1. Selection of welding materials
Choosing appropriate welding consumables is an important prerequisite for ensuring welding quality. Generally, the same or similar welding materials as duplex stainless steel pipes are used for welding, such as ER2209, ER2553, etc. During the welding process, attention should be paid to the gas protection of the welding area to prevent oxidation.
2. Preheating temperature
Increasing the preheating temperature can reduce the risk of welding deformation and cracks. Under normal circumstances, the preheating temperature of duplex stainless steel pipes is controlled at 100-200°C, and a slow and even heating method is used to avoid problems such as deformation or cracks caused by excessive local heat.
3. Welding parameters
Reasonable welding parameters are the key to ensuring welding quality. Appropriate current, voltage, speed and other parameters should be selected based on the diameter, wall thickness, welding direction and other factors of the pipe. At the same time, parameters such as arc length and welding speed should be strictly controlled during the welding process to avoid various welding defects.
4. Post-weld treatment
After welding is completed, necessary post-weld processing should be carried out, such as slag removal, polishing, etc. At the same time, non-destructive testing of the welds must be carried out to ensure welding quality.
3. Example sharing
In actual work, we need to combine the specific welding conditions and flexibly use the above welding processes to achieve the best welding effect. For example, in a petrochemical project, we used ER2209 welding consumables, the preheating temperature was 150°C, the welding parameters were controlled at current 225A, voltage 20V, and welding speed 10cm/min, and finally achieved the expected welding effect.
In short, the welding process of duplex stainless steel pipes needs to be flexibly adjusted according to the characteristics of the pipes, and key points such as welding materials, preheating temperatures, and welding parameters must be mastered to achieve scientific and standardized welding and ensure product quality and service life.
Gnee Company Team
