The appearance of "pitting" and "dents" on the surface of seamless steel tubes is a common quality defect. These surface imperfections not only affect the product's appearance but, more importantly, reduce the corrosion resistance and service life of the seamless tubes. Understanding the causes of these defects is crucial for improving the surface quality of seamless steel tubes.

Analysis of Pitting Causes

Pitting typically manifests as groups of small pits on the surface of seamless tubes. Its main causes include factors related to the material itself and issues in the production process. In terms of material, an excessive amount of non-metallic inclusions in the steel billet can lead to pitting; these inclusions detach during the rolling process. Additionally, bubbles in the steel billet that become exposed during rolling can also form similar defects.

The pickling process in production is another significant factor. Over-pickling or improper control of acid concentration can cause localized over-corrosion on the tube surface, resulting in uniformly distributed pitting. By optimizing pickling process parameters and strictly controlling acid concentration and temperature, Tenjan Steel Tube Co., Ltd. has effectively prevented such issues.

Formation Mechanism of Dents

Dents are larger depressions on the surface of seamless tubes, usually caused by mechanical damage or rolling defects. During hot rolling, the embedding of scale into the surface is a common cause of dents. When the roll surface is damaged or has foreign material adhering to it, periodic dents can form on the tube surface.

Improper operation during cold processing can also cause dents. For example, defects or improper adjustment of straightening rolls can leave regular dents on the tube surface. Through regular equipment maintenance and ensuring the surface quality of rolls and straightening rolls, Tenjan Steel Tube Co., Ltd. has prevented the generation of such defects at the equipment level.

Preventive Measures and Solutions

Systematic measures are required to prevent pitting and dents on the surface of seamless steel tubes. First, strictly control the quality of raw materials to ensure the purity of the steel billet and reduce the content of non-metallic inclusions. Tenjan Steel Tube Co., Ltd. uses high-quality continuous casting round billets to guarantee material quality from the source.

Second, optimize production process parameters. Reasonably control heating temperature and time to reduce scale formation; precisely adjust rolling processes to avoid mechanical damage; strengthen surface protection between processes to prevent collision damage. The company ensures effective control at every stage through a comprehensive production management system.

Quality Inspection and Defect Handling

Tenjan Steel Tube Co., Ltd. has established a strict surface quality inspection system. Each seamless tube is assessed for surface quality using a combination of visual inspection and instrument detection. Different handling measures are taken based on the severity of discovered surface defects.

Minor pitting defects can be eliminated through grinding, while more severe dents require decisions based on their depth and distribution. The company is equipped with professional surface treatment equipment capable of effectively repairing surface defects, ensuring that all products meet quality standards upon leaving the factory.

Conclusion

Pitting and dent defects on the surface of seamless steel tubes can be prevented and eliminated through strict quality control. Leveraging extensive production experience and a comprehensive quality management system, Tenjan Steel Tube Co., Ltd. ensures the provision of seamless steel tube products with excellent surface quality. Choosing Tenjan means choosing assurance. For more product information, please feel free to contact us anytime.