Steel Pipe

Steel pipes are long, hollow tubes that are used for a variety of purposes. They are produced by two distinct methods which result in either a welded or seamless pipe. In both methods, raw steel is first cast into a more workable starting form. It is then made into a pipe by stretching the steel out into a seamless tube or forcing the edges together and sealing them with a weld. The first methods for producing steel pipe were introduced in the early 1800s, and they have steadily evolved into the modern processes we use today. Each year, millions of tons of steel pipe are produced. Its versatility makes it the most often used product produced by the steel industry.

Steel pipes are found in a variety of places. Since they are strong, they are used underground for transporting water and gas throughout cities and towns. They are also employed in construction to protect electrical wires. While steel pipes are strong, they can also be lightweight. This makes them perfect for use in bicycle frame manufacture. Other places they find utility is in automobiles, refrigeration units, heating and plumbing systems, flagpoles, street lamps, and medicine to name a few.

History

People have used pipes for thousands of years. Perhaps the first use was by ancient agriculturalists who diverted water from streams and rivers into their fields. Archeological evidence suggests that the Chinese used reed pipe for transporting water to desired locations as early as 2000 b.c. Clay tubes that were used by other ancient civilizations have been discovered. During the first century a.d., the first lead pipes were constructed in Europe. In tropical countries, bamboo tubes were used to transport water. Colonial Americans used wood for a similar purpose. In 1652, the first waterworks was made in Boston using hollow logs.

Development of the modern day welded steel pipe can be traced back to the early 1800s. In 1815, William Murdock invented a coal burning lamp system. To fit the entire city of London with these lights, Murdock joined together the barrels from discarded muskets. He used this continuous pipeline to transport the coal gas. When his lighting system proved successful a greater demand was created for long metal tubes. To produce enough tubes to meet this demand, a variety of inventors set to work on developing new pipe making processes.

An early notable method for producing metal tubes quickly and inexpensively was patented by James Russell in 1824. In his method, tubes were created by joining together opposite edges of a flat iron strip. The metal was first heated until it was malleable. Using a drop hammer, the edges folded together and welded. The pipe was finished by passing it through a groove and rolling mill.

Russell's method was not used long because in the next year, Comelius Whitehouse developed a better method for making metal tubes. This process, called the butt-weld process is the basis for our current pipe-making procedures. In his method, thin sheets of iron were heated and drawn through a cone-shaped opening. As the metal went through the opening, its edges curled up and created a pipe shape. The two ends were welded together to finish the pipe. The first manufacturing plant to use this process in the United States was opened in 1832 in Philadelphia.

Gradually, improvements were made in the Whitehouse method. One of the most important innovations was introduced by John Moon in 1911. He suggested the continuous process method in which a manufacturing plant could produce pipe in an unending stream. He built machinery for this specific purpose and many pipe manufacturing facilities adopted it.

While the welded tube processes were being developed, a need for seamless metal pipes arouse. Seamless pipes are those which do not have a welded seam. They were first made by drilling a hole through the center of a solid cylinder. This method was developed during the late 1800s. These types of pipes were perfect for bicycle frames because they have thin walls, are lightweight but are strong. In 1895, the first plant to produce seamless tubes was built. As bicycle manufacturing gave way to auto manufacturing, seamless tubes were still needed for gasoline and oil lines. This demand was made even greater as larger oil deposits were found.

As early as 1840, ironworkers could already produce seamless tubes. In one method, a hole was drilled through a solid metal, round billet. The billet was then heated and drawn through a series of dies which elongated it to form a pipe. This method was inefficient because it was difficult to drill the hole in the center. This resulted in an uneven pipe with one side being thicker than the other. In 1888, an improved method was awarded a patent. In this process the solid billed was cast around a fireproof brick core. When it was cooled, the brick was removed leaving a hole in the middle. Since then new roller techniques have replaced these methods.

Design

There are two types of steel pipe, one is seamless and another has a single welded seam along its length. Both have different uses. Seamless tubes are typically more light weight, and have thinner walls. They are used for bicycles and transporting liquids. Seamed tubes are heavier and more rigid. The have a better consistency and are typically straighter. They are used for things such as gas transportation, electrical conduit and plumbing. Typically, they are used in instances when the pipe is not put under a high degree of stress.

Certain pipe characteristics can be controlled during production. For example, the diameter of the pipe is often modified depending how it will be used. The diameter can range from tiny pipes used to make hypodermic needles, to large pipes used to transport gas throughout a city. The wall thickness of the pipe can also be controlled. Often the type of steel will also have an impact on pipe's the strength and flexibility. Other controllable characteristics include length, coating material, and end finish.

Raw Materials

The primary raw material in pipe production is steel. Steel is made up of primarily iron. Other metals that may be present in the alloy include aluminum, manganese, titanium, tungsten, vanadium, and zirconium. Some finishing materials are sometimes used during production. For example, paint may be used if the pipe is coated. Typically, a light amount of oil is applied to steel pipes at the end of the production line. This helps protect the pipe. While it is not actually a part of the finished product, sulfuric acid is used in one manufacturing step to clean the pipe.

The Manufacturing
Process

Steel pipes are made by two different processes. The overall production method for both processes involves three steps. First, raw steel is converted into a more workable form. Next, the pipe is formed on a continuous or semicontinuous production line. Finally, the pipe is cut and modified to meet the customer's needs.

Ingot production

• 1 Molten steel is made by melting iron ore and coke (a carbon-rich substance that results when coal is heated in the absence of air) in a furnace, then removing most of the carbon by blasting oxygen into the liquid. The molten steel is then poured into large, thick-walled iron molds, where it cools into ingots.
• 2 In order to form flat products such as plates and sheets, or long products such as bars and rods, ingots are shaped between large rollers under enormous pressure.

Producing blooms and slabs

• 3 To produce a bloom, the ingot is passed through a pair of grooved steel rollers that are stacked. These types of rollers are called "two-high mills." In some cases, three rollers are used. The rollers are mounted so that their grooves coincide, and they move in opposite directions. This action causes the steel to be squeezed and stretched into thinner, longer pieces. When the rollers are reversed by the human operator, the steel is pulled back through making it thinner and longer. This process is repeated until the steel achieves the desired shape. During this process, machines called manipulators flip the steel so that each side is processed evenly.
• 4 Ingots may also be rolled into slabs in a process that is similar to the bloom making process. The steel is passed through a pair of stacked rollers which stretch it. However, there are also rollers mounted on the side to control the width of the slabs. When the steel acquires the desired shape, the uneven ends are cut off and the slabs or blooms are cut into shorter pieces.

Further processing

• 5 Blooms are typically processed further before they are made into pipes. Blooms are converted into billets by putting them through more rolling devices which make them longer and more narrow. The billets are cut by devices known as flying shears. These are a pair of synchronized shears that race along with the moving billet and cut it. This allows efficient cuts without stopping the manufacturing process. These billets are stacked and will eventually become seamless pipe.
• 6 Slabs are also reworked. To make them malleable, they are first heated to 2,200° F (1,204° C). This causes an oxide coating to form on the surface of the slab. This coating is broken off with a scale breaker and high pressure water spray. The slabs are then sent through a series of rollers on a hot mill and made into thin narrow strips of steel called skelp. This mill can be as long as a half mile. As the slabs pass through the rollers, they become thinner and longer. In the course of about three minutes a single slab can be converted from a 6 in (15.2 cm) thick piece of steel to a thin steel ribbon that can be a quarter mile long.
• 7 After stretching, the steel is pickled. This process involves running it through a series of tanks that contain sulfuric acid to clean the metal. To finish, it is rinsed with cold and hot water, dried and then rolled up on large spools and packaged for transport to a pipe making facility.

Pipe making

• 8 Both skelp and billets are used to make pipes. Skelp is made into welded pipe. It is first placed on an unwinding machine. As the spool of steel is unwound, it is heated. The steel is then passed through a series of grooved rollers. As it passes by, the rollers cause the edges of the skelp to curl together. This forms an unwelded pipe.
• 9 The steel next passes by welding electrodes. These devices seal the two ends of the pipe together. The welded seam is then passed through a high pressure roller which helps create a tight weld. The pipe is then cut to a desired length and stacked for further processing. Welded steel pipe is a continuous process and depending on the size of the pipe, it can be made as fast as 1,100 ft (335.3 m) per minute.
• 10 When seamless pipe is needed, square billets are used for production. They are heated and molded to form a cylinder shape, also called a round. The round is then put in a furnace where it is heated white-hot. The heated round is then rolled with great pressure. This high pressure rolling causes the billet to stretch out and a hole to form in the center. Since this hole is irregularly shaped, a bullet shaped piercer point is pushed through the middle of the billet as it is being rolled. After the piercing stage, the pipe may still be of irregular thickness and shape. To correct this it is passed through another series of rolling mills.

Final processing

• 11 After either type of pipe is made, they may be put through a straightening machine. They may also be fitted with joints so two or more pieces of pipe can be connected. The most common type of joint for pipes with smaller diameters is threading—tight grooves that are cut into the end of the pipe. The pipes are also sent through a measuring machine. This information along with other quality control data is automatically stenciled on the pipe. The pipe is then sprayed with a light coating of protective oil. Most pipe is typically treated to prevent it from rusting. This is done by galvanizing it or giving it a coating of zinc. Depending on the use of the pipe, other paints or coatings may be used.

Quality Control

A variety of measures are taken to ensure that the finished steel pipe meets specifications. For example, x-ray gauges are used to regulate the thickness of the steel. The gauges work by utilizing two x rays. One ray is directed at a steel of known thickness. The other is directed at the passing steel on the production line. If there is any variance between the two rays, the gauge will automatically trigger a resizing of the rollers to compensate.

Pipes are also inspected for defects at the end of the process. One method of testing a pipe is by using a special machine. This machine fills the pipe with water and then increases the pressure to see if it holds. Defective pipes are returned for scrap.

Where to Learn More

Books

Pipe Characteristic Handbook. Williams Natural Gas Company Engineering Group. Pennwell Publishing. 1996.

Kirk Othmer Encyclopedia of Chemical Technology. John Wiley & Sons. New York: 1992.

Steel Pipe: A Guide for Design and Installation. American Water Works Association. 1989.

—PerryRomanowski

5 Advantages of Using Steel Pipes in Construction

What are the advantages of using steel pipes in construction?

1. Durability
2. Resistance to corrosion
3. Easily malleable
4. Recyclable
5. Cost-efficient

Steel pipes have become a widely-used material in the construction business for decades now. It is viewed by contractors and builders as an alloy of iron that boasts desirable properties. Oftentimes, steel pipes are chosen over other materials. With that, the advantages of using steel pipes in construction are something to be kept in mind.

As the leading steel pipe supplier in the Philippines, we at Supreme Pipe believe that the demand for this material will continue to rise. Read on to see how steel pipes can benefit your construction project today!

Durability

There are two main uses for steel pipes in construction – structural and transportation. For structural purposes, steel pipes are inserted deep underground before the foundation is laid to provide stability. If you see a disruption in your local area, then those are most likely because construction workers are laying steel pipes.

As for transportation, steel pipes are used for oil, gas, sewage, and water. In other projects, it supports the flow of hazardous chemicals as well. In some cases, steel pipes are used as bollards to protect establishments and people from vehicle-ramming accidents.

All of these applications demand the durability of materials. This is where the strength of steel pipes is a desirable advantage.

Unlike other materials, its durability enables it to withstand high pressure, vibrations, and shock. Rest assured that you won’t have to constantly replace steel pipes for many years beyond installation.

Resistance to Corrosion

Corrosion is arguably one of the most common problems in construction. After all, it leads to compromising the structural integrity of projects. Unlike other pipes, steel pipes are ideal to work with because of their resistance to corrosion.

For example, plastic pipes that experienced wear and tear may no longer be conducive for application. Copper pipe fittings are not corrosion-resistant, making them more likely to pose dangers to entire structures.

Galvanization is a process that involves the application of a layer of zinc coating to steel pipes. This is what makes the product more prone to rusting.

With a corrosion-resistant layer, it’s far safer to continue using steel pipes. They would be able to maintain superior performance quality, making them perfect for high-pressure applications.

Easily Malleable

Builders seek materials that are easy to fabricate because it gives them freedom in terms of construction planning. It can also mean reduced physical waste during last-minute changes.

As a material, steel is flexible. It is a metal used to achieve numerous construction needs because it is highly malleable. This property refers to a material’s ability to be formed into different shapes without breaking.

Steel pipes have high tensile strength, making it perfect for supporting all kinds of structures. Rest assured that it will not suffer from breakage when you use it for your projects.

From commercial spaces, laboratories, to industrial sectors – steel pipes offer a wide range of applications because of malleability.

Recyclable

With an alarming rise in environmental problems, contractors and builders are being called upon to reduce waste and make use of recyclable materials. This is where a steel pipes’ recyclability makes it advantageous to work with.

Steel is the most recycled material on the planet. In fact, it is more recyclable than all the other materials combined. It retains an 86% recycling rate. According to a study, a staggering 69% of steel gets recycled after use in North America alone.

When the pipes are no longer needed, they can simply be melted down and be used from one product to another. Its property allows it to be recycled continually with no degradation in performance quality.

Cost-Efficient

Using steel pipes can help you cut down on different construction project costs.

Given its innate strength, a small amount of the metal goes a long way in supporting foundations.

The less material you need to install in a project, the less labor workforce will be needed. Of course, fewer work hours will lead to less money spent on wages.

In addition, steel pipes are significantly cheaper than other materials. Its price has remained low because manufacturers are making use of recycled steel to create new products. On the other hand, materials made of concrete cannot be recycled.

Let’s not forget that steel pipes don’t need to be replaced constantly, making it a cost-efficient option for construction projects.

Key Takeaway

In the Philippines, steel pipes are used for a number of industries. However, the advantages of using steel pipes in construction are arguably the most evident.

If you’re looking to use steel pipes for a project, make sure you choose the one with superior quality. At Supreme Pipe, we provide you with just that.

Click here to learn more about our products today.

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