What is the effect of excessive welding of stainless steel pipe

What is excessive welding

Excessive welding, simply put, is in the welding of stainless steel pipe, welding time is too long, welding heat input is too high or welding too many times, beyond the reasonable range of welding process.

Its performance is often more obvious. For example, the weld may be too wide and too high, and the color of the welded area may change, becoming dark or even black. Moreover, excessive welding may also lead to pipe deformation, the original straight stainless steel pipe may be bent or twisted after welding, affecting its appearance and use performance.

Potential risk:

Impact on the material of stainless steel pipe

Reduced corrosion resistance: stainless steel pipe has good corrosion resistance because of its surface has a dense layer of chromium oxide protective film. However, excessive welding will make the temperature of the welding area is too high, this layer of protective film may be destroyed, which will lead to stainless steel pipe in the use of the process of more susceptible to corrosive media, shorten its service life.

Impact on mechanical properties: excessive welding produces excessive heat will make the grain growth of stainless steel pipe, which will reduce the strength, toughness and plasticity and other mechanical properties of the pipe. In some occasions that need to withstand greater pressure or tension, over-welded stainless steel pipe may fracture or deformation and other problems, bringing safety hazards to the project.

The impact on the quality of welding

Produce welding defects: over welding is prone to cause a variety of welding defects, such as porosity, cracks, slag and so on. The existence of porosity will weaken the strength of the weld, while cracks may gradually expand in the process of use, leading to weld fracture. Slag will affect the denseness of the weld and reduce the quality of the welded joint.

Reduce the reliability of welded joints: irregular shape of the weld and uneven internal organization caused by excessive welding will make the mechanical properties of the welded joints uneven, and the stress concentration phenomenon is likely to occur when the load is borne, thus reducing the reliability and stability of the welded joints.