Welded steel pipe, also called welded pipe, is a steel pipe made of
steel plates or strips that are welded after being curled and
formed. The length is usually 6 meters. The production process of
welded steel pipes is simple, the production efficiency is high,
there are many varieties and specifications, and the equipment
investment is low, but the general strength is lower than that of
seamless steel pipes.
product description
Since the 1930s, with the rapid development of continuous rolling
production of high-quality strip steel and the advancement of
welding and inspection technology, the quality of welds has been
continuously improved, and the varieties and specifications of
welded steel pipes have been increasing day by day, and they have
replaced non-woven steel pipes in more and more fields. Sewing
steel pipe. Welded steel pipes are divided into straight seam
welded pipes and spiral welded pipes according to the form of the
weld. Classification by production method: Process classification -
arc welded pipe, resistance welded pipe, (high frequency, low
frequency) gas welded pipe, furnace welded pipe.
Smaller diameter welded pipes use straight seam welding, while
large diameter welded pipes mostly use spiral welding; according to
the shape of the end of the steel pipe, it is divided into round
welded pipes and special-shaped (square, rectangular, etc.) welded
pipes; according to different materials and uses, it is divided
into mining fluids Welded steel pipes for transportation,
galvanized welded steel pipes for low-pressure fluid
transportation, electric welded steel pipes for belt conveyor
rollers, etc. According to the specification and size table in the
current national standard, sort by outer diameter*wall thickness
from small to large.
Product Standards
Common materials for welded pipes are: Q235A, Q235C, Q235B, 16Mn,
20#, Q345, L245, L290, X42, X46, X60, X80, 0Cr13, 1Cr17,
00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.
The blanks used in welded steel pipes are steel plates or strips.
Due to their different welding processes, they are divided into
furnace welded pipes, electric welded (resistance welded) pipes and
automatic arc welded pipes. Because of their different welding
forms, they are divided into two types: straight seam welded pipes
and spiral welded pipes. Because of their end shapes, they are
divided into round welded pipes and special-shaped (square, flat,
etc.) welded pipes. Welded pipes are divided into the following
varieties due to their different materials and uses:
GB/T3091-2008 (Welded steel pipe for low-pressure fluid
transportation): Mainly used to transport water, gas, air, oil,
heating hot water or steam and other general lower pressure fluids
and other pipes. Its representative material is: Q235A grade steel.
GB/T14291-2006 (Welded steel pipe for mining fluid transportation):
Mainly used for straight seam welded steel pipes for mine air
pressure, drainage, and shaft gas discharge. Its representative
materials are Q235A and B grade steel.
GB/T12770-2002 (Stainless steel welded steel pipes for mechanical
structures): Mainly used for machinery, automobiles, bicycles,
furniture, hotel and restaurant decoration and other mechanical
components and structural parts. Its representative materials
include 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.
GB/T12771-1991 (Stainless steel welded steel pipe for fluid
transportation): Mainly used to transport low-pressure corrosive
media. Representative materials are 0Cr13, 0Cr19Ni9, 00Cr19Ni11,
00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc.
In addition, welded stainless steel pipes for decoration (GB/T
18705-2002), stainless steel welded pipes for building decoration
(JG/T 3030-1995), and welded steel pipes for heat exchangers
(YB4103-2000).
Production Process
The production process of straight seam welded pipe is simple, the
production efficiency is high, the cost is low, and the development
is rapid. The strength of spiral welded pipes is generally higher
than that of straight seam welded pipes. Welded pipes with larger
diameters can be produced from narrower billets, and welded pipes
with different diameters can also be produced from billets of the
same width. However, compared with straight seam pipes of the same
length, the weld length is increased by 30~100%, and the production
speed is lower.
Large diameter or thicker welded pipes are generally made directly
from steel blanks, while small welded pipes and thin-walled welded
pipes only need to be directly welded through steel strips. Then
simply polish and brush it.
Supplement: The welded pipe is welded with strip steel, so its
original status is not as high as the seamless pipe.
Welded pipe process flow
Raw material uncoiling - flattening - end shearing and welding -
looper - forming - welding - internal and external weld bead
removal - pre-correction - induction heat treatment - sizing and
straightening - eddy current testing - cutting off - hydraulic
inspection - pickling - final inspection (Strictly
controlled)-packaging-shipping.
Features
The production process of straight seam welded pipe is simple, the
production efficiency is high, the cost is low, and the development
is rapid. The strength of spiral welded pipes is generally higher
than that of straight seam welded pipes. Welded pipes with larger
diameters can be produced from narrower billets, and welded pipes
with different diameters can also be produced from billets of the
same width. However, compared with straight seam pipes of the same
length, the weld length is increased by 30~100%, and the production
speed is lower.
Application scope
Products are widely used in water supply projects, petrochemical
industry, chemical industry, electric power industry, agricultural
irrigation, and urban construction. They are one of the twenty key
products developed in my country.
For liquid transportation: water supply and drainage. For gas
transportation: coal gas, steam, liquefied petroleum gas.
For structural purposes: piling pipes, bridges; pipes for docks,
roads, building structures, etc. [1]
Category Editor Broadcast
Classified by use
It is further divided into general welded pipes, galvanized welded
pipes, oxygen blown welded pipes, wire casings, metric welded
pipes, roller pipes, deep well pump pipes, automotive pipes,
transformer pipes, welded thin-walled pipes, welded special-shaped
pipes, scaffolding pipes and spiral welded pipes .
General welded pipe: General welded pipe is used to transport
low-pressure fluid. Made of Q195A, Q215A, Q235A steel. It can also
be made of other mild steels that are easily weldable. Steel pipes
are subject to hydraulic pressure, bending, flattening and other
experiments, and have certain requirements for surface quality. The
delivery length is usually 4-10m, and delivery of fixed length (or
multiple lengths) is often required. The specifications of welded
pipes are expressed in nominal diameter (millimeters or inches).
The nominal diameter is different from the actual. According to the
specified wall thickness, there are two kinds of welded pipes:
ordinary steel pipes and thickened steel pipes.
Galvanized steel pipe: In order to improve the corrosion resistance
of steel pipes, general steel pipes (black pipes) are galvanized.
Galvanized steel pipes are divided into two types: hot-dip
galvanizing and electro-galvanizing. Hot-dip galvanizing has a
thick zinc layer and electro-galvanizing has a low cost.
Oxygen blowing welded pipe: used as oxygen blowing pipe for
steelmaking. Generally, small diameter welded steel pipe is used,
with eight specifications ranging from 3/8 inch to 2 inch. Made of
08, 10, 15, 20 or Q195-Q235 steel strip. In order to prevent
corrosion, some are aluminized.
Wire casing: It is an ordinary carbon steel electric welded steel
pipe. It is used in concrete and various structural power
distribution projects. The commonly used nominal diameter is from
13-76mm. The wire sleeve has a thin wall and is mostly used after
being coated or galvanized, requiring a cold bending test.
Metric welded pipe: specifications are used in the form of seamless
pipes, welded steel pipes expressed in outer diameter * wall
thickness mm, with tropical or cold zone welding of ordinary carbon
steel, high-quality carbon steel or general low alloy steel, or
with tropical welding Then it is made by cold drawing method.
Metric welded pipes are divided into general-purpose and
thin-walled pipes. They are generally used as structural parts,
such as transmission shafts, or to transport fluids. Thin-walled
pipes are used to produce furniture, lamps, etc. The strength and
bending test of the steel pipe must be ensured.
Roller tube: used for belt conveyor roller electric welded steel
pipe, generally made of Q215, Q235A, B steel and 20 steel, with a
diameter of 63.5-219.0mm. There are certain requirements for the
curvature of the pipe, the end face to be perpendicular to the
center line, and the ovality. Generally, water pressure and
flattening tests are conducted.
Transformer tube: used to manufacture transformer radiator tubes
and other heat exchangers. It is made of ordinary carbon steel and
requires flattening, flaring, bending and hydraulic testing. Steel
pipes are delivered in fixed lengths or multiple lengths, and there
are certain requirements for the bending of the steel pipes.
Special-shaped pipes: square pipes, rectangular pipes, hat-shaped
pipes, hollow rubber steel pipes for doors and windows welded from
ordinary carbon structural steel and 16Mn and other steel strips.
They are mainly used as agricultural machinery components, steel
windows and doors, etc.
Electrically welded thin-walled tubes: mainly used to make
furniture, toys, lamps, etc. In recent years, thin-walled tubes
made of stainless steel strips have been widely used in high-end
furniture, decorations, fences, etc.
Spiral welded pipe: It is made by rolling low-carbon carbon
structural steel or low-alloy structural steel strips into pipe
blanks at a certain spiral angle (called forming angle), and then
welding the pipe seams. It can be made of narrower pipes. Strip
steel produces large diameter steel pipes. Spiral welded pipes are
mainly used for oil and natural gas transmission pipelines, and
their specifications are expressed by outer diameter * wall
thickness. Spiral welded pipes are either single-sided or
double-sided. Welded pipes should ensure that the hydraulic
pressure test, tensile strength and cold bending performance of the
weld meet the regulations.
Classification by production method
(1) According to process - arc welded pipe, resistance welded pipe
(high frequency, low frequency), gas welded pipe, furnace welded
pipe.
(2) According to the welding seam - straight seam welded pipe,
spiral welded pipe.
Classification by cross-sectional shape
(1) Simple cross-section steel pipes - round steel pipes, square
steel pipes, oval steel pipes, triangular steel pipes, hexagonal
steel pipes, rhombus steel pipes, octagonal steel pipes,
semi-circular steel pipes, and others.
(2) Complex cross-section steel pipes - unequal hexagonal steel
pipes, five-petal plum blossom-shaped steel pipes, double-convex
steel pipes, double-concave steel pipes, melon-shaped steel pipes,
conical steel pipes, corrugated steel pipes, watch case steel
pipes, and others.
Classified by wall thickness
Thin-walled steel pipes, thick-walled steel pipes.
Classification by end shape
Divided into round welded pipes and special-shaped (square, flat,
etc.) welded pipes.
Classification supplement
1. Ordinary carbon steel wire casing (GB/T3640-88) is a steel pipe
used to protect wires in electrical installation projects such as
industrial and civil buildings and installation of machinery and
equipment.
2. Straight seam electric welded steel pipe (YB242-63) is a steel
pipe with the weld seam and the steel pipe longitudinally parallel.
Usually divided into metric electric welded steel pipes, electric
welded thin-walled pipes, transformer cooling oil pipes, etc.
3. Spiral submerged arc welded steel pipe (SY5036-83) for
pressure-bearing fluid transportation is made of hot-rolled steel
strip coils as pipe blanks, spirally formed at constant
temperature, and welded by double-sided submerged arc welding. It
is used for pressure-bearing fluid transportation. Spiral seam
steel pipe. Steel pipes have strong pressure-bearing capacity and
good welding performance. They have undergone various rigorous
scientific inspections and tests and are safe and reliable to use.
The steel pipe has a large diameter, high transportation
efficiency, and can save investment in laying pipelines. Mainly
used for pipelines transporting oil and natural gas.
4. Spiral seam high-frequency welded steel pipe (SY5038-83) for
pressure-bearing fluid transportation is made of hot-rolled steel
strip coils as pipe blanks, spirally formed at constant
temperature, and welded by high-frequency lap welding method. It is
used for pressure-bearing fluid transportation. Spiral seam high
frequency welded steel pipe. Steel pipes have strong
pressure-bearing capacity, good plasticity, and are easy to weld
and process. After various strict and scientific inspections and
tests, they are safe and reliable to use. The steel pipes have
large diameters, high transportation efficiency, and can save
investment in laying pipelines. Mainly used for laying pipelines
transporting oil, natural gas, etc.
5. Generally, spiral seam submerged arc welded steel pipes for
low-pressure fluid transportation (SY/T5037-2000) are made of
hot-rolled steel strip coils as pipe blanks, which are often heated
and spirally formed, and are made by double-sided automatic
submerged arc welding or single-sided welding. Submerged arc welded
steel pipes are used for transporting general low-pressure fluids
such as water, gas, air and steam.
6. Spiral seam high-frequency welded steel pipe (SY5039-83) for
general low-pressure fluid transportation is made of hot-rolled
steel strip coils as pipe blanks, spirally formed at constant
temperature, and welded by high-frequency lap welding. It is used
for general low-pressure fluid transportation. Seam high frequency
welded steel pipe.
7. Spiral welded steel pipe for piles (SY5040-83) is made of
hot-rolled steel strip coils as pipe blanks, spirally formed at
constant temperature, and made by double-sided submerged arc
welding or high-frequency welding. It is used for civil
construction structures and docks. , bridges and other foundation
piles.Zhengde Welded steel pipe, also known as welded pipe, is a steel
pipe made by welding steel plates or strips after being rolled and
formed. Welded steel pipes are divided into straight seam welded
pipes and spiral welded pipes according to the form of welds.
Classified by production method: arc welded pipe, resistance welded
pipe, (high-frequency, low-frequency) gas welded pipe, furnace
welded pipe. The production process of straight seam welded pipe is
simple, with high production efficiency, low cost, and rapid
development. The strength of spiral welded pipes is generally
higher than that of straight seam welded pipes. Narrow billets can
be used to produce larger diameter welded pipes, and billets of the
same width can also be used to produce welded pipes of different
diameters. However, compared to straight seam pipes of the same
length, the weld length increases by 30-100% and the production
speed is lower. Thick wall coil products include: large coil, large
diameter thick wall coil, various materials thick wall coil, hot
rolled thick wall coil, cold rolled thick wall coil, etc.
All welded pipes can be made into galvanized welded pipes, which
can be found through product consultation on the homepage.
DN | Welded steel pipe (ordinary) | Welded steel pipe (thickened) | Seamless steel pipe (hot rolled) | Spiral welded steel pipe |
pg≤1.0Mpa | pg≤1.6Mpa | pg≤2.5Mpa | pg≤1.6Mpa |
| D×∮ | (Kg/m) | D×∮ | (Kg/m) | D×∮ | (Kg/m) | D×∮ | (Kg/m) |
DN15 | 21.3*2.75 | 1.25 | 21.3*3.25 | 1.44 | ---- | ---- | ---- | ---- |
DN20 | 26.8*2.75 | 1.63 | 26.8*3.5 | 2.01 | ---- | ---- | ---- | ---- |
DN25 | 33.5*3.25 | 2.42 | 33.5*4 | 2.91 | 32*3.5 | 2.46 | ---- | ---- |
DN32 | 42.3*3.25 | 3.13 | 42.3*4 | 3.77 | 38*3.5 | 2.98 | ---- | ---- |
DN40 | 48*3.5 | 3.84 | 48*4.25 | 4.58 | 45*3.5 | 3.58 | ---- | ---- |
DN50 | 60*3.5 | 4.88 | 60*4.5 | 6.16 | 57*3.5 | 4.62 | ---- | ---- |
DN65 | 75.5*3.75 | 6.64 | 75.5*4.5 | 7.88 | 73*4 | 6.81 | ---- | ---- |
DN80 | 88.5*4 | 8.34 | 88.5*4.75 | 9.81 | 89*4 | 8.38 | ---- | ---- |
DN100 | 114*4 | 10.85 | 114*5 | 13.44 | 108*4 | 10.26 | ---- | ---- |
DN125 | 140*4.5 | 15.04 | 140*4.5 | 18.24 | 133*4 | 12.72 | ---- | ---- |
DN150 | 165*4.5 | 17.81 | 165*5.5 | 21.63 | 159*4.5 | 17.14 | 168*5 | 20.1 |
DN200 | ---- | ---- | ---- | ---- | 219*6 | 31.52 | 219*5 | 31.52 |
DN250 | ---- | ---- | ---- | ---- | 273*8 | 52.28 | 273*7 | 45.92 |
DN300 | ---- | ---- | ---- | ---- | 325*8 | 62.54 | 325*7 | 54.9 |
DN350 | ---- | ---- | ---- | ---- | 377*9 | 81.67 | 377*7 | 63.87 |
DN400 | ---- | ---- | ---- | ---- | 426*9 | 92.55 | 426*7 | 72.33 |
DN450 | ---- | ---- | ---- | ---- | 480*9 | 104.53 | 478*7 | 81.31 |
DN500 | ---- | ---- | ---- | ---- | 530*9 | 115.62 | 529*7 | 90.11 |
DN600 | ---- | ---- | ---- | ---- | 630*9 | 137.82 | 630*7 | 107.5 |
Our Advantages
Longitudinally welded pipes
The production process of straight seam welded pipe is simple, with
high production efficiency, low cost, and rapid development. The
strength of spiral welded pipes is generally higher than that of
straight seam welded pipes. Narrow billets can be used to produce
larger diameter welded pipes, and billets of the same width can
also be used to produce welded pipes of different diameters.
However, compared to straight seam pipes of the same length, the
weld length increases by 30-100% and the production speed is lower.
Therefore, smaller diameter welded pipes mostly use straight seam
welding, while larger diameter welded pipes mostly use spiral
welding.Straight seam welded pipes are divided into longitudinal
submerged arc welding (LSAW) and electric resistance welding (ERW).
Square tube
Square tube is a term for square and rectangular pipes, which
refers to steel pipes with equal sides. It is made of rolled steel
strip after process treatment. Generally, the strip steel is
unpacked, flattened, curled, and welded to form a circular tube,
which is then rolled into a square tube and cut to the required
length. Also known as square and rectangular cold formed hollow
steel, abbreviated as square tube and rectangular tube, with codes
F and J respectively. The allowable deviation of the wall thickness
of rectangular pipes shall not exceed 10% of the nominal wall
thickness when the wall thickness is not greater than 10mm, and
shall not exceed 8% of the wall thickness when the wall thickness
is greater than 10mm, except for the wall thickness of corner and
weld areas. The typical delivery length of square tube is
4000mm-12000mm, with the majority being 6000mm and 12000mm.
SSAW spiral welded pipe
Spiral welded steel pipes refer to steel pipes with joints on the
surface that are formed by bending and deforming steel strips or
steel plates into circular or square shapes and then welding them.
According to different welding methods, it can be divided into arc
welded pipes, high-frequency or low-frequency resistance welded
pipes, gas welded pipes, furnace welded pipes, Bondi pipes, etc.
According to the shape of the weld seam, it can be divided into
straight seam welded pipes and spiral welded pipes. Welded steel
pipes are used in petroleum drilling and mechanical manufacturing
industries. Furnace welded pipes can be used as water and gas
pipes, and large-diameter straight seam welded pipes can be used
for high-pressure oil and gas transportation, etc; Spiral welded
pipes are used for oil and gas transportation, pipe piles, bridge
piers, etc. Welded steel pipes have lower costs and higher
production efficiency than seamless steel pipes.
Thick walled coiled tube
Thick walled coiled pipes, as the name suggests, are rolled out of
steel plates. T-shaped welded pipes are the main type of coiled
pipes, while spiral pipes and straight seam pipes are not strictly
speaking coiled pipes. Before rolling pipes, it is necessary to
familiarize oneself with technical requirements such as drawings,
process material performance, etc., select an appropriate rolling
machine, and determine whether to roll cold, warm, or hot. The
specification and model range of hot-rolled thick walled steel
pipes: diameter 400 to 3000mm, wall thickness 4 to 300mm, and
length produced according to user needs. Products include: large
coil tubes, large diameter thick wall coils, thick wall coils of
various materials, hot rolled thick wall coils, cold rolled thick
wall coils, etc.
Quality first: production and inspection in strict accordance with
production standards;
Price advantage: discounts based on real market prices;
Transaction security: There will be no loss of customer funds;
After-sales guarantee: the customer's problem is our problem;
Long-term cooperation: quality assurance, price advantage, sincere
service can last for a long time.Detailed Photos
Packaging & Shipping
Company Profile
Shandong Zhengde Metal Manufacturing Co., Ltd. is a production and sales company integrating hot-rolled steel
coils, cold-rolled steel coils, galvanized steel coils,
color-coated steel coils, section steel, steel pipes, steel wires,
metal mesh, stainless steel, aluminum, copper and other metal
products integrated large enterprises. Five production and sales
bases have been formed in Binzhou, Liaocheng, Wuxi, Tianjin, Jinan
and Tai'an, with more than 100 production lines, 4 nationally
recognized laboratories, 2 technical engineering centers, and 5
enterprise technology centers. Products are exported to more than
50 countries and regions such as North America, South America,
Europe, Africa, Oceania, Middle East, and Southeast Asia.
Certifications