Stainless steel polished tubes are widely used in various industrial and civil fields for their excellent corrosion resistance, aesthetics and heat resistance. However, even high-quality stainless steel polished tubes may have the problem of black surface in some cases.
- Countermeasures for welding blackening
The high temperature during welding can easily cause the surface of stainless steel to oxidize, causing the weld area to blacken. Solutions include:
Increase the purity of argon gas: Using high-purity argon gas for welding can significantly improve the brightness of the weld.
Weld back protection: When welding polished tubes, argon gas protection must be performed inside the tube to prevent oxidation of the back weld layer and the formation of welding defects.
Back protection agent replacement method: If gas protection is not possible, a special welding protection agent can be used to simply and efficiently prevent back oxidation of the weld.
- Normal phenomenon of surface oxide film
Under long-term air contact, the oxide film generated on the surface of the tube may slightly affect the appearance, but it has no adverse effect on the tube itself. This is a natural protection mechanism and does not require excessive treatment. If the appearance brightness needs to be improved, polish it again.
- Surface cleaning suggestions
If the weld area is found to be obviously blackened, you can use pickling passivation paste for treatment. This chemical cleaning method can effectively remove the black oxide layer and restore its original finish after rinsing.
As an expert in stainless steel solutions, MTSCO is committed to providing you with reliable quality and reasonably priced products and services. Our product range covers polished pipes, seamless pipes, welded pipes, BA/AP polished pipes, pipe fittings, flanges and forgings. If you have any questions or needs, please feel free to contact us. We are happy to provide you with comprehensive support.