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A Comprehensive Comparison: Forged versus Seamless Pipes

Reading Time: 10 minutes

This article explains the main differences existing between “Forged Pipes” vs “Seamless Pipes” and the reasons why forged pipes may have advantages over standard seamless pipes in heavy-duty applications that require enhanced chemical and mechanical properties (for example: fluids conveyance within nuclear power plants) or in specific circumstances.

What is a Forged Pipe?

A forged pipe (or a forging in general) is manufactured by:

  • heating a steel ingot above its deformation temperature, a value that depends upon the material grade (for instance, the deformation temperature of carbon steel is above 600 degrees C°), and
  • shaping the ingot under a forging press with a compression force, and
  •  applying CNC machining to the roughly formed shape coming out of the press to achieve the final form and the given tolerances

Forged products of any material grade can be manufactured, and the production flow is represented in the picture below:

The production process of forged pipes is itemized (the mill produces just one pipe at a time) and it is mainly oriented to special sizes or applications and heavy components. The final CNC machining allows to produce with precise tolerances (starting from -0/+1 mm on each dimension).

The production process of forged pipes involves several steps, combining forging and machining techniques to create high-quality seamless pipes with enhanced mechanical properties. Here’s an overview of the production process of forged pipes:

  1. Billet Preparation:
    • The process begins with the preparation of solid cylindrical billets made of steel or other suitable materials.
    • These billets are typically produced through methods such as continuous casting or hot rolling and are cut to the desired length for further processing.
  2. Heating:
    • The billets are heated to high temperatures in a controlled atmosphere furnace to make them more malleable and easier to deform.
    • Heating is crucial for reducing the material’s yield strength and facilitating plastic deformation during the forging process.
  3. Forging:
    • The heated billets are placed under a forging hammer or press, where they undergo plastic deformation to shape them into the desired form of pipes.
    • The forging process involves applying compressive forces to the billets to deform them into cylindrical shapes resembling pipes.
    • Forging may be performed in multiple stages to achieve the desired dimensions, shapes, and mechanical properties of the forged pipes.
  4. Piercing:
    • After forging, the rough forged blanks are pierced to create a hollow tube with a uniform inner diameter.
    • Piercing involves forcing the forged blanks through a series of dies and rollers to remove excess material and form the inner surface of the pipes.
  5. Rolling and Sizing:
    • The pierced blanks are then elongated and reduced in diameter through a series of rolling passes to achieve the desired dimensions and wall thickness.
    • Rolling and sizing processes may involve hot or cold rolling techniques, depending on the material properties and requirements of the forged pipes.
  6. Heat Treatment:
    • Once the pipes are formed and sized, they undergo heat treatment processes such as annealing or tempering to improve their mechanical properties and microstructure.
    • Heat treatment helps to relieve internal stresses, refine the grain structure, and enhance the strength, toughness, and ductility of the forged pipes.
  7. Machining:
    • After heat treatment, the forged pipes may undergo machining operations such as turning, boring and threading to achieve the final dimensions, surface finish, and tolerances required for their intended applications.
    • Machining helps to refine the surface finish, remove any surface defects, and ensure the dimensional accuracy of the forged pipes.
  8. Testing and Inspection:
    • Throughout the production process, forged pipes undergo rigorous testing and inspection to ensure quality and conformance to specifications.
    • This may include non-destructive testing methods such as ultrasonic testing, eddy current testing, and visual inspection, as well as destructive testing methods such as tensile testing and hydrostatic testing.
  9. Finishing and Packaging:
    • Once the forged pipes have passed all quality checks and inspections, they are carefully finished, cleaned, and packaged for shipping to customers or distribution centers.
    • Proper packaging helps to protect the pipes during transit and storage, ensuring they arrive in optimal condition.

In summary, the production process of forged pipes involves a combination of forging and machining techniques to create seamless pipes with enhanced mechanical properties and dimensional accuracy. By following stringent quality control measures and employing advanced manufacturing technologies, forged pipe manufacturers can deliver reliable and durable products that meet the demanding requirements of various industries and applications.

The picture below represents a forging press of approximately 12.000 tons:

forged steel press

What is a Seamless Pipe?

Differently from a forged pipe, which is produced as described above, a seamless pipe is produced starting from a heated steel bar, laminating it on a piercer, and rolling it in a mandrel mill. This process applies to carbon steel grades (which represent the most used material grade for seamless pipes) and it’s called the Mannesmann process (based on the name of its Inventor).

To learn more about conventional seamless pipes, and their production processes (Mandrell or Mannesmann), please refer to this dedicated article.

The production process of seamless pipes is fully automated and mainly oriented to standard sizes and large quantities (an order could go from minimum quantity of 20 pipes to a pipeline order with 5.000 km / 450 pipes of the same size). Pipes are not mechanically CNC machined except for the ends (pipe ends are beveled or threaded to allow connection of each pipe).

piercing mill seamless pipes

Sizes of Forged vs. Seamless Pipes

The size of a forged pipe is defined by:

  • Outside diameter (OD)
  • Inside Diameter (ID)

Forged pipes are also called “ID controlled” or “Minimum Wall Thickness Pipes” (as a min thickness is granted).

Instead, the size of a seamless pipe is defined by:

  • Outside Diameter
  • Wall Thickness (WT)

Seamless pipes are also called “OD controlled pipes” or “Average Wall Thickness Pipes”.

The theoretical size of each pipe is different from the actual one (due to limitations in production, and the international norms allow some dimensional tolerances).

For example, in a OD controlled size OD711 mm x WT 50 mm, the actual ID might show a 25 mm difference from ordered (= theoretical) one.

This size difference (actual vs. theoretical) might generate unexpected cost and delays during installation at site. This due to the fact, for instance, that the welding of two pipes with different ID might require longer time or extra machining of pipe ends (that were not accounted for during the pipe work engineering process).

Imperfect welding might be very critical in offshore applications or for pipes installed within a power plant (as high temperature steam might generate unwanted vortex movements, cavitation and creep problems to all the ancillary utilities existing in the plant).

Differences in Dimensional Range

Theoretically, a forged pipe could be produced in any desired size. The question is: when is it better to source forged vs. seamless pipes?

In general, forged pipes are more cost-efficient, compared to seamless pipes, in the following cases and applications:

  • Larger OD (outside diameter): forged pipes show an overall cost advantage for larger OD pipes, say OD > 18” as a rule of thumb
  • Heavier wall thickness pipes: forged pipes are the elective the choice for applications that require heavy wall thickness pipes, example from 40/50 mm WT upwards
  • Special Dimensional Tolerance or Surface Finishing: due to its fine manufacturing process, forged pipes can be produced to custom dimensions and precise tolerances (whereas, as explained above, seamless pipes show a constant divergence between actual vs. theoretical sizes)
  • Small lots (due to the fact that the minimum order size for a forged mill is just 1 pipe, whereas seamless pipes manufactures have minimum lot quantities of several tons, generally above 10)

On the contrary, Seamless Pipes are more cost-efficient in the following cases:

  • OD: standard sizes from 12,7 mm (1/2″) to 457 mm (18″)
  • Project requires pipes with standard wall thickness, example below 25/30 mm
  • Large lots: minimum order is 200 meters / 20 pipes per size

The image below shows the competitive range for forged pipes (vs. seamless pipes) in terms of pipe OD (outside diameter) and WT (wall thickness):

TYPICAL APPLICATIONS OF FORGED STEEL PIPES

Forged seamless pipes find applications across a wide range of industries due to their superior strength, durability, and reliability. Some of the key fields of application for forged seamless pipes include:

1. Oil and Gas Industry:
– Forged seamless pipes are extensively used in the oil and gas industry for exploration, production, transportation, and refining processes.
– They are employed in drilling operations, well completion, pipeline construction, and transmission of crude oil, natural gas, and refined petroleum products.
– These pipes withstand high-pressure, corrosive environments, and extreme temperatures encountered in upstream, midstream, and downstream operations.

2. Petrochemical and Chemical Industry:
– Forged seamless pipes are crucial components in petrochemical and chemical plants for conveying various chemicals, acids, and corrosive fluids.
– They are used in reactors, heat exchangers, distillation columns, and other process equipment where resistance to chemical corrosion and high temperatures is essential.

3. Power Generation:
– Forged seamless pipes play a vital role in power generation facilities such as thermal power plants, nuclear reactors, and renewable energy installations.
– They are utilized in boilers, steam turbines, condensers, and heat recovery systems for transporting steam, water, and other fluids at high temperatures and pressures.

4. Aerospace and Defense:
– Forged seamless pipes are used in aerospace and defense applications for manufacturing aircraft components, missile systems, and military vehicles.
– They are employed in critical systems such as hydraulic systems, fuel lines, and structural components requiring lightweight yet strong materials with high fatigue resistance.

5. Mechanical and Automotive Engineering:
– Forged seamless pipes find applications in mechanical engineering and automotive industries for manufacturing shafts, axles, gears, and other precision components.
– They are used in high-performance automotive exhaust systems, suspension components, and drivetrain assemblies requiring superior strength and durability.

6. Infrastructure and Construction:
– Forged seamless pipes are used in infrastructure and construction projects for structural support, piling, and foundation works.
– They are employed in bridges, buildings, tunnels, and offshore structures for structural applications requiring high load-bearing capacity and resistance to corrosion and environmental factors.

7. Mining and Exploration:
– Forged seamless pipes are utilized in mining and exploration activities for drilling, extraction, and transportation of minerals, ores, and fluids.
– They are employed in drilling rigs, wellbore casing, and pumping systems for mining operations and mineral processing plants.

8. Marine and Offshore:
– Forged seamless pipes are employed in marine and offshore applications for offshore drilling, production platforms, and subsea pipelines.
– They withstand harsh marine environments, high pressures, and corrosive seawater conditions encountered in offshore oil and gas exploration and production.

Overall, forged seamless pipes are indispensable components in various industries and applications where high-performance piping solutions are required to withstand extreme conditions and ensure reliable operations.

As a general indication, heavy wall-thickness forged pipes are used in more demanding applications than conventional seamless pipes.

Power Generation steam lines, for instance, require high chrome content (alloy grade 11, grade 22, grade 91, grade 92) and heavy wall thickness lines to resist the high temperatures generated by the energy production process.

A controlled ID Diameter pipe allows better dimensioning during the engineering stage, reduces welding costs during pipe installation, and furthermore reduces vortex fluid movements & creep risks inside the piping of the plant.

Offshore parts subject to High Mechanical Stress like Risers, J-Lay Collars, and Spool Pieces are supplied in X grades (X60/X70).

Those parts require high mechanical properties, in particular very high tensile strength at low temperatures (for example: an expected crush with the offshore pipeline could create serious damage to the pipelines) and require very strict machining tolerances (for example: pipelines need to be clean with pigs on routine basis).

Another common application of forged pipes is for OCTG Couplings in Upstream applications (for example: couplings for OCTG casing pipes size 18 5/8”) for heavy dimensions & heavy thickness that cannot be produced by using the standard seamless production process.

J-lay collars forged

Forged J-Lay Collars

forged y pieces

Forged Y-Pieces

forged spool pieces

Forged Spool Pieces

forged riser

Forged Riser

Some examples of forged steel products for application in the oil & gas, power generation, and heavy manufacturing industries

Key Manufacturers of Forged SEAMLESS Pipes

The market for forged pipes is a niche segment of the larger pipes market and is populated by a large number of small/medium-sized manufacturers.

The world’s most qualified forgings mills are located in Northern Italy (more than 20 suppliers) and Germany, along with some smaller production sites in China.

For Seamless Pipes, we have identified 2 categories of manufacturers (depending on the steel grade family):

  • Carbon steel pipes: global supply is dominated by global groups such as Tenaris + Vallourec + Sumitomo, while Chinese manufacturers are playing a smaller role. Markets like the USA, Saudi Arabia, and Russia see a strong presence of local suppliers, with sales limited to their local markets
  • Stainless Steel pipes: European manufacturers (Salzgitter DMV / Tubacex /Sandvik) are sharing the market with growing Chinese competition

Here is a list of global-scale manufacturers (multinational companies) known for producing forged steel pipes:

1. Vallourec: Vallourec is a global leader in the production of seamless and welded steel tubes and pipes. They offer a wide range of forged steel pipes for various industries, including oil and gas, power generation, and petrochemicals.

2. Tubos Reunidos: Tubos Reunidos is a Spanish manufacturer specializing in the production of seamless steel pipes, including forged pipes for the oil and gas industry, energy sector, and mechanical applications.

3. Nippon Steel Corporation: Nippon Steel Corporation is a Japanese steelmaker known for its expertise in producing high-quality steel products, including forged pipes for offshore and onshore applications in the oil and gas industry.

4. TMK Group: TMK Group is a leading global manufacturer of steel pipes, including seamless and welded pipes for various industries. They produce forged steel pipes for drilling, exploration, and production applications in the oil and gas sector.

5. Tenaris: Tenaris is a multinational manufacturer of seamless and welded steel pipes and related services. They offer a wide range of forged steel pipes for use in critical applications such as oil and gas drilling, refining, and transportation.

6. Borusan Mannesmann: Borusan Mannesmann is a Turkish manufacturer of seamless steel pipes, including forged pipes for energy, construction, automotive, and industrial applications.

7. JFE Steel Corporation: JFE Steel Corporation is a Japanese steelmaker known for its production of high-quality steel products, including forged pipes for the oil and gas industry, mechanical engineering, and automotive applications.

8. United States Steel Corporation (U.S. Steel): U.S. Steel is an American steel producer offering a variety of steel products, including forged pipes for energy, infrastructure, and construction applications.

9. Sandvik AB: Sandvik AB is a Swedish multinational company specializing in high-performance materials and solutions, including forged steel pipes for demanding applications in the oil and gas, chemical, and aerospace industries.

10. Ovako Group: Ovako Group is a European manufacturer of engineering steel products, including forged pipes for mechanical applications in the automotive, mining, and construction sectors.

It’s important to note that this list is not exhaustive, and there are many other manufacturers around the world producing forged steel pipes for various industries and applications. Additionally, the availability of specific products may vary depending on geographical location and market demand.

Please contact us in case you need recommendations based on steel grade, size, and pipe weight.

Material Grades Forged vs. Seamless Pipes

The table below shows the most common material grades of seamless pipes and their forged equivalent:

MATERIAL TYPESMLS PIPE GRADEFORGED GRADE
CS - Carbon Steel - High TemperatureASTM A106 gr B / A53 gr B / API 5L gr B/X42 PSL1ASTM A105
CS - Carbon - Low TemperatureASTM A 333 gr 6ASTM A350LF2
CS - Carbon SteelAPI 5L gr B / X42 PSL1
CS - Carbon SteelAPI 5L gr B / X42 PSL2A694 F42
CS - Carbon SteelAPI 5L gr X42 PSL2
CS - Carbon SteelAPI 5L gr X52 PSL1
CS - Carbon SteelAPI 5L gr X52 PSL2ASTM A694 F52
CS - Carbon SteelAPI 5L gr X65 PSL1
CS - Carbon SteelAPI 5L gr X65 PSL2A694 F65
CS - Carbon Steel - GalvanizedASTM A 53 gr. BASTM A105
AS - AlloyASTM A 335 P11ASTM A182 F11
AS - AlloyASTM A 335 P22ASTM A182 F22
AS - AlloyASTM A 335 P5ASTM A182 F5
AS - AlloyASTM A 335 P9ASTM A182 F9
AS - AlloyASTM A 335 P91ASTM A182 F91
SS - StainlessASTM A 312 TP304-304LASTM A182 F304-F304L
SS - StainlessASTM A 312 TP316-316LASTM A182 F316-F316L
SS - StainlessASTM A 312 TP321ASTM A182 F321
SS - Duplex 22ASTM A790 UNS S31803ASTM A182 F51
SS - Superduplex 25ASTM A790 UNS S32750 / 32760ASTM A182 F53 / F55
SS - Inconel - Nichel Alloy 6625ASTM B444 UNS N06625ASTM B564 UNS N06625
SS - Inconel - Nichel Alloy 8825ASTM B423 UNS N08825ASTM B564 UNS N08825
CUNI - Cupronickel (CuNi 90/10)ASTM B466 UNS C70600UNS C70600
CUNI - Cupronickel (CuNi 70/30)

Conclusion

In conclusion, forged steel pipes are indispensable components in numerous industries, providing reliable and durable solutions for transporting fluids, gases, and solids in demanding environments. From their robust manufacturing process to their diverse applications and inherent advantages, forged steel pipes continue to play a vital role in infrastructure development, industrial processes, and technological advancements worldwide. As industries evolve and demand for high-performance piping solutions grows, forged steel pipes remain at the forefront of innovation and excellence, ensuring the safe and efficient operation of critical systems across the globe.

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The information provided in this blog post is intended for general informational purposes only and should not be construed as professional advice. While we strive to provide accurate and up-to-date information, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability, or availability of the content contained herein. Any reliance you place on the information presented in this blog post is strictly at your own risk. We disclaim any liability for any loss or damage, including without limitation, indirect or consequential loss or damage, or any loss or damage whatsoever arising from reliance on information contained in this blog post. We encourage readers to verify the accuracy and relevance of any information presented here with other sources and seek professional advice or guidance where appropriate. Links to third-party websites or resources provided in this blog post are for convenience only and do not imply endorsement or approval of the content, products, services, or opinions expressed on those websites. We have no control over the nature, content, and availability of those sites and assume no responsibility for their accuracy, legality, or decency. We reserve the right to modify, update, or remove any content in this blog post at any time without prior notice. By accessing and using this blog post, you acknowledge and agree to these terms and conditions. If you do not agree with these terms, please refrain from accessing or using the information provided herein.

About the Author

Johnathan Maxwell

Johnathan Maxwell

Jonathan Maxwell, with his quarter-century tenure, has become a cornerstone in the oil and gas industry, with a laser focus on the intricacies of piping system design and analysis. He embarked on this career path after graduating with a Mechanical Engineering degree from a prestigious U.S. institution, landing his initial role at a leading oil and gas firm based in Texas. His relentless commitment and deep understanding of material science and fluid dynamics have seen him rise through the ranks, with a particular passion for pipes and tubes in oil and gas applications anchoring his journey.As a revered Senior Piping Systems Analyst, Jonathan has helmed numerous international projects, in the US, in Africa, North Europe, and Australia, crafting and executing sophisticated piping strategies in both onshore and offshore settings. His proficiency in selecting appropriate pipe materials, conducting thorough stress analyses, and honing system optimization has markedly pushed forward the boundaries of pipeline technology.Jonathan's influence extends beyond practical applications; he has been pivotal in shaping industry standards, participating actively in several technical committees and working groups aimed at fortifying safety and enhancing system performance. His published works and studies are highly regarded, positioning him as a prominent figure at conferences and seminars worldwide.His legacy, however, is not only in his technical prowess but also in his role as a mentor. Jonathan has nurtured a new cadre of engineers, imparting the principles of best practice and innovation in piping system design. His dedication to spreading knowledge reached a milestone with the publication of "Fluid Flow Dynamics," now deemed critical literature in the sector.In his ongoing consultancy role, Jonathan contributes to prominent oil and gas projects, ensuring a synergy between operational efficiency, ecological stewardship, and safety. His rich industry insight and forward-thinking approach render him an invaluable asset to both seasoned experts and emerging talents.Jonathan's collaboration with Projectmaterials.com has been instrumental. His expertise has shaped the discourse on piping topics, contributing directly to the content creation and refinement of all related articles. His editorial guidance ensures that the information disseminated is both accurate and of the highest caliber.

Should you wish to reach out to the author of this article, we invite you to contact us via email.

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13 Responses

    1. Thank you for your appreciation and for sharing the link to Metalica Forging Inc. It’s great to see that you are a market leader in the field of stainless steel flange manufacturing in India. Your expertise in this area must be valuable to those seeking high-quality flanges.

      In the context of the previous conversation about forged and seamless pipes, it’s interesting to note that both forged and seamless manufacturing processes are crucial in producing various components, including flanges. The article highlights the differences between forged and seamless pipes, such as the manufacturing process, sizes denominations, dimensional range, and applications.

      Considering your expertise in manufacturing stainless steel flanges, it would be insightful to discuss how the manufacturing processes for pipes and flanges differ, and how these differences might impact the final product. Additionally, if you have any specific insights or experiences related to the topic of forged or seamless flanges, we would greatly appreciate your input.

      Thank you again for sharing your knowledge and expertise on stainless steel flange manufacturing in India.

    1. Thank you for your kind words, Girish Metal India! We’re glad to hear that you found the article on forged vs. seamless pipes informative. It’s always great to provide valuable information to our readers.

      We appreciate you sharing your link for Stainless Steel Round Bar Manufacturers in India. It’s important to have reliable sources when looking for specific products. We encourage our readers to explore different options and find the best manufacturers that suit their needs.

      If you have any further insights or thoughts on the topic of forged vs. seamless pipes, we’d love to hear them. Thank you again for your contribution to the discussion!

  1. Nice info, Goyal Steel Tubes, the oldest dealer of MS Pipes and Tubes in Delhi-NCR, deals in all sizes and variety of MS Pipes, stocked from reputed companies like APL Apollo, Jindal, Surya etc.
    Send your pipe related queries on 9650705448, call on 9910495448 or find us on google- Goyal Steel Tubes click on the first link.

  2. Interesting, could you please add the names of the suppliers of forged pipes in Europe? We have been scouting for suppliers lately, without success. help appreciated, Mark

    1. Dear Mark, please get in touch with us. We will send you the list of the forged steel pipes manufacturers in Italy (among the top world’s suppliers, both in terms of technical know how and cost effectiveness) and in Germany. Thank you for your interest in our article. Best, Projectmaterials

  3. I think that this article is really very informative. You have explained the various applications of Stainless Steel Seamless Pipes and forged pipes in this article. You have also explained the materials and sizes in great detail. I have clearly understood the difference between these two types of pipes. Thank you very much for sharing this article with us.

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