GB1588786A - Production of metal strip or sheet - Google Patents

Production of metal strip or sheet Download PDF

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Publication number
GB1588786A
GB1588786A GB729078A GB729078A GB1588786A GB 1588786 A GB1588786 A GB 1588786A GB 729078 A GB729078 A GB 729078A GB 729078 A GB729078 A GB 729078A GB 1588786 A GB1588786 A GB 1588786A
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GB
United Kingdom
Prior art keywords
segments
roll gap
hopper
shielding plate
powder
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
Application number
GB729078A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
British Steel Corp
Original Assignee
British Steel Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from GB29779/76A external-priority patent/GB1544534A/en
Application filed by British Steel Corp filed Critical British Steel Corp
Priority to GB729078A priority Critical patent/GB1588786A/en
Publication of GB1588786A publication Critical patent/GB1588786A/en
Expired legal-status Critical Current

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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
    • B22F3/18—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces by using pressure rollers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B15/00—Details of, or accessories for, presses; Auxiliary measures in connection with pressing
    • B30B15/30—Feeding material to presses
    • B30B15/302—Feeding material in particulate or plastic state to moulding presses
    • B30B15/308—Feeding material in particulate or plastic state to moulding presses in a continuous manner, e.g. for roller presses, screw extrusion presses

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

Description

(54) PRODUCTION OF METAL STRIP OR SHEET (71) We, BRITISH STEEL CORPORATION, a Corporation incorporated and existing under the Iron and Steel Act 1967 whose principal office is at 33 Grosvenor Place, London, S.W.1X 7JG England, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to the production of metal strip or sheet (hereinafter referred to simply as strip), and more particularly to the compaction of particulate metalliferous material into strip or sheet form. The term 'metalliferous material' as used herein includes metals, metal containing and metal bearing materials.
Conventionally, a compaction mill includes a pair of rolls mounted with their rotational axes spaced in a substantially horizontal plane to define a roll gap therebetween; particulate material, e.g. metal powder, is fed into the mill from a hopper mounted with its discharge orifice positioned above the roll gap of the mill. To confine powder to the roll gap it is necessary to seal the spacing between the ends of the rolls.
Previous proposals for sealing these spaces have included use of endless belts which frictionally engage the opposed end surfaces of the rolls from points above to the bottom of the roll gap. The belts extend into openings formed in the end walls of the hopper and an adjustably mounted strip is located within each opening to regulate the surface area of belt in contact with the powder within the hopper. Other proposals for sealing the ends of the roll gap have included the use of rolls provided with overlapping flanges at their ends and discs rotatable so that their peripheries engage the opposed end surfaces of the rolls in the region of the roll gap.
These propsals all suffer from the disadvantages that the belts, flanges or rotating discs tend to draw increasingly excessive amounts of powder into the end zones of the roll gap as the rolling speed of the mill increases. The rate at which powder enters the roll gap is consequently not uniform across the length of the roll gap which leads to strip being produced of uneven thickness and density. In extreme cases the increased flow of powder to the end zones of the roll gap can result in roll failure due to the high local pressures generated.
The presence of the previously mentioned adjustable strips to regulate the surface area of belt in contact with the powder in the hopper only partially alleviates the problem of increased powder flow into the end zones of the roll gap since even relatively a small surface area of belt exposed to the powder draws powder into the roll gap end zones at a significantly greater rate than flows by gravity into the roll gap intermediate the end zones. In consequence, the edges of the strip emerging from the compaction mill are of increased density thus necessitating trimming to achieve the required consistent density and thickness across the width of the strip.
In our British patent specification no.
1544534 there is disclosed apparatus for compacting particulate metalliferous material into strip form which comprises a compaction mill, movable endless belts positioned one at each end of the roll gap of the mill in frictional engagement with the end faces of the rolls to close off the ends of the roll gap and a powder hopper mounted with its discharge orifice positioned above and extending across substantially the full length of the roll gap of the mill. Shielding plate assemblies are positioned one behind each side wall of the hopper and are movable relative thereto to positions in which they at least partially protrude below the lower margin of the hopper side walls to define the lengthwise extending boundaries of the discharge orifice of the hopper.
The present invention is an improvement in or modification of the invention described and claimed in the above-mentioned patent.
According to the present invention, apparatus for compacting particulate metalliferous material into strip form comprises a pair of compaction rolls mounted with their ro tational axes spaced apart in a substantially horizontal plane to define a roll gap there between, movable endless belts positoned one at each end of the roll gap in engagement with the end faces of the rolls to close off the ends of the roll gap, a hopper for feeding particulate material into the roll gap mounted with its discharge orifice positioned above and extending across substantially the full length of the roll gap, and shielding plate assemblies positioned one externally of each side wall of the hopper and including a plurality of mutually slidcable segments arranged to move towards and away from the roll gap to positions in which they protrude to a greater or lesser extent below the lower edges of the hopper side walls to define the lengthwise extending boundaries of the discharge orifice of the hopper.
Each hopper side wall may include a flexible extension which protrudes downwardly below the lower margin of the hopper side wall and extends across the entire width of the roll gap. The shielding plate segments may be mounted for sliding movement between the opposite faces of the hopper side walls and backing plates. The segments may extend across the entire width of each hopper side wall or partially across the width thereof.
The contacting side edges of adjacent segments may be provided with cooperating tongues and grooves. The individual sigments may be moved by means of pneumatic or hydraulic piston/cylinder devices, one such device being connected to move one or a number of individual segments. Alternatively, the individual segments may be moved by means of a series of cams.
The lower margins of the several segments which comprises each shielding plate may be shaped to provide a substantially smooth and regular contour at the lower edge of the shielding plate.
Movement of the segments may be controlled through transducers in response to changes in mill operating parameters or to dimensional or density errors detected in the strip leaving the mill.
In a preferred use of the apparatus described above the particulate material consists of metallic powder, e.g. iron, mild or stainless steel, nickel, copper, aluminium or metalliferous ore. The powder may be produced by a water atomisation technique.
The invention will now be described by way of example with reference to the accompanying diagrammatic drawings in which: Figure 1 is a side elevational view in section of apparatus in accordance with the invention, Figure 2 is a side elevational view of an edge belt and shutter assembly used to retain metal powder within the sides of the roll gap of the mill illustrated in Figure 1, Figure 3 is a front elevational view of one hopper side wall and associated shielding plate employed in the mill illustrated in Figure 1, and Figure 4 illustrates an alternative hopper side wall and shielding plate construction to that illustrated in Figure 3.
The invention will be described with reference to the production of metal strip by roll compacting metal (e.g. steel) powder produced by a water-atomisation technique.
Where appropriate, throughout the following description, like integers bear the same reference numerals.
The compaction mill illustrated in Figure 1 includes a pair of cooperating contra-rotating rolls 1, 2 which together define a roll gap 3 and which are mounted with their rotational axes spaced apart in a substantially horizontal plane. The roll gap 3 may be varied by movement of one roll towards or away from the other in a known manner.
A hopper 4 is mounted above the rolls 1, 2 to feed metal powder P into the roll gap 3.
The hopper 4 comprises end walls 5 between which are mounted two inwardly inclined side walls 6 carrying flexible extensions 7 which project part-way into the entry portion of the roll gap 3. Shielding plates 8 are positioned one behind each hopper side wall 6 and carry flexible extensions 9. The extensions 9 of the shielding plates 8 and the flexible extensions 7 of the hopper side walls 6 are preferably manufactured from springy metal and are curved particularly at their lower ends so that they engage the barrel surfaces of the rolls 1, 2 in the vicinity of the roll gap 3. The lower margins of the flexible extensions of the shielding plate and the flexible extensions of the side walls together define the lengthwise extending boundaries of a slot through which powder P present in the hopper 4 is fed into the roll gap 3. The slot extends over the full length of the roll gap 3.
Backing plates 11 are positioned one behind each shielding plate 8.
The hopper 4 is formed at its upper end with flanges (not shown) which extend outwardly to positions above the chocks of the rolls 1, 2. Hydraulic jacks (not shown) are positioned between the opposed surfaces of the flanges and the chocks and are operable to move the hopper 4 towards or away from the roll gap 3.
As shown in Figure 2, the ends of the roll gap 3 are closed by endless belts 18 which track around idle pulleys 19 and frictionally engage the opposed end faces of the rolls 1, 2 in the vicinity of the roll gap. Sufficient drive may be applied to the belts to overcome the mechanical resistance of the pulleys and to ensure that the speeds of the belts are matched to the speeds of the rolls. Each belt 18 is urged by its respective lower pulley l9a into contact with one pair of end faces of the rolls 1, 2 between positions above and just below the bottom of the roll gap 3 so as to seal off the ends of the roll gap. An adjustable skid 20 is provided to maintain tight contact between each belt 18 and the respective opposed end facees of the rolls.Shutters 22 are mounted within channels defined between the opposed surfaces of the end walls 5 and plates 23 secured to the end walls and are movable vertically to regulate the surface area of belt 18 in contact with the powder within the hopper 4. Movement of the shutters is effected by pegs 24 located in suitably shaped slots formed in the plates 23.
As will be seen from Figure 3 each shielding plate 8 comprises a plurality of mutually slidable elongate segments 14. The segments 14 are connected one to each of a plurality of hydraulic or pneumatic piston/cylinder devices 25 operable to move its respective segment to a position in which it protrudes to a greater or lesser extent below the lower generally horizontally extending margin of the side wall extension 7. The side edges of the segments are formed with cooperating tongues and grooves to enable adjacent segments readily to slide relative to one another.
The segments 14 are positioned between the opposed faces of the hopper side walls 6 and the backing plates 11 and comprise rigid upper portions which support the flexible extensions 9 of springy metal. The lower edge of each segment is so shaped that the margin defined by these edges is substantially smooth and regular in the positions taken up by the segments during normal operation of the mill.
In the alternative construction illustrated in Figure 4 the elongate segments 14 are moved by means of cams 26 carried by a rotatable rod positioned above the shielding plate. The cams 26 bear against spring loaded rods 27 mounted in contact with the upper surface of each segment 14. The cams increase in size towards the outer ends of the rod so that the outer segments are moved downwardly to an increasingly greater extent than the inner segments.
In the arrangements illustrated in both the Figure 3 and the Figure 4 movement of the segments 14 towards and away from the roll gap is controlled through transducers 2 operable in response to changes in mill operating parameters or errors in the dimensions and/or density of the strip product.
At start up of the mill each shielding plate assembly 8 is so positioned that the lengthwise extending boundaries of the feed slot of the hopper are defined solely by the lower margins of the flexible extensions 7 of the hopper side walls (as indicated by broken line in Figure 3). As the mill accelerates, the hopper 4 is raised to increase the flow of powder to the roll gap; simultaneously each shielding plate assembly 8 is lowered relative to the hopper so that the lower edges of the flexible extensions 9 of at least the outermost elongate segments 14 partially overlap the lower margin of the respective side wall extension 7.The protruding extenions 9 of the segments 14 adjacent the end zones of the roll gap shield the powder approaching these end zones from the rolls 1, 2 thereby offsetting the tendency of the edge belts 18 to draw powder into these end zones thereby to maintain the rates at which powder enters the roll gap substantially uniform across the entire length of the roll gap. When operating at the normal operating speed of the mill, the extensions 9 of the elongate segments 14 all protrude completely below the lower margins of the flexible extensions 7 so that the edge portions of the lengthwise extending boundaries of the feed slot are now defined by the lower edges of these extensions 9.By controlled movement of the individual segments at speeds intermediate start up and normal running speeds the flow of powder into the roll gap can be controlled to enable normal running speed to be achieved without high density bands of powder appearing at the edges or other locations along the length of the roll gap.
WHAT WE CLAIM IS: 1. Apparatus for compacting particulate metalliferous material into strip from comprising a pair of compaction rolls mounted with their rotational axes spaced apart in a substantially horizontal plane to define a roll gap therebetween, movable endless belts positioned one at each end of the roll gap in engagement with the end faces of the rolls to close off the ends of the roll gap, a hopper for feeding particulate material into the roll gap mounted with its discharge orifice positioned above and extending across substantially the full length of the roll gap, shielding plate assemblies positioned one externally of each side wall of the hopper and including a plurality of mutually slideable segments arranged to move towards and away from the roll gap to positions in which they protrude to a grater or lesser extent below the lower edges of the hopper side walls to define the lengthwise extending boundaries of the discharge orifice of the hopper.
2. Apparatus as claimed in Claim 1 wherein each shielding plate assembly comprises a backing plate extending across the entire width of the roll gap and a plurality of segments slidable between the backing plate and the adjacent side wall of the hopper.
3. Apparatus as claimed in Claim 2 wherein the segments together extend across the entire width of each backing plate or partially across the width thereof.
4. Apparatus as claimed in Claim 2 or Claim 3 wherein the contacting side edges of adjacent segments are provided with cooperating tongues and grooves and the individual segments are moved by means of pneumatic or hydraulic piston/cylinder de
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. below the bottom of the roll gap 3 so as to seal off the ends of the roll gap. An adjustable skid 20 is provided to maintain tight contact between each belt 18 and the respective opposed end facees of the rolls. Shutters 22 are mounted within channels defined between the opposed surfaces of the end walls 5 and plates 23 secured to the end walls and are movable vertically to regulate the surface area of belt 18 in contact with the powder within the hopper 4. Movement of the shutters is effected by pegs 24 located in suitably shaped slots formed in the plates 23. As will be seen from Figure 3 each shielding plate 8 comprises a plurality of mutually slidable elongate segments 14. The segments 14 are connected one to each of a plurality of hydraulic or pneumatic piston/cylinder devices 25 operable to move its respective segment to a position in which it protrudes to a greater or lesser extent below the lower generally horizontally extending margin of the side wall extension 7. The side edges of the segments are formed with cooperating tongues and grooves to enable adjacent segments readily to slide relative to one another. The segments 14 are positioned between the opposed faces of the hopper side walls 6 and the backing plates 11 and comprise rigid upper portions which support the flexible extensions 9 of springy metal. The lower edge of each segment is so shaped that the margin defined by these edges is substantially smooth and regular in the positions taken up by the segments during normal operation of the mill. In the alternative construction illustrated in Figure 4 the elongate segments 14 are moved by means of cams 26 carried by a rotatable rod positioned above the shielding plate. The cams 26 bear against spring loaded rods 27 mounted in contact with the upper surface of each segment 14. The cams increase in size towards the outer ends of the rod so that the outer segments are moved downwardly to an increasingly greater extent than the inner segments. In the arrangements illustrated in both the Figure 3 and the Figure 4 movement of the segments 14 towards and away from the roll gap is controlled through transducers 2 operable in response to changes in mill operating parameters or errors in the dimensions and/or density of the strip product. At start up of the mill each shielding plate assembly 8 is so positioned that the lengthwise extending boundaries of the feed slot of the hopper are defined solely by the lower margins of the flexible extensions 7 of the hopper side walls (as indicated by broken line in Figure 3). As the mill accelerates, the hopper 4 is raised to increase the flow of powder to the roll gap; simultaneously each shielding plate assembly 8 is lowered relative to the hopper so that the lower edges of the flexible extensions 9 of at least the outermost elongate segments 14 partially overlap the lower margin of the respective side wall extension 7.The protruding extenions 9 of the segments 14 adjacent the end zones of the roll gap shield the powder approaching these end zones from the rolls 1, 2 thereby offsetting the tendency of the edge belts 18 to draw powder into these end zones thereby to maintain the rates at which powder enters the roll gap substantially uniform across the entire length of the roll gap. When operating at the normal operating speed of the mill, the extensions 9 of the elongate segments 14 all protrude completely below the lower margins of the flexible extensions 7 so that the edge portions of the lengthwise extending boundaries of the feed slot are now defined by the lower edges of these extensions 9.By controlled movement of the individual segments at speeds intermediate start up and normal running speeds the flow of powder into the roll gap can be controlled to enable normal running speed to be achieved without high density bands of powder appearing at the edges or other locations along the length of the roll gap. WHAT WE CLAIM IS:
1. Apparatus for compacting particulate metalliferous material into strip from comprising a pair of compaction rolls mounted with their rotational axes spaced apart in a substantially horizontal plane to define a roll gap therebetween, movable endless belts positioned one at each end of the roll gap in engagement with the end faces of the rolls to close off the ends of the roll gap, a hopper for feeding particulate material into the roll gap mounted with its discharge orifice positioned above and extending across substantially the full length of the roll gap, shielding plate assemblies positioned one externally of each side wall of the hopper and including a plurality of mutually slideable segments arranged to move towards and away from the roll gap to positions in which they protrude to a grater or lesser extent below the lower edges of the hopper side walls to define the lengthwise extending boundaries of the discharge orifice of the hopper.
2. Apparatus as claimed in Claim 1 wherein each shielding plate assembly comprises a backing plate extending across the entire width of the roll gap and a plurality of segments slidable between the backing plate and the adjacent side wall of the hopper.
3. Apparatus as claimed in Claim 2 wherein the segments together extend across the entire width of each backing plate or partially across the width thereof.
4. Apparatus as claimed in Claim 2 or Claim 3 wherein the contacting side edges of adjacent segments are provided with cooperating tongues and grooves and the individual segments are moved by means of pneumatic or hydraulic piston/cylinder de
vices, one such device being connected to move one or number of individual segments.
5. Apparatus as claimed in Claim 2 or Claim 3 wherein the individual segments are moved by means of a series of cams carried on a rotatable shaft positioned above each shielding plate.
6. Apparatus as claimed in any one of Claims 1 to 5 wherein the lower margins of the several segments which comprise each shielding plate assembly are shaped to provide a substantially smooth and regular contour at the lower edge of the shielding plate assembly.
7. Apparatus as claimed in any one of the preceding claims wherein movement of the segments is controlled through transducers in response to changes in mill operating parameters or to dimensional or density errors detected in the strip leaving the mill.
8. Apparatus for compacting particulate metalliferous material into strip form substantially as herein described with reference to Figures 1, 2 and 3 or Figures 1, 2 and 4 of the accompanying drawings.
GB729078A 1976-07-16 1978-05-04 Production of metal strip or sheet Expired GB1588786A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB729078A GB1588786A (en) 1976-07-16 1978-05-04 Production of metal strip or sheet

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB29779/76A GB1544534A (en) 1976-07-16 1976-07-16 Production of metal strip or sheet
GB729078A GB1588786A (en) 1976-07-16 1978-05-04 Production of metal strip or sheet

Publications (1)

Publication Number Publication Date
GB1588786A true GB1588786A (en) 1981-04-29

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB729078A Expired GB1588786A (en) 1976-07-16 1978-05-04 Production of metal strip or sheet

Country Status (1)

Country Link
GB (1) GB1588786A (en)

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee