Q235 hot-dip galvanized steel pipe, with its excellent corrosion resistance, economy, and processing performance, has become the mainstream galvanized steel pipe material in construction, fire protection, and agricultural irrigation. As a leading domestic galvanized steel pipe manufacturer, we use Q235 carbon structural steel as the base material and, through the hot-dip galvanizing process and full-process quality control, create galvanized steel pipe products with stable performance and long service life, providing reliable protection for various projects.
Q235 steel, as a low-carbon structural steel, has a carbon content controlled between 0.14% and 0.22%, possessing good weldability, cold bending, and impact resistance. Its yield strength reaches 235MPa, and its tensile strength is 375-500MPa, meeting the pressure requirements of galvanized steel pipes in DN15-DN300 specifications. During the hot-dip galvanizing process, the zinc layer forms an iron-zinc alloy layer with the steel substrate, with a thickness uniformity error ≤5μm, effectively preventing coating peeling. Salt spray testing has verified that Q235 hot-dip galvanized steel pipes can withstand 1000 hours in a 3% NaCl solution without red rust, extending their service life by 3-5 times compared to ordinary black pipes.
We employ an automated hot-dip galvanizing production line, ensuring the performance of Q235 hot-dip galvanized steel pipes through the following key processes:
(1) Pre-treatment optimization: A three-step process—pickling, washing, and fluxing—thoroughly removes oxide scale from the steel strip surface. The flux concentration (ZnCl₂ + NH₄Cl) is precisely controlled at 200-250 g/L to ensure a dense coating.
(2) Galvanizing parameter control: The zinc pot temperature is maintained at 450±5℃, and the immersion time is adjusted according to the pipe diameter (2 minutes for DN50 and below, 3 minutes for DN100 and above). The coating thickness reaches 65-85 μm, conforming to GB/T 13912 standard.
(3) Post-treatment strengthening: Centrifugal zinc spraying and air cooling eliminate internal stress in the coating, achieving a surface finish of Ra3.2 μm and reducing fluid transport resistance.
The application scenarios of Q235 hot-dip galvanized steel pipe are as follows:
(1) Building fire protection: As the main pipe of the fire hydrant system, it can withstand a working pressure of 0.8MPa and has no leakage after 10 years of use.
(2) Agricultural irrigation: DN80 pipe buried in alkaline soil for 5 years has a zinc layer loss rate of only 0.02mm/year;
(3) Municipal engineering: Participating in a city-integrated pipe gallery project, the efficiency of on-site connection of a single 12-meter pipe is increased by 40%, and the construction cost is reduced by 15%.
Post time: Nov-05-2025