What should we do if there is a problem in steel welding?

In the welding process of steel bar processing, some quality problems that often occur and generally exist are very harmful and easy to cause major engineering accidents. Lack of penetration Not fully welded, refers to the failure to form crystallization or welding in the welding area is not strong, joint upsetting or deformation is too small, resulting in uneven extruded burr, and serious expansion phenomenon. During the construction, welding parameters should be reasonably selected. At the beginning of welding, the welding should be fully preheated to ensure the heating part of the weldment and reduce the internal temperature gradient. At the same time, the appropriate firing flow should be selected to ensure the weldment to obtain a good temperature distribution. Joint oxidation Specifically, the welding joint is partially covered with oxide film, resulting in smooth surface, or in the welding process around the welding joint, due to strong oxidation resulting in the loss of metallic luster of the site. The prevention and control should first ensure the continuity of the burning process, and the use of appropriate top forging welding, the process should be as fast as possible to accelerate the top forging speed to avoid oxidation, and should ensure that there is a suitable plastic deformation in the joint, in order to facilitate the removal of oxides. Brittle fracture of welded junction The reason for this phenomenon is that the joint part breaks suddenly under low stress state, and the fracture is flush and the grain is very fine. The prevention and control of this phenomenon: should be combined with the characteristics of the steel bar to choose the appropriate welding process, general low alloy steel bar is suitable for preheating flash welding, welding difficult Ⅲ grade bars, it should be heat treatment, and should avoid rapid heating and cooling, heat treatment with a temperature slightly over 600℃. Weld burn End contact with the electrode performance for steel parts produced in the process of welding melting state, it can lead to local brittle fracture, and fracture are radioactive stripes, the prevention should be in the welding of this phenomenon will be reinforced end 13 cm within the scope of the rust stain and dirt, clean, and shall ensure that the electrode surface clean to ensure that the electrical conductivity, The steel bar should be clamped during welding and heating treatment. Take off a point It shows that the molten iron slurry around the solder joint is not full, and gently beating or beating will lead to the separation of the solder joint. To prevent this phenomenon, the welding parameters should be reasonably selected, and the welding can be carried out after passing the test. Before welding, the steel bar surface corrosion, oxide scale and debris should be cleaned up. After the welding parts that have caused the off-point should be readjusted, the current should be increased and the power time should be extended for the second repair welding. And the welding finished products should be double the test pieces to ensure that the repair welding is qualified. Solder joint burnt It is mainly shown that the upper and lower electrodes of the welding site and the contact parts of the steel bar are burned, or the molten iron slurry overflow around the solder joint is too large, leading to the black appearance of the site. To prevent and control this phenomenon, welding parameters should be adjusted in time, transformer technology should be reduced and the power on time should be shortened. Before welding, the surface should be cleaned up to avoid affecting the conductive effect. The electrode surface should be guaranteed to be flat, the electrode cooling cycle has no leakage, and the second rewelding of the solder joint is strictly prohibited. Brittle fracture of cold bending It refers to the phenomenon that the welding joint appears brittle break when the welding parts are cold bending. The prevention and control of this kind of phenomenon should effectively detect the chemical composition of the steel material and provide detection reports. Once the content of sulfur, phosphorus and other elements of the steel exceeds the standard, the welding process should be avoided. If the steel is cold drawn low carbon steel in the construction, cold drawing strength test should be carried out before the welding construction. If the strength is too high, repeated bending test should be carried out. Welding construction should be prohibited for the unqualified steel in the test.铜焊丝,Copper Welding Rods,铝焊丝,aluminium welding wire,镍焊条,Nickel electrode,药皮焊条,Flux Coated Brazing Welding Rods