Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01B—SOIL WORKING IN AGRICULTURE OR FORESTRY; PARTS, DETAILS, OR ACCESSORIES OF AGRICULTURAL MACHINES OR IMPLEMENTS, IN GENERAL
  • A01B15/00—Elements, tools, or details of ploughs
  • A01B15/02—Plough blades; Fixing the blades
• • 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
  • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
  • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
  • B22F7/062—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools involving the connection or repairing of preformed parts
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02F—DREDGING; SOIL-SHIFTING
  • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
  • E02F9/28—Small metalwork for digging elements, e.g. teeth scraper bits
  • E02F9/2808—Teeth
  • E02F9/285—Teeth characterised by the material used
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
  • B22F2005/001—Cutting tools, earth boring or grinding tool other than table ware
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy

Definitions

• the present invention relates to wear-resistant materials. It is well known that metal plate or sheet materials can be made more wear-resistant by changes in their composition (alloying) or by surface treatments after formation. The expense of selecting special materials and/or carrying out hardening processes is frequently greater than can be justified by the increase in component life which is obtained. It is also known to protect metal surfaces by applied coatings or by the application of tiles of alumina or other ceramics. In this case softer metals can be used, for example mild steel instead of an alloy steel, and very good abrasion resistance is obtained, but if the tiles are subject to the action of large particles or lumps cracking takes place as a result of impact and the tiles tend to tear away from the underlying metal.
• British Patent Specification No. 1,480,057 describes the use of blunt or broken cutting tool blades in the form of lamellae composed of metallic carbides, nitrides, borides and/or silicides to form wear zones on metallic bodies.
• the lamellae lie parallel to the surface of the wear zone and are secured in position in a groove or recess by means of solder or adhesive.
• the lamellae are edge-on to the wear zone and are cast into the metallic body. While this may be a valuable way of using up old cutting blades, it is not a satisfactory method for obtaining good wearresistance at a reasonable cost.
• a wear-resistant material comprising a metal plate with a number of cavities or perforations formed therein, each of which has secured in it a platelet of oxide ceramic material of greater wear-resistance than the metal, the thickness of each platelet being disposed generally perpendicular to the surface of the metal plate so that the faces of the platelets are generally parallel to the surface of the plate, and the distance between adjacent platelets being in no case less than the thickness of the platelets.
• the oxide ceramic material which is preferably composed principally of alumina, can be preformed as platelets of any desired shape by known pressing and sintering techniques.
• the metal plate which is usually iron or steel, is also preformed by conventional techniques.
• Perforated metal plate for example, is readily available as a standard industrial product.
• the securing of the platelets in their cavities may be achieved simply by a mechanical fit resulting from the relative shape and dimensions or may be aided by the use of cement or adhesive. In either case the cooperation of the hard ceramic material and the softer and more ductile metal around it results in exceptional wear-resistance and greatly increased life.
• ferrous metals are used because the parts in question are normally made from such merals and they cooperate well with the alumina ceramics.
• other metals such as aluminium, can also be used in conjunction with oxide ceramics and improvements in wear resistance will be obtained with such combinations.
• the platelets may be discs but are not necessarily circular. Perforated metal plate with circular perforations is readily available and in this case circular ceramic discs with a thickness approximately equal to that of the metal plate are preferably used. However noncircular perforations having a rounded contour are also obtainable and other shapes of perforation or cavity can be made without too much difficulty. In each case the platelets are shaped to the appropriate contour. Normally the thickness or depth of each inserted platelet will be less than the minimum overall dimension of its face.
• perforated sheet metal commonly has webs between the holes which are no narrower than the thickness of the sheet. For the thickest sheet the resultant open area can be about 50% and larger open areas can be obtained when the same size of hole is used on thinner sheet.
• perforated plate When perforated plate is used the two sides can be made equally wear-resistant but in many cases only a single wear resistant surface is required.
• Commercial perforated plate often has slightly tapering holes and if the platelets are made with a similar taper a tight fit is obtained. It is also possible to use flanges on the discs or to clamp the discs in position from one side and in such cases the use of adhesive or cement is less necessary. For high-temperature applications an aluminous cement may be used.
• the material in accordance with the invention has the advantage that it can, within limits, be bent and cut on site without specialized equipment.
• the metal surfaces may, if required, be hardened before the ceramic platelets are inserted.
• Fig. 1 is a side elevation of a mould-board plough having a landside constructed of wear-resistant material in accordance with the invention
• Fig. 2 is an enlarged detail of the landside of Fig.1
• Fig. 3 is a perspective view of one bucket of a bucket wheel in which the bucket has a hinged bottom composed of wear-resistant material in accordance with the invention.
• the share is supported by a leg 10 from a beam (not shown).
• a mould-board 11 lifts and turns the soil while a landside 12 runs along the cut made by the point 13 of the share and thereby keeps the share running straight.
• the landside 12 runs in sliding contact with the vertical surface of the freshly cut ground and is thus subjected to severe sliding and impact abrasion.
• the landside 12 is secured to the plough share by coach bolts 14 and 15 to enable it to be removed and replaced.
• the landside is either made of expensive high-grade steel with the object of prolonging the period between initial fitting and replacement or is made of lower grade material to reduce the cost of replacements.
• the landside incorporating the invention is shown in more detail in Fig.2. It comprises a plate 16 of mild steel type EN9 in accordance with British Standard 970:1955.
• the plate is 10 mm thick and in addition to holes for the reception of the fastening bolts 14 and 15 it has eight perforations 17 each of which has a contour of parallelogram shape with rounded corners.
• the perforations 17 receive ceramic platelets 18 of corresponding shape and thickness which are composed of dense sintered alumina ceramic of 97.5% purity.
• the platelets 18 are secured in the perforations 17 by means of an epoxy adhesive.
• Each of the platelets 18 is arranged with its upper edge in advance of its lower edge with respect to the direction of movement of the plough share.
• the forward platelet 18A is spaced from the adjacent platelet by a web of metal approximately twice as wide as that separating each of the other pairs of platelets.
• the perpendicular distance between the inclined sides of these other pairs of platelets is 10 mm, which is equal to the thickness of the metal plate 16.
• a steel strengthening plate 19 is welded to the back of the plate 16.
• the plate 19 extends behind the three rearmost platelets 18 and thus provides additional support for these platelets, more especially against impact loading which might force the platelets out of their perforations.
• An additional ceramic insert 20 in the form of a circular disc is disposed in advance of the recess occupied by the head of the bolt 15. This is intended to increase the resistance to wear in the region ahead of the bolt head and thus avoid grooving, thereby preventing increased abrasion of the bolt head.
• Fig. 3 illustrates the application of the invention to a basket 21 of a bucket wheel.
• the bucket 21 is of conventional construction, having scraper teeth 22 at its forward edge to facilitate picking up of the spoil and a hinged bottom flap 23 which is opened at the appropriate point in the roration of the wheel in order to deposit the spoil.
• the inner surface of the bottom flap 23 is subject to heavy wear by impact and abrasion and to increase its wear resistance it is provided in accordance with the invention with a regular pattern of circular ceramic inserts 24 over its whole surface.
• the flap is of 10 mm thickness.
• the ceramic inserts are held in perforations extending through the thickness of the flap. They are arranged in staggered rows with a uniform centre to centre spacing in all directions.
• the inserts are of 25 mm diameter and at a centre to centre spacing of 35 mm. (They are not shown to scale in the drawing).
• the inserts cover approximately 50% of the total area.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Mining & Mineral Resources (AREA)
• Materials Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Chemical & Material Sciences (AREA)
• Civil Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Structural Engineering (AREA)
• Composite Materials (AREA)
• Soil Sciences (AREA)
• Environmental Sciences (AREA)
• Crushing And Pulverization Processes (AREA)
• Compositions Of Oxide Ceramics (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 1982
  • 1982-06-04 EP EP82901605A patent/EP0080473A1/de not_active Withdrawn
  • 1982-06-04 WO PCT/GB1982/000167 patent/WO1982004375A1/en unknown
  • 1982-06-09 ZA ZA824048A patent/ZA824048B/xx unknown

Non-Patent Citations (1)

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