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
  • B23K35/30—Selection of soldering or welding materials proper with the principal constituent melting at less than 1550 degrees C
  • B23K35/3053—Fe as the principal constituent
  • B23K35/308—Fe as the principal constituent with Cr as next major constituent
  • B23K35/3086—Fe as the principal constituent with Cr as next major constituent containing Ni or Mn
• • 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, 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, 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
  • B23K35/3608—Titania or titanates
• • 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, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
  • B23K35/365—Selection of non-metallic compositions of coating materials either alone or conjoint with selection of soldering or welding materials
• • 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, 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, 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
  • B23K35/3602—Carbonates, basic oxides or hydroxides
• • 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, 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, 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
  • B23K35/361—Alumina or aluminates
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12014—All metal or with adjacent metals having metal particles
  • Y10T428/12028—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
  • Y10T428/12063—Nonparticulate metal component
  • Y10T428/12104—Particles discontinuous
  • Y10T428/12111—Separated by nonmetal matrix or binder [e.g., welding electrode, etc.]
  • Y10T428/12125—Nonparticulate component has Fe-base
  • Y10T428/12132—Next to Fe-containing particles
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12014—All metal or with adjacent metals having metal particles
  • Y10T428/12028—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
  • Y10T428/12063—Nonparticulate metal component
  • Y10T428/12139—Nonmetal particles in particulate component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12861—Group VIII or IB metal-base component
  • Y10T428/12951—Fe-base component
  • Y10T428/12972—Containing 0.01-1.7% carbon [i.e., steel]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
  • Y10T428/2913—Rod, strand, filament or fiber
  • Y10T428/2933—Coated or with bond, impregnation or core
  • Y10T428/294—Coated or with bond, impregnation or core including metal or compound thereof [excluding glass, ceramic and asbestos]
  • Y10T428/2951—Metal with weld modifying or stabilizing coating [e.g., flux, slag, producer, etc.]
  • Y10T428/2953—Titanium compound in coating

Definitions

• the present invention relates to a coated electrode for use in welding alloys with a carbon content lower than 0.030%, more especially alloy steels with such a carbon content.
• the invention relates, more especially, to an electrode the coating of which contains a binder in addition to a mixture constituted by powdered alloy metals, deoxidizers, magnesium oxide and aluminum oxide (these two oxides being in a combined state), titanium oxide and/or zirconium oxide (these two oxides being either free or combined), fluidifiers (fluxes) and silicates of various metals.
• the expression coefficient of basicity expresses the ratio B/A in which B expresses the number ofgram-molecules or CaO-l-tMgO -l-BaO-l- K O+Na O+LiO +CaF and -A expresses the number of gram-molecules of SiO +TiO ZrO It is known that if alloy steels, in particular stainless steels containing 18% chromium and 8% of nickel or 18% chromium, 8% nickel and 3% molybdenum, have a carbon content higher than 0.050%, the risk arises that intercrystalline corrosion will occur during Welding or thermal treatments, due to the precipitation of carbides.
• Coated electrodes as generally employed for welding these alloy steels are known as low carbon electrodes; if they are of good quality, in most cases they allow the deposition of a metal the carbon content of which is lower than 0.060%.
• Such electrodes are either of the type having a coefficient of basicity at least equal to 3 and the coating of which contains compounds with an acid affinity, such as titanium oxide and/or zirconium oxide, as well as complex silicates of various metals, in
• the mixture of powders added to the binder to constitute the coating generally contains from 15 to 25% of alkaline earth carbonates, from 35 to 45% of titanium oxide and/or zirconium oxide and from 5 to 15% of complex silicates, in addition to alloy metals, deoxidizers and fluidifiers based on compound containing fluorine.
• wires are chosen the carbon content of which is relatively small, approximately 0.020% at most, for example, and provided that rigorous selection is made of the raw materials for the coating, so that they do not contribute much carbon, it is quite easy to deposit metal for welding alloy steels, the carbon content of which does not exceed 0.050%.
• Such choice of wire and of raw materials does not, however, in the majority of cases, allow the deposition of Welding metal the carbon content of which is lower than 0.030%.
• the odds that welding metal will be deposited with a carbon content less than 0.020% are only one to two in a hundred, even in the case when the wire has a very low carbon content.
• electrodes with a coeflicient of basicity lower than 0.6 contribute less carbon in relation to the Wire than electrodes with a coefficient of basicity higher than 3, the first-mentioned electrodes having a carbonate-content lower than the last-mentioned ones, there is little hope of regularly reaching, for the deposited metal, a carbon content that is at most equal to 0.020% by employing electrodes with a coefficient of basicity lower than 0.6.
• the present invention has for its principal object to provide an electrode which will allow the regular deposition of welding metal for welding alloys and alloy steels, the carbon content of which is not more than 0.015% higher than the carbon content of the wire.
• the electrode according to the invention contains at most 6% of basic carbonates, from 3.5 to 10% of deoxidizing alloys, at most 1% of organic substances, from 3 3 to 10% of free MgO, from 3 to 10% of free A1 with the weight ratio of MgO to A1 0 lying between 0.3 and 3.33, and from 13 to 35% of metal powders which enter into the composition of the deposited alloy.
• a content of basic carbonates that is equal to, at most, 6% of the total weight of the powders which form part of the constitution of the coating and a content of organic substances equal to at most 1% of the total weight of powders have the effect of lowering the carbon content of the deposited metal. If the basic carbonates and the organic substances are dispensed with entirely, it may be that the carbon content of the deposited metal will not exceed the carbon content of the wire by more than 0.005%
• alkaline or alkaline-earth carbonates by silicates, titanates or aluminates would likewise have the effect of decreasing the degree of basicity too greatly, lowering it to, for example, less than 0.6. In addition, certain of them would harden upon contact with water or free alkalis.
• oxides of alkaline and alkaline earth metals in the free state have been envisaged, but only magnesium oxide is suitable; the other oxides of this kind are much too reactive with water for coating and conservation of the electrodes to be possible with them.
• a 10% proportion of magnesium oxide is used in the absence of basic carbonate. If basic carbonate is present, the proportion of magnesium oxide is that much the less, the greater the proportion of basic carbonate, and is only 3% when the mixture contains the maximum of 6% of alkaline carbonate.
• the use of free magnesium oxide has the disadvantage that fusion takes place with sputtering, and that removal of the slag is troublesome.
• the electrode according to the invention does not have these two disadvantages, thanks to the other features it possesses.
• the electrode In order to facilitate removal of the slag, the electrode must simultaneously satisfy the three following conditions: (1) the proportion of free magnesium oxide should lie between 3 and 10% of the total weight of the powders; (2) the free magnesium oxide should be mixed with a proportion of free aluminum oxide likewise lying between 3 and 10% of the total weight of the powders; (3) the ratio of the amount of free magnesium oxide to the amount of free aluminum oxide should lie between 0.3 and 3.33.
• the mixture of powders may accordingly comprise, for example, the same proportion .of each of these two free oxides, for example 6% (the ratio of the two oxides being then equal to 1) or 3% of magnesium oxide and 10% of aluminum oxide (a ratio equal to 0.3) or 10% of magnesium oxide and 3% of aluminum oxide (a ratio equal to 3.3
• the electrode should contain an amount of metal powders (contributing the alloy elements) that lie between 13% and 35 of the total weight of the mixture of powders used for the coating.
• the diameter of the coating can thus be increased without increasing the amount of slag, and by reason of this fact, fusion proceeds more gently and the weldling procedure is carried out more easily.
• the lower limit of 13% is not a critical limit, in practice sputtering is acceptable when the mixture contains this proportion of metal powders.
• the upper limit of 35% is also not a critical limit. But if the mixture contains more than 35% of metal powders, the amount of slag that may form from a coating having a given diameter such as is commonly employed in practice may become too small. The increase in the coating diameter that would then perforce be adopted in order to form a suitable amount of slag would make manipulation of the electrode during welding more difficult.
• Ferro-alloys often contribute carbon to the deposited metal. Accordingly it is also preferable to limit the content of ferro-alloys whenever it i possible to replace deoxidizing ferro-alloys by the deoxidizing metal elements that they contain.
• the mixture of dry powders entering into the composition of the coating .of the electrode should, as in the case of known electrodes, be associated with one or more aqueous alkaline silicates, the proportion of which is from 15 to 30% of its weight.
• Carbon contents in the deposited metal lower than 0.030% and even lower than 0.020% are obtained, according to whether the wire constituting the core of the electrode contains at most 0.020% of carbon or at most 0.010% of carbon, together with the following mixture of dry powders:
• This mixture is characterized by the absence of carbonates and of organic substances, by a maximum content of titanium oxide and/or zirconium oxide of 35% and by a minimum content of these oxides of 20%.
• the metal powders present in the coating depend on the particular composition of the alloy (and in particular alloy steel) that is to be deposited.
• the alloy elements in powder form most used nowadays are chromium, nickel, molybdenum, titanium and niobium, these elements being present either separately almost free from foreign elements, or as alloys with one another or in the form of ferro-alloys; in the latter case they are present in a proportion lying between 3.5 and 10% of the total weight of the dry powders.
• an electrode according to the invention for use in welding stainless steel with 18% chromium and 8% nickel there will be, for instance, a mixture of powders of chromium, nickel and/or ferro-chromium and/or ferro-nickel in addition to iron powder, these powders being in proportions such that, bearing in mind the composition of the wire, the compoistion of the metal deposited corresponds substantially to the composition of the alloy steel parts to be welded.
• an electrode the core of which, having a weight of 23 grams and a composition corresponding to 18% chromium, 8% nickel and 74% iron, is covered with a coating layer of 16 grams containing 30% of a mixture of metal powders intended to enter into the deposited metal and consisting of 53% chromium, 5% nickel and 42% iron.
• composition of this metal expressed in percentages by weight is therefore:
• chromium 8.06% of nickel
• a stainless steel can be deposited which contains approximately 17.5% chromium, nickel, 2.5% molybdenum and 70% iron, from an electrode the coating of which contains 30% of the following mixture of powders: 36% chromium, 18.65% nickel, 16% molybdenum and 29.35% iron, the said coating being applied to a wire having the following composition: 18% chromium, 8% nickel, 0% molybdenum and 74% iron and the ratio of the weights being 16 g. of coating to 23 g. of wire.
• these may be chosen from among the ferro-alloys such as Fe-Mn, Fe-Ti, Fe-Si-Ti and/ or from among metallic elements such as Mg, Al, Ti, Si and Ca, taken individually or in association with each other.
• ferro-alloys such as Fe-Mn, Fe-Ti, Fe-Si-Ti and/ or from among metallic elements such as Mg, Al, Ti, Si and Ca, taken individually or in association with each other.
• a coating composition that gave particularly favourable results in the case of the welding of stainless steel containing 18% chromium and 8% nickel is as follows:
• This mixture of dry powders was mixed with 290 parts by weight of aqueous alkaline silicate.
• This electrode was connected to the positive pole of a source of direct current delivering a current of amperes during the welding of two chamfered plates placed edge to edge, either with both plates horizontal or with one vertical and the other horizontal. Fusion was fairly gentle and projections were few in number. Slag well covered the weld metal behind the pool of such metal and its removal was effected easily by a process of light chipping.
• the weld bead had the appearance of a series of fine and regular striations. In the case of welding horizontal sheets placed edge to edge this bead was slightly concave, whereas in the case of welding a vertical sheet to a horizontal one the head was very slightly convex.
• the weight of deposited metal was of the weight of the wire. Chemical analysis of this metal yielded the following results:
• the steel to be welded comprises 18% chromium, 8% nickel and 3% molybdenum, all that is required is to replace the above wire by a wire having the same composition as the steel to be welded and to introduce 10% of molybdenum powder in place of 10% of iron powder in the mixture of powders.
• the same type of steel, containing chromium, nickel and molybdenum, may also be welded using a steel wire having 18% chromium and 8% nickel, provided that sufiicient molybdenum powder be incorporated in the mix: ture of metal powders for the deposited metal to have the desired composition.
• a coated electrode as claimed in claim 1, wherein Free A1 0 10 the said mixture of powders comprises: Fluxing agents in the form of CaF 7.48 from 20 to 35% of the group TiO and ZrO Complex silicates and organic substances 9.05 from 4 to 8% of fluxing agents of the group alkaline Powders of metallic alloying substances 29.52
• Percent 10 WILLIAM L. JARVIS Primary Examiner Deoxidizing substances of the group manganese and ferromanganese 6.70 TiO 29.92 117206, 207; 148-24, 26

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Nonmetallic Welding Materials (AREA)

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Cited By (9)

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Citations (1)

• 1965
  • 1965-10-14 BE BE670918D patent/BE670918A/xx unknown
• 1966
  • 1966-04-01 GB GB14711/66A patent/GB1119435A/en not_active Expired
  • 1966-10-10 CH CH1459066A patent/CH465367A/fr unknown
  • 1966-10-10 FR FR79318A patent/FR1515020A/fr not_active Expired
  • 1966-10-11 US US585737A patent/US3490942A/en not_active Expired - Lifetime
  • 1966-10-13 DE DE19661508346 patent/DE1508346A1/de active Pending

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