What is Steel Pipe? Types, Sizes, Dimensions, Weights

HSAW Spiral Dammam KSA Steel Pipe

Steel pipe, a seemingly simple product, forms the backbone of countless applications in our everyday lives. From the towering skyscrapers to the intricate plumbing systems in our homes, steel pipe plays a vital role in construction, manufacturing, and infrastructure. This article covers the definition of steel pipe, explores its properties, uses, manufacturing processes, and various types. We will also equip you with the knowledge to choose the right steel pipe for your specific needs.

What is Steel Pipe?

Steel pipe is a long, hollow cylinder made of steel that is used primarily for transporting fluids and gasses. Unlike tubes, which have a smaller diameter and prioritize precision, pipes are designed to handle high pressure and fluid flow. Its strength, durability, and resistance to harsh environmental conditions make it an essential component in various industries, from construction to oil and gas exploration. Steel pipes are also used in plumbing, heating, and electrical systems due to their robust nature and versatility.

Steel Pipe Uses

The applications of steel pipe are vast and encompass a wide range of industries. Here are some prominent examples:

  1. Construction: Used for structural support in buildings, bridges, and other infrastructure projects. Steel pipes are used to make scaffolding poles, allowing construction workers to access hard-to-reach areas.
  2. Oil and Gas: Essential for transporting crude oil, natural gas, and other hydrocarbons from extraction points to refineries and processing plants.
  3. Plumbing: Galvanized steel pipes, coated with zinc for additional corrosion resistance, are used in residential and commercial plumbing systems for carrying water, gas, and sewage.
  4. Industrial: Used in manufacturing plants and factories to transport chemicals, steam, and other materials.
  5. Medical: They are used in the medical field for various applications, including medical equipment, surgical tools, dental treatments, and pharmaceutical assistance.
  6. Agriculture: Steel pipes are used in irrigation systems, transporting water to crops and fields. They can also serve as support structures for greenhouses and fencing.

How is Steel Pipe Made?

The manufacturing process of steel pipes involves several steps, each crucial for ensuring the pipe’s strength, durability, and compliance with industry standards:

  1. Raw Material Selection: High-quality steel is chosen based on the intended use of the pipe.Melting and Casting: Steel is melted in a furnace and cast into billets or slabs.
  2. Forming: The billets or slabs are then heated and rolled into a cylindrical shape.
  3. Electric Resistance Welding (ERW): This is the most common method. Coiled steel sheets are formed into a cylindrical shape and their edges are heated with high-frequency electric current. The molten metal fuses together, creating a strong weld.
  4. Seamless Pipe Manufacturing: For seamless pipes, the billet is pierced to create a hollow tube, then rolled and stretched to the desired size. This method produces pipes with superior strength and is often used for high-pressure applications.
  5. Sizing and Shaping: Pipes are sized and shaped according to specifications through a series of rollers.
  6. Heat Treatment: Pipes undergo heat treatment to improve their mechanical properties.
  7. Inspection and Testing: Pipes are inspected for defects and tested for strength, durability, and compliance with standards.

Differences Between Pipe and Tube

Though often used interchangeably, pipes and tubes are distinct in several ways:

  1. Dimensions: Pipes are measured by their inner diameter, while tubes are measured by their outer diameter. Moreover, pipes generally have a larger diameter compared to tubes.
  2. Applications: Pipes are designed for high pressure and fluid flow. So, they are generally used for transporting fluids and gasses, while tubes are used in structural applications, heat exchangers, and mechanical components.
  3. Tolerances: Pipes prioritize strength and pressure handling, so they have a wider range of acceptable tolerances in terms of wall thickness and diameter. Tubes, on the other hand, require higher precision for applications involving tight-fitting components.
  4. Manufacturing: Tubes often undergo additional processing and finishing steps, such as cold drawing, to achieve precise dimensions and surface finishes.

Types of Steel Pipe

Steel pipes come in various types, each designed for specific applications and conditions:

  1. Carbon Steel Pipes: Known for their strength and durability, used in oil and gas industries.
  2. Stainless Steel Pipes: Resistant to corrosion and high temperatures, used in chemical, food, and pharmaceutical industries.
  3. Alloy Steel Pipes: Made with a mixture of metals to achieve specific properties, used in high-stress applications.
  4. Galvanized Steel Pipes: While not as strong as stainless steel, they are still used in industrial piping systems, especially for plumbing and outdoor applications.
  5. Tool Steel Pipes: Tool steel pipes are tough, strong, ductile, and corrosion resistant. They are softer compared to other types of steel and can retain cutting edges in high temperatures.
  6. Black Steel Pipe (Uncoated): This is the most common type, used for general construction and low-pressure applications. It’s susceptible to rust and requires painting or coating for protection in exposed environments.

These types of steel pipes cater to various industrial needs based on their properties and applications. Each type offers specific advantages and is chosen according to the requirements of the project or industry.

Steel Pipe Specifications

Steel pipes are classified based on various specifications that determine their suitability for different applications:

  1. Sizes: Defined by nominal diameter (ND) or nominal pipe size (NPS), ranging from small (1/8 inch) to large (60 inches) diameters. Diameter determines the flow capacity.
  2. Dimensions: Includes outside diameter (OD), inside diameter (ID), and wall thickness.
  3. Weight: Determined by the pipe’s size and wall thickness, usually measured in pounds per foot or kilograms per meter. It helps determine transportation costs and structural load considerations.
  4. Schedules: Indicates the wall thickness relative to the diameter, with common schedules including SCH 40, SCH 80, and SCH 160. Higher schedules mean thicker walls and higher pressure capacity.

How to Choose the Right Steel Pipe

Choosing the right steel pipe involves considering several factors to ensure it meets the specific needs of the application:

  1. Application: Determine the primary use, such as transporting fluids, structural support, or high-temperature environments.
  2. Material: Choose the appropriate type of steel based on corrosion resistance, strength, and temperature tolerance.
  3. Size and Schedule: Select the nominal diameter and schedule based on the flow requirements and pressure ratings.
  4. Compliance: Ensure the pipe meets industry standards and certifications, such as ASTM, API, or ASME.
  5. Environmental Conditions: Will the pipe be exposed to harsh elements or extreme temperatures? Galvanized or coated pipes offer better corrosion resistance outdoors.
  6. Cost: Balance the initial cost with long-term performance and maintenance requirements.
  7. Supplier Reputation: Choose a reputable supplier with a track record of delivering high-quality products and reliable customer service.

Consulting with a qualified engineer or supplier is highly recommended, especially for complex projects involving high pressures or critical applications. They can help you navigate the selection process and ensure you choose the most suitable steel pipe for your specific needs.


In conclusion, steel pipes are integral to a wide range of industries due to their strength, versatility, and durability. Understanding the different types, specifications, and manufacturing processes helps in selecting the right pipe for specific applications, ensuring efficiency, safety, and longevity in various projects and operations.