Carbon Steel Pipe

The development of production technology of steel (Steel pipe) starts at the rise of the bicycle industry, the development of oil in the early 19th century, ships during the two world wars, boilers, aircraft manufacturing, manufacturing after World War II thermal power boilers, chemical industrial development and oil and gas drilling and transport, have a strong impetus to the development of the steel industry in the variety, yield and quality.

Pipe not only for transporting fluid and powdered solids, heat exchange, manufacture of mechanical parts and containers, it is an economic steel. Building structure with steel pipe manufacturing grid, pillars and mechanical support, can reduce weight, save 20 to 40 percent metal, and can be realized mechanized factory construction. Not only can save with a steel pipe manufacturing steel highway bridges, simplified construction, and can greatly reduce the area of ​​the coating of the protective layer, save investment and maintenance costs.

English name: steel pipe, seamless steel pipe, welded steel pipe

Classification method of producing: hot-rolled seamless pipe, cold drawn pipe, precision steel pipe

table of Contents

1 classification

▪ Material

▪ Press connection Category

▪ Press plated coating characteristics

▪ by purpose

▪ Press the cross-sectional shape

2 component test

3 Identification

4 Regulations

5 Specification

6 Dimensions term

▪ Size

▪ deviations and tolerance

▪ Delivery length

▪ uneven thickness

▪ ovality

▪ curvature

▪ size tolerance

7 standards

▪ mechanical indicators

▪ welded steel pipe standards

▪ seamless steel pipe Standard

8 steel rolling

Categories edit

According to the production method

Pipe according to production methods can be divided into two categories: seamless steel pipe and pipe joints, pipe joints referred to as straight pipe joints.

1. seamless steel pipe according to production methods can be divided into: hot-rolled seamless pipe, cold drawn pipe, precision steel tubes, thermal expansion tubes, cold spinning tube and squeeze tubes.

Seamless steel pipe with high-quality carbon steel or alloy steel, hot-rolled, cold-rolled (pull) of the points.

Bundles of steel

Bundles of steel

2. welded steel pipe because of different welding process is divided into stove pipe, welded (ERW) pipes and automatic arc welded pipe, welding its different forms is divided into two Longitudinal and spiral welded pipe, its end shape is divided circular pipe and shaped (square, flat, etc.) pipe.

Welded steel pipe is rolled into a tube-shaped steel sheet spiral seam to seam or welded, in the manufacturing method, is divided into low pressure liquid delivery welded steel pipe, spiral seam welded steel pipe, straight welded pipe, welded pipe. Seamless steel tubes for various industries liquid pressure pipelines and gas pipelines. Welded pipes can be used for water pipes, gas pipes, heating pipes, electrical pipes.


Pipe by pipe material (ie steel) can be divided into: carbon pipe and alloy pipe, stainless steel tubes.

Carbon tube can be divided into ordinary carbon steel and quality carbon structural tube.

Alloy tube can be divided into: low-alloy tube, alloy structure tube, high alloy pipe, high-strength pipe. Bearing tube, heat-resistant acid stainless steel tube, precision alloy (such as Kovar) pipe and high-temperature alloy tubes.

Press connection classification

Pipe by pipe end connection can be divided into: light pipe (pipe end without thread) and threading pipe (pipe end with thread).

Car wire tube is divided into: ordinary cars wire pipe and threading pipe end upsetting.

Thick threading pipe can be divided into: external upset (with external thread), internal upset (with internal thread) and the inner and outer thickening (with external thread), etc. threading pipe.

If you press threading pipe thread types can be divided into: ordinary cylindrical or conical thread and special thread etc. threading pipe.

In addition, according to user needs, threading pipe is generally equipped with fittings delivery.

Press plated coating characteristics

Press plated steel pipe coating features can be divided into: clarinet (not plated coating) and plated coating tube.

Coating possession galvanized pipe, aluminum pipe, chrome pipes, tubes and other alloy layer infiltration was steel.

Coated pipe outer coating tube, pipe coating, pipe coating inside and outside. Usually with a plastic coating, epoxy, epoxy coal tar and various type of anti-corrosion coating of glass material. Galvanized pipe and tube is divided into KBG, JDG tube, threaded pipe, etc.

By Application

1. Line tube. Such as: water, gas pipes, steam pipes seamless pipe, oil pipeline, oil and gas line pipe. Agricultural irrigation faucet with a pipe and sprinkler pipe.

2. Thermal Equipment tube. Such as the general use of boiling water tube boilers, superheated steam pipes, superheater locomotive boiler tubes, opium pipe, small pipe, brick arch pipe and high-temperature high-pressure boiler tubes.

3. Mechanical industrial pipe. Such as aviation structural tube (tube, oval tube, flat oval tube), automobile axle tube, axle tubes, structural tubes for tractor, tractor oil cooler tube, farm with a square tube and rectangular tube, pipe and transformer bearings tubes.

The petroleum geological drilling pipe. Such as: oil drilling pipe, drill pipe (Kelly and hexagonal drill), drill collar, oil tubing, casing and various fittings, geological drilling pipe (core pipe, casing, active drill pipe, drill collar Press hoop and pin joints, etc.).

5. Chemical industrial pipe. Such as: petroleum cracking tubes, chemical equipment and piping tube heat exchangers, acid-resistant stainless pipe, fertilizer use high-pressure pipe and transporting chemical medium pipe.

6. Other departments tube. Such as: container tube (high pressure gas cylinders with pipes and general container tube), instrumentation tube, watch shell pipe, hypodermic needles and tubes and other medical devices.

Press the cross-sectional shape

Steel grades and different specifications of steel products is extremely diverse, its performance varies. All of these changes should be as user requirements or conditions of work and distinction. Typically, steel products according sectional shape, production method, pipe materials, connection methods, plated coating characteristics and intended use classification.

Pipe according to a cross-sectional shape can be divided into: circular pipe and shaped pipe.

Profiled steel refers to a variety of non-circular cross-section of the pipe. The major ones are: a square tube, rectangular tube, oval tube, flat oval tubes, half tubes, hexagonal tubes, hexagonal tube, scalene hexagonal tubes, pipes equilateral triangle, pentagon Plum, octagonal tube, convex shaped tube, double convex tube. Double concave tube, more concave tube, oval-shaped tube, flat tube, diamond-shaped tube, star tube, parallelogram tubes, ribbed tubes, drop-shaped tube, finned tubes, twisting different tube, B-tube, D tube and multilayer tube.

Pipe according to the profile shape and is divided into: sectional steel and variable cross-section steel. Variable Section (or variable cross-section) pipe refers sectional shape along the longitudinal direction of the tube on the inside and outside diameter and wall thickness variations occur cyclic or acyclic steel. The main are: outer conical tubes, tapered inner tube, the outer stepped tube, ladder pipes, cycle section, bellows, spiral, finned pipe and barrel with a double-track and so on.

Component test editor

(1) GB3087-2008 “low-pressure boiler seamless steel pipe” requirement. Chemical composition of test methods according to GB222-84 and GB223 “steel and alloy chemical analysis methods,” the relevant section.

(2) GB / T5310-2008 “high-pressure boiler seamless steel pipe” requirement. Chemical composition and test methods according to GB222-84 “steel and alloy chemical analysis method”, the relevant part of GB223 “steel and alloy chemical analysis method” in.

(3) the chemical composition of imports of boiler tube inspection in accordance with relevant provisions of the standard contract.

Identification editor

1. shoddy steel pipe prone to fold.

Fold is formed on the surface of a variety of steel fold, this defect often throughout the product’s longitudinal direction. The reason is due to shoddy factory folded pursuit of high efficiency, reduction is too large, resulting in the ears, it creates a rolling fold down when the product will crack when folded bending, the strength of steel big drop.

2. Ma often shoddy steel pipe outer surface phenomenon.

Pock is due to the groove worn steel surface irregularities caused serious irregularities defects. Because of shoddy steel pipe manufacturers to pursue profits, often the most excessive rolling groove.

3. Shoddy steel surface is easy to produce scarring.

There are two reasons: (1). Shoddy steel material uneven impurities. (2). Shoddy material manufacturers guides poorly equipped, easy to stick steel, easy to produce scarring after these impurities roll bite.

4. Too shoddy material surface is easy to crack, because it’s blank adobe, adobe many pores, adobe in cooling

Process due to thermal stress, cracks, crack after rolling there.

5. Shoddy steel easily scratched because of shoddy steel pipe manufacturers poorly equipped, prone to glitches, scratches steel surface. Deep scratches reduce the strength of steel.

6. No shoddy steel metallic luster, pale red color of pig iron or similar reasons two two, its stock is adobe. 2, inferior-rolling temperature is not standard, they are visually steel temperature, so the region can not be prescribed by austenite rolling, properties of steel naturally not compliance.

7. Shoddy steel cross ribs thin and low, often sufficient dissatisfaction with the phenomenon, because manufacturers to achieve large negative tolerance, finished in front of a few larger reduction, iron type is too small, pass fully satisfied.

8. Shoddy steel pipe oval cross-section, because the manufacturers in order to save material, the first two tracks finished roll reduction is too large, the strength of this steel is greatly decreased, and does not conform to the standard dimensions of rebar.

9. High-quality steel components of uniform, high tonnage cold shear, cut the head end surface smooth and tidy, but shoddy material due to the material is poor, there are often cut off the meat first end face of the phenomenon, namely uneven, and no metallic luster. And because wood product manufacturers cut shoddy little head, head and tail will be a big ears.

10. Shoddy steel material containing impurities, the density of steel is small, and size tolerance serious, so in the absence of vernier calipers case, you can check it for weighing. For example, for steel 20, the national standards set forth in the maximum negative tolerance of 5%, while its length 9M single theoretical weight of 120 kg, its minimal weight should be: 120 X (l-5%) = 114 公斤The actual weight of the weighing out single smaller than 114 kg, it is shoddy steel, because it is a minus tolerance of 5%. Generally the whole amount commensurate would be better, mainly taking into account the accumulated error and probability theory this problem.

11. Shoddy steel pipe inner diameter fluctuations due; l, steel surface temperature instability of yin and yang. 2, the composition of the steel uneven. 3, due to poor equipment, low-intensity ground, rolling big bounce. There will be big changes in the same week, so easy to produce steel discontinuity break.

12. Trademarks and printing high-quality tube are relatively standardized.

13. Three pipe diameter of more than 16 large thread pitch between the two trademarks are over IM.

14. Inferior longitudinal reinforcement steel rebar often wavy.

Fifteen. Shoddy steel pipe manufacturers because there is no traffic, so the package is relatively loose. Side of the oval.

Practice editing

Double-sided submerged arc welding straight seam steel pipe

1. The board probe: used to manufacture large diameter submerged arc welding after straight seam steel pipe into the production line, the first full-board ultrasonic testing;

2. Milling: The milling machine for two-sided edge steel mill, so as to meet the requirements of the plate width, plate edge parallelism and groove shape;

3. Pre-curved side: the use of pre-bending machine plate edge pre-bending, the plate has to meet the requirements of the curvature of the edge;

4. Forming: JCO molding machine in the first half of the pre-bent steel plate after repeatedly stepping through stamping, pressed into a “J” shape, and then the other half equally bent steel plate, pressed into a “C” shape, finally forming an opening The “O” shape

5. presoldered: make straight seam welded steel pipe after forming the seam and the use of gas welding (MAG) welding continuously;

6. Within welding: The tandem multi-wire submerged arc welding (up to five wire) in the inside straight seam welded steel pipe;

7. outer welding: The tandem multi-wire submerged arc welding straight seam welded outer arc welded pipe;

The ultrasonic inspection Ⅰ: inside and outside of the straight seam welded steel pipe on both sides of the base metal and weld seam 100% inspection;

9. X-ray inspection Ⅰ: internal and external weld 100 percent inspection of X-ray television industry, using an image processing system to ensure detection sensitivity;

10. Expanding: the entire length of the submerged arc welding straight seam steel pipe is expanded in diameter to improve dimensional accuracy and to improve the distribution of internal stress of the steel pipe;

11. Pressure test: the hydrostatic test machine for pipe after expanding by-root test to ensure the pipe to test pressure requirements of the standard, the machine has an automatic recording and storage capabilities;

12. chamfer: The steel tube inspection conducted after the end processing, to pipe end beveling size requirements;

13. Ultrasonic Inspection Ⅱ: root again by ultrasonic testing to check for straight seam welded steel pipe in expanding, defects may arise after the water pressure;

14. X-ray examination Ⅱ: expanding the steel pipe after hydrostatic test and X-ray industrial TV inspection and pipe end welds film;

15. A magnetic particle inspection of the tube ends: this check to detect defects in the tube end;

16. The anti-corrosion and coating: anti-corrosion steel pipe after passing the galvanizing and coating according to user requirements.

Spiral Pipe Process

(1) the volume of raw materials ie steel, wire, flux. Go through rigorous physical and chemical testing before it is put.



Production of spiral steel pipe

Production of spiral steel pipe

(2) strip head and tail docking, a single wire or twin-wire submerged arc welding, in the rolled steel by automatic submerged arc welding.

(3) before forming the strip after flattening, cutting, trimming, planing, surface transport and to clean up the crimping process.

(4) electrical contacts on both sides of pressure control conveyor cylinder pressure to ensure the smooth delivery of the strip.

(5) The external control or internal control roller shape.

(6) The weld gap control device to ensure that the weld gap to meet the welding requirements, diameter, volume and the wrong side of the weld gap have been strictly controlled.

(7) are used in welding and outside welding Lincoln welding machine single-wire or twin-wire submerged arc welding, thereby obtaining a stable welding specifications.

(8) finished welding the weld were injured after a online continuous ultrasonic instrument automatically checks to ensure 100% coverage of non-destructive testing spiral weld. If defects, automatic alarm and spraying tags, production workers and so at any time adjusting the process parameters, and remove defects.

(9) using air plasma cutting machine will cut a single tube.

(10) cut into a single pipe, each consisting of three steel head first to conduct a rigorous inspection system, the mechanical properties of the weld inspection, chemical composition, fusion status, pipe surface quality and after NDT inspection, to ensure Pipe Technology After passing to formally put into production.

(11) has marked the site of continuous acoustic testing on welds, through manual ultrasonic and X-ray review, if there are defects after repair again after destructive testing, until the confirmation defects have been eliminated.

(12) strip butt weld, and intersect with spiral weld small joint where the pipe all through the X-ray television or film examination.

(13) each pipe after hydrostatic test pressure radial seal. Test pressure and time by steel pipe pressure microcomputer detection device is strictly controlled. Test parameters are automatically printed record.

(14) pipe end machining, so that the end vertical slope altercation and accurate control of the blunt edge.

Specification Editing

(1) Specifications: spiral pipe specifications shall be set out in the import and export trade contracts. General should include standard grades (type code), reinforced the nominal diameter, nominal weight (mass), of equal length and a predetermined tolerance value of these indicators. Our standard recommendation 8,10,12,16,20,40mm nominal diameter spiral pipe series. Delivery times length divided foot length and two kinds. China’s exports of rebar length selection range of 6 ~ 12m, Japanese rebar length selection range of 3.5 ~ 10m.

(2) the appearance of quality: ① surface quality. Related standards for rebar surface quality makes provision requiring ends should be cut too flat, the surface may not have cracks, scarring and folded, may not exist on the use of harmful defects; ② Dimensions deviation allowable value. And steel rebar bending of geometry requirements provided for in the relevant standard. As our standard, straight bars bending of not more than 6mm / m, the total curvature is not greater than 0.6% total length of steel.

Dimensions term edit


A, nominal size: the nominal size is specified in the standard, the ideal size of the user and the company hopes to get, and it is indicated in the contract order size.

B, actual size: actual size is obtained in the production process, the size is often larger or smaller than the nominal size. This is greater than or less than the nominal size of the phenomenon known as bias.

C, m weight: weight per meter = 0.02466 * thickness * (OD – Wall Thickness)

Deviations and tolerances

A, deviation: in the production process, because the actual size is difficult to achieve nominal size requirement that is often greater than or less than the nominal size, so the standard set forth in the actual size and nominal allow a difference between the size. The difference is positive is called positive deviation, negative difference is called negative bias.

B, Tolerance: standards set forth in the positive and negative deviation absolute value sum is called tolerance, also called “tolerance.”

Deviation is directional, that is “positive” or “negative” means; the tolerance is not directional, therefore, the deviation value is called “positive tolerance” or “negative tolerance” is called is wrong.

Delivery length

Delivery length, also known as user requirements length or contract length. There are several provisions of the standard length for delivery:

A, usually the length (also known as non-random length): Where the length over the length of the standard provisions and no fixed length requirements are referred to as normal length. Such as structural tube standard: hot rolled (extrusion, expansion) steel 3000mm ~ 12000mm; cold drawn (rolled) pipe 2000mmm ~ 10500mm.

B, random length: cut length should be within the usual length, it is the contract required a fixed length dimension. But the actual operation are absolute cut-length cut is unlikely, and therefore the standard length for a predetermined length of positive deviation allowed.

Structural tube criteria:

Production cut length tube timber rate is usually lower than that of the length of the tube by a big margin, the company proposed fare increase request is reasonable. Companies are not consistent markups, usually based on the base price increase of about 10%.

C, double length: double length should be within the usual length, the contract should specify the single double length and the total length constituting a multiple (eg 3000mm × 3, 3 multiple that is 3000mm, the total length of 9000mm). In practice, it should be based on the total length plus allow positive deviation 20mm, plus a single double length of each cut should be left margin. Structural tube, for example, provisions remain cut margin: diameter ≤159mm is 5 ~ 10mm; outer diameter> 159mm is 10 ~ 15mm.

If the standard deviation is no double length and cutting margin provisions negotiated by both parties and specified in the contract. Double length with the same cut length, will produce a significant reduction in finished product rate enterprises, therefore, the company proposed increases are reasonable, its rate of increase with the length of the rate of increase is substantially the same length.

D, length range: Range length in the usual length, when the user requires a fixed range in which the length of time, to be specified in the contract.

Example: A typical length of 3000 ~ 12000mm, and cut length range of 6000 ~ 8000mm or 8000 ~ 10000mm.

Visible, in length than the length and double length requirements relaxed, but generally tightened length than many, will give producers to bring lower timber rates. Therefore, the company proposed fare increase is justified, its rate of increase in the general base price increase of about 4 percent.

Uneven thickness

Pipe wall thickness can not be around the same as the wall thickness of the objective existence of unequal phenomenon in its cross-sectional and longitudinal pipe body, namely uneven thickness. In order to control this unevenness, in some steel standards set forth in the uneven thickness allows indicators, the general provisions of not more than 80% of the wall thickness tolerance (by both parties after consultation execution).


Circular in cross-section the outer diameter of the steel pipe there ranging phenomenon, i.e., there are not necessarily mutually perpendicular maximum outside diameter and minimum diameter, the difference between the maximum and minimum outer diameter is the outer diameter ellipticity (with or without roundness). In order to control ovality, some steel standards set forth in the permit ovality indicators, generally defined as no more than the diameter tolerance of 80% (by both parties after consultation execution).


Pipe in the longitudinal direction of the curved shape, with the number that is called showing its curve of curvature. Curvature specified in the standard are generally divided into the following two:

A, the local curvature: with one meter long steel ruler against the amount of the maximum bending at its chord height measured (mm), is the local curvature value in units of mm / m, representation as 2.5mm / m . This method is also applicable to the curvature of the tube end.

B, the total full-length Bending: use a piece of string, from both ends of the tube taut, measuring pipe bend maximum chord height (mm), and then converted into a length (meters) of a percentage, is the pipe length direction The total length of curvature.

For example: pipe length is 8m, the measured maximum chord height 30mm, total length of the tube bending degree should be:

0.03 ÷ 8m × 100% = 0.375%


Oversize or call dimension beyond the standard tolerances. Where “size” mainly refers to the outer diameter and wall thickness of steel pipe. Oversize usually someone used to call “tolerance out of line”, which equated to deviations and tolerance is not tight, it is called, should be called “deviation outrageous.” Deviations here may be “positive”, it may be “negative”, rarely “positive and negative” bias are outrageous phenomenon in the same batch of steel pipe.

Note: The calculation of theoretical weight calculation formula commonly used profiles:

m = F × L × ρ

m- quality Kg; F- off area m2 / m; L- length m; ρ- density * Kg / m3

☆ where: F-off area calculation method:

1, the steel F = a2

2, pipe F = 3.1416 × $ (D- $) D- Diameter $ – Thickness

3, steel, flat steel F = a × $ a- width

Related Standard Editor

Mechanical indicators

Mechanical properties of steel is to ensure that the steel end-use properties (mechanical properties) is an important indicator, it depends on the chemical composition and heat treatment system steel. In the steel standard, according to different requirements, the provisions of the tensile properties (tensile strength, yield strength or yield point elongation) and hardness, toughness index, as well as user requirements of high and low temperature properties.

① Tensile strength (σb)

Specimens during stretching, the pull-off exposure to the most vigorous (Fb), stress (σ) divided by the original specimen cross-sectional area (So) income, known as the tensile strength (σb), units N / mm2 (MPa). It represents a metal material to resist damage maximum capacity under tension. The formula is:

Where: When Fb– specimen pull off exposure to the most vigorous, N (Newton); So– original specimen cross-sectional area, mm2.

② yield point (σs)

Metallic material having a yield phenomenon, the specimen during the tensile force is not increased (remains constant) could continue to stress elongation, called yield point. If the force generating decline, should distinguish between upper and lower yield point. Unit yield point is N / mm2 (MPa).

The yield point (σsu): sample yield and maximum stress occurs first drop before; lower yield point (σsl): When excluding the initial transient effects, the yield phase of the minimum stress.

Yield point is calculated as follows:

Where: Fs– process of tensile yield strength (constant), N (Newton) So– original specimen cross-sectional area, mm2.

③ percentage elongation (σ)

In the tensile test, the specimen fractured gauge increased its percentage of the length of the original gauge length, called elongation. In σ expressed in units of%. The formula is:

Where: L1– specimen fractured gauge length, mm; L0– original specimen gauge length, mm.

④ section shrinkage (ψ)

In the tensile test, the specimen fractured its biggest percentage reduction in the amount of the original cross-sectional area of ​​the cross-sectional area of ​​the reduced diameter, known as section shrinkage. To ψ said that the unit is%. Calculated as follows:

Where: S0– original specimen cross-sectional area, mm2; S1– specimen fractured necking at least cross-sectional area, mm2.

⑤ hardness index

Metallic materials resist indentation capacity hard objects surface, called hardness. Depending on the test methods and scope, it can be divided into Brinell hardness, Rockwell hardness, Vickers hardness, Shore hardness, micro hardness and high temperature hardness. For pipe commonly used are Brinell, Rockwell, Vickers hardness of three kinds

A, Brinell hardness (HB)

With a certain diameter of the ball or carbide ball to the specified test force (F) is pressed into the pattern surface, after removing a predetermined holding time test force, indentation diameter measurement sample surface (L). Brinell hardness test force value is obtained by dividing the spherical surface area of ​​the indentation providers. With HBS (ball), said unit N / mm2 (MPa).

The formula is:

Where: Test force F– pressed into the surface of the metal sample, N; D– test ball diameter, mm; d– average diameter of the indentation, mm.

Brinell hardness measurement more accurate and reliable, but generally only applies to HBS 450N / mm2 (MPa) below the metal material for hard steel or thin plate does not apply. In the steel standard, the most widely used Brinell hardness, often with indentation diameter d to represent the hardness of the material, both intuitive and convenient.

Example: 120HBS10 / 1000130: expressed 10mm diameter ball at 1000Kgf (9.807KN) test force, keep the 30s (seconds) measured Brinell hardness value of 120N / mm2 (MPa).

B, Rockwell hardness (HK)

Rockwell hardness test with Brinell hardness test, are indentation test method. The difference is that it is a measure of the depth of the indentation. That is, in the early Yong test force (Fo) and total test force (F) has the role of the indenter (gold steel cone or ball) onto the surface of the sample, after a predetermined hold time, removing the main test force is calculated by measuring the residual hardness indentation depth increment (e). Its value is unknown numbers to sign HR said that using a ruler has A, B, C, D, E, F, G, H, K, etc. 9 ruler. Which are commonly used in steel hardness test scale generally A, B, C, i.e. HRA, HRB, HRC.

Welded steel pipe standards

Welded steel pipe also known, is a steel plate or strip after curl forming welded in

Welded steel pipe

Welded steel pipe

. Welded steel pipe production process is simple, high production efficiency, different specifications, less investment in equipment, but the general strength of less than seamless steel tubes. Since the 1930s, with the progress of high-quality steel rolling production and the rapid development of welding and inspection techniques, weld quality continues to improve, welded steel pipe increasing varieties and specifications, and in more and more areas instead of no pipe joints. Seam welded steel pipe in the form of divided Longitudinal and spiral welded pipe.

Longitudinal production process is simple, high production efficiency, low cost, rapid development. The strength of the spiral welded pipe is generally higher than the Longitudinal, can narrow the billet production of large diameter pipe, you can also use the same width of the billet production of different pipe diameters. However, compared with the same length of straight pipe seam weld length of 30 to 100%, and lower production rate.

Therefore, smaller diameter pipe were powered by straight seam welded, large diameter spiral welded pipe for the most part.

Low pressure liquid delivery welded steel pipe (GB / T3091-2008), also known as general welded pipe, commonly known as the clarinet. Welded steel pipe is used for conveying water, gas, air, oil and heating steam and other general low pressure fluid and other purposes. Then divided into ordinary steel pipe wall thickness and thicker steel; took over end into the form without steel tube (fluorescent tubes) and with steel pipe. Low pressure liquid delivery welded steel pipe for conveying fluids in addition to direct, but also widely used as low pressure liquid delivery galvanized welded steel pipe raw pipe.

1. Low fluid delivery galvanized welded steel pipe (GB / T3091-2008), also known as galvanized welded steel pipe, commonly known as white tube. Is used for conveying water, gas, air and steam heating oil, warm water and other general low pressure fluid or other uses hot-dip galvanized welded (furnace brazed or welded) pipe. Then divided into ordinary steel pipe wall thickness galvanized steel and thicker galvanized steel; took over end into the form of a threaded galvanized steel and non-threaded galvanized steel band. Pipe specifications with nominal diameter (mm) that the nominal diameter is the diameter of the approximation. Traditionally commonly expressed in inches, such as 1 / 2,3 / 4,1,2 and so on.

2 ordinary carbon steel wire casing (YB / T5305-2006) is an industrial and civil construction, installation of equipment and other electrical installation work for the protection of steel wires.

3. straight seam welded steel pipe (GB / T13793-2008) is parallel to the longitudinal welds and steel pipe. For general structures, usually divided into metric welded steel pipe, welded thin-walled tubes and the like.

4. Pressure fluid transport spiral submerged arc welded pipe (SY / T5037-2000) is a hot-rolled steel strip coils for the tube, often warm spiral shape, with double-sided submerged arc welding method for pressurized fluid conveying spiral pipe joints. Strong pressure steel, welding performance, through a variety of rigorous scientific examination and testing, the use of safe and reliable. Pipe diameter, high transmission efficiency, and can save the laying of pipeline investments. Mainly used to transport oil, natural gas pipelines.

5. Pressure fluid transport with spiral seam high frequency welded steel pipe (SY / T5038-2000) is a hot-rolled steel strip coils for the tube, often warm spiral shape, using high frequency lap welding method for pressure fluid transport spiral seam high frequency welded steel pipe. Strong pressure steel, plastic, and easy welding and machining molding; through a variety of strict and scientific inspection and testing, safe and reliable, pipe diameter, high transmission efficiency, can save the laying of pipeline investments. Mainly used for laying transport oil and natural gas pipelines.

7. The general low pressure liquid delivery spiral seam high frequency welded steel pipe (SY / T5039-2000) is a hot-rolled steel strip coils for the tube, often warm spiral shape, using high frequency lap welding method for general low pressure fluid with spiral seam high frequency welded steel pipe.

8. Pile with spiral welded steel pipe (SY / T5768-2000) is a hot-rolled steel strip coils for the tube, often warm spiral shape, using double-sided submerged arc welding or high frequency welded for civil engineering structures, docks , bridges and other infrastructure pile with steel pipe.

Seamless Steel Tube Standard

Seamless steel pipe is a hollow cross-section, no seams around the long bar of steel. Seamless steel pipe having a hollow cross section, can be used as pipeline fluids, such as transportation of oil, gas, gas, water and some solid materials, pipes and so on. Compared seamless steel pipe and solid steel bar, etc., the same torsional strength in bending, lighter, is an economic cross-section steel, widely used in the manufacture structural parts and mechanical parts, such as drill pipe, automotive transmission , bicycle frames and construction using steel scaffolding. Seamless steel pipe manufacturing annular parts, can improve material utilization, simplify the manufacturing process, saving materials and processing time, such as bearing rings, jack sets, etc., are widely used to manufacture steel. Steel pipe or a variety of conventional weapons indispensable material, barrel, barrel would have to make steel. Pipe according to different cross-section shapes can be divided into tube and shaped tubes. Since in perimeter of equal conditions, the largest area of ​​a circle, with the circular tube can carry more fluid. In addition, the circular cross section to withstand internal or external radial pressure, the force is uniform, so the vast majority of pipe is pipe. However, the tube also has some limitations, such as under conditions that plane bending of the tube is not as good as square, rectangular tube bending strength of a large number of farm machinery skeleton, steel and wood furniture on the popular square, rectangular tube. According to different uses should also have other cross-sectional shape shaped pipe.

1. Structural seamless steel pipe (GB / T8162-2008) is used for seamless steel tubes for general structural and mechanical structure.

2. The transmission fluid with seamless steel pipe (GB / T8163-2008) is generally seamless steel pipe used for conveying water, oil, gas and other fluids.

3. The low-pressure boiler seamless pipe (GB / T3087-2008) is used to manufacture various structural low and medium pressure boiler superheater

Sanitary stainless steel pipe

Sanitary stainless steel pipe

Steam pipes, boiling water pipes and super heated steam locomotive boiler tubes, opium pipe, small pipe and brick arch effective high-quality carbon structural steel hot-rolled and cold drawn (rolled) seamless steel pipe.

4. The high-pressure boiler quality carbon steel seamless steel pipe (GB5310-2008) is used to manufacture high-pressure and more pressure water tube boiler heating surface with steel, alloy steel and heat-resistant stainless steel seamless steel tubes.

5. Fertilizer equipment high pressure seamless steel pipe (GB6479-2000) is applicable to operating temperature -40 ~ 400 ℃, working pressure of high-quality carbon structural steel and alloy steel 10 ~ 30Ma of chemical equipment and pipeline of seamless steel tubes.

6. petroleum cracking seamless pipe (GB9948-2006) is applicable to the oil refinery furnace tubes, heat exchangers and pipe seamless steel pipe.

7. Geological Drilling Pipe (YB235-70) is for core drilling geological department of the steel used by applications can be divided into the drill pipe, drill collar, core pipe, casing and precipitation tubes.

8. Diamond core drilling seamless pipe (GB / T3423-82) is a drill, core rods used for diamond core drilling seamless steel pipe casing.

9. The oil drilling pipe (YB528-65) for oil drilling within the thickening or external upset ends of seamless steel tubes. Steel sub-threading and not two, Threading Pipe Fittings links, not threading methods and tools useful butt joint connection.

10 ships with carbon steel seamless pipe (GB5312-2009) is to create Class I pressure vessels piping, Ⅱ grade pressure piping, boilers and Superheater carbon steel seamless steel tubes. Carbon steel seamless pipe wall temperature does not exceed 450 ℃, alloy steel seamless pipe wall temperature exceeds 450 ℃.

11. The automobile axle casing seamless steel pipe (GB3088-82) is the manufacture of automobile axle casing and drive shaft tubes Bridge shell quality carbon structural steel and alloy steel hot-rolled seamless steel tubes.

12. The diesel engine with high-pressure pipe (GB3093-2002) is to create high-pressure diesel injection systems of cold drawn seamless tubes.

13. Hydraulic and pneumatic cylinder with precision internal diameter seamless pipe (GB8713-88) is the manufacture of hydraulic and pneumatic cylinder with precision seamless cold drawn or cold rolled with precision diameter size.

14. cold-drawn or cold rolled precision seamless steel pipe (GB3639-2000) is used for mechanical structure with high dimensional accuracy, hydraulic equipment and surface finish of a good cold-drawn or cold rolled precision seamless steel tubes.

15. The structure of stainless steel seamless pipe (GB / T14975-2002) is widely used for hot rolling chemical, petroleum, textile, medical, food, machinery and other industrial corrosion resistant pipes and structural parts and components made of stainless steel ( extrusion, expansion) and cold drawn (rolled) seamless steel pipe.

16. A fluid transport stainless steel seamless pipe (GB / T14976-2002) is used for the transmission fluid of hot-rolled stainless steel (extrusion, expansion) and cold drawn (rolled) seamless steel pipe.

17. In addition to shaped seamless steel pipe seamless steel pipe of other cross-sectional shape in general. Press the pipe cross-section can be divided into different shapes and sizes and so shaped seamless steel pipe wall thickness (code D), shaped seamless steel pipe wall thickness range (code named BD), variable diameter seamless steel pipe shaped (code named BJ). Shaped seamless steel tubes are widely used in various structural parts, tools and mechanical parts.