Welding is widely used in the construction industry, mechanical manufacturing and many other industries. In the welding process, many unexpected problems are often encountered, such as welding cracks, which are detrimental to the welding parts and affect the quality of the welding parts. Here we discuss the causes of welding cracks and the prevention measures.
Firstly, there are generally three main causes of weld cracks.
1. Excessive welding heat
When the heat input to the weld pool is too high, the thermal expansion and contraction are too large, and the residual stress generated will be too large, causing welding cracks. To prevent this, measures should be taken to keep the heat input low, such as adjusting the current, using large wire diameters, using shielding gases with low thermal conductivity, and so on.
2. Excessive welding speed
When the welding speed is too fast, the heat input is difficult to control, and the cooling rate is high, which easily causes the precipitation of welding defects, resulting in weld cracking. Generally, the welding speed should be slow, the current should be increased appropriately, and the molten pool should be more solidified.
3. Unreasonable welding gap
Welding gap is too small to form welding cracks because of improper convection and difficulty in melting layers. We can choose appropriate welding wire according to the operating conditions, such as narrowing the gap, increasing current and increasing the welding speed.
Secondly, what are the preventive measures for weld cracking?
1. Choose suitable welding process and welding materials
In welding cracks cases different welding processes should be used for different welding materials and the best welding process should be chosen. The selection of welding materials is also very important, different materials have different requirements for the parameter selection and welding method, and the best choice should be analyzed.
2. Proper selection of welding parameters
The proper selection of welding parameters such as current, voltage and speed is the most important factor to prevent welding cracks. When the parameters are too high, the welding temperature will be higher, and when the parameters are too low, the welding penetration will be insufficient. Therefore, it is very important to properly adjust the welding parameters.
3. Strictly control the welding process
To prevent welding cracks, the welding process must be strictly controlled. During the welding process, the welding tools should be adjusted and adjusted in time. After welding, the rear cover and welding surface should be checked in time to ensure that no welding defects are generated during the welding process.
In conclusion, weld cracks are very common problems during welding. To prevent cracking, it is very important to choose the right welding process and welding material, properly adjust the welding parameters, and strictly control the welding process.
