Copper has excellent electrical conductivity, thermal conductivity, corrosion resistance, ductility and certain strength.Widely used in electricity, electricity, chemical industry, food, power, transportation, aerospace industry.Are copper alloys, such as zinc, real, in which 10 or more alloying elements are added to form a solid solution?;Silicon bronze made of white copper by adding nickel;Put aluminum is aluminum bronze and so on.Copper and copper alloy can be connected through brazing, resistance welding and other processes, in today's industrial development, welding has become the dominant position.Electrode arc welding, TIG welding, MIG welding and other processes, easy to achieve copper and copper alloy welding.There are four main factors influencing the weldability of copper and copper alloys: one is the influence of high thermal conductivity.The thermal conductivity of copper is 7-11 times higher than that of carbon steel. When the carbon steel with the same thickness as welding is adopted, the copper is difficult to melt, and the filler metal and base metal cannot be fused well.Second, the hot crack tendency of welding joint is larger.During welding, copper and impurities in the molten pool form eutectic with low melting point, which makes copper and copper alloy have obvious hot brittleness and generate hot crack.Third, the porosity produced by the defect is much more serious than carbon steel, is the hydrogen hole.The fourth is the change of welding joint performance.Grain coarsening, plasticity reduction, corrosion resistance reduction, etc.
(1) manual arc welding edge of red copper.When the thickness of the welding exceeds 4mm, preheating is required before welding, and the preheating temperature is generally around 400-500℃.Copper 107 electrode welding, the power supply should be dc inverse connection.Welding should use short arc, welding rod can not roll.The linear movement of the electrode can improve the forming of the electrode.The long welding should adopt section welding method.The welding speed must be as fast as possible.In the case of multilayer welding, the interlayer slag must be completely removed.Welding shall be carried out in a well-ventilated place to prevent copper poisoning.After welding, hammer with flat head to eliminate stress and improve welding quality.
(2) manual arc welding of red copper in manual arc welding of red copper, wire 201 (special red copper wire) and wire 202 are used, and also wire of red copper, such as T2.Before welding, the dirt such as oxide film and oil on the welding edge and the surface of the wire should be cleaned to avoid the defects such as blowhole and flux.The cleaning methods are mechanical cleaning and chemical cleaning.When the thickness of the butt joint plate is less than 3mm, and the thickness of the plate without opening groove is 3~10, the groove is v-shaped and the groove Angle is 60-70.When the thickness of the plate is more than 10mm, x-groove and groove Angle shall avoid 60-70 unwelded, generally leaving no blunt edge.According to the thickness of the plate and the groove size, the installation clearance of the butt joint should be within the range of 0.5~1.5.Manual arc welding of red copper usually adopts dc tangent, that is, tungsten junction negative electrode.In order to eliminate the porosity, it is necessary to improve the welding speed, reduce the consumption of argon, and preheat the welding to ensure the reliable welding and welding penetration of the root.When the plate thickness is less than 3mm, the preheating temperature is 150-300℃;When the thickness of the plate is more than 3mm, the preheating temperature is 350-500℃.High preheating temperature will reduce the mechanical properties of welded joints.
(3) carbon arc welding of red copper, electrode carbon electrode and graphite electrode used in carbon arc welding.In the same case, the welding wire used in copper-carbon arc welding and gas welding can also be cut with base material, gas agent 301 and other flux of red copper.Is it true?Welding brass welding methods are gas welding, carbon arc welding, manual arc welding and arc welding.
(4) manual arc welding brass brass in addition to copper 227 and copper 237, but also can use homemade electrode.Brass arc welding, the use of dc power supply tangential method, the electrode on the negative.The surface of the weld should be cleaned well before welding.Groove Angle is generally not below 60-70 ° c, in order to improve welding formation, welding preheat 150-250 ° c.Operation through short arc welding, not horizontal and forward and backward direction of swing, only linear movement, high welding speed.Photos of contact with corrosive media such as seawater and ammonia?The welds must be annealed after welding to remove the welding stress.
(5) brass manual arc welding true?Other manual arc welding can use wire 221, wire 222 and wire 224, the same material as the base material as the filling material.Welding can be direct - current connection, also can be ac.In ac welding, the evaporation of zinc is lighter than in dc tangential welding.Generally, there is no need to preheat before welding, and only preheat when the thickness difference is large.The welding speed must be as fast as possible.After welding, the welds are heated to 300-400℃ for annealing treatment to eliminate the welding stress and prevent the cracks in use.(3) brass carbon arc welding brass carbon arc welding of the case, according to the components of the base metal select wire 221, wire 222, wire 224 and other wire, the production of the photo?It can also be welded with wires.Welding can use flux 301 and so on.In order to reduce evaporation and burning loss of zinc, welding must be performed in short arc operation.
Dc TIG welding technology is widely used in the welding of copper and copper alloys, with good welding air forming and good internal and external quality. Under the protection of argon gas, the molten pool is pure, the porosity is few, the thermal crack effect is small, and the operation is easy to grasp.When the thickness is ≤4mm, there is no need for preheating before welding, and argon gas can be directly used to preheat. When the temperature of the molten pool is close to 600℃, the filler welding wire is added to realize welding.For copper with a thickness of more than 4mm, the pure copper must be preheated to 400-600 ℃.Preheat copper alloy welding at 200-300℃.300TSP, 315TX dc TIG welding machine for pure copper, silicon bronze, phosphorus bronze, true?Copper alloys such as white copper can be welded.The 300WP5 and 300/500wx4 ac/dc TIG welders can use ac TIG to weld aluminum bronze (removing surface oxide film with ac square wave) and dc TIG to weld the copper mentioned above.Copper and copper alloy with thickness of 3~14mm or 14mm almost all adopt MIG welding, with high welding efficiency, large melting depth and fast welding speed (generally 3~4 times of TIG welding), realizing high efficiency, high quality and low cost economic benefits.Before welding copper material, the preheating temperature should be met (pure copper 400~600℃, copper alloy 200~300℃). The welding wire is chemically very similar to the base material, and the argon purity is ≥99.98%