Galvanized Sheet Iron Insulated Pipe

• ​Introduction

Galvanized Sheet Iron Insulated Steel Pipe is a composite pipeline system that integrates a steel pipe base, a galvanized sheet iron protective layer, and an intermediate insulation layer. It is mainly used to transport mediums (such as hot water, steam, and chilled water) that require temperature control in industrial production, building heating, ventilation, and air conditioning (HVAC) systems, as well as municipal engineering. The core design concept is to prevent heat loss or gain of the transported medium through the insulation layer, while the galvanized sheet iron outer layer provides corrosion resistance and mechanical protection for the insulation layer and the inner steel pipe, ensuring the pipeline’s long-term stable operation in harsh environments (such as humidity, dust, and chemical erosion).

• ​Main Functions

Temperature Maintenance：Reduces heat loss of hot medium (e.g., steam, hot water) or cold loss of cold medium (e.g., chilled water) during transportation.

Corrosion protection：Protect the inner steel pipe from electrochemical corrosion caused by moisture, oxygen, and chemical substances in the environment.

Mechanical Protection：Resists external impacts, collisions, and friction, preventing the insulation layer .

• ​Tubing Standards

ASTM A53，ASTM A106； EN 10255，EN 10240，EN 13941； GB/T 3091，GB/T 13793，GB/T 9711，GB/T 8163，GB 50264-2013.

• ​Material & Performance

Working Steel Pipe: ASTM A53: Grade A、B，ASTM A106: Grade A、B、C； EN 10255: S195T、S235JRH、S275JRH、S355JRH； GB/T 3091: Q215A/B、Q235A/B、Q355B, GB/T 8163：10#，20#，Q355，Q420， GB/T 13793: Q195、Q215A/B、Q235A/B、Q355B、Q390B；

Insulation Layer: Polyurethane foam (PUR) （Nominal Density：60(+15/-5) kg/m³，Thickness ：32-60mm，Thermal Conductivity: ≤ 0.029 W/m·K@50℃，Closed Cell Content: ≥90%，Water Absorption: <5%，Temperature Resistance：-40℃ ~ 120℃）;

Outer Jacket: Hot-Dip Galvanized Sheet Iron (Zinc Coating Thickness ≥ 85μm).

• ​Manufacturing Process

Select steel pipes that meet the standards (ASTM A53, GB/T 3091, etc.), and conduct quality inspection (including dimensional measurement, surface defect inspection, and pressure test) to ensure no cracks, holes, or other defects.

Perform derusting treatment on the outer surface of the steel pipe (such as shot blasting or pickling) to remove rust, oil stains, and impurities, improving the adhesion between the base pipe and the insulation layer.

Polyurethane foam insulation: Use the “on-site foaming” process—wrap the outer surface of the base pipe with a mold, inject polyurethane raw material (polyol and isocyanate) into the mold, and the raw material undergoes a chemical reaction to form a dense foam insulation layer.

Conduct thermal insulation performance testing (measure thermal conductivity), pressure testing (test the base pipe’s pressure bearing capacity), and corrosion resistance testing (sample salt spray test) on the finished pipeline.

Mark the pipeline with specifications, material, pressure rating, and production date, and package it with protective materials to prevent damage during transportation.