Pipes are hollow cylindrical tubes that have been used for a variety of purposes by humans for thousands of years. Pipes can be made of nearly any material; however, because the current definition of a pipe demands more than just hollow tubes that transmit fluid, metals have grown more prevalent in pipe construction. Steels, as a metal alloy, offer a wide range of mechanical and chemical properties that may be used in even the most extreme situations; as a result, steel pipes are now used in a wide range of applications for transportation, manufacturing, and structural purposes. Steel pipes can be made from various grades of steel using various production methods that vary depending on the application requirements.
What is a Steel Pipe?
Steel pipes are long, hollow tubes that are used for a variety of purposes in a variety of locations. Because of their adaptability, pipes are the most commonly utilized commodity manufactured by the steel industry. They are often utilized to transport fluid liquids and tiny solid particles. Because of their high strength, they may also be used in subsurface water and gas transit across cities, as well as in construction for functions like as heating, plumping, and so on. For thousands of years, people have used and manufactured pipes for a variety of purposes. Archeological evidence confirms that ancient agriculturists or Chinese people used pipes constructed of various materials, such as wood or bamboo, for water conveyance as early as 2000 BC. Since the 1800s, incredible advances in steel pipe technology have been made, including improved production methods, the development of applications for their use, and the introduction of rules and standards that control their certification.
How is Pipe Used?
Pipes are used in building, transportation, and manufacturing. Steel pipe materials, design qualities, and production methods have evolved and varied in response to the use.
Application in Structure
Structural use is most typically associated with building and construction, and the building material is commonly referred to as steel tubes. Steel tubes are used to lend strength and stability to very tall buildings or constructions. End-bearing piles and friction piles are two types of steel pipes used in structural applications to distribute the load of the building. Steel pipes are pushed deep into the earth before the foundation is erected in certain applications, providing significant support to the building, especially when the ground is unstable. Another structural application of steel pipes is scaffolding poles which allow construction workers to access all areas of the building that are out of reach. They are made by linking steel tubes into each other as a cage that surrounds the building.
Steel pipes are used in manufacturing for a wide range of applications. One of the most popular ways to give a safety element for staircases and balconies, or for bicycles and pedestrians on the street, is with guard rails. Steel pipes can be used as security bollards, which are intended to block off a space from vehicle traffic in order to safeguard persons, structures, or infrastructure. Additionally, steel pipes are a choice for exterior site furnishings. Steel tubes are bent to produce several commercial bike racks. Steel has a high level of strength and toughness, making it secure against robbers.
Steel pipes are most frequently used for product transportation since the properties of the raw material make them ideal for long-term installations. As was previously said, different applications call for various properties. For example, a steel pipe used in low-pressure applications is not expected to have extremely high strength because it is not exposed to heavy loads. Due to the dangerous nature of the product and the potential for rising pressure, more specialized applications for usage in the oil and gas industry may need more exacting requirements. These demands increase the price and make quality control more important.
Design Pipes for Application
Seamless and welded-seam pipes are two different types of pipes with various applications. Since seamless pipes are typically lighter and thinner, they are most frequently employed in the manufacture of bicycles and the transmission of fluids. To achieve superior consistency and longevity, seam-welded pipes are heavier and more stiff. Plumbing, electrical conduit, and gas transportation pipes are often seam-sealed. For the application’s required properties to be maintained during production, a number of parameters should be regulated. For instance, the diameter of a pipe is constructed with consideration for its intended usage. Large diameter pipes can be utilized for transportation across cities, whereas smaller diameter pipes can be used for hypodermic needles. The wall thickness of the pipe directly influences the pipe’s strength and flexibility, making it another crucial component to manage. As will be discussed later, length, coating, and end finish are other variables that can be controlled.
Types of Steel Used in Pipes
Approximately 90% of the world’s steel pipe manufacturing is made of carbon steels. They often perform poorly when used alone and contain a small amount of alloying materials. Since they have adequate mechanical characteristics and machinability, they could be more affordable and preferable for applications with a focus on low stress. Carbon steels are less suitable for use in high-pressure applications and harsh environments because they lack alloying elements, making them less resistant to high loads. Carbon steels may be preferred for pipes primarily due to their superior ductility and resistance to bending under load. They are frequently used in the automobile, marine, and transportation of oil and gas industries. Carbon steel grades A500, A53, A106, and A252 can be used either seamed or seamless.
A pipe’s resistance to extreme temperatures and high pressures is increased by the inclusion of alloying elements, which enhance the mechanical properties of steel. Nickel, chromium, manganese, copper, etc., which are included in the composition between 1 and 50 weight percent, are the most common alloying elements. Because different alloying elements contribute to the product’s mechanical and chemical qualities in different ways, the chemical composition of steels is also altered in accordance with application requirements. In industries like the oil and gas sector, refineries, petro-chemistry, and chemistry plants where there are high loads and unstable conditions, alloyed steel pipes are typically employed.
The family of alloyed steels might also contain stainless steel. Chromium, whose weight percentage in stainless steel ranges from 10 to 20 weight percent, is the principal alloying component. The primary goal of adding chromium to steel is to give it stainless characteristics by reducing corrosion. In harsh environments where corrosion resistance and high strength are essential, such as in the oil and gas sector, the marine industry, and water purification systems, stainless steel pipes are typically used. The stainless steel grades 304/304L and 316/316L can be used to make pipes. While 304 grade exhibits excellent corrosion resistance and strength, 316 series has reduced strength and can be welded because to low carbon content.
Steel pipes that have been coated with zinc to prevent corrosion are known as galvanized pipes. Corrosive chemicals are prevented from corroding the pipe with a zinc coating. Galvanized pipe was previously the most popular type of pipe used for water supply lines, but due to the labor and time required to cut, thread, and install galvanized pipe, it is now only occasionally utilized outside of repairs. These pipes can range in diameter from 12 mm (0.5 inches) to 15 cm (6 inches). They come in 6 meters (20 feet) length options. Galvanized pipe is still used in bigger commercial applications for water delivery, nevertheless. The 40–50 year lifespan of galvanized pipes is a significant drawback. Although the steel is covered in a zinc coating that prevents exterior substances from reacting with it and corroding it, if the conveyed substances are corrosive, the pipe may begin to erode from the inside. Galvanized steel pipes must therefore be maintained and upgraded at certain times.
Pipe Types on Production Processes
According to the production processes, pipes are divided into two groups: seamless pipes and seamed pipes. Seamed pipes need to be welded after rolling, whereas seamless pipes can be made in one step during rolling. Seamed pipes can be divided into two groups based on the geometry of the seams, which can be either helical or straight. Although there is some disagreement about whether seamless or seamed steel pipes are superior, both welded and seamless pipe manufacturers are able to make steel pipes with excellent quality, dependability, and corrosion resistance. When choosing a pipe type, the application criteria and financial factors should be the major considerations.
The process for producing seamless pipes typically entails several difficult phases, beginning with the drilling of billets’ hollow interiors. When compared to welded tubes, seamless tubes are more difficult to manage for outside diameter and wall thickness. Cold work increases mechanical qualities and tolerances. The ability to manufacture seamless pipes with heavy and substantial wall thicknesses is their main benefit. They are regarded as demonstrating greater mechanical qualities and corrosion resistance than seamed pipes because they don’t have a weld seam. Also anticipated from seamless pipes is a superior ovality or roundness. They are typically employed more frequently in applications involving harsh environmental factors like high pressure, high loading, and strong corrosivity.
A steel plate that has been rolled into a tubular shape by a seam or a spiral seam is joined together to create the welded steel pipe. There are various methods for creating welded pipes, depending on the exterior dimension, wall thickness, and use. Each process begins with a hot steel billet or flat strip, which is then stretched, forced to come together, and then joined with a weld to form a pipe. Compared to seamless pipes, seamed pipes offer tighter tolerances but thinner wall thickness. Seamed pipes may be favored over seamless pipes for other reasons, including shorter lead times and reduced costs. Surface finishing of the pipe’s outside and inside should be monitored during production, nevertheless, as weld seams may be vulnerable locations where any crack could spread and cause the pipe to shatter.
The raw steel is initially cast into a more usable beginning form (hot billet or flat strip) in both manufacturing processes. The heated steel billet is then stretched into a seamless pipe or the edges of the flat steel strip are pressed together and joined with a weld.