Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
  • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
  • B23K35/24—Selection of soldering or welding materials proper
  • B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400°C
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
  • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
  • B23K35/36—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
  • B23K35/3601—Selection of non-metallic compositions, e.g. coatings or fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest with inorganic compounds as principal constituents
  • B23K35/3611—Phosphates

Definitions

• This invention relates to novel fluxes for use in soldering of stainless steels and to the soldering of stainless steels with said fluxes.
• the major ingredient of the improved fluxes of the present invention is a phosphorouscontaining acid.
• orthophosphoric acid is most advantageously utilized, both from the standpoint of its functioning and its commercial availability and low cost, but phosphorous acid (usually available in aqueous solution in 70-72% concentrations) can be employed.
• the orthophosphoric acid may be in the form of aqueous orthophophoric acid containing as low as 40% orthophosphoric acid, or it may be as high as about so-called commercial 115% phosphoric acid, but it is preferred to utilize about 75% to 105% orthophosphoric acid.
• metallic copper or any copper salt can be used, it is advantageous to avoid the use of copper chloride or other copper halides, or copper sulfate or copper nitrate since they leave somewhat corrosive residues.
• copper salts which can be used are copper acetate, basic cupric chromate, cupric dichromate, copper salicylate, cupric phosphite, and cupric phosphate.
• cupric phosphate [Cu (PO -3H O] can be added to the orthophosphoric acid, it is especially advantageous to incorporate the copper ion by adding cupric or cuprous carbonate, particularly basic copper carbonate ['CuCO -Cu(OH) to the orthophosphoric acid.
• Copper salt complexes can also be used such as those formed from copper salts and ammonia or amines. Copper oxides and copper hydroxides can also be employed as the source of the copper ion as, indeed, can also metallic copper or copper-base alloys, although such sources of copper are not preferred. Cuprous oxide reacts, of course, to at least some extent with the orthophosphoric acid to produce copper phosphate. While it is particularly desirable that the copper salt be fully soluble in the phosphorus-containing acid, such is not essential as the copper salt may be dispersible or suspendable in said acid.
• metallic copper is essentially not soluble in orthophosphoric acid, where metallic copper, or a copper-base alloy, or an insoluble copper salt is used as the copper source, it should be employed as a finely divided powder so that a dispersion or suspension is formed in the phosphorouscontaining acid.
• copper salt as used in the claims, is intended to cover copper in the form of its simple salts, complex salts, or other copper-containing compounds.
• metallic copper as used in the claims, is intended to cover metallic copper or copper alloys as, for example, copper bronzes, brasses, and the like.
• the copper salts may comprise from as low as about 1% to as high as about 40% by weight of the phosphorus-containing acid.
• the copper salt it is more desirable to employ from about 5% to about 20% of the copper salt, with about 10% being a good average in most cases.
• metallic copper it is desirably employed in amounts in the range of about 1% to 10%, better still, about 2% to 5%, by Weight of the phosphorus-containing acid.
• ammonia organic amines such as cyclohexylamine or triethanolamine, or ammonium phosphates can be added which act protectively against adverse effects which might occur on overheating the joints to be soldered during the soldering operation.
• the proportions thereof are variable, but, generally, it is desirable that, when used, they comprise from about 20% to about by weight of the phosphorus-containing acid.
• Surfactants of the nonionic type and exemplified by normally solid, paste or liquid Pluronics (Wyandotte Chemicals Corp.) can also be incorporated.
• the Pluronics are condensates or adducts of ethylene oxide with hydrophobic bases, in the form of polyoxypropylene glycols generally having a molecular weight of 1200 or higher, and are disclosed, for example, in US. Patents Nos. 2,674,619 and 2,677,700.
• Other nonionic surfactants can be used such as ethylene oxide adducts of hydrophobic materials such as ethylene oxide adducts of C C linear and branched chain alcohols, including oxo alcohols, and ethylene oxide adducts of C -C alkyl phenols, said nonionic surfactants being, per se, well known and being disclosed in many US.
• Nonionic surfactants function, in certain instances, to improve the homogeneity of the fluxes, and they also tend to enhance the wetting and spreading properties of the fluxes during the soldering operation.
• the nonionic surfactants, where utilized, are desirably employed in amounts of about 2 to 25%, particularly 3 to 10%, by weight of the phosphorus-containing acid.
• the fluxes of the present invention can be used in liquid or solid, generally paste, form. Particularly where they are used in connection with the soldering of pipe joints, it is especially desirable, for ease of application, that said fluxes be employed as thick or heavily viscous liquids or, better still, in solid or paste form.
• EXAMPLE 2 G. Orthophosphoric acid (75 100 Basic copper carbonate 10 EXAMPLE 3 G Orthophosphoric acid (105%) 100 Cuprous chloride 20 EXAMPLE 4 G. Orthophosphoric acid (75 100 Mono-ammonium phosphate 40 Basic copper carbonate 8 Pluronic 84 15 The basic copper carbonate is initially mixed with the Orthophosphoric acid, as described in Example 1, then the remaining ingredients are incorporated under conditions of agitation to form a homogeneous mixture.
• Such stainless steels are those containing chromium, for instance, of the order of 18% chromium; those containing chromium and titanium, for instance, those containing of the order of 12% chromium and 2% titanium; those containing varying proportions of chromium and nickel; and those containing varying proportions of chromium, titanium, nickel and vanadium.
• Illustrative of such stainless steels are those sold commercially under the trade designations 300 series and 400 series, and TI- CHROME (Crucible Steel Corporation).
• various solders can be employed such as, for instance, 50% tin50% lead; 60% tin40% lead; 95% tin-5% antimony; 40% tin60% lead; 30% tin70% lead; and variants of such solders and other known soft solders. It is especially desirable to use approximately 50% tin50% lead solders since they have good flow properties at relatively low temperatures.
• a flux for use in soldering stainless steels which comprises, as essential ingredients, a major proportion of at least one phosphorus-containing acid selected from the group of orthophosphoric acid and phosphorus acid, and a minor proportion of at least one member selected from the group of (a) finely divided copper and (b) copper salts.
• the method of making a flux for use in soldering stainless steels which comprises admixing approximately 100 parts of 75105% phosphoric acid with from 1 to 20 parts of basic copper carbonate and with from 20 to 60 parts of an ammonium phosphate, said parts being by weight.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Electric Connection Of Electric Components To Printed Circuits (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

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Family Applications (1)

Country Status (4)

Cited By (24)

• 1969
  • 1969-05-02 US US821482A patent/US3597285A/en not_active Expired - Lifetime
  • 1969-08-21 GB GB41816/69A patent/GB1270864A/en not_active Expired
  • 1969-08-22 CA CA060227A patent/CA928196A/en not_active Expired
• 1972
  • 1972-02-16 BE BE779424A patent/BE779424Q/fr not_active IP Right Cessation

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