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

• the present invention relates to a method of pretreatment of simply shaped standard parts for chip-free cold working, made of iron and steel, in which aqueous suspensions are used which contain phosphoric acid suspended substances with laminar lattice structure, such as molybdenum disulfide, graphite, as well as surfactants and, where appropriate, other additives. These agents are applied to standard parts under certain conditions of use and certain control specifications.
• Aqueous dispersions which contain phosphoric acid, molybdenum disulfide, organic thickeners and, for example nitric acid in addition, are mentioned in British Pat. No. 767,572.
• the application of the agent to the surface of the workpiece to be shaped takes place by means of brushes, while the additional use of heat will lead to acceleration of the reaction and drying of the coating.
• the use of this method is also cumbersome and timeconsuming.
• the procedure comprises the following steps: cleansing; rinsing with water; phosphatizing, for example with a zinc phosphate solution; rinsing with water at about 80C.; treatment in a stable aqueous suspension at 80-85C., containing molybdenum disulfide, binder and film-forming agent; and rotating the drum in air to dry the parts, with supplementary use of hot air, when required.
• the procedure here described yields outstanding forming results, but has the disadvantage that it is cumbersome and time-consuming, due to the multiplicity of the various steps.
• the method according to the invention offers the advantage that, in a very simple application involving only one stage, small massproduced parts made of iron and steel can simultaneously be phosphatized and given a lubricating coating, while control of the thickness of film, within close tolerances, and its adaptation to the needs of the particular manner of cold working, are possible. Further, it is advantageous that no waste water is produced by the process. Thus, it is a process which does not contribute to pollution by creating waste rinse water.
• the method, according to the invention, for the pretreatment of simply shaped iron and steel small massproduced parts of chip-free cold working uses suspensions, in themselves known, which contain phosphoric acid, suspended substances with laminar lattice structure, surfactants and, when required, thickeners, as well as difficultly soluble phosphate-forming cations. It is characterized in that the scalefree workpieces, at a preheated temperature between 50 and 150C., preferably to C, carry out a relative motion with reference to one another in a moving, for example rotating or vibrating, container and thus are brought into contact with so much aqueous suspension that 5-50 g. of active content of the suspension is applied per square meter of workpiece surface.
• active content here means the non-vaporizable portion of the suspension. Motion in the container is continued until the predominant portion of the water has evaporated.
• the improvement comprises preheating the workpieces or parts to a temperature between 50 and C.
• a relative motion of the workpiece is then effected so as to cause intercontact of the pieces while simultaneously contacting the parts with the above-mentioned suspension, the active content of the suspension being in the range 5-50 g/m of workpiece surface area.
• the relative motion is continued until a predominant part of the water in the suspension has evaporated.
• the aqueoussuspension which, within the scope of the invention, are used preferably contain so much phosphoric acid that the relation by weight of H PO H O (0.01-0.25) l.
• the group of laminar structure pigments includes (among others) molybdenum disulfide, tungsten sulfide, boron nitride and graphite.
• the portion by weight of the laminar structure pigment preferably, is between 30% and 99% active content.
• the surfactants used must be stable to acid and are used to wet the metal and/or pigment surface. They may be selected from the group of nonionic, anionic, cationic and even amphoteric surface-active substances. Cationic substances, for example oleic acidimidazoline derivatives, have been found to be very advantageous.
• thickeners When thickeners are also used, they can be chosen from the group of known inorganic and organic thickening agents. Typical examples are bentonite, finely divided silica, cellulose derivatives, polysaccharides, polyacrylamides and the like. Zinc, calcium, manganese, iron, magnesium and others enter the picture as cations which form difficultly soluble phosphates.
• film-forming products for example acidstable synthetic resin dispersions and water-soluble high molecular organic compounds. Too vigorous evolution of foam during the processs of motion can be counteracted by the use of suitable antifoam agents, for example from the group of silicone oils.
• the suspensions may, in addition, contain means of enhancing the attack of aqueous phosphoric acid on the steel surface.
• means of enhancing the attack of aqueous phosphoric acid on the steel surface include particularly oxidizing agents, such as nitrates, nitrites, hydrogen peroxide and the like.
• oxidizing agents such as nitrates, nitrites, hydrogen peroxide and the like.
• Small amounts of the more noble metals, such as copper, nickel and cobalt have similar effects. It is advantageous to stay within the framework of the following weight percent concentrations for the suspension to be used in connection with the invention:
• the workpiece used in connection with the invention include for example wire sections, sheet metal disks, blocks, sections of rods, cylindrical and rectangular metal parts.
• the surface of the workpieces be free of scale and other hard non-metallic impurities.
• thin films of rust, grease or oil do no harm.
• Phosphatizing of the parts before making use of the method according to the invention is not necessary, but, one the other hand, also does no harm.
• the envi- -ronment-friendly processes which are suitable for cleaning the workpiece are, particularly, radiation, ignition under protective gas and scouring in drums or vibrating tanks. However, it is also possible to make use of known pickling processes.
• the preheated temperature of the parts as required within the scope of the in-- vention, namely 50-l50C., preferably 70100C., can be attained, for example, by heating in an oven, by washing in hot water, as well as by the action of radiation or hot air.
• the parts are placed, for example, in rotating drums, in vibrating troughs or drains.
• the relative motion can be intensified by incorporating baffles. It is the purpose of these measures that the workpiece will rub together superficially, slide over one another and strike together in the course of the treatment.
• the extent of the active content primarily relates to the surface of the workpieces. But, this may also relate to the weight of the workpieces, if there is any more or less reliable relation between surface and weight.
• the lower range is used for less severe shaping, and the upper range for more severe shaping. It was surprising to find that, with the method according to the invention, the thickness of the lubricating film is relatively uniform even on all surfaces of non-uniformly shaped workpieces.
• Treatment in the moving tank is carried out in such a way that, at the end, most of the water has evaporated.
• the energy required to evaporate the solvent is often furnished adequately by the elevated temperature of the parts. Removal of the solvent vapor can be facilitated by blowing air onto or into the contents of the tank.
• neutralizing agents may, for example, be: zinc oxide powder, calcium oxide powder, calcium carbonate powder, magnesium oxide powder, but also neutralizing compounds from the alkali group, for example sodium carbonate, trisodium phosphate, borax.
• compressible bodies in addition to the workpieces.
• These may serve to prevent surface damage due too severe impact, when heavy objects are being treated.
• compressible bodies the abrasion of which has a lubricating effect
• an additional advantage is the'incorporation of the fines in the lubricating layer.
• Compressible bodies with lubricating properties include. for example, polyethylene, polypropylene, polyamide and polymeric fluorinated hydrocarbons.
• the size the number of such bodies per tank filling depend on the nature of the tank motion and the number and size of the workpieces. They may be present as relatively large particles, but the use of fine-grained material is also possible. Under some circumstances, this may be incorporated in the lubricant layer without further comminution.
• Table I shows some typical recipes for suitable aqueous suspensions. The proceedue, according to the invention, will now be explained, in the light of some Examples:
• EXAMPLE 1 100 kg of scaly steel wire sections, with a diameter of 15 mm and a length of l5 mm also, were first pickled in 15% hydrochloric acid at room temperature for 25 minutes, and thus freed of scale. They were then rinsed in water and given a second rinse in water at C. In this way, the pieces gained the necessary preheat temperature.vThey were then transferred into a cylindrical drum with axis of rotation 45-from vertical, and g Agent No. l/m of workpiece surface (Table l) was poured over them. This corresponds to about 39 g active content/m workpiece surface. The parts were tumbled in a drum for 15 minutes, while the drum turned at 30 rpm.
• EXAMPLE 2 100 kg of sheet steel discs, with rust and scale-free surfaces, but covered with a thin grease film, 80 mm in diameter and 5 mm thick, were preheated by immersion in water at approximately 100C. They were then transferred to a vibrating trough and, after the addition of 40 g of Agent No. 7 (Table I) were subjected to vibration. The amount of suspension used corresponded to about 22 g active content per m of workpiece surface. The vibration continued for 15 minutes, while warm air was blown over the surface of the parts during the entire time. Here too, a firmly adhering phosphate lubricating film was formed by the treatment, making possible entirely acceptable cold working when the parts were molded into bowls.
• aqueous suspensions which contain phosphoric acid, suspended substances with laminar lattice structures and surfactants
• the improvement comprising preheating said workpiece to a temperature between 50 and 150C, effecting a motion of said workpieces relative to each other sufficient to cause intercontact while simultaneously contacting said workpieces with said suspension having active content in an amount of between 5 and 50 g/m of workpiece surface area and comprising 550% of a laminar lattice compound, 0.5-14% H PO and 005-1 surfactant, and continuing said motion until a predominant part of the water is said suspension has been evaporated.

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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)
• Extrusion Of Metal (AREA)
• Chemical Treatment Of Metals (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=5861019

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Cited By (7)

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Citations (8)

Family Cites Families (1)

• 1972
  • 1972-11-07 DE DE2254378A patent/DE2254378A1/de active Pending
• 1973
  • 1973-06-18 FR FR7322098A patent/FR2205585B1/fr not_active Expired
  • 1973-06-20 BE BE132511A patent/BE801200A/xx unknown
  • 1973-09-26 AT AT829673A patent/AT322941B/de not_active IP Right Cessation
  • 1973-10-02 NL NL7313517A patent/NL7313517A/xx not_active Application Discontinuation
  • 1973-10-18 CA CA183,670A patent/CA999806A/en not_active Expired
  • 1973-10-31 BR BR8548/73A patent/BR7308548D0/pt unknown
  • 1973-11-02 GB GB5103373A patent/GB1395669A/en not_active Expired
  • 1973-11-02 CH CH1547373A patent/CH591568A5/xx not_active IP Right Cessation
  • 1973-11-05 US US413102A patent/US3869894A/en not_active Expired - Lifetime
  • 1973-11-06 IT IT30960/73A patent/IT999229B/it active
  • 1973-11-06 JP JP48124053A patent/JPS5230258B2/ja not_active Expired
  • 1973-11-07 SE SE7315126A patent/SE390035B/xx unknown

Patent Citations (8)

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