US3839026A - PROCESS FOR THE PRODUCTION OF METAL STRIP FROM Fe POWDER - Google Patents

PROCESS FOR THE PRODUCTION OF METAL STRIP FROM Fe POWDER Download PDF

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Publication number
US3839026A
US3839026A US00369614A US36961473A US3839026A US 3839026 A US3839026 A US 3839026A US 00369614 A US00369614 A US 00369614A US 36961473 A US36961473 A US 36961473A US 3839026 A US3839026 A US 3839026A
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United States
Prior art keywords
strip
coating
rolling
slurry
metal
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Expired - Lifetime
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US00369614A
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English (en)
Inventor
A Harris
W Gibbon
I Davies
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British Steel Corp
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British Steel Corp
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Priority claimed from GB913067A external-priority patent/GB1212681A/en
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Assigned to BRITISH STEEL CORPORATION reassignment BRITISH STEEL CORPORATION ASSIGNOR AGREED TO TRANSFER THE ENTIRE INTEREST UNDER SAID PATENTS SUBJECT TO CONDITIONS RECITED, SEE DOCUMENT FOR DETAILS Assignors: BRITISH IRON AND STEEL RESEARCH ASSOCIATION, THE
Assigned to BRITISH STEEL CORPORATION reassignment BRITISH STEEL CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BRITISH IRON AND STEEL RESEARCH ASSOCIATION, THE
Assigned to MIXALLOY LTD, ANTELOPE INDUSTRIAL ESTATE, , reassignment MIXALLOY LTD, ANTELOPE INDUSTRIAL ESTATE, , ASSIGNS THE ENTIRE INTEREST, SUBJECT TO LICENSE AND CONDITIONS RECITED Assignors: BRITISH STEEL CORPORATION
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    • 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
    • B22F7/02—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 layers
    • B22F7/04—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 layers with one or more layers not made from powder, e.g. made from solid metal
    • 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
    • B22F5/006—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of flat products, e.g. sheets
    • 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
    • B22F2998/10—Processes characterised by the sequence of their steps

Definitions

  • the present invention sets out to provide a different route for the production of ferrous metal strip (particularly but not exclusively, strip in the range of 0.001 of an inch to 0.02 of an inch in thickness) using powdered metal as the starting material.
  • said coating comprising a suspension of powdered ferrous metal in an aqueous film-forming binder material
  • ferrous metal includes substantially pure iron and iron alloys in which iron is the major constituent.
  • the binder material is a cellulose derivative e.g., a ce1lulose ether such as methyl cellulose.
  • the objective is to produce cohension between the metal particles without heating the green strip (i.e., the strip after compaction but prior to sintering) to the melting point of the metal.
  • This objective can be achieved in the case of soft iron and mild steel powders formed in a coating of from 0.001 to 0.005 of an inch thick by maintaining the green strip at a temperature of from about 750 to 1,200C. for a period which will normally be of the order of to 60 seconds, for example seconds.
  • the sintering step may, however, be carried out at any temperature up to l,400C. for an appropriate time up to 4 minutes.
  • the sintering step should be carried out in a reducing atmosphere, for example in hydrogen or cracked ammonia. Any further sintering operations carried out in the strip may be effected under similar conditions.
  • the temperature and period of sintering will vary according to the nature of the metal powder and final properties required. in the case of stainless steel powders for example, the temperature and duration of sintering would be up to l,400C. for up to a period of about four minutes.
  • the binder used for forming the suspension with the powdered metal is preferably a film-forming binder material which is readily volatilised in the sintering step.
  • the binder composition is in the form of an aqueous solution of dispersion and may or may not require heating to induce film-forming. Film-forming cellulose derivatives have proved to be suitable and in addition to other advantages have the advantage of low cost.
  • a typical binder composition may be made by forming a 1.5 percent by weight aqueous methyl cellulose solution and a satisfactory suspension may be made with iron powder by mixing percent by weight of iron powder with 30 percent by weight of this solution.
  • the resulting suspension is a viscous mass which can be readily coated onto a support surface such as a belt or drum.
  • the suspension may be deposited onto the support surface by any of the known coating methods.
  • the preferred methods are by roller coating or extrusion but alternative methods include spraying and using a doctor blade.
  • relatively thick strip for example, of the order of 0.02 inch, it is advisable to employ a suspension having a low water content (in order to avoid possible subsequent difficulties in removing residual water from the selfsupporting layer) and in such cases it may be more convenient to deposit the viscous suspension by extrusion.
  • the viscosity of the slurry should be between 1,000 and 10,000 centipoises. In high speed deposition relatively low viscosity slurries are preferred e.g. between 3,000 and 5,000 centipoises.
  • the viscosity of the slurry can be varied by employing a higher or lower proportion of binder material.
  • the water is preferably removed by forced drying although in some circumstances some or all of the water may be allowed to evaporate at normal ambient temperature.
  • the function of the support surface is to support the coating of powdered metal and binder until the binder has formed a self-supporting film and as indicated above the support surface is conveniently a metal belt or drum e.g., of stainless steel.
  • a very thin metal coating for example 0.0005 inch in thickness may be plated onto one or both sides of the strip after the first compaction and/or sintering.
  • the size of the metal particles employed in the process of the present invention depends upon the thickness of the strip which it is desired to fabricate. In the manufacture of steel strip of the order of 0.001 to 0.005 inch in thickness, iron powder having a particle size in the order of minus 300 British Standard mesh is suitable. Clearly, the smaller the particle size of the powdered metal, the higher the density of the metal strip produced after the first rolling and sintering. Naturally, when producing comparatively thick strip, the particle size of the powder need not be so small.
  • Ferrous metal powder of the desired particle size may be produced in a number of ways.
  • One of the cheapest sources of iron powder is by milling sponge iron produced by direct reduction of iron oxide concentrates.
  • Other sources of powdered metal include condensation of metal vapours and precipitation of metal from solution.
  • a promising source of cheap iron powder is waste pickle liquor which contains quantities of ferrous chloride.
  • a powder product can be obtained by reduction of the ferrous chloride with hydrogen.
  • the strip may be subjected to an additional rolling operation followed by an additional sintering step. This has the effect of increasing the density of the product and improving its mechanical properties.
  • the strip may be subjected to a light planishing in order to improve its shape and appearance.
  • the rolling loads employed in the first compaction step are not critical but it is preferred to roll at 2 to 30 tons per inch width. For example, using 12 inch diameter rolls in a two high mill an 0.004 inch mild steel strip was typically rolled at tons per inch width in the first compaction.
  • first compacted densities e.g. 80 percent and usually -90 percent of theoretical density
  • relatively moderate rolling loads e.g., up to 20 tons- /inch width using 12 inch diameter rolls.
  • the first sintering times are kept short, e.g., 24O seconds, so that little or no spherodisation of porosity occurs but sufficient strength is obtained to allow the subsequent processing.
  • the amount and shape of the porosity is such that a fully dense material (e.g. 99 percent theoretical density) can be achieved with the minimum of rolling.
  • rolling reductions in the second pass are typically up to 15 percent extension (resulting in a 10 percent to 30 percent reduction in thickness) and this can be achieved in a single pass through a rolling mill.
  • the second compaction is followed by a second sinter, which preferably is an in-line treatment similar to the first sinter, although batch heat treatments can be effected in the second sinter.
  • the process of the present invention enables alloy strips of accurately determined composition to be prepared by virtue of the fact that the powdered ingredients of the alloy can be accurately measured for incorporation in the coating. Normally, however, a powdered alloy is used when making an alloy strip. Furthermore, since the metal strip is produced in accordance with the invention with a minimum of rolling operations the metallurgical changes occurring in the production of the strip from the powdered metal layer are minimised.
  • a further advantage arising from the manufacture of metal strip from powdered metal is that materials can be produced having special properties.
  • the corrosion-resistant material may be a metal such as nickel, or chromium and in such a case the coating may be applied by plating the iron powder prior to forming the coating of powdered metal. It has been found that iron powder can be readily plated with about 4 percent by weight of nickel and the resulting strip has very pronounced corrosionresistant properties.
  • a self-supporting coating containing nickel plated iron powder can be compacted and sintered to produce a steel strip having corrosion-resistant properties without breaking the coating around the iron powder.
  • Metal strip having other special properties may also be produced and it has been found useful to plate stainless steel powders with iron in order to reduce the necessary sintering temperature.
  • Plating of the powder may be achieved using an electroless plating solution or by making the powder the cathode of an electrolyte cell.
  • FIG. 1 is a schematic drawing of apparatus for producing ferrous strip.
  • a reservoir 1 contains a supply of metal powder binder suspension and this is transferred by a series of rollers 2 to an endless steel belt 3, the thickness of the coating being controllable by the spacing and speed of the rollers.
  • a drying oven 4 in which the water is evaporated.
  • the drying oven preferably incorporates a forced air supply.
  • the strip After passage through the drying oven 3, or where no drying oven is present, over the radiant heater, and after cooling, the strip is sufficiently self-supporting to be handled and it is then passed through the rollers 5 and 6 of a two high mill where the strip is compacted. These rollers are normally adjusted to apply a rolling load of between 2 and 30 tons eg tons per inch width of the coating.
  • a sintering furnace 7 which contains a reducing atmosphere, such as hydrogen or cracked ammonia and which is maintained at a temperature of between 750 and l,200 C. The speed of travel of the strip is adjusted so that the strip is preferably heated to this temperature for a period of between and 30 seconds.
  • the green strip between the first compaction and sintering steps, though capable of being handled is still somewhat fragile and care is necessary, particularly in the sintering furnace 7 since there is a very short stage when the binder has been burnt off and the temperature has not risen sufficiently for sintering of themetal particles to occur.
  • the green strip is conveniently transported through the furnace on a metal belt, which may be a mesh belt in order to reduce the amount of heat removed from the furnace.
  • the green strip may be passed through the furnace on a cushion of reducing gas, gas curtain seals being provided at each end of the furnace to reduce loss of gas and lateral gas streams being used to guide the strip through the furnace.
  • the bed of the furnace may comprise a series of closely spaced rotating rollers.
  • the strip produced after passage through the furnace 7 is a commercially useful product but its properties can be improved by subjecting it to an additional rolling by passage through a rolling mill 8 and an additional sintering step in a sintering furnace 9.
  • the rolling mill 8 is set to apply a rolling load which preferably produces a percentage extension of l to 5% and the sintering furnace 9 has a reducing atmosphere and operates at a similar temperature to furnace 7.
  • the shape and surface qualities of the strip may be improved by passage through a pair of planishing rollers 10 and 11 from which the strip can then be coiled on a roll 12. If desired the strip may be subjected to carburising or chromising either during or after one or both of the sintering steps.
  • a process for the production of ferrous strip from ferrous metal powder comprising the steps of:
  • said coating comprising a slurry formed of a suspension of powdered ferrous metal in an aqueous film-forming binder material
  • a process as claimed in claim 1 wherein said slurry has a viscosity between approximately 1,000 centipoises and approximately 10,000 centipoises.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Powder Metallurgy (AREA)
  • Manufacture Of Metal Powder And Suspensions Thereof (AREA)
US00369614A 1966-11-18 1973-06-13 PROCESS FOR THE PRODUCTION OF METAL STRIP FROM Fe POWDER Expired - Lifetime US3839026A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB913067A GB1212681A (en) 1966-11-18 1966-11-18 Process for the production of metal strip from powdered metal
GB5186166 1966-11-18

Publications (1)

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US3839026A true US3839026A (en) 1974-10-01

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US (1) US3839026A (US07345094-20080318-C00072.png)
BE (1) BE706698A (US07345094-20080318-C00072.png)
DE (1) DE1583732C3 (US07345094-20080318-C00072.png)
ES (1) ES347304A1 (US07345094-20080318-C00072.png)
FR (1) FR1552998A (US07345094-20080318-C00072.png)
LU (1) LU54888A1 (US07345094-20080318-C00072.png)
NL (1) NL166635C (US07345094-20080318-C00072.png)
SE (1) SE404588B (US07345094-20080318-C00072.png)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4225346A (en) * 1978-09-08 1980-09-30 Bell Telephone Laboratories, Incorporated Process for fabricating porous nickel bodies
US4592780A (en) * 1984-04-07 1986-06-03 Mixalloy Limited Production of flat products in strip sheet or like form
US4594217A (en) * 1985-03-07 1986-06-10 Scm Corporation Direct powder rolling of dispersion strengthened metals or metal alloys
US4602954A (en) * 1984-04-07 1986-07-29 Mixalloy Limited Metal strip
US4680161A (en) * 1985-09-02 1987-07-14 Daido Metal Company Ltd. Method of producing sliding composite material
US4772322A (en) * 1986-05-20 1988-09-20 John Bellis Production of flat products from particulate material
JPS6458479A (en) * 1987-06-05 1989-03-06 Mikusaroi Ltd Manufacture of article containing abrasive grain
US5011654A (en) * 1989-07-29 1991-04-30 Roy Mathers Production of flat products
FR2831891A1 (fr) * 2001-11-05 2003-05-09 Centre Nat Rech Scient Procede de fabrication de plaques en composite metal/ceramique
US20060039817A1 (en) * 2004-07-27 2006-02-23 General Electric Company Preparation of sheet by injection molding of powder, consolidation, and heat treating
US20090160105A1 (en) * 2006-07-06 2009-06-25 Plansee Se Process for Producing an Extruded Shaped Body
CN110038542A (zh) * 2018-01-17 2019-07-23 中国石油化工股份有限公司 一种制备烯烃环氧化用银催化剂的α-氧化铝载体的方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IE39215B1 (en) * 1973-05-03 1978-08-30 British Steel Corp Improvements in or relating to the production of metal strrip from powder

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3223523A (en) * 1963-07-05 1965-12-14 C K Williams & Co Inc Methods for improving pressed properties and characteristics of sintered powder metal compacts
US3268368A (en) * 1963-10-21 1966-08-23 Sherritt Gordon Mines Ltd Process for the production of wrought nickel strip and sheet of low hardness
US3323879A (en) * 1963-09-04 1967-06-06 Sylvania Electric Prod Powdered metal films
US3326676A (en) * 1965-05-05 1967-06-20 Deventer Werke G M B H Method of producing coherent bodies of metallic particles
US3330654A (en) * 1964-04-28 1967-07-11 Kennecott Copper Corp Continuous process for producing sheet metal and clad metal
US3335002A (en) * 1965-10-13 1967-08-08 Texas Instruments Inc Manufacture of alloy foils
US3418114A (en) * 1967-11-28 1968-12-24 Comstock Co The Method of producing a metal sheet by slip casting
US3476528A (en) * 1965-10-13 1969-11-04 Texas Instruments Inc High-temperature braze shim stock
US3658517A (en) * 1968-07-10 1972-04-25 British Iron Steel Research Production of strip from powdered metal
US3681062A (en) * 1968-07-18 1972-08-01 Summers & Sons Ltd John Method of producing a metallic length

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3223523A (en) * 1963-07-05 1965-12-14 C K Williams & Co Inc Methods for improving pressed properties and characteristics of sintered powder metal compacts
US3323879A (en) * 1963-09-04 1967-06-06 Sylvania Electric Prod Powdered metal films
US3268368A (en) * 1963-10-21 1966-08-23 Sherritt Gordon Mines Ltd Process for the production of wrought nickel strip and sheet of low hardness
US3330654A (en) * 1964-04-28 1967-07-11 Kennecott Copper Corp Continuous process for producing sheet metal and clad metal
US3326676A (en) * 1965-05-05 1967-06-20 Deventer Werke G M B H Method of producing coherent bodies of metallic particles
US3335002A (en) * 1965-10-13 1967-08-08 Texas Instruments Inc Manufacture of alloy foils
US3476528A (en) * 1965-10-13 1969-11-04 Texas Instruments Inc High-temperature braze shim stock
US3418114A (en) * 1967-11-28 1968-12-24 Comstock Co The Method of producing a metal sheet by slip casting
US3658517A (en) * 1968-07-10 1972-04-25 British Iron Steel Research Production of strip from powdered metal
US3681062A (en) * 1968-07-18 1972-08-01 Summers & Sons Ltd John Method of producing a metallic length

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4225346A (en) * 1978-09-08 1980-09-30 Bell Telephone Laboratories, Incorporated Process for fabricating porous nickel bodies
US4592780A (en) * 1984-04-07 1986-06-03 Mixalloy Limited Production of flat products in strip sheet or like form
US4602954A (en) * 1984-04-07 1986-07-29 Mixalloy Limited Metal strip
US4594217A (en) * 1985-03-07 1986-06-10 Scm Corporation Direct powder rolling of dispersion strengthened metals or metal alloys
US4680161A (en) * 1985-09-02 1987-07-14 Daido Metal Company Ltd. Method of producing sliding composite material
US4772322A (en) * 1986-05-20 1988-09-20 John Bellis Production of flat products from particulate material
JPS6458479A (en) * 1987-06-05 1989-03-06 Mikusaroi Ltd Manufacture of article containing abrasive grain
US5011654A (en) * 1989-07-29 1991-04-30 Roy Mathers Production of flat products
FR2831891A1 (fr) * 2001-11-05 2003-05-09 Centre Nat Rech Scient Procede de fabrication de plaques en composite metal/ceramique
WO2003039792A1 (fr) * 2001-11-05 2003-05-15 Centre National De La Recherche Scientifique Procede de fabrication de plaques en composite metal/ceramique
US20060039817A1 (en) * 2004-07-27 2006-02-23 General Electric Company Preparation of sheet by injection molding of powder, consolidation, and heat treating
US7387763B2 (en) 2004-07-27 2008-06-17 General Electric Company Preparation of sheet by injection molding of powder, consolidation, and heat treating
EP1754559A1 (en) * 2005-08-19 2007-02-21 General Electric Company Producing sheet by extruding powder, sintering, HIP and heat treating
US20090160105A1 (en) * 2006-07-06 2009-06-25 Plansee Se Process for Producing an Extruded Shaped Body
CN110038542A (zh) * 2018-01-17 2019-07-23 中国石油化工股份有限公司 一种制备烯烃环氧化用银催化剂的α-氧化铝载体的方法

Also Published As

Publication number Publication date
NL166635B (nl) 1981-04-15
SE404588B (sv) 1978-10-16
BE706698A (US07345094-20080318-C00072.png) 1968-05-17
FR1552998A (US07345094-20080318-C00072.png) 1969-01-10
DE1583732C3 (de) 1974-01-10
ES347304A1 (es) 1969-05-01
LU54888A1 (US07345094-20080318-C00072.png) 1968-02-08
NL166635C (nl) 1981-09-15
NL6715654A (US07345094-20080318-C00072.png) 1968-05-20
DE1583732B2 (de) 1973-06-14
DE1583732A1 (de) 1972-03-02

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Owner name: BRITISH STEEL CORPORATION, 33 GROSVENOR PLACE, LON

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:BRITISH IRON AND STEEL RESEARCH ASSOCIATION, THE;REEL/FRAME:004146/0319

Effective date: 19811008

Owner name: MIXALLOY LTD, ANTELOPE INDUSTRIAL ESTATE, RHYDYMWY

Free format text: ASSIGNS THE ENTIRE INTEREST, SUBJECT TO LICENSE AND CONDITIONS RECITED;ASSIGNOR:BRITISH STEEL CORPORATION;REEL/FRAME:004146/0326

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Owner name: BRITISH STEEL CORPORATION, 33 GROSVENOR PLACE LOND

Free format text: ASSIGNOR AGREED TO TRANSFER THE ENTIRE INTEREST UNDER SAID PATENTS SUBJECT TO CONDITIONS RECITED;ASSIGNOR:BRITISH IRON AND STEEL RESEARCH ASSOCIATION, THE;REEL/FRAME:004146/0331

Effective date: 19790330

Owner name: MIXALLOY LTD, ANTELOPE INDUSTRIAL ESTATE, ,

Free format text: ASSIGNS THE ENTIRE INTEREST, SUBJECT TO LICENSE AND CONDITIONS RECITED;ASSIGNOR:BRITISH STEEL CORPORATION;REEL/FRAME:004146/0326

Effective date: 19830207