Electroslag Welding technique. Electroslag process proceeds steadily at current densities of about 0.1 A / mm 2 (in arc welding, the order of 20-30 A / mm 2 ). Therefore possible to replace the wire electrodes on the plate or strip electrodes. However, if you can not use the feeder plate electrodes (lack of space on the product, etc.) and welding products of complex cross section (plate electrode should be fixed) to compensate for the lack of metal to fill the space between the electrodes and the electrodes and the edges of the base metal using consumable welding method mouthpiece. In this case, the electrode plate shape can repeat the form of welded edges and be part of.
Current lead wire to the electrode via a sliding contact with the melt plate electrode (mouthpiece). When contact-slag welding rods of different cross-sectional After formation of the desired metal bath come off the welding current and sediment of the upper rod. This method can be welded to the flat surface of the rods.
The stability of the electroslag process, the shape of the weld and base metal penetration depth depends on the parameters of welding. The main parameters are: welding speed V, the welding current I St. , feed rate of the electrode V p , welding voltage U C in the thickness of the metal, per one electrode, the electrode spacing z. Auxiliary components of the regime: the gap between the edges b, of the flux, the depth of the slag bath h w B, the speed of reciprocating movement of the electrode, its "dry" crash L z , the cross section of electrodes, etc. The depth of the slag bath, depending on the strength of the welding current varies from 25 to 70 mm. The speed of the reciprocating movement of the electrode of 25-40 m / h Sukhoi crash electrode 60-80 mm.
With increasing current strength increases the rate of melting of the electrode and increases the depth of the metal bath h w B. The joint width varies slightly. With the increase of the electrode feed rate v pr (typically 100-500 m / h), the electrode is immersed in the slag bath in more depth. This reduces the welding voltage U St , metal bath depth h m B and the width of the joint b w . Ratio of weld shape (shape metal bath) decreases with increasing current and podvyshaetsya with increasing diameter of the electrode and the welding voltage.
The number of electrode wires, their diameter and the cross section of plate electrodes or melting mouthpieces, the speed of delivery and other parameters are chosen so as to get the speed and welding voltage to ensure stability of the process and the required size and shape of the seam.
Application of electroslag welding makes fundamental changes in production technology of large-sized products. It is possible to replace the large cast or forged details of welded-cast or welded-forged from smaller forgings or castings.
Preparations for welding should be collected, taking into account shrinkage of the joint after welding. Slides for a snug fit and forming devices to smooth out the edges of the last joint of the burrs, scale, and so the width to 100 mm. To display the outside seam shrinkage cavity at the end of the seam set off, and the withdrawal of fusions at the beginning of the seam - the input bar, which is removed after welding cutting. To begin welding in a pocket formed by the input bars, poured flux that melts the welding arc to obtain the required size of the slag bath. After this arc is shunted by the slag, and the process goes - electroslag.
Before you start welding slag can be poured, melted in a special mold. For guidance electroslag bath you can use special fluxes, electrically conductive solid state. Original process of welding of circular joints. Welding start on the front plate. During further rotation of welding products in the early part of the defective weld seam to close the cut. With the closure of the joint rotation of the product stops and starts moving the welding set up as in the usual straight seam welding. The closure of the suture and the withdrawal of shrinkage cavity is carried out with a special pocket of the wafers or die.
See also:
Electroslag Welding Technology
Electroslag Welding
Electroslag Welding Technique
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