Anti-Corrosive Technology Of Anti-Corrosive Steel Pipe

In recent years, the demand for steel pipe insulation pipes in various industries has increased. The manufacturing process of China's steel pipe anti-corrosion plants has been relatively mature, and various types of anti-corrosion can be produced. The performance advantage of 3PE anti-corrosive steel pipes is most prominent.

The equipment commonly used in the production of anti-corrosive and heat-preservation steel pipes include pipe buffer platforms, pipe-drawing units, traction machines, pipe-penetrating machines, high-pressure gunners, repair platforms, transmission lines, steel pipe preheating furnaces, and shot blasting machine hosts. 3PE anti-corrosion steel pipe shall be applied to the inspection table and the transmission line of unqualified steel pipes in the inspection.

Not only can they be used for good insulation of steel pipes, but the product quality has also passed strict inspection.

3pe Pipe

Anti-corrosion pipe is specifically manufactured by first inspecting the anti-corrosion pipe, comprehensively inspecting the steel pipe under various conditions, and making it meet the conditions for making insulated steel pipes. Inspect the steel pipe for corrosion, check and remove the embroidery on the steel pipe.

The next step is to put the rust-resistant and anti-corrosion steel pipe in a polyethylene casing for pipe forming. However, after the head is repaired, polyurethane foam is injected into it, and the gap must be fully filled to make it fully filled. Inspection of anti-corrosion steel pipes, inspection of finished products of finished insulation steel pipes.

At present, domestic steel pipe insulation technology has been put on the market, and 3PE pipe has been widely used in the market. Among them, the high-temperature steam insulation pipe has good molding, small bulk density, low thermal conductivity, thermal insulation, good sound absorption, and corrosion resistance.

It is layered, staggered in the insulation layer, and segmented with stainless steel bands. In addition to the physical and chemical properties of the thermal insulation materials, which meet the current national product industry standards, the special application requirements of deep-buried "steel-sleeve" pipelines for green-to-thermal insulation pipelines should be achieved.

3PE anti-corrosion uses a three-layer PE anti-corrosion structure for the pipeline: the first layer of epoxy powder (FBE> 100um), the second layer of adhesive (AD) 170-250um, and the third layer of polyethylene (PE) 2.5-3.7mm.

The three materials are integrated into one body, and are firmly combined with the steel pipe to form an excellent anti-corrosive layer. The range of pipe diameter is Φ60 ～ Φ1420, and the wall thickness range is 2.5-18mm. This is a good anti-corrosion method, which can generally increase the service life of 50 years. It not only prolongs the replacement cycle of underground pipeline equipment, but also greatly saves costs. State building provides a powerful role!

3PE anti-corrosion is the most commonly used anti-corrosion method, which is characterized by simple production process, good anti-corrosion effect, and low price. It is a generally accepted anti-corrosion method for the pipeline manufacturing industry.

We are spiral pipe supplier china, if you have any demand for our products, please feel free to contact us.

Classification And Performance Characteristics Of Galvanized Steel Pipes

Galvanized steel pipe manufacturer china shares with you that steel is susceptible to rust and corrosion in air, water or soil. In recent years, 10% of the steel in the domestic steel production industry is corroded every year, and the steel production enterprises suffer a part of the economic losses each year. In order to improve the corrosion resistance of the steel without affecting the appearance quality of the steel, the industry has tried to galvanize the surface of the steel to prevent the surface of the steel from rusting and tissue damage.

1 Principle of galvanizing

Zinc is stored in an air-dry space to maintain its performance stability. If the air humidity is high, a dense basic zinc carbonate film will be produced on the zinc surface, which can block the air from contacting the inside. In a specific environment, the damage of the galvanized layer exposes the steel substrate, and the steel substrate reacts with zinc to form a special microbattery. The steel substrate that becomes the cathode is also protected.

Galvanized Steel Pipe

2 Classification of galvanized steel pipe

Galvanized steel pipe is divided into two types: hot-dip galvanized steel pipe and cold gi galvanized steel pipe. The hot-dip galvanized steel pipe has a thick zinc layer, which has the advantages of uniform coating, strong adhesion and long service life. Cold galvanized (electroplated) has low cost, and its corrosion resistance is much worse than hot galvanized steel pipe. Due to the strong corrosion resistance of hot-dip galvanized steel pipes, the amount of cold-galvanized steel pipes is gradually decreasing, and the use of hot-dip galvanized steel pipes is dominant. The following is a detailed introduction of two types of galvanized steel pipes.

2.1 Hot-dip galvanized pipe

This type of steel pipe makes the molten metal zinc and iron substrate react with each other to form an alloy layer, so that the plating layer and the substrate closely adhere to each other. The working process of hot-dip galvanized steel pipe: first pickling the steel pipe, washing the iron oxide on the surface of the pipe body; washing with NH4Cl and ZnCl2 aqueous solution or mixed aqueous solution in the tank, and then placing it in the hot-dip galvanizing tank for hot-dip galvanizing Zinc. The molten plating solution reacts with the substrate to form a zinc-iron alloy layer (the zinc-iron alloy layer has a dense structure and strong corrosion resistance). The steel tube base, the pure zinc layer and the alloy layer have been fused into one body, so it has strong corrosion resistance. Hot-dip galvanized steel pipe is hot-dip galvanized welded steel pipe for low-pressure fluid transportation. It is hot-dip galvanized inside and outside on the basis of welded steel pipe, so that the inner and outer walls of the steel pipe are galvanized at the same time, which greatly improves the corrosion resistance of steel pipes, reaching 20 times that of ordinary steel pipes Right and left, hot-dip galvanized steel pipe is widely used as a pipeline or metal structure in fire protection engineering, gas transportation, petroleum processing, industry, water conservancy, engineering construction, and residential construction.

2.2 Cold-galvanized pipe

The cold galvanized steel pipe is a steel pipe that has been degreased and rust-free, and shows no pollution and wetness. When the DC power is turned on, the zinc ions on the anode migrate to the cathode and discharge on the cathode, so that the surface of the steel pipe is coated with zinc. Cold galvanizing is electro-galvanizing. The surface of the steel pipe is smooth and flat. The zinc layer and the steel pipe substrate are layered independently. The zinc layer is simply attached to the steel pipe substrate and easily falls off. The zinc layer is thinner and the amount of galvanized is less, only 10g-50g / m2, and its own corrosion resistance is relatively low. Therefore, the amount of cold galvanized steel pipe is relatively small.

3 Performance characteristics of galvanized steel

①The surface of the steel is covered with a layer of pure zinc with a certain thickness and a dense structure, which blocks the possibility of contact between the corrosion solution and the steel, thereby preventing the steel from being corroded by the solution. The zinc layer will form a thin, dense and hardly water-soluble zinc oxide layer on the surface of the air, which can prevent the steel substrate from contacting the air and rusting. In addition, if zinc oxide reacts with other components in the air to form an insoluble zinc salt, it can also have a good anticorrosive effect. ②The iron-zinc alloy layer with dense structure and strong anti-corrosion performance can be used in marine construction and industrial anti-corrosion. ③Zinc-iron is miscible due to strong bonding, so it has good wear resistance. ④The ductility of zinc is good, and its alloy layer can be firmly attached to the steel substrate. Therefore, in the industrial production, hot-plated parts can be formed by rolling, bending, cold stamping and wire drawing, and the coating is not damaged. ⑤After hot-dip galvanizing of the steel structure, it is equivalent to an annealing treatment, which can effectively improve the mechanical properties of the steel substrate, eliminate the stress during the forming and welding of the steel, and facilitate the turning of the steel structure. ⑥The surface of the hot-dip galvanized steel pipe is bright and beautiful. ⑦Pure zinc layer is the most plastic layer in hot-dip galvanizing layer. Its properties are basically close to pure zinc and it has ductility, so it is flexible.

Because galvanized steel pipe has the advantage of strong anti-corrosion performance compared with ordinary steel pipe, and the anti-corrosion performance is mainly determined by the quality of galvanized steel of galvanized steel pipe. Therefore, the national standard puts forward stricter requirements for the quality of galvanized steel of galvanized steel pipe .

Do You Know The Classification Of Seamless Steel Tubes?

Water seamless steel pipe supplier to share with you: seamless steel pipe, is the largest amount of industrial pipes, the largest variety of specifications.

Basically divided into:

There are two types of seamless steel tubes for fluid transportation and seamless steel tubes with special properties. The former is a steel pipe commonly used in process pipelines, and the latter is a steel pipe for boilers, a cracking furnace pipe, and a heat exchanger steel pipe.

Can be divided into:

Carbon seamless steel pipe, chrome molybdenum seamless steel pipe and stainless, acid-resistant seamless steel pipe.

According to the nominal pressure, it can be divided into:

Low pressure (0≤1.0MPa), medium pressure (1.0 <10MPa =, high pressure (≥10MPa)).

❶Carbon seamless steel pipe

Commonly used manufacturing materials are 10 #, 20 #, 16Mn steel.

Its specification range is: hot-rolled outer diameter φ32 ～ 630mm, cold-drawn outer diameter φ6 ～ 200mm, single tube length 4-12m, and allowable operating temperature is -40 ～ 450 ℃.

It is widely used to transport various non-corrosive media to steel, such as steam, oxygen, compressed air, oil products, and oil and gas. also known as oil line seamless steel pipe.

Oil Line Seamless Steel Pipe

❷Low alloy steel seamless steel pipe

Refers to alloy steel pipes containing a certain proportion of alloying elements.

There are usually two types:

One is a low-alloy steel pipe containing manganese, called an ordinary low-alloy steel pipe, such as 16Mn, 15MnV, etc .; the other is a low-alloy steel pipe containing chromium, molybdenum, and other elements, called a chromium-molybdenum steel pipe.

Commonly used are 12CrMo, 15CrMo, 12Cr2Mo, 1Cr5Mo, etc. The specifications range is outer diameter φ10 ～ φ273mm, the length of a single pipe is 4-12m, and the applicable temperature range of chrome molybdenum steel pipe is -40 ～ 550 ℃.

Low-alloy seamless steel pipes are mostly used to transport various high-temperature oil products, oil and gas, and less corrosive salt water, and low-concentration organic acids.

❸Stainless acid-resistant seamless steel pipe

According to the different contents of various metals such as chromium, nickel and titanium, there are many varieties, such as Cr13, 00Cr17Ni14Mo2, 1Cr18Ni12Mo2Ti, 1Cr18Ni9Ti, etc.

The most used amount of these steel grades is 1Cr18Ni9Ti, which is often expressed on the construction drawings by the simplified material code 18-8, and the applicable temperature range is -196 ~ 700 ° C.

It is used to transport various corrosive media such as nitric acid, acetic acid and urea in chemical production.

❹High pressure seamless steel pipe

Its manufacturing material is basically the same as the seamless steel pipe described above, except that the pipe wall is thicker than the medium and low pressure seamless steel pipe, and the thickest pipe wall is 40mm.

For example, the specifications of high-pressure seamless steel pipes for fertilizer equipment are φ14 × 4 (mm) ～ 273 × 40 (mm), the length of a single tube is 4-12m, the applicable pressure range is 10-32MPa, and the operating temperature is -40 ～ 400 ℃.

The above high-pressure seamless steel pipes are used in petrochemical plants to transport media such as raw gas, hydrogen nitrogen, synthesis gas, water vapor, and high-pressure condensate.

❺Low temperature steel pipe

In the cold area of the introduced project, the amount of material is STPL-39, STPL-46, and the operating temperature can reach -105 ° C.

Low temperature steel pipes are divided into seamless steel pipes and seam steel pipes. The nominal diameter of seamless low temperature steel pipes is 15 ~ 400mm, and the wall thickness is the same as that of carbon steel pipes. The nominal diameter of seam low temperature steel pipes is 400 ~ 1100mm, and the wall thickness is 6 ～ 10mm, standard length of single tube is 6m.

It is suitable for conveying various non-corrosive low-temperature medium pipes. At present, there is no domestic production of steel pipes corresponding to this standard.

Storage Management Methods Of Various Steel Pipe Stocks

Galvanized welded steel pipe supplier china share with you:

Choose the right venue and storeroom:

1) The site or warehouse where the steel is kept should be selected in a clean and well-drained place away from factories and mines that produce harmful gases or dust. Weeds and all debris should be removed on the site, and the steel should be kept clean.

2) Do not stack in the warehouse with materials that are corrosive to steel, such as acids, alkalis, salts, and cement. Different types of steel should be stacked separately to prevent confusion and prevent contact corrosion.

3) Large sections, rails, thick steel plates, large-diameter steel pipes, forgings, etc. can be stacked in the open air.

4) Small and medium-sized steel, wire rods, steel bars, medium-caliber steel pipes, steel wires, and wire ropes can be stored in well-ventilated sheds, but they must be up and down.

5) —Some small steels, thin steel plates, steel strips, silicon steel sheets, small-caliber or thin-walled steel pipes, various cold-rolled and cold-drawn steels, and expensive and easily corroded metal products can be stored in the warehouse.

6) Treasury should be selected according to geographical conditions. Generally, general closed warehouses are used, that is, warehouses with roofs and walls, tight doors and windows, and ventilation facilities.

7) Treasury requires ventilation in sunny days, and close moisture-proof in rainy days, and often maintain a suitable storage environment.

Reasonable stacking, first release:

1) The principle of stacking is required to be palletized according to variety and specifications under the conditions of stable palletizing and ensuring safety, and different types of materials must be palletized separately to prevent confusion and mutual corrosion.

2) It is forbidden to store articles that have a corrosive effect on steel near the stacking site.

3) The bottom of the stack should be high, solid and flat to prevent the material from being wet or deformed.

4) The same materials are stacked according to the human bank, which facilitates the implementation of the advanced first-come-first-served principle.

5) The steel sections stacked in the open air must have wooden pads or slabs underneath. The stacking surface is slightly inclined to facilitate drainage, and the materials should be placed flat to prevent bending and deformation.

6) The height of stacking should not exceed 1.2m for manual operation, 1.5m for mechanical operation, and 2.5m for stacking width.

7) A certain aisle should be left between the stack and the stack. The inspection path is generally 0.5m. The access path depends on the size of the material and the transportation machinery, and is generally 1.5-2.0m.

8) The bottom of the stack should be elevated. If the warehouse is a cement floor with a rising sun, the height should be 0.lm; if it is muddy, the height should be 0.2-0.5m. If it is an open-air site, the cement floor is 0.3-0.5m high and the sand and mud surface is 0.5-0.7m high.

9) If it is piled in the open air, the angle steel and channel steel should be laid down, that is, the mouth should be down, and the I-shaped steel should be placed vertically.

Protective box packaging:

Carbon steel seamless pipe manufacturer is a preservative or other plating and packaging that is applied before leaving the factory. This is an important measure to prevent corrosion of the material. It must be protected during transportation and loading. Shelf life of materials.

Keep the warehouse clean and strengthen the maintenance of materials

1) Before entering the warehouse, pay attention to prevent rain or mixed impurities, and use different methods to clean the material that has been rained or soiled. For example, use a wire brush with high hardness and a cloth with low hardness. Cotton and other things.

2) The material should be checked frequently after the warehouse, if there is any rust, the rust layer should be removed.

3) After the surface of general steel is cleaned, it is not necessary to apply oil, but high-quality steel, alloy thin steel plates, thin-walled pipes, and alloy steel pipes need to be coated with anti-rust oil after derusting before storing.

4) For severely rusted steel, it should not be stored for a long time after derusting, and it should be used as soon as possible.

Steel appearance quality inspection

When performing the appearance quality inspection before the steel warehouse, you must pay attention to the following:

1) When observing the surface of hot rolled steel with naked eyes, there must be no cracks, folds, scars, delaminations or inclusions. Indentation and partial protrusion, depression, and pitting are allowed, but its height or depth must not be greater than the relevant technical standards. Partial defects are allowed to be removed, but lateral removal is not allowed. The depth of removal from the actual size must not exceed the allowable negative deviation value of the steel of that size.

2) When observing the surface of cold-drawn steel with the naked eye, the surface should be clean, smooth, bright or dull, without cracks, scars, inclusions, hair lines, folds, and scale. Individual small scratches, rips, dark spots, concave surfaces, pits, etc. are allowed with a depth not greater than the nominal size deviation from the actual size.

3) The appearance of profile steel should be smooth and tidy, and its roundness, side width, height, thickness, length, twist, slope, scission, wave bend and unevenness shall not exceed the deviations specified in the relevant standards.

4) The section steel should be straightened, the steel plate should be flattened, and the edges must be cut at right angles. In addition to the above requirements, the rail ends and bolt hole surfaces must be free of shrinkage, delamination and cracks, and both ends should be milled flat.

5) The wall thickness, surface sugar, roundness and unevenness of the steel pipe shall all meet the technical standards. The joint threads of threaded steel pipes, galvanized steel pipes and geological pipes shall be oiled, and protective rings shall be provided.

6) Galvanized steel and galvanized steel pipe shall not have defects such as cracks, layer formation and missing plating.

Galvanized Steel Pipe

Specification And Application Of Seamless Steel Tube

Seamless steel pipe production method:

1. Hot-rolled seamless steel pipe

Hot - rolled seamless tube is generally produced in the automatic tube rolling set.After inspection and removal of surface defects, the solid tube billet is cut into the required length, then the core is settled on the perforating end of the tube billet, and then it is sent to the heating furnace for heating and perforating on the perforator.In the perforation at the same time continuously rotating and forward, in the role of the roller and the head, the tube blank internal cavity gradually formed, called capillary.And then send it to the automatic tube rolling machine for inheritance rolling.At last, the whole machine has the same wall thickness, and the diameter is determined by the sizing machine to meet the specification requirements.It is a better method to produce hot - rolled seamless steel tube by continuous rolling mill.

2. Cold rolling and cold drawing

To obtain seamless tubes of smaller size and better quality, cold rolling, cold drawing, or a combination of the two 

3. The extrusion method

By extrusion, the heated billet is placed in a closed extrusion cylinder, and the perforated rod moves with the extrusio

Specification and application of seamless steel tube:

The carbon steel seamless pipe has a hollow section and can be used as a conduit for conveying fluids, such as oil, natural gas, gas, water, and some solid materials.Compared with solid steel such as round steel, seamless steel tube has the same bending and torsional strength and lighter weight. It is a kind of economic section steel, widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, automobile transmission shaft, bicycle frame and steel scaffolding used in construction.Ring parts made of seamless steel tube can improve material utilization, simplify manufacturing process, and save materials and processing time.Steel pipe or a variety of conventional weapons indispensable materials, gun barrel, gun barrel to steel pipe to manufacture.

1. Seamless steel tube for structure (GB/ t8162-2008) is the seamless steel tube for general structure and mechanical structure.

2. Seamless Steel Pipe (GB/ t8163-2008) is the oil line seamless steel pipe used for conveying water, Oil, gas and other fluids.

3. Seamless steel tube for low and medium pressure boiler (gb3087-1999) is used for manufacturing various structures of low and medium pressure boiler overheating

Steel tube can be divided into round tube and shaped tube according to the shape of cross section area. Since the area of the circle is the largest when the circumference is the same, more fluid can be transferred with the circular tube.In addition, when the ring section is under internal or external radial pressure, the force is relatively uniform, therefore, the vast majority of steel tubes are circular tubes. But, circular tube also has certain limitation, if be subjected to the condition of plane bending, circular tube is inferior to square, rectangle tube bending strength is big, a few agricultural machinery have skeleton, steel wood furniture to be used commonly square, rectangle tube.Special shaped steel tubes with other cross section shapes are required for different purposes.

 

Seamless Steel Pipe

What Is The Difference Between Galvanized Steel Pipe And Welded Steel Pipe?

When building a house, when decorating, when processing operations, often will use a large number of steel pipe, the existence of steel pipe, gave it a great meaning, for people's life and work to bring great convenience. Because a lot of places are used Steel tube, so now there are many different kinds of pipes, common is galvanized and welding the two tubes, they are two very different products, there are differences in many ways, the following specific for everybody introduced galvanized steel pipe and welded steel pipe. Galvanized steel pipe can be used in the pipeline laying of lighting, power, telephone, fire protection and other systems in new construction and transformation projects (JDG, KBG, thin-wall galvanized steel pipe), can be laid in the open and dark, can be laid in the wall, can also be laid in the ceiling.Not suitable for corrosive sites and explosive dangerous environment.Welded steel tubes with hot dip or electric galvanizing coating on the surface of galvanized steel tubes. 

Galvanized Steel Pipe

Galvanizing can increase the corrosion resistance of steel pipes and prolong their service life. Galvanized steel pipe USES is very wide, in addition to a general low pressure fluid such as water, gas, oil line pipe, also used as oil industry, especially the ocean oil field oil well pipe, oil pipe, chemical coking equipment of oil heater, the condensing, exchange of coal distillation wash oil cooler for tube, and trestle pile, mining tunnel supporting frame tube, etc. Hot dip galvanized steel pipe is widely used in various modern manufacturing industries.

Galvanized welded steel pipe supplier china tells you the difference between the two products.

Welded Steel Pipe

Difference one: mode of production

At the time of production, the difference is particularly obvious, because made of galvanized steel pipe is need to slowly dissolve, and welded steel pipe is welded directly, so the welding steel pipe at the time of production is more convenient, galvanization steel tube is more time-consuming, but it is precisely because the difference between this galvanized steel pipe and welded steel pipe, so cause they are quite different in other ways too.

Difference two: appearance

We know their production mode is quite different, which leads directly they also have great differences in appearance, everybody can easily tell the difference between galvanized steel pipe and welded steel pipe, galvanized steel pipe appearance often have a layer of metal layer, as a whole is very smooth and uniform color, but the welded steel pipe because at the time of production is directly rough, so it looks not nice.

Difference three: price

In view of these two different types of pipes, there are great differences in the production methods and appearance, so their price differences are directly caused. Galvanized steel pipes are more beautiful and time-consuming to make, so the price of pipes of the same specification is much more expensive than that of welded steel pipes.The difference between galvanized steel pipe and welded steel pipe directly affects their social status, if it is to buy the building materials of these two materials, so in the eyes of delicate people, often prefer galvanized steel pipe, welded steel pipe is suitable for ordinary families.

The Introduction Of Welded Pipe

Galvanized welded steel pipe supplier china to share with you: Welded steel pipe, also known as the welded pipe, is made of steel plate or strip after the curly forming of the welded steel pipe, generally fixed feet 6 meters.Welding steel tube production process is simple, high production efficiency, variety specifications, equipment investment, but generally less than seamless steel tube strength.

With the rapid development of high quality strip rolling production and the progress of welding and inspection technology, the weld quality is constantly improving, the variety and specification of welded steel pipe is increasing, and in more and more fields instead of seamless steel pipe.

Classification by production method: process classification - arc welding pipe, resistance welded pipe, (high frequency, low frequency) gas welded pipe, furnace welded pipe.The smaller diameter welded pipe adopts straight seam welding, while the larger diameter welded pipe adopts spiral welding.According to the shape of the end of the steel pipe, it can be divided into circular welded pipe and special-shaped (square, rectangular, etc.) welded pipe.According to the different materials and USES are divided into mine fluid transport welded steel pipe, low pressure fluid transport with galvanized welded steel pipe, belt conveyor roller welding steel pipe.According to the size table of current national standard, sort by outside diameter * wall thickness from small to large.

It is divided into general welded pipe, galvanized welded pipe, oxygen-blown welded pipe, wire sleeve, metric welded pipe, idler pipe, deep well pump pipe, automobile pipe, transformer pipe, welded thin-walled pipe, welded special-shaped pipe, scaffold pipe and spiral welded pipe.

General welded pipe: general welded pipe to transport low pressure fluid.Made of steel Q195A, Q215A and Q235A.Other soft steels that are easy to weld can also be used.The steel pipe should be tested by water pressure, bending, flattening, etc., which requires certain surface quality. The delivery length is usually 4-10m.The specification of welded pipe with nominal diameter (mm or in) nominal diameter and the actual different, welded pipe according to the specified wall thickness of ordinary steel pipe and two kinds of thickened steel pipe, steel pipe according to the end of the form and with thread and without thread two kinds.

Galvanized welded steel pipe: to improve the corrosion resistance of steel pipe, the general steel pipe (black pipe) is galvanized.Galvanized steel pipe is divided into hot dip galvanized and electric galvanized two kinds, hot dip galvanized galvanized layer thick, low cost of electric galvanized.

Oxygen-blowing pipe: used for oxygen-blowing pipe in steelmaking, generally used for small-diameter welded steel pipe, 8 kinds of specifications from 3/8 "to 2".Made of 08, 10, 15, 20 or q195-q235 steel strip.For corrosion prevention, some are aluminized.

Wire bushing: also known as ordinary carbon steel welded steel pipe, used in concrete and various structure power distribution projects, the commonly used nominal diameter from 13-76mm.Wire sheath tube wall is thin, most of the coating or galvanized after use, the cold bending test is required.

Metric welded pipe: specification for seamless pipe form, welded steel pipe with outer diameter * mm wall thickness, welded with ordinary carbon steel, high quality carbon steel or general low alloy steel with tropical, cold zone, or after tropical welding by cold dialed method.Metric welded pipes are divided into general energy and thin wall, commonly used as structural parts, such as transmission shaft, or fluid transport, thin wall for the production of furniture, lamps and lanterns, to ensure the strength of steel tube and bending test.

Idler tube: used for belt conveyor idler welding steel tube, generally made of Q215, Q235A, B and 20 steel, diameter 63.5-219.0mm.There are certain requirements on the bending degree of the pipe, the end face should be perpendicular to the center line, and the ellipticity.

Transformer tube: used for making transformer heat exchangers and other heat exchangers, made of ordinary carbon steel, which requires flattening, flaring, bending and hydraulic tests.Steel tube is delivered with fixed or double ruler, there are certain requirements on the bending of steel tube.

Special-shaped pipe: square pipe, rectangular pipe, cap pipe, steel pipe for door and window, welded by common carbon structure steel and 16Mn steel belt, mainly used for agricultural machinery components, steel window and door.

Welded thin wall tube: mainly used for making furniture, toys, lamps, etc.In recent years, the thin wall pipe made of stainless steel belt is widely used, such as high-grade furniture, decoration and fence.

Spiral steel pipe: the spiral steel pipe is made of low carbon structural steel or low alloy structural steel with a certain spiral Angle (called forming Angle) and then welded together to make the pipe. It can be used to produce large diameter steel pipe with a narrow strip.Spiral welded pipe is mainly used for oil and natural gas pipeline, its specification is expressed by outer diameter * wall thickness.Spiral welded pipe has single-side welding and double-side welding, welded pipe should ensure that hydraulic test, weld tensile strength and cold bending performance to meet the requirements.