Polished stainless steel tubes have multiple advantages such as corrosion resistance, high temperature resistance, and bright appearance, so they are popular in the construction, medical, energy and food industries. However, during use or processing, the surface may appear black, affecting the appearance and even the use effect.
How to deal with blackened surface after welding:
Higher purity argon
Using high-purity argon for welding can help reduce oxidation in the welding area and improve the overall finish.
Inner weld protection cannot be ignored
Especially for polished stainless steel tubes, argon protection must be applied on the back of the weld. Otherwise, the back is easily oxidized during welding and defects are formed.
Alternative: welding protective agent
If conditions do not allow the use of argon protection, you can also choose to apply welding back protective agent. When heated, the protective agent will form an isolation barrier to effectively prevent oxidation.
Natural formation and treatment of oxide film
Oxygen in the air reacts with stainless steel to form a protective oxide film. This black film layer usually does not affect the performance of stainless steel. If you only pursue higher appearance requirements, you can choose to re-polish the surface.
Tips for using pickling passivation paste
If there are black marks on the welding area, you can use pickling passivation paste to clean it. This product can effectively corrode the surface oxides, and the black spots can be removed by rinsing with clean water to restore the original luster.
MTSCO focuses on providing high-quality stainless steel pipes and accessories, and is equipped with a complete technical support team. We will wholeheartedly solve various surface treatment problems for you, welcome to inquire!
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