Seamless steel pipe-manufacturing process,application,specification

What is a seamless steel pipe?

A steel pipe made of a single piece of metal with no seams on its surface is called a seamless steel pipe.According to the production method,the seamless pipe is divided into hot rolled pipe,cold rolled pipe,cold drawn pipe,extruded pipe,and so on.

According to the shape of the section,the seamless steel tube is divided into two types:circular shape and a special shape.The shaped tube has a plurality of complicated shapes such as square shape,elliptical shape,triangular shape,hexagonal shape,melon shape,star shape,etc.

The maximum diameter is 650mm and the minimum diameter is 0.3mm.

Depending on the application,there are thick-walled tubes and thin-walled tubes.Seamless steel pipes are mainly used for petroleum geological drilling pipes, cracking pipes for petrochemicals,boiler tubes,bearing tubes,and high-precision structural steel tubes for automobiles,tractors,and aviation.

ASTM A106 Gr B seamless steel pipes

ASTM A106 Gr B seamless steel pipes

Manufacturing process of seamless steel pipes:

Seamless steel pipe begins as a solid cylindrical hunk of steel called a billet.While still hot,billets are pierced through the center with a mandrel.The next step is rolling and stretching the hollow billet.The billet is precisely rolled and stretched until it meets the length,diameter and wall thickness as specified by the customer order.It is suitable for bending,flanging,foming and welding.The most advantage is increasing the ability of withstanding higher pressure. So it is widely used for boiler and pressure vessel, automotive area, oil well, and equipment components.

Q345B seamless steel pipes

Q345B seamless steel pipes

Application of seamless steel pipes:

Seamless steel pipes are used in a wide range of applications.The general-purpose seamless steel pipe is rolled from ordinary carbon structural steel,low-alloy structural steel or alloy structural steel,and has the largest output,and is mainly used as a pipe or structural component for conveying fluid.

According to the use of three types of supply: a, according to chemical composition and mechanical properties;b,according to mechanical properties;c,according to water pressure test supply.Steel pipes supplied in categories a and b, if used to withstand liquid pressure,are also subjected to hydrostatic testing.

Special-purpose seamless pipes include boiler seamless pipes,chemical power, geological seamless steel pipes and petroleum seamless pipes.

Seamless steel pipes have hollow sections and are used in large quantities as pipes for transporting fluids, such as pipes for transporting petroleum,gas,water and certain solid materials.Compared with solid steel such as round steel, the steel pipe has a lighter weight when it has the same bending and torsional strength, and is an economical section steel.

A/SA-106 Grades B & C can withstand temperatures up to 800F,making it fit for services ranging from structural supports to steam drum headers.

API 5L X Grades 42 thru 70 are used as platforms on off shore rigs and by the water and petroleum industry for transport of liquids.

small diameter seamless steel pipes

small diameter seamless steel pipes

Materials of seamless steel pipes:

Carbon steel:A106 Gr B,ASTM A106 Gr C,ASME SA106 Gr B,A53 Gr B,API 5L GrB,P245GH,P235GH,ST35.8,ST 37,P235GH,P245 GH,etc

Stainless steel:ASTM A312 TP304,TP304L,TP316,TP316L,TP321,TP347,etc

Alloy steel: A335 P1,P5,P9,P11,P12,P22,A333 Gr 3,Gr6,etc

16Mn:Q235B,ST52,S355JR,A350 LF2 CL1,etc

Standards of seamless steel pipes:

We provide seamless steel pipe as standard:

ASTM A106: seamless carbon steel pipe for high-temperature service
ASTM A53: pipe,steel,black and hot-dipped,zinc-coated,seamless
ASTM A179: cold-drawn low-carbon steel heat exchanger and condenser tubes
ASTM A192: seamless carbon steel boiler tubes for high pressure
DIN 1629: seamless circular tubes of non alloys steel with special quality requirement
DIN 2391-1: seamless precision steel tubes
JIS G3454,G3455,G3456: carbon steel pipe for pressure service
EN 10208: seamless steel pipes for pipeline fluids
API 5L: American Petroleum Institute specification for pipeline transportation systems in the petroleum and natural gas industries.
We can also process seamless pipe orders to client provided specifications.

Seamless steel pipe supplied by Haihao Group can be cut,threaded or grooved.And the coating method includes black/red lacquer,varnish painting,hot dip galvanization,etc.If you want to know more about seamless steel pipes or other piping products(like butt welding pipe fittings,forged pipe fittings and flanges),please email