperature.
In accordance with the invention this object is solved in a surprisingly simple way by the characterizing measures of patent claim 1, wherein the features described in the sub claims, which relate to engineering and shaping measures, have been found to be especially advantageous.
Due to the bulge according to the invention it is possible to compensate or neutralize thermal stresses, wherein the bulge or bulges are provided at locations of maximum thermal stress, i.e., preferably in the end regions of the inner pipe or inner pipe wall, respectively.
The size of the bulges) according to the invention depends on the dimensions of the pipe blank and also, of course, on the hot-wor~ing temperature. The bulge(s) should be dimensioned such that the inner pipe or inner pipe wall, respectively, is practically completely smoothed out upon heating of the pipe blank or compact to the hot-working temperature. The expansion or elongation of the inner pipe caused by the differences in temperature may be calculated from the start on the basis of the following equation:
-`` 1Zæ~7 IT tic) x Pipe (mm) x where T temperature difference expressed in C, L length of the pipe blank or compact expressed in (mm), and coefficient of thermal expansion.
Preferably, the bulges extend radially outwardly and are formed by means of rollers or rolls or the like, wherein both male and female mounds may be employed.
It is highly significant that the bulges should have a "gentle or shallow curved shape", especially in the tray-sessional regions between bulge and inner pipe or inner pipe wall, respectively. Thus the bulge cross-section is somewhat trough-shaped, the radii of transition being approximately in the range of the radius of the inner pipe wall. The formation of folds should be prevented at all costs.
As explained above, the bulges according to the invention permit stretching or elongation of the inner pipe or inner pipe wall upon heating of the pipe blank or compact to the hot-working temperature without any problems, so that the inner pipe wall will be smoothed out.
With especially large pipe blanks it will be appropriate prior to the formation of the bulges to anneal the cores-pounding locations, e.g. the end regions of the inner pipe and to remove the oxide layer formed thereby.
2~7[)~
below, a preferred embodiment of a pipe blank or compact configured and employed according to the invention will be described with reference to the accompanying drawing, which is a cross-section of a pipe blank or compact prior to hot-working. In the drawing indicates the pipe blank or compact, 11 indicates the casing outer wall, 12 indicates the casing inner wall which is concentric with the casing outer wall, 13 indicates the annular casing bottom, and 14 indicates the annular casing cover.
Each end of the inner pipe or inner pipe wall 12 is formed with a radially outwardly extending bulge 15, 16 which permits thermal expansion of the inner pipe upon heating of the tubular casing 10 to the hot-working temperature such that the inner pipe wall 12 will be smoothed out. With longer and larger-sized tubular casings 10 it is possible to provide at each end two or more bulges corresponding to the bulges 15, 16 and extending across the circumference of the inner pipe or inner pipe wall. As will also be apparent from the drawing, the bulges 15, 16 have relatively shallow cross-sections, ire., the radii of transition are rota-lively large and are within the range of the radius of thinner pipe wall 12.
The pipe blank or compact 10, which is heated to the hot-working temperature and has its inner pipe wall 12 smoothed out, may then be extruded in a conventional manner to form the final piping.
The depth and the radii of transition r1, r2 and r3 depend on the dimensions of the pipe blank or compact 10, on the powder material used, on the material of inner pipe wall 12 and outer pipe wall 11, and on the hot-working temperature LO
Preferably, the bottom radius r2 is twice as large as the radii of transition r1 and r3 in the transitional region between bulge and inner pipe.
All of the features disclosed in the application papers are claimed as being essential to the invention insofar as they are novel over the prior art either singly or in combine-lion.
below, a preferred embodiment of a pipe blank or compact configured and employed according to the invention will be described with reference to the accompanying drawing, which is a cross-section of a pipe blank or compact prior to hot-working. In the drawing indicates the pipe blank or compact, 11 indicates the casing outer wall, 12 indicates the casing inner wall which is concentric with the casing outer wall, 13 indicates the annular casing bottom, and 14 indicates the annular casing cover.
Each end of the inner pipe or inner pipe wall 12 is formed with a radially outwardly extending bulge 15, 16 which permits thermal expansion of the inner pipe upon heating of the tubular casing 10 to the hot-working temperature such that the inner pipe wall 12 will be smoothed out. With longer and larger-sized tubular casings 10 it is possible to provide at each end two or more bulges corresponding to the bulges 15, 16 and extending across the circumference of the inner pipe or inner pipe wall. As will also be apparent from the drawing, the bulges 15, 16 have relatively shallow cross-sections, ire., the radii of transition are rota-lively large and are within the range of the radius of thinner pipe wall 12.
The pipe blank or compact 10, which is heated to the hot-working temperature and has its inner pipe wall 12 smoothed out, may then be extruded in a conventional manner to form the final piping.
The depth and the radii of transition r1, r2 and r3 depend on the dimensions of the pipe blank or compact 10, on the powder material used, on the material of inner pipe wall 12 and outer pipe wall 11, and on the hot-working temperature LO
Preferably, the bottom radius r2 is twice as large as the radii of transition r1 and r3 in the transitional region between bulge and inner pipe.
All of the features disclosed in the application papers are claimed as being essential to the invention insofar as they are novel over the prior art either singly or in combine-lion.
Claims (8)
1. A method of making pipes by powder metallurgy, in which a thin-walled casing consisting of an inner pipe wall and an outer pipe wall and a bottom and wherein the casing is closed on the side remote from said bottom by means of an annular cover, is filled with a metal and/or metal alloy powder and is subjected to a cold-isostatic pressure, thereby producing a solid or dimensionally stable pipe blank which is then hot worked, comprising a step prior to hot working of forming in at least one end region of said inner pipe wall at least one circumferentially extending bulge, and thereafter hot working said blank with said bulge.
2. The method of claim 1, wherein said circumferentially extending bulge is formed by a step including application of roll means in said end region of at least one end of said inner pipe wall to form said at least one bulge as a radially outwardly extending bulge.
3. The method of claim 1 wherein each of the two end regions of said inner wall is formed with said at least one circumferentially extending bulge.
4. The method of claim 1, therein prior to forming of said at least one bulge includes the step of annealing the pipe blank and subsequently removing the oxide layer formed thereby.
5. The method of claim 1, wherein said at least one bulge is formed with relatively large radii of transition in the transitional regions between the bulge and the inner pipe wall so that the bulge has a relatively shallow cross-section.
6. A pipe blank adapted to be filled with metal powder and subsequently hot worked to form a pipe member, comprising an inner wall having a radial bulge in at least one end portioon, an outer wall, a first closure secured to said inner wall and outer wall to close the corresponding end, and an end cover secured to said inner wall and said outer wall to close the second end.
7. The pipe blank of claim 6, wherein said inner wall has said radial bulge in both end portions.
8. The pipe blank of claim 7, wherein each of said bulges includes large radii of transition in the transitional regions between said bulge and said inner pipe wall and so that said bulge has a relatively shallow cross section.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3338367.7 | 1983-10-21 | ||
| DE3338367A DE3338367C1 (en) | 1983-10-21 | 1983-10-21 | Process for the powder metallurgical production of pipes and pipe bolts (semi-finished products) |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1228707A true CA1228707A (en) | 1987-11-03 |
Family
ID=6212471
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000466063A Expired CA1228707A (en) | 1983-10-21 | 1984-10-22 | Method of making pipes by powder metallurgy and pipe blanks made in accordance therewith |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0141349B1 (en) |
| JP (1) | JPS60169504A (en) |
| KR (2) | KR890004603B1 (en) |
| BR (1) | BR8405321A (en) |
| CA (1) | CA1228707A (en) |
| DE (2) | DE3338367C1 (en) |
| ES (1) | ES8600986A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10018196B2 (en) | 2014-01-17 | 2018-07-10 | Diamet Corporation | Rotating body, rotating body material, and method of manufacturing rotating body |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3520910C2 (en) | 1985-06-11 | 1987-04-02 | Avesta Nyby Powder AB, Torshälla | Process for the production of extrusion billets, for the powder metallurgical production of tubes |
| FI100422B (en) * | 1994-07-11 | 1997-11-28 | Metso Paper Inc | Preparation of roller |
| KR102251808B1 (en) * | 2018-08-17 | 2021-05-20 | 박성일 | Trigger type hand piece |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| FR2492291A1 (en) * | 1980-10-22 | 1982-04-23 | Uk I Sp | Container for hot extrusion of metal powder - with flow-modifying profiling element(s) to improve prod. yield |
-
1983
- 1983-10-21 DE DE3338367A patent/DE3338367C1/en not_active Expired
-
1984
- 1984-10-18 DE DE8484112604T patent/DE3466656D1/en not_active Expired
- 1984-10-18 EP EP84112604A patent/EP0141349B1/en not_active Expired
- 1984-10-19 BR BR8405321A patent/BR8405321A/en not_active IP Right Cessation
- 1984-10-19 JP JP59220293A patent/JPS60169504A/en active Granted
- 1984-10-19 ES ES536956A patent/ES8600986A1/en not_active Expired
- 1984-10-20 KR KR1019840006580A patent/KR890004603B1/en not_active IP Right Cessation
- 1984-10-22 CA CA000466063A patent/CA1228707A/en not_active Expired
-
1987
- 1987-08-11 KR KR1019870008810A patent/KR890004604B1/en not_active IP Right Cessation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10018196B2 (en) | 2014-01-17 | 2018-07-10 | Diamet Corporation | Rotating body, rotating body material, and method of manufacturing rotating body |
Also Published As
| Publication number | Publication date |
|---|---|
| KR890003494A (en) | 1989-04-15 |
| EP0141349B1 (en) | 1987-10-07 |
| ES536956A0 (en) | 1985-11-01 |
| KR890004603B1 (en) | 1989-11-20 |
| JPH0515763B2 (en) | 1993-03-02 |
| ES8600986A1 (en) | 1985-11-01 |
| EP0141349A1 (en) | 1985-05-15 |
| KR890004604B1 (en) | 1989-11-20 |
| JPS60169504A (en) | 1985-09-03 |
| DE3466656D1 (en) | 1987-11-12 |
| KR850004036A (en) | 1985-07-01 |
| DE3338367C1 (en) | 1985-09-26 |
| BR8405321A (en) | 1985-09-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1077691A (en) | Method for producing clad steel pipes | |
| MX9706870A (en) | Method for making aluminum alloy sheet products. | |
| CA2244548A1 (en) | Method and apparatus for hydroforming metallic tube | |
| US5836065A (en) | Extended jacket end, double expansion hydroforming | |
| CA2235853A1 (en) | Method and apparatus for hydroforming metallic tube | |
| US4584170A (en) | Method of making pipes by powder metallurgy and pipe blanks (semi-finished products) made in accordance therewith | |
| CA1228707A (en) | Method of making pipes by powder metallurgy and pipe blanks made in accordance therewith | |
| JP2776796B2 (en) | Metal tube thickening processing method | |
| EP0761340A3 (en) | A process for gear-rolling a high accuracy gear | |
| SU653006A1 (en) | Die to unit for expanding hollow articles by internally applied pressure | |
| EP0194827A2 (en) | Superplastic forming | |
| SU1049184A1 (en) | Method of producing sintered articles with high density (its versions) | |
| GB2091141A (en) | Manufacture of axle bracket halves | |
| SU1159669A1 (en) | Method of producing articles from high-strength materials difficult to deform | |
| JPH03132B2 (en) | ||
| JPS6120365B2 (en) | ||
| SU1606245A1 (en) | Method of producing shaped annular articles | |
| CN206997709U (en) | It is a kind of to produce equipment of the casting with hollow core pipe | |
| SU1509182A1 (en) | Method of hot rolling powders of high-speed steel | |
| US3584367A (en) | Method for producing corrugated tubes having multiple walls | |
| RU2173598C2 (en) | Method for making expanded annular blanks of high alloys | |
| SU1014660A1 (en) | Method of producing tubes of sintered refractory materials | |
| US3037272A (en) | Method of making fine-grain chromium | |
| JPH01266930A (en) | Method for necking pipe end of pipe product | |
| JPS61190006A (en) | Production of hot extruded clad metallic pipe by powder metallurgical method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |