Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
  • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
  • B21B45/0239—Lubricating
  • B21B45/0245—Lubricating devices
  • B21B45/0263—Lubricating devices using solid lubricants
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface treatment
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C24/00—Coating starting from inorganic powder
  • C23C24/02—Coating starting from inorganic powder by application of pressure only
  • C23C24/06—Compressing powdered coating material, e.g. by milling
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
  • C21D8/0236—Cold rolling
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
  • C21D8/0278—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular surface treatment
  • C21D8/0284—Application of a separating or insulating coating

Definitions

• the invention relates to improved techniques of treating certain steels with molybdenum disulfide to de ⁇ crease friction and to increase resistance to corrosion.
• Molybdenum disulfide (M0S2) is a well known, versatile dry film lubricant. Inherent basal cleavage occurring within its atomic structure results in low lamellar shear strength and contributes to its superior anti-friction or lubricious properties. There is evidence to show that this property is caused by Van der aals type bonding between two molecular unit cells on the basal plane connecting the six-fold symmetry of the respective layers comprising the crystal structure as a whole. It is pre ⁇ cisely these chemical bonds, relatively long in physical length, which cause low lamellar shear strength and there ⁇ fore low dry friction measurement on sliding and rotating contact.
• the chemical bonding occurring in the crystal plane located at right angles to the basal plane is more typical of the mono-valent type, shorter in physical length and therefore many times stronger.
• Recent studies show the hardness for the basal plane as measured on the Vickers Scale to be 32 Kg./mm and that for the crystal plane to be 900 Kg./mm , the latter thus being harder by a multiple of nearly 29.
• Such a difference in physical measurements within a single unit crystal causes anisotropy, a condition which permits implantation of molybdenum disul- phide into metal surfaces to be practical and achievable.
• an inorganic film containing M0S2 and bonded to the spring material has
• Such high wear items as piston rings, bearings, journals, valve stems, shafts, and the like, for instance, are composed of various grades of high
• Cold drawn wire for use in stranded wire construc ⁇ tions such as wire rope for lifting mechanisms, ship board cable systems, aircraft control cable and the like, and for use in coil springs such as compression, extension and torsion types, is also typically manufactured from various high carbon steel alloys.
• the finished wire is furnished to the spring manufacturer, for example, and the springs them ⁇ selves are formed by various operations including coiling, grinding, secondary forming, stress relieving, plating and, in many instances, special packing.
• the wire for stranded wire constructions is also shipped to a separate place for manufacture of the rope itself.
• the wire for both springs and rope is produced by a combination of cold working, annealing and final ' tempering operations to a predetermined diameter and shipped on spools, reels or loose wound coils.
• Aircraft carrier arresting cables represent another area of utility for M0S2.
• Current practice is to reduce friction and corrosion of such cables by repeated applicatons of a barrier film, such as grease. But the grease is gradually removed from the cable during use and causes the flight deck to become slippery in critical places. In addition, the grease, being flammable, is a fire hazard, and its elimination would thus provide safer opera- ting conditions.
• Another carrier-related problem is corro ⁇ sion of internal aircraft control cables by salt air, and those too ought to be improved both in longevity and corro ⁇ sion resistance by 0S2.
• the invention takes advantage of certain proper ⁇ ties of medium to high carbon and stainless steels when they are cold worked in order to bring them down to a predeter ⁇ mined finished size.
• cold working is meant operations such as drawing, forging, rolling and other standard methods of cold working metal
• intermediate to high carbon and stainless steels are meant carbon steels, such as AISI-SAE Nos. 1035 to 1095 and AISI-SAE stainless Types 301, 302, 304, 316, 316L, 416, and the like, all of which are “interstitial” in nature or structure and typically used for high surface wear applica ⁇ tions.
• OMPI working process involves a succession of cold workings interspersed by a succession of annealings, the number of each and their arrangement depending upon the extent to which the metal must be reduced in cross sectional size, sometimes referred to as "breaking down" of the metal to finished size.
• a byproduct of the annealing operation is a phenomenon called "carbide precipitation" owing to the interstitial nature of the metals concerned.
• the metal substrate forms macro-molecular carbon clusters between asperities on the metal's surface from which the heat of the annealing process removes the carbon and thereby creates decarbonized voids on the surface of the metal.
• These voids are more pronounced in size at the end of an annealing operation than they are at the end of a subsequent cold working operation.
• the essence of the invention is the application of the MoS 2 to the metal after the final anneal ⁇ ing operation but before the final cold working operation, the final annealing operation in this case in effect con ⁇ stituting a preparation of the metal for deposit of the MoS-.
• the surface hardness of the metal is less than it is after final cold working and tempering.
• the final cold working owing to the extreme pressure under which it occurs, will effectively embed the 0S2 into the micro-structure of the metal substrate.
• the anisotr ⁇ phic properties of the MoS 2 allow the latter better to penetrate the voids than is possible when the MoS2 is applied to the metal substrate after final cold working when the substrate possesses a higher superficial hardness.
• Mo is in micro-powder form which is sulfonated to obtain MoS ⁇ , also a powder. That is then sometimes mixed with graphite in a liquid carrier such as perchlorethylene, the graphite being added to improve lubricity at lower loads.
• a liquid carrier such as perchlorethylene
• the M0S2 in the foregoing state is further mixed with an inorganic binding agent such as sodium silicate.
• an inorganic binding agent such as sodium silicate.
• the steel is coated, in the manner hereafter described, with the foregoing mixture and the perchlorethylene "flash evaporated" before the final cold working operation. Where corrosion is not a problem this manner of practicing the invention is satisfactory.
• the invention is practiced in another form in which graphite is omitted and an organic based synthetic resin system is used as the binding agent in place of sodium silicate.
• the system includes a corrosion inhibiter in the form of a "redox" resin.
• redox a corrosion inhibiter
• the latter are synthetic polymers having a highly cross-linked hydro-carbon matrix with inherent reversible functional groups attached, such as quinone-hydro-quinone, which are alternately oxidized and reduced.
• redox resins When redox resins are present and in intimate contact within the surface interface, they act as solid electrolytes facilitating an electrical balance, chemically speaking, and cause the rate at which the various reactions occur to be slowed. Corrosion protection is afforded the base alloy even in the absence of a sacrificial addition of anodi protection.
• the invention will first be set forth in terms o 5 a partially predicted application to the manufacture o piston ring material for internal combustion engines.
• Piston rings for that purpose are typically fabri ⁇ cated from various high carbon steel alloys.
• the material is furnished the ring manufacturer in the form of 0 flat strips of cross-sectional dimensions, for example, of .61 mm by 2.70 mm in the case of material for oil control rings, produced by a combination of cold working, annealing and final tempering operations.
• the invention would be practiced by the manufacturer of the strips before 15 the latter are shipped to the ring maker. Assume, for example, a strip of the above dimensions in finished size whose cross sectional area is thus 1.665 mm .
• the invention may be practiced in this instance by coiling an interim size strip, after preparation 5 by final annealing, on a take-off drum providing a low back tension on the strip and then recoiled on a suitable take-up drum spaced from the former drum in a sometimes called "coil-to-coil" operation.
• a tank which may be open to the atmosphere, of perhaps 84 0 litre capacity and equipped with a suitable stiring device.
• a liquid carrier such as perchlor- ethylene and an inorganic bonding agent such as sodium silicate, all more or less at room temperature.
• a thermostatically con ⁇ trolled oven or furnace capable of maintaining a temperature of about 260° C over a distance of 2 linear metres.
• the strip from the take-off drum is then led by suitable well known means through the mixture in the tank, which is agitated by the stirring device in order to keep the MoS2 in. suspension, from which it emerges "wet", and then through the oven where the perchlorethylene is "flash evaporated” in order to produce a dry bonded film of MoS 2 on the strip, the latter being finally recoiled on the takeup drum, all at the rate of about 3.65 linear metres per minute.
• the strip from the take-up drum is next finally cold worked to its finished cross-sectional dimen ⁇ sion in the usual manner and then tempered at about 200° C.
• the temperatures of the strip during the deposit of the MoS-, the riddance of the carrier liquid and the final cold working and tempering operations, should be kept below the oxidation temperature of the MoS 2 which is about 425-480° C. Even so, the oxidation rate of MoS- to MoO- is quite slow and studies have shown that MoS 2 does not lose its lubricity at those temperatures until 30% or so has been oxidized.
• the depth of the inclusion is a function of the depth of the respective decarburized zones; that is to say, the degree of inclusion appears constant at about 55-60% of the starting depth of the zones concerned for a given amount of cold working. It was also concluded that annealing of the steel before treatment produces a rela- tively soft ferritic transformation near the surface compared with the underlying pearlite and therefore lends itself to substrate embodiment by the implantation process of the invention.
• the lubricated ring better withstands high operating loads, better operates for short periods with boundary lubrication, better distributes local loads, and betters the wear charac ⁇ teristics of the mating surfaces. This is especially important adjacent top and bottom dead centers since the greatest wear of a cylinder wall in an internal combustion engine has been found to occur where piston direction changes and where the oil film is unable to accumulate sufficient thickness to separate the two opposing surfaces. This is because the zero velocity of the piston at those two points means that the hydrodynamic requirement of relative velocity between opposing surfaces is not met at these precise locations.
• the lubricated rings provides supplemental lubrication at these points at these crucial times, something a chrome plated ring cannot do, as well as over the entire cylinder wall during the critical breakin period of a new engine.
• the invention will next be set forth in terms of a predicted application to the manufacture of cold drawn wire for use in springs and stranded wire constructions.
• the wire after the latter annealing operation may be coiled on a pay-off reel with which is appropriately associated a take-up reel for a coil-to-coil coating operation.
• a refrigerated tank of perhaps 70 to 80 litre capacity into which is placed a mixture of solid, micro-meter sized MoS 2 , organic based binding agents, such as phenolic-vinyl-resin or epoxy-vinyl-resin, together with redox resins to act as corrosion inhibiting agents, and a quick drying composite solvent or liquid carrier consisting of 60% cellulose acetate, 30% xylene, and 10% methyl ethyl ketone.
• the refrigeration of the tank is regulated to keep the mixture at a temperature between 0° and 5° C owing to the volatility of the solvent.
• a thermostatically controlled oven or furnace capable of maintaining a temperature of 260° C over a dis ⁇ tance of 2 linear metres.
• the wire from the pay-off reel is then led by well-known means through the mixture in the tank which is agitated by a suitable stirring device in order to keep the MoS 2 in suspension.
• the wire then emerges from the tank “wet” and into the oven where the solvent is "flash evaporated” in order to leave a dry bonded film of MoS- on the wire.
• the latter is recoiled on the take-up reel at the rate of 3 to 3-1/2 linear metres per minute, the rapid rate of reaction of the resins concerned being essential because -12-
• the wire is trans ⁇ ferred to a suitable wire drawing installation and reduced in cross-sectional area, that is to say, cold worked, to its 5 previously mentioned finished diameter.
• cold working in this case should be kept at temperatures below about 315° C because the resins involved tend to decompose above that point.
• the wire would retain improved ductility and toughness compared to hot dipped galvanized wire because the brittle alloy between the zinc and the steel interface would be eliminated. The same or similar advantages would also accrue to such wire when employed in
• the invention is also believed applicable to other high wear components previously mentioned, such as bearings, journals, shafts and so forth, on which it would be prac ⁇ ticed in manners analogous to those described in the cases 30 of piston rings and wire.
• the invention is believed appli ⁇ cable as well to instances where the surface voids in the steel are achieved by preparatory means other than anneal ⁇ ing, such as by grinding, etching, sand blasting or pickling -of the material before the final cold working operation.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Manufacturing & Machinery (AREA)
• Other Surface Treatments For Metallic Materials (AREA)

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• 1982
  • 1982-04-09 EP EP19820901482 patent/EP0076317A4/de not_active Withdrawn
  • 1982-04-09 JP JP57501481A patent/JPH0694044B2/ja not_active Expired - Lifetime
  • 1982-04-09 WO PCT/US1982/000437 patent/WO1982003575A1/en not_active Application Discontinuation

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