Classifications

• • 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
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process

Definitions

• Both the phosphate material and the fatty acid compositions are applied so that a substantially dry coating is formed substantially upon contact of the respective material with the metal surface.
• the metal surface is at an elevated temperature when the coating materials are applied and both the phosphate material and the fatty acid composition are desirably in the form of aqueous solution.
• the present invention includes a process for treating a metal surface to form thereon a lubricant coating suitable for use in a metal forming operation, which process comprises applying a phosphate material to the metal surface, effecting a controlled reaction between the phosphate material and the metal surface to form a phosphate coating which is at least partially unreacted wth the metal surface, the application of said phosphate material being carried out so as to form a substantially dry coating, substantially upon contact with the metal surface, applying a fatty acid soap composition to the thus-coated surface and effecting a controlled reaction between the soap composition and the phosphate coating to form a soap coating'which is at least partially unreacted with the phosphate coating and the metal surface, the application of the soap composition being carried out so as to form a substantially dry coating, substantially upon contact with the surface.
• the application of the coating material by the above method may, be controlled to obtain a desired coating weightl on th e surface and the residual coating remaining onthe metal surface after the deforming operation is easily
• the phosphate material. whichtis. first applied to the metal surface towbe deformed is 'preferably an aqueousphosphate-containingsolution.
• aqueousphosphate-containingsolution various solutions of this type, as are known to..tho"se 'in theLart; may be used, including aqueous:solutions of'alkali metal phosphate and aqueous acidic solutionsof'variousmetal I phosphates, such as zinc phosphatesymanganese phosphates, and the like.
• a lubricant concentrate composition which has been found to be particularly useful in one which is an admixture of from about 3 to 75% by weight of an alkali metal pyrophosphate or an alkali metal tetraborate, from about 15 to 97% by weight of a soap of a fatty acid and water in an amount up to about 80% by weight of the composition, wherein at least 0.2% by weight of the lubricant composition, but less than 50% by weight of the soap present in the composition is a fatty acid soap selected from the group consisting of fatty acid soaps of lithium, potassium, ammonium, calcium, magnesium, zinc or aluminum, the remainder of the fatty acid soap being a fatty acid soap of sodium.
• Lubricant concentrate compositions of this type are described in US. Pat. 3,313,729, issued Apr. 11, 1967, the disclosure of which patent is hereby incorporated in the present specification.
• a particularly preferred composition of this type contains the following components in the amounts indicated:
• the soap lubricant concentrate compositions of this type are desirably dissolved in water in amounts sufficient to form an aqueous working lubricant composition having a viscosity which is suitable for spraying. Desir'ably, however, the 'viscosity of the working lubricant ,eompositionis as high as possible, while still permitting spraying, as the use of extremely dilute solutions of low viscosity necessitates the application of greater amounts of solution in order to obtain the desired coating weights on the metal surface.
• the working lubricant compositions used will'contain the concentrate material in amounts within the range of about 0.1 to 4 pounds per gallon, with amounts within the range of about 0.5 to 2 pounds per gallon being preferred.
• a working lubricant solution containing the concentrate in an amount of about 1 pound per gallon has been found to give excellent results.
• the viscosity of the working lubricant composition will, of course, vary depending upon the concentration of the component, as well as the nature of these materials and the application technique used, in many instances, aqueous working lubricant compositions, of the above type, having a viscosity within the range of about 2000 to 10,000 centipoises have been found to be particularly useful.
• the phosphate composition and the soap composition may be applied in any convenient manner which will produce a substantially dry coating and which will effect the controlled reaction of the coating materials to form a coating which is at least partially unreacted with either the metal surface or the other coating material.
• a substantially dry coating it is intended to mean that there is substantially no migration of the coating components of the compositions applied, i.e., the phosphate material or the soap material, once the composition has been brought into contact with the surface to be treated.
• the overspray material and the coating components of the composition applied remain substantially in the area of the surface which they originally contact.
• this control of the reaction between the coating material and the substrate is effected by controlling the rate of dehydration of the solutions of the coating materials from the substrate after application. Such control may result by the control of the quantity of the coating solutions applied and/or control of the amount of heat which is available to effect the dehydration.
• the reaction of these materials with the substrate is controlled to the extent that the resulting coating is at least partially unreacted with the substrate and that the amount of reaction obtained is less than that which is normally obtained in the conventional application of these coating materials.
• the application is carried out so that there is a controlled metal loss from the metal substrate to which the phosphate coatings are applied, which metal loss is less than that which is normally obtained when the materials are applied in conventional manner, as for example, by spraying, immersion, or the like techniques.
• the reaction of the phosphate coating materials with the metal substrate is controlled to the extent that, desirably, there is a maximum weight loss of the substrate of less than about milligrams per square foot, and preferably less than about 60 milligrams per square foot. Similar controls of the reaction of the fatty acid soap lubricant materials are also effected.
• any suitable application technique which will give this substantially dry coating of the coating materials applied and Where the coatings produced are at least partially unreacted, either with each other or the metal surface as has been described, may be used.
• spray type applications and particularly those wherein the materials applied are in a relatively finely divided state or mi-s are preferred.
• the use ofgas atomized spray techniques have been found to give particularly satisfactory results and, for this reason, at the present time such application techniques arepreferred. It is to be appreciated, however, that in some instances,
• the preferred atomizing gas used is air, although other suitable atomizing gas which will not adversely aifect the materials being applied may also be used.
• the coating material to be applied is pumped under pressure through a suitable nozzle from which it is atomized and sprayed with air also under pressure.
• material pressures within the range of about 3 to 30 pounds per square inch are desirable, with pressures within the range of 5 to pounds per square inch being preferred.
• the pressure of the atomizing air for these phosphate materials is desirably within the range of about 10 to about 60 pounds per square inch with pressures within the range of about 10 to about 30 pounds per square inch being preferred.
• material pressures within the range of about 3 to about 30 pounds per square inch have been found to be desirable with pressures within the range of about 5 to pounds per square inch being preferred.
• the atomizing air pressures for the soap composition materials have desirably been found to be Within the range of about 10 to 60 pounds per square inch, with pressures within the range of about 12 to 30 pounds per square inch being preferred.
• the material and atomizing gas pressures which are used will depend upon the particular conditions of that application.
• the choice of the pressures used will depend upon the viscosity of the compositions being applied, the coating weight which is desired, as well as the number and placement of the spraying nozzles with respect to the metal surface which is to be coated. Accordingly, depending upon the particular combination of the above factors which are used, in some instances material pressures and atomizing gas pressures which are outside of the typical ranges which have-been set forth hereinabove may also be used.
• the metal surface to be treated is in the form of metallic sheet or strip, and preferably a ferrous metal sheet or strip, although other metals may also 'be treated. It is preferred that the metal sheet or strip be at an elevated temperature, in order to expedite the forming of a substantially dry coating of the material applied on the metal surface. Desirably, the metal surface is at a temperature of at least about 60 degrees centigrade with temperatures within the range of about 70 to 120 degrees cent :grade being preferred. If desired, the metal surface may be preheated prior to the application of the coating materials so as to be at the preferred elevated tempera ture when the materials are applied.
• the metal sheet or strip has been subjected to a polishing operation, it has frequently been found that the temperature of the metal will be raised sufficiently during this operation so that a separate preheating of the metal is not necessary, and the application of the coating material may be carried out on the metal as it leaves the flat. polisher.
• This is, of course, advantageous in that it reduces both the processing time required as well as the'ar nount of processing equipment and space for the installation of the treating line.
• the phosphate composition is applied to the metal surface to be treated prior to the application of the soap composition.
• the phosphate coating solution may be applied manually using an air atomized spray gun, it is preferred that the metal surface be passed through a spray zone containing a number of air atomized spray nozzles.
• the number of such nozzles used will, of course, depend upon the width of the metal sheet or strip to be coated, as well as the particular spray pattern and the placement of the nozzles which are used.
• the spray nozzles are positioned in the spray zone so that substantially complete coverage of the metal surface is obtained in a single pass through the spray zone.
• Polished steel bumper blanks 30% inches wide by 89 inches long by 0.94 inch thick, directly from the polishing machine at a temperature of 75 degrees centigrade, were then passed through a 4-foot spray zone at a conveyor speed of 50 feet per minute.
• the phosphating solution at a temperature of 18 degrees centigrade, was sprayed on both the top and bottom of the sheet, by means of an air atomized spray nozzle, three nozzles being directed at both the top and bottom of the sheet.
• the material pressure for the spray nozzles was 7 pounds per square inch and the atomizing air pressure used was 12 pounds per square inch.
• the time for each of the blanks to pass through the spray zone was 4.8 seconds.
• the spray nozzles used were air atomized spray nozzles wherein the material pressure was 10 pounds per square inch and the atomizing air pressure was 15 pounds per square inch.
• the time for passage of the sheets through the second spray zone was 4.8 seconds.
• the hot, dry, coated sheets were then unloaded from the conveyor and stacked. It was found that the combined weight of phosphate coating and lubricant on the sheets was within the range of about 100 to 150 milligrams per square foot.
• the coated sheets were then formed into bumpers, using the regular production presses after which, the formed bumpers were cleaned with water only and were satisfactorily plated using regular production operations.
• Example 2 The procedure of Example 1 was repeated using a material pressure of 5 pounds per square inch for the phosphate material and an atomizing air pressure of pounds per square inch and using a material pressure of 11 pounds per square inch for the lubricant and an atomizing air pessure of 21 pounds per square inch. Using this procedure, it .was found that the combined weight of phosphate coating and lubricant formed on the sheets was within the range of 60-90 milligrams per square foot. These sheets, like those produced in Example 1, were satisfactorily formed into bumpers and plated, using normal production methods, with only a cleaning with water between the forming and plating operations.
• Example 3 The procedure of Example 1 was repeated with the exception that the material pressure and atomizing air pressure for the phosphate were 10 and 15 pounds per square inch, respectively and the material pressure and atomizing air pressure for the lubricant were 13 and pounds per square inch, respectively. Using this procedure a combined phosphate and lubricant coating of 140-200 milligrams per square foot was formed on the sheets, which sheets were formed into bumpers, cleaned with water and then plated, using normal production methods.
• a method for treating metal surfaces to form thereon a lubricant coating suitable for use in metal forming operations, which comprises applying a phosphate material to the metal surface, effecting a controlled reaction between the phosphate material and the metal surface, by controlling the rate of dehydration of the phosphate material from the metal surface, forming a phosphate coating which is at least partially unreacted with the metal surface, the amount of reaction with the metal surface being such that upon removal of the phosphate coating, the metal loss from the surface is less than about milligrams per square foot, the application of said phosphate material being carried out so as to form a substantially dry coating, substantially upon contact with the surface, applying a fatty acid soap composition to the thus-coated surface and effecting a controlled reaction between the soap composition and the phosphate coating to form a soap coating which is at least partially unreacted with the phosphate coating and the metal surface, the application of the soap composition being carried out so as to form a substantially dry coating, substantially upon contact with the surface.
• fatty acid soap composition is formed from a concentrate which contains the following components in the amounts indicated:
• Tetrapotassium pyrophosphate 3-75 by weight Tetrapotassium pyrophosphate 3-75 by weight.
• Lithium stearate 0.2 to not more than 50% by weight of the soap present.
• a method of deforming metal which comprises forming a lubricant coating on the metal surface to be deformed in accordance with the method of claim 1 and, thereafter, deforming the thus-coated metal surface.
• phosphate material is an aqueous solution containing the following components in the amounts indicated:

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• Chemical & Material Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Lubricants (AREA)
• Chemical Treatment Of Metals (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=24900695

Family Applications (1)

Country Status (4)

Cited By (4)

• 0
  • FR FR170784A patent/FR96026E/fr not_active Expired
• 1968
  • 1968-04-18 US US722148A patent/US3556867A/en not_active Expired - Lifetime
  • 1968-11-25 BE BE724416D patent/BE724416A/xx unknown
  • 1968-11-30 ES ES360901A patent/ES360901A2/es not_active Expired

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