To adjust the welding current and speed of a used pipe welder for pipes of varying thicknesses, it's first important to establish a basic adaptation logic based on the pipe's material properties. Different pipe materials exhibit significant differences in thermal conductivity and melting points, which directly determine the required energy input during welding. For example, if parameters for a pipe with high thermal conductivity and a low melting point are set according to those for a high-melting-point material, burn-through is likely to occur. Conversely, if the current is insufficient or the speed is too high for a pipe with slow thermal conductivity and a high melting point, inadequate fusion can result. Therefore, before making adjustments, it's important to first understand the pipe's material properties. This will then serve as a preliminary guideline for adapting the current and speed. This ensures that subsequent adjustments are tailored to the material's characteristics and avoid weld defects caused by a mismatch between material and parameters.
When processing thinner pipes, the key to adjustment is controlling the energy input to prevent excessive heating and deformation. This type of pipe has thin walls and weak overall rigidity. If the welding current is too high, high-temperature energy will quickly concentrate in the weld joint area, easily causing problems such as burn-through and edge curling. If the welding speed is too slow, the prolonged high temperature will expand the heat-affected zone, causing the pipe to bend and deform after welding, affecting the subsequent forming accuracy. Therefore, when adjusting, the current should be appropriately reduced while maintaining a relatively fast welding speed. This combination of "low current + fast speed" ensures basic fusion of the weld joint while minimizing the impact of high temperature on the overall pipe structure and maintaining the pipe's morphological stability after welding.
For medium-thick pipes, adjustments require a balance between weld strength and production efficiency. This type of pipe requires a moderate level of welding energy, requiring sufficient current to ensure complete fusion of the weld joint and reliable weld strength, while avoiding the risk of reduced production efficiency due to excessively slow welding speeds. When adjusting, first set basic current and speed parameters, then make fine adjustments based on the appearance of the weld. If the weld surface is rough or has noticeable porosity, this could indicate insufficient current or excessive speed. Increase the current or reduce the speed accordingly. If the weld is too wide or the heat-affected zone is excessive, this could indicate excessive current or excessive speed. Adjust the parameters in the opposite direction until the weld is smooth and the fusion line is continuous, while also maintaining a reasonable production pace.
For thicker pipes, adjustments focus on increasing welding energy input to ensure the weld penetration meets the required depth, while also avoiding inappropriate speed control that could compromise weld quality. These pipes have thicker walls, requiring sufficient current to penetrate the pipe wall and form a deep fusion zone, ensuring structural strength after welding. However, simply increasing the current without adjusting the speed can lead to insufficient exposure to high temperatures, preventing full fusion, while too slow a speed can cause the weld to overheat and produce coarse grains. Therefore, during adjustments, the current intensity must be significantly increased while the speed must be kept relatively slow. This allows the current ample time to penetrate the weld, ensuring the desired weld depth and avoiding issues like delamination and incomplete penetration.
Taking into account the characteristics of the used pipe welding machine, adjustments must be tailored to the machine's actual operating conditions. After long-term use, core components such as welding heads and transformers may experience performance degradation, leading to decreased current output efficiency and reduced speed control accuracy. For example, the welding head coils of some older machines may age, resulting in lower actual energy output compared to new machines at the same current setting. In this case, adjusting parameters based on new machine parameters will result in insufficient energy. Therefore, before adjustments are made, test welds should be conducted to observe the actual output of the used pipe welding machine. If poor weld quality is observed, the current can be increased or the speed can be reduced to compensate for performance loss and ensure that the parameter adjustments are suitable for the machine's actual operating conditions.
Dynamic fine-tuning during welding is also a crucial step in adaptation, requiring flexible parameter optimization based on real-time operating conditions. In actual production, pipe thickness can vary slightly. Even within the same batch, thickness inconsistencies can occur due to fluctuations in the production process. Furthermore, changes in the welding environment's temperature and humidity can also affect welding performance. Therefore, during continuous welding, close monitoring of the weld joint is crucial. If any abnormalities are detected in a particular section of pipe, immediate determination should be made as to whether they are due to thickness deviation or environmental changes. Targeted adjustments to the current and speed should be made to avoid batch welding defects caused by fixed parameters being unable to adapt to dynamic working conditions.
After parameter adjustments are completed, multi-dimensional verification is required to confirm the effectiveness of the adjustments and subsequent optimizations should be conducted. After adjustments are made, a small batch of test welds can be conducted. The welded pipes should then be inspected for appearance defects, dimensional compliance, and mechanical properties. This will determine whether the weld joints contain defects, meet dimensional standards, and meet strength requirements. If any issues are detected, analysis should be conducted to determine whether they are caused by inappropriate current or speed parameters, and further adjustments can be made. If the test passes, the parameter settings for that pipe thickness can be recorded and created into a unique parameter profile. This profile can then be used to directly recall and fine-tune the parameters based on actual conditions when welding pipes of the same thickness, improving adjustment efficiency and welding stability.
