Galvanizli Boru

Three advantages of UNIASEN galvanized carbon steel pipes

• Strong anti-rust ability: using advanced hot-dip technology, the zinc layer is uniform, and the life is 3-5 years longer than ordinary pipes
• Affordable price: direct supply from our own factory, 10-15% cheaper than similar products on the market
• Complete specifications: various sizes from DN15 to DN600 are available in stock

Characteristics of galvanized carbon steel pipe

Material Characteristics

Galvanized steel pipe mainly uses low-carbon steel (carbon content ≤ 0.25%) or carbon structural steel. Common grades include Q195, Q215, and Q235 series. Among them, Q235B has a yield strength of ≥235MPa, a tensile strength of 375-500MPa, and an elongation of ≥10%, taking into account both strength and toughness. The surface is a zinc-iron alloy layer (hot-dip galvanizing) or a pure zinc layer (electrogalvanizing), which protects the substrate from corrosion through the “sacrificial anode” principle. The thickness of the hot-dip galvanizing layer is usually 35-100μm, and the corrosion resistance time of the salt spray test is over 500 hours.

The sizes cover a wide range, DN50-DN600, with standard wall thicknesses of SCH5S, SCH20S, SCH20, SCH20, SCH30, SCH40, SCH60, SCH80, XS, XXS and so on.Its outer diameter ranges from 60.3 mm to 609.6 mm.

The surface treatment of galvanized steel pipes is divided into two methods: hot-dip galvanizing and electro-galvanizing. Cold-dip galvanizing has been banned by the country due to insufficient corrosion resistance, and only hot-dip galvanizing can be used in key scenarios such as firefighting.

Galvanized steel pipes can provide customized services. Size customization supports non-standard lengths (3-12 meters), special-shaped pipes (square pipes/round pipes) and special wall thicknesses.

size specification

• Degreasing: alkaline solution (NaOH concentration of 10%-20%) 60-80 ℃ soaking 10-30 minutes, thoroughly remove oil;
• Acid Cleaning: hydrochloric acid (10%-20%) soaking at room temperature for 15-45 minutes to remove the Rust and corrosion; need to add corrosion inhibitors to prevent over-corrosion;
• Plating: Zinc chloride ammonium solution (ZnCl₂ 200-300g/L + NH₄Cl 100-200g/L) at 60-80 °C for 1-3 minutes.

Hot Dip Galvanizing:

• Zinc Liquid Temperature: 440-470 ℃ (cast iron parts need to be ≥ 540 ℃), dip plating time of 1-5 minutes (depending on the thickness of the workpiece to adjust);
• Zinc Layer Formation: iron – zinc reaction to produce δ-phase (FeZn) ₇) and ζ-phase (FeZn₁₃) alloy layer.

Post-treatment:

• Vibration to remove zinc tumors → water cooling (50-80℃) → chromate passivation (delay white rust generation).

• Annealing of hot rolled steel sheets (800-830°C) to improve the organizational structure;
•  Electrolytic cleaning to remove surface impurities.

Zinc Plating:

• cathode workpiece immersed in electroplating solution containing zinc ions, current density 10-50A/dm², coating thickness 3-15μm;
• optional zinc-nickel alloy plating (corrosion resistance increased by 30%).

Post-treatment:

•  Passivation (chromate/chrome-free passivation) → drying → coil slitting.

2. Quality control

• Thick coating: zinc layer thickness 30-120μm, salt spray corrosion resistance over 500 hours;
• Strong adhesion: metallurgical bonding, the zinc layer is not easy to fall off;
•  Long life: outdoor use up to 20 years or more.

ApplicationsFirefighting pipeline (GB 50084 standard), municipal water supply, high-pressure oil pipeline, and bridge structure support.

•  Low cost: the energy consumption of electroplating is only 1/3 of hot-dip galvanizing;
• Smooth surface: No zinc tumor, suitable for precision processing;
• Weak corrosion resistance: thin zinc layer, outdoor life of 3-5 years.

ApplicationsLight industrial fields with low requirements for corrosion resistance, such as household appliance shells and automobile parts.

• Low initial investment: hot-dip galvanizing rust prevention treatment costs only 1/3-1/2 of other coatings.
• Full-cycle economy: reduced maintenance frequency (no need to repair in 50 years), the comprehensive cost is more than 40% lower than stainless steel pipe.

• Flexible connection: support threaded, welded, grooved clamps and other connection methods to adapt to different engineering needs;
• Efficient construction：The galvanizing process is completed in the factory to avoid waiting time for on-site painting; standardized fittings (e.g., DN150/DN300) are used to achieve rapid assembly.

• 20 years + professional team:The core team comprises over 20 experts in carbon steel pipe, with backgrounds in material science, welding technology, fluid mechanics, and other relevant fields, providing comprehensive technical support from selection to construction of supplementary materials throughout the entire process.
• Multi-industry application verification: The products are used in petrochemical, construction, water conservancy, coal mining machinery, and other heavy industries, with a cumulative service of more than 500 projects worldwide. Supplementary materials are available.

Scale Production and Sourcing AdvantagesGlobalized Export Service Capability

• International compliance certification: certified by API 5L, ASTM A53, and other European and American standards, support customized compliance with EN 10219/DIN 2441 and other regional norms.
• Logistics network coverage:Self-export to the Middle East, Africa, Europe, and other regions, providing a variety of trade terms;
  Cooperative shipping companies to ensure space and emergency orders can start the air transport channel.

Deep Customization and Agile DeliveryProduct Flexibility Customization:Delivery guarantee mechanism: orders for hierarchical production planning, scheduling, and delivery; digital tracking real-time feedback production nodes; delivery deviation automatic warning.Full-cycle Technical Services

• Pre-sales design: provide material selection and structure optimization solutions for special working conditions (such as high-pressure oil transmission and low-temperature environments);
• Post-sales response:48 hours to issue a solution to quality disputes.
• Provide global third-party testing organizations to collaborate on goods inspection services.