What must be paid attention to in butt welding of 2205 duplex stainless steel pipe? This kind of welding materials and raw materials belong to the special materials prone to air oxidation in the whole process of overlap welding in argon arc welding machine, the fluidity of molten steel is poor, and the weld formation operation is not easy to grasp. Next, let's briefly introduce it in detail.
Common problems in the welding of 2205 duplex stainless steel pipe: in terms of welding materials, the welding wire used for sa2205 stainless steel plate is matched, and the welding material is er2205. The strength of this kind of welding wire is higher than that of general 308 welding wire. During welding, the welding wire connector shall be maintained in the steam maintenance of porcelain nozzle as far as possible to prevent air oxidation of the wire.
During groove butt welding, the gap at the weld root must be strictly controlled. Taking the groove connection as an example, the gap at the root is controlled within 4mm. Due to the large amount of weld closure of this kind of welding raw materials. For the reinforcement of fixed fixed mouth welding structure, the bridging point can be selected for accurate positioning welding, or the fixed plate with the same material can be added to connect both sides of the groove.
In the case of weld fillet welding position, be sure to control the gap of corner connection, and control the inversion variable. The total flow in welding shall exceed the gas pressure of general stainless steel plate. 2205 duplex stainless steel pipe is close to the welding characteristics of special materials. It must be 6 maintained for more than 10 seconds at the arc stopping part to completely avoid air oxidation on the connector and end.
In the case of welding fillet weld and groove connection, the welding wire must select the method of point wire addition to carry out high-temperature melt drop connection. Because the welding wire of 2205 duplex stainless steel pipe has very high fluidity and viscosity in the whole welding process, the weld formation is all joint formation. In addition, a layer of plastic film covers the melting pool of the welding wire and moves forward with the welding wire. After welding, the plastic film of the solid layer must be removed with a soft brush. During the whole filling process of this kind of welding wire, this air oxide film is very easy to cause defects in the weld. In case of fillet welding, only pressure bead welding can be used in case of large fillet welding.
It is not allowed to weld more than 8mm at one time. If the excess is too large, it is very easy to cause the upper edge misalignment. The low fluidity of such welding materials will lead to higher misalignment. The method of point and wire feeding is to select the parallel line walking handle, walk for 2mm, and then take it home, so as to continuously feed the wire. In this way, excellent forming can be obtained in the weld bead.
In case of internal lap welding of 2205 duplex stainless steel pipe groove, argon filling maintenance must be done well on the reverse side, and wire feeding at the connection point is also selected for internal lap welding. When welding to the bypass operation point, be sure to cut off the support point. Then heat the spot welding and float the arc during welding to avoid electric shock when welding to the support point. After the erection in the groove is completed, the weld shall be bright with a soft bristle brush.