Q235 hot-dip galvanized steel pipe, with its excellent corrosion resistance, cost-effectiveness, and processability, has become a mainstream steel pipe material for construction, fire protection, agricultural irrigation, and other fields. As a leading domestic galvanized steel pipe manufacturer, we use Q235 carbon structural steel as the base material. Through hot-dip galvanizing and comprehensive quality control, we create steel pipe products with stable performance and long service life, providing reliable support for various projects.
Q235 steel, a low-carbon structural steel with a carbon content controlled between 0.14% and 0.22%, combines excellent weldability, cold bending, and impact resistance. Its yield strength reaches 235 MPa, and its tensile strength reaches 375-500 MPa, meeting the pressure requirements of galvanized steel pipes in sizes from DN15 to DN300. During the hot-dip galvanizing process, the zinc layer forms an iron-zinc alloy layer with the steel substrate, with a thickness uniformity error of ≤5μm, effectively preventing coating flaking. Salt spray tests have shown that Q235 hot-dip galvanized steel pipes can withstand 1,000 hours in a 3% NaCl solution without rusting, extending their service life by 3-5 times that of ordinary black pipes.
We utilize an automated hot-dip galvanizing line, ensuring the performance of Q235 hot-dip galvanized steel pipes through the following key processes:
- Pre-treatment Optimization: A three-step process of pickling, water washing, and flux coating thoroughly removes surface scale from the steel strip. The flux coating (ZnCl₂ + NH₄Cl) concentration is precisely controlled at 200-250g/L to ensure a dense coating.
- Galvanizing Parameter Control: The zinc bath temperature is maintained at a constant 450±5°C, and the galvanizing time is adjusted based on the pipe diameter (2 minutes for pipes under DN50 and 3 minutes for pipes over DN100). The resulting coating thickness reaches 65-85μm, meeting GB/T 13912 standards.
- Post-treatment Enhancement: Centrifugal zinc removal and air cooling eliminate internal stresses in the coating, achieving a surface finish of Ra 3.2μm and reducing fluid flow resistance.
Q235 hot-dip galvanized steel pipes are used in the following scenarios:
- Building fire protection: Serving as the main steel pipe for fire hydrant systems, they withstand a working pressure of 0.8 MPa and have remained leak-free for 10 years.
- Agricultural irrigation: DN80 steel pipes buried in alkaline soil for five years experienced a zinc loss rate of only 0.02 mm/year.
- Municipal engineering: Participating in a city’s integrated pipeline corridor project, on-site connection efficiency for a single 12-meter steel pipe was increased by 40%, reducing construction costs by 15%.
Post time: Aug-15-2025