The Impact of Processing on Product Quality: Three Key Judgment Points

The Impact of Processing on Product Quality: Three Key Judgment Points
The details of the production process can quickly determine the quality of galvanized rectangular pipes and avoid purchasing "substandard" products:
Check the zinc coating adhesion: Use a hard object (such as a key) to lightly scratch the pipe surface. The zinc coating of hot-dip galvanized pipes should not peel or flake off, leaving only a slight scratch. If the zinc coating flakes off with a single scratch, it may be due to incomplete pre-treatment (oil stains/scale) or insufficient zinc bath temperature.
Check the weld quality: The weld seam of high-quality galvanized pipe should be smooth, free of pores and slag inclusions, and the zinc coating should evenly cover the weld seam (no missing plating). If the weld seam is raised or has pinholes, it may be due to unstable welding current or insufficient pressure from the extrusion rollers, which can lead to rust. Measuring cross-sectional dimensions: Use a caliper to measure the length, width, and wall thickness of the rectangular tube. The error should comply with national standards (e.g., wall thickness error ≤ ±0.1mm). If the dimensional deviation is large (e.g., the marked 20×40mm is actually 19×39mm), it indicates that the roller accuracy during the forming stage is insufficient, which will affect the installation adaptability.