Some common quality problems often occur in the welding process of steel bar processing, which are harmful and easy to cause major engineering accidents. Then, let's understand what to do if there are problems in the welding process of steel bar!

flash welding

Unmelted means that crystals cannot be formed in the welding area, the welding is unstable, the joint upsetting and deformation are too small, the extruded burr is uneven, and there is a large expansion phenomenon. The welding parameters shall be reasonably selected during the construction, and the welding shall be fully preheated at the beginning of the welding to ensure the heating part of the welding components and reduce the internal temperature gradient. At the same time, the appropriate combustion flow shall be selected to ensure the good temperature distribution of the welding components. At the same time, the welding construction shall not be carried out with excessive transformer series.

OXIDATION OF WELD

Specifically, since a part of the weld joint is covered with an oxide film, the surface becomes smooth, or strong oxidation occurs during welding, resulting in the loss of metallic luster of the part. In its prevention and control, we must first ensure the continuity of the sintering process, speed up the forging speed as much as possible in the appropriate upper forging welding process, and ensure that the joint part has appropriate plastic deformation to avoid oxidation.

Welded mouth brittle

The reason for this phenomenon is that in the low stress state, the joint part suddenly breaks, the fracture surface is flush, and the crystal grains are fine. To prevent this phenomenon, it is necessary to select appropriate welding technology according to the characteristics of steel bars. General low alloy steel muscles are suitable for preheating flash welding. In order to heat treat the muscles with higher welding difficulty, it is necessary to avoid rapid heating and cooling, and the temperature during heat treatment is slightly higher than 600.

Welding place

It is shown that the contact part between the steel bar and the electrode is melted during welding, causing local brittle failure, and the section is radioactive streaks. The prevention and control of this phenomenon requires removing rust, dirt, etc. within 13cm of the end of the steel bar during welding, cleaning the electrode surface to ensure conductivity, and clamping the steel bar during welding and heating treatment.

No score

Since the dissolved iron paste around the welding processing point is not full, slight tapping or falling may cause the welding point to separate. In order to prevent this phenomenon, the welding parameters should be reasonably selected, and the welding should be carried out after the test. Before welding, it is necessary to clean up the corrosion, oxide scale and garbage on the surface of the steel bar. After readjusting the parameters of the welding parts that have led to the removal of points, secondary welding such as variable current and extension of power-on time is carried out. Twice the test piece is used for the welding finished products to ensure the welding is qualified.

Burned solder joints

The main phenomenon of welding processing is that the upper and lower electrodes of the welding part and the contact part of the steel bar, the molten iron slurry overflows the flow around the welding point is too large, and the part is black. The prevention and control of this phenomenon should adjust the welding parameters in time, reduce the transformer technology, shorten the power-on time, clean the surface modification before welding, do not affect the conductive effect, ensure that the electrode surface is smooth, the electrode cooling cycle has no leakage, and implement secondary re-welding at the welding point,

cold bending brittle fracture

Welding process refers to the phenomenon of brittle fracture of welded joints during cold bending. The prevention and control of this phenomenon requires effective detection of the chemical composition of steel materials and the detection report. When the content of sulfur and phosphorus and other elements in the steel exceeds the standard, welding technology should be avoided. When the steel is cold drawn low carbon steel during construction, cold drawing strength detection should be carried out before welding construction. When the strength is too high, repeated bending tests should be carried out. Welding construction of steel that fails the test is strictly prohibited.

The above is what to do if there is a problem in the welding of steel bars. If you need to know more, please feel free to contact us!