Getting to Know Seamless and Welded Pipes

Summary – Steel pipes can be made in the form of seamless and welded pipes. Though the method of manufacture is very different, the pipes mostly display the same properties and are considered interchangeable.

Steel pipes are the standard pipes used for a variety of works across industries. Their inherent strength and durability coupled with the light weight features make them suitable for varied purposes across industries. There are many steel round pipe manufacturers that produce these pipes in varying specifications based on the properties required for specific applications. Different grading systems are in place to categorize the steels based on these properties.

The two most common types of steel pipes used across the world are seamless and welded pipes.

A seamless pipe is made by stretching the raw solid steel billets by heating and perforating into the form of a hollow tube. As the name goes, seamless pipes do not have any seam welds. They are used for different purposes like transporting oil and gas and also general plumbing applications.

A welded pipe is also known as Electric Resistance Welded or ERW pipe. They are also popular and commonly used in the piping industry. It is usually made from strips of hot-rolled steel that are passed through forming rolls. In case steel coils are used, they are first uncoiled and then smoothed and cut and processed to form pipes. The edges are then forced together and sealed electrically with a weld, hence the name. The heat for welding is generated by the resistance to flow of electric current to form a tight and robust joint. No filler materials are added at the seam. The pipes will display one longitudinal seam along their entire length.

Both types of pipes can be made in both carbon steel and stainless steel.

Seamless pipes were always considered mechanically stronger and technically superior than their welded counterparts. But the welded HR pipe manufacturers were considered an efficient alternative primarily on the basis of price affordability. However, given the enormous advancements in modern welding technologies (like high frequency induction technology and other techniques); even the performance of ERW pipes is now almost on par with the seamless ones. Therefore, they are becoming interchangeable in some applications.

Mahalakshmi Profiles Pvt. Ltd (www.mahalakshmiprofiles.in) is one of the leading MS pipe manufacturers in Hyderabad. They manufacture ERW pipes in varying lengths and thicknesses - ranging from 15m NB to 80mm NB and 1.2mm to 4mm thickness, in round, square and rectangle sections. The company can also produce customized sections to meet the specific customer requirements, but subject to size limitations. The high quality M.S. billets for making the hot rolled strips and subsequently the ERW pipes are primarily procured by the company from renowned companies like the Visakhapatnam Steel Plant (RINL) & Steel Authority of India Ltd (SAIL). Under the automation plans, the square pipe manufacturers have now moved to producing narrow width hot rolled coils instead of the usual strips or flats.