Welding of copper.
Consider welding in protective gases. This method allows to obtain welds with the highest properties (mechanical, corrosion, etc.) as well as the weld metal contains a minimal amount of impurities.
Perform Welding TIG (tungsten) and consumable electrodes. Use inert with respect to the copper gases: argon, all in accordance with GOST 10157-73 varieties, helium (99.9%), nitrogen (with an additional drainage and cleaning of its sat-Kagel). These gases do not dissolve in the copper and with it, do not interact. It is advisable to use gas mixtures such as 70-5 - t-80% Ar + 20 g-30% N2, and argon for the economy to increase productivity (increased depth of penetration).
Use a tungsten or lantanirovannye ittrirovan nye-electrodes with a diameter of 6 mm. As filler metal for welding consumable and non-consumable electrode wire of suitable copper and its alloys, which are identical to the composition of the base metal, but contain deoxidizing agents (copper grades MO, Ml, M2; copper-silicon bronze BrKMts 1.3, chrome bronze BrH 0 and 7).
Welded edges and the welding wire is carefully cleaned of oxides and contaminants: the edge - by mechanical means (sandpaper, wire brush, etc.), wire - etching in a solution consisting of nitric, sulfuric and hydrochloric acids, followed by washing in water, alkali, water and dried with hot air. In some cases (welding in nitrogen) is used to improve the quality of the flux on the basis of boron, which is applied to the filler metal, or lay in the ditch lining. Preparation of edges depends on the thickness of the metal. When the thickness of the metal d <5 mm - without bevel edges, at h = 6 - 12 mm - V-shaped and with a greater thickness - X-shaped cutting with an opening angle of 70-90 degrees. for non-consumable electrode and 60 - 70 deg. for melting without blunting. Details of welding are collected at the tack (increment up to 400 mm) or in a special rigid devices, less strain. To form the root of the weld using backing from the pre-pro-tempered graphite or copper (in this case with water cooling it.) Metal thickness of 5 mm welded heated to a temperature of 350 deg. C. With increasing thickness of the metal heater increases up to temperatures of 600-800 degrees. C. For non-consumable electrode welding performed on an alternating current or direct current, straight polarity. When welding with consumable electrode using DC reverse polarity. The choice of the diameter of the tungsten electrode and additives depends on the thickness of the base metal. welding current during welding tungsten electrode is selected depending on the diameter of the electrode current and the type of shielding gas. When welding in nitrogen or a mixture of nitrogen and helium, the current strength is reduced by 10-15%, and the voltage increases by 15-20%. When welding consumable electrode in inert gases are used for conventional semi-automatic gas-shielded welding, and welding wire with a diameter of 1-2 mm , welding current 150 - 200 A for wire 1 mm in diameter and 300-450 A for wire 2 mm in diameter, arc voltage 22-26 V, welding speed depends on the section of the seam. When welding brass, bronze and copper-nickel alloys most commonly used tungsten electrode,% as welding consumable electrode is more intense evaporation of zinc, tin, etc. If you are using consumable electrode of small diameter (0.8-1.4 mm) it is sufficient for well-welded brass and copper alloys. Due to the lower thermal conductivity of these alloys preheating (100-150 deg. C) is required when the metal thickness over 12 mm. Other methods of welding. Among other methods of welding copper and its alloys are the most important manual arc welding with consumable electrode and mechanized submerged arc welding.
Mechanized submerged arc welding can be non-consumable carbon or graphite electrode in the usual way, and consumable electrode. When welding carbon electrode edges are collected on a graphite lining, top brass strip joint is applied, which serves as a filler metal. Arc between a carbon electrode, in the form of a flat edged spatula, and the product under a layer of flux. Typically used the flux grade OSC-45 is deoxidizers zinc contained in the filler metal. method is suitable for welding of metal up to 10 mm. Electrode diameter to 18 mm, current up to 1000 A, arc voltage 18-21 V, welding speed 6-25 m / h Welding is performed at a constant current of reverse polarity. Preliminary heating of the electrode short-circuiting the product prior to welding. For mechanized welding consumable electrode submerged arc welding machines use a standard type DT-1000, and fluxes such as OSC-45, AN-348A and AN-20. Welding wire with a diameter of 3-5 mm of copper grades Ml, M2 or bronze CMC 3-1, 4-3 and others Brotze containing deoxidizing agents. single pass welding, the first layers in the multi-pass welding is carried out on the graphite lining and cushioned flux. In the absence of preheating the beginning suture is placed on pin bar. When the thickness of sheets up to 15 mm connection without bevel edge, with a greater thickness - V-shaped cutting with an opening angle of 90 deg., Blunting of 2-5 mm, no gap. With Dual (split) of the electrode metal thickness up to 30 mm can be welded without cutting edge with the location of the electrodes across the joint. Welding lead to a direct current of reverse polarity welding wire with a diameter of 5 mm without preheating edges. flux used for welding and lining prior to welding, must be calcined at a temperature of 300-400 degrees. C. When used for welding filler wire of copper weld metal and its properties are slightly different from those of the parent metal. Alloying of the weld metal during welding deoxidizers using filler metal of bronze greatly reduces its thermal and electrical conductivity. used for welding brasses fluxes grades ANF-5 or CPE-5 and the electrodes of copper wire, which reduces the waste of zinc positive results when welding copper and copper alloys are attained when using ceramic flux of K-13 School) and the IMS-1.
For manual metal arc welding electrodes use electrodes brands "Komsomolets 100", ST, and ABI-1. To mark the electrode rods "Komsomolets" used copper grade Ml and M2, has a thick coating composition: 15% fluorspar, feldspar 12.5%, 25% of the siliceous copper, ferro-manganese 47.5% (sodium silicate 20% by weight of dry ingredients .) The coating thickness of 0.4 mm, it is applied by dipping, followed by drying and calcination at 300 deg. C for 2 h in the ST electrodes are used a rod of bronze BrKMts 3-1. Welding electrodes are 4-6 mm in diameter, short arc without transverse vibrations of a direct current of reverse polarity. Welding current I = (50 - 60) de. Welding with coated electrodes can obtain joints with good strength properties, but because of what is happening deoxidizers weld metal doping affects its thermal and electrical properties (electrical conductivity of the seam is 20-25% of the electrical conductivity of the base metal). Carbon electrodes used is limited, graphite or carbon rods have diameters of 4 20 mm, as the filler metal wire rods are used with a diameter of 3-5 mm of copper grades M0 or Ml, or bronze Br.KMts 3-1. Welding can be performed without special protection or use of flux in the form of borax or boric slag. Flux can be applied to the pre-filler rods by dipping it into a solution of sodium silicate or on edge in the form of powder. sheets up to 4 mm thick welded with no cutting edges, with a greater thickness is required cutting with an opening angle of 70 - 90 deg. Welding lead to a direct current straight polarity long-arc (Ud> 40), it is necessary to prevent carburization of the metal during the formation of CO and porosity. Before you start welding requires heating to a temperature of initial sites of 250 deg. C. Welding current I = (45 - 55) / de, the arc voltage U = 40 - 50 V. The welding is feasible only in the down position after welding is recommended to weld forging at a temperature of 550-800 degrees. C and subsequent cooling in water, as the rapid cooling of the prevention-ical Su2O segregation at grain boundaries and embrittlement of the metal. Among other methods for welding copper, sometimes used are arc plasma (metal thickness up to 50 mm) and an electron beam.
See also:
Welding of Aluminum
Titanium
Welding Magnesium
Welding of Titanium
Copper
Welding of Copper
Refractory Metals
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