Due to certain factors (such as non-metallic inclusions, gases, process selection, or improper operation), spiral pipes may have defects during smelting or hot processing, which seriously affect the quality of materials or products and sometimes lead to the scrapping of materials or products.

Common Defects and Causes of Spiral Steel Pipes: Loosening, bubbles, shrinkage residue, non-metallic inclusions, segregation, white spots, cracks, and various abnormal fracture defects in spiral steel pipes can all be detected through macroscopic inspection. There are two types of macroscopic inspection: acid leaching inspection and fracture inspection. The following is a brief introduction to common macroscopic defects revealed by acid leaching:

1. Causes of segregation in spiral pipes: During casting and solidification, due to selective crystallization and diffusion, certain elements may aggregate, leading to uneven chemical composition. Based on their different distribution locations, segregation can be classified into ingot segregation, center segregation, and point segregation. The macroscopic characteristics are those of acid-leached samples. When analyzed as corrosive or gas inclusions, they appear as dark-colored, irregularly shaped, slightly concave, flat-bottomed spots with numerous dense microporous spots. If it is a corrosion-resistant component, it will have light-colored, irregularly shaped, and smoother micro-bumps.

2. Reasons for the spiral tube hole. During hot working, steel cannot be welded due to solidification shrinkage and gas release of low-melting-point materials.

Based on their basic distribution, they can be divided into management center type and general loose type. On the side-heat acid leaching surface, the pores are irregular polygons with narrow pits at the bottom.

These different pit structures often allow for more analysis, and in severe cases, they tend to connect into a sponge-like structure.

Time：22/10/2026 16:26:10

Common Defects and Causes of Spiral Steel Pipes: Loosening, bubbles, shrinkage cavities, residues, non-metallic inclusions, segregation, white spots, cracks, and various abnormal fracture defects in spiral steel pipes.

Causes of Segregation in Q235 Spiral Pipes: During casting and solidification, selective crystallization and diffusion can cause the aggregation of certain elements, leading to uneven chemical composition. Depending on the distribution location, this can be classified as ingot segregation, center segregation, and point segregation.

Causes of porosity in Q235 spiral tubes: During hot working, gaps are created by the solidification shrinkage of low-melting-point materials and the release of gas, preventing the steel from being welded. Based on their basic distribution, porosity can be divided into two types: centrally located type and generally loose type.

Time：15/10/2026 17:37:58

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