Seamless Pipes

Petrosadid: Seamless Pipes

PETROSADID is a leading supplier of seamless pipes providing an extensive selection of all grades and dimensions to the oil & gas, petrochemical, chemical and power industries. We work closely together with certified pipe manufacturers from around the world and have a huge range of different seamless pipes constantly on stock ranging from Hot Rolled to Cold Drawn pipes.

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Seamless Steel Pipe is made from a solid round steel ‘billet’ which is heated and pushed or pulled over a form until the steel is shaped into a hollow tube.

Seamless pipes are finished in accordance with customer needs regarding dimensional and wall thickness specifications as well as heat treatment for more demanding applications. In general a seamless pipe is manufactured in sizes from 1/8” to 24” according to current standards API, ASTM, and ASME.

In the production of steel pipes, steel is molded and reshaped with different machinery at different temperatures. One of the steel manufacturing processes is steel rolling, which involves metal stock passing through a pair of rolls. Rolling produces flat steel sheets of a specific thickness, and the process is classified according to the temperature at which the metal is rolled. If the temperature of the metal is above its recrystallization temperature, or the temperature at which the grain structure of the metal can be altered, then the process is termed as hot rolling. If the temperature of the metal is below its recrystallization temperature, the process is termed as cold rolling.

Cold Drawn Seamless Pipe

Cold drawn seamless pipe is usually required where the end product is either safety and/or quality critical.

The method for making cold-drawn seamless pipes involves taking a round "billet" or bar of steel and boring it in the center, turning it, cutting it, heating it to make it more pliable, then "drawing" it (extruding or pulling it) to make it a longer and thinner pipe. As the pipe cools, "cold working" begins. Cold working involves pulling the pipe over a stationary die and a mandrel. This increases the pipe's hardness and improves its surface condition and grain structure while reducing the pipe to the desired size and thickness.

Petrosadid: Seamless Pipes

Hot-Rolled Seamless Pipe

Different from cold rolling which is performed below the recrystallization temperature, hot rolling is conducted above the temperature. Hot rolled seamless pipes offer higher torsional rigidity than cold rolled ones, thus it offers better torsional resistance than cold rolled tubes.


Hot rolled seamless steel pipe can damage the cast microstructure of the steel ingot, refinement of the crystal grains of the steel, and eliminate the defects of the microstructure, so that the the steel organization compacting, improve the mechanical properties. This improvement is reflected in the rolling direction, so that the steel is no longer to a certain extent isotropic; pouring the formation of bubbles, cracks, and osteoporosis, under high temperature and pressure can also be welded together.


• After the hot rolling, the nonmetallic inclusions in the interior of a steel (mainly sulfides and oxides, as well as the silicate) was pressed into a sheet, stratified (laminated) phenomenon appears. The layering of the steel in the thickness direction by the pull performance deteriorated significantly, and may appear in the weld shrinkage interlayer tear. Weld shrinkage induced local strain often reach several times the yield point strain, the strain is much greater than the load caused;

• Residual stress caused by uneven cooling. The residual stress is the stress of internal self-phase equilibrium in the absence of external force, the hot-rolled steel of various cross-sectional has a residual stress such Usually steel sectional dimension is the greater, the greater the residual stresses. Residual stress is self-phase equilibrium, but the steel members in the performance external force or have a certain influence. Such as deformation, stability, anti-fatigue may adversely.

• Hot-rolled steel products, poor control of thickness and edge width. We are familiar with the thermal expansion and contraction, even if the beginning of the hot-rolled out are standard length, thickness, or there will be some negative final after cooling, this negative differential edge width wider the increasing thickness of the performance of the more obvious.

Petrosadid: Seamless Pipes

Highlights of the Seamless Pipes


API 5L Gr. (B, X42, X52, X60, X65, X70, X80)

A53 Gr. B

A106 Gr. (A, B, C)

A335 (P1, P11, P12, P22, P5, P9, P91, P92)

A333 Gr. (3, 6)

A312 (TP304/304L, TP316/316L, TP321, TP321H, TP347, TP347H)

A312 (UNS S31254, UNS N08367, UNS N08925, UNS N08926)

A790 (UNS S31803 / S32205 – Duplex 2205)

A790 (UNS S32550/ S32750/ S32760 - Super Duplex 2507)

ASTM B 466

ASTM B 861 Gr. 2

Nickel 200/201 - B161

Alloy 400 - B165

Alloy 600 - B167

Alloy 625 - B705

Alloy 800H/ 800HT - B407

Alloy 825 - B423

Alloy 276 - B622


ASME 36.10, ASME 36.19 are the key specifications covering the standardization of dimensions of welded and seamless wrought steel pipe. ASME B16.25 covers the preparation of butt weld connections between pipes and ASME B16.49 covers the marking details.

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