Pipes are typically classified according to three core dimensions: material, manufacturing process, and application. Different types of iron pipes have significant differences in performance and applicable scenarios. The specific classifications are as follows:
By Material
This is the most basic classification method, determining the core performance of the iron pipe.
Cast Iron Pipes
Gray Cast Iron Pipes: High brittleness and poor toughness, but inexpensive. In the past, they were widely used for civil water supply and drainage, and agricultural irrigation, but are now gradually being replaced by ductile iron pipes.
Ductile Iron Pipes: The toughness of cast iron is improved through spheroidization treatment. Their strength is close to that of steel pipes, and they have strong corrosion resistance and settlement resistance. They are the mainstream pipe material for municipal rainwater and sewage pipe networks and main water supply pipelines.
Malleable Cast Iron Pipes: Commonly known as “malleable iron pipes,” they are relatively soft and easy to process, mainly used for making pipe fittings (elbows, tees), rather than for long-distance water/gas transmission.
Steel Pipes
Made from steel, their strength and toughness are far superior to cast iron pipes, with many sub-types:
Carbon Steel Pipes: Made from carbon steel, they are cost-effective and widely used for water supply and drainage, heat transfer, and general industrial fluid transportation.
Alloy Steel Pipes: Containing alloying elements such as chromium, molybdenum, and nickel, they are resistant to high temperatures, high pressure, and corrosion, and are used in chemical, power, and petroleum industries (such as transporting high-temperature steam and corrosive media).
Stainless Steel Pipes: Containing ≥10.5% chromium, they have excellent corrosion resistance and are used in food processing, pharmaceuticals, and seawater desalination, where high hygiene or corrosion resistance is required.
By Manufacturing Process
This mainly applies to steel pipes; different processes directly affect the pressure bearing capacity and applicable scenarios of the pipes.
Seamless Steel Pipes
Without welding seams, they have high overall strength and strong pressure bearing capacity, and are divided into hot-rolled seamless steel pipes and cold-drawn seamless steel pipes:
Hot-rolled seamless steel pipes: Larger diameter and thicker wall thickness, used for high-pressure fluid transportation and mechanical structural components;
Cold-drawn seamless steel pipes: High precision and smooth surface, used for precision instruments, hydraulic systems, etc. Welded Steel Pipes
Made by welding steel plates or strips, they are less expensive than seamless steel pipes and are divided into two categories:
Straight-seam welded steel pipes: The weld seam is straight, and the pipe diameter is relatively small. They are used for low-pressure water supply and drainage, gas pipelines, and conduit pipes;
Spiral-seam welded steel pipes: The weld seam is spiral-shaped, with a large diameter (up to over 3 meters), and good rigidity. They are used for municipal gas main pipelines and large-diameter water pipes in sewage treatment plants.
Classification by Use
Categorized according to the application scenario and conveyed medium, providing greater specificity:
Iron pipes for water supply and drainage: such as ductile iron water pipes, PVC-lined cast iron drainage pipes, and carbon steel water pipes;
Iron pipes for gas transmission: such as galvanized welded steel pipes and spiral-seam steel pipes (requiring anti-corrosion treatment);
Iron pipes for heating: such as heat-resistant alloy steel pipes and insulated steel pipes (with an outer insulation layer);
Industrial iron pipes: such as corrosion-resistant alloy pipes for chemical use and high-pressure seamless steel pipes for petroleum use.
Post time: Feb-05-2026