What is the difference between seamless pipe and ordinary steel pipe?

 Seamless tubes (SMLS) are significantly different from ordinary steel pipes in many aspects. The following is a comparison from four aspects: definition, manufacturing process, performance and application fields.

1. Definition

Seamless tube: Made from a single piece of metal, there are no welding gaps or cast connections, so its strength and durability are higher than ordinary steel pipes. The quality of seamless steel tube is usually higher because more steps and processes are required in its production.

Ordinary steel tube: Usually welded from steel plates or strips, with welds (welded steel pipe). During the manufacturing process of ordinary steel pipes, two or more steel plates can be connected by welding.

2. Manufacturing process

Seamless tube: Manufacturing seamless steel tube requires a series of complex process steps, such as selecting appropriate raw materials, heating, plastic deformation, cooling, straightening, etc. Especially seamless steel tubes used in high-pressure or highly corrosive environments require additional heat treatment and surface treatment steps.

Ordinary steel tubes: The manufacture of ordinary steel pipes mainly relies on welding technology. The steel plates or strips are cut and welded according to the designed drawings, and finally formed into the required shape and size.

3. Performance differences

Seamless tube: Since seamless steel tube has no welds, its overall strength and durability are better. It is more resistant to high pressure, high temperature, and highly corrosive environments and can meet more demanding working environments.

Ordinary steel tube: Ordinary steel pipe has relatively poor strength and durability due to the presence of welds. However, its manufacturing cost is low and it is suitable for some occasions that do not require high performance.

4. Application fields

Seamless tube: Seamless steel tube is mainly used in pipeline systems in petroleum, natural gas, chemical industry, electric power and other industries, as well as in machinery manufacturing, construction and other fields. In these fields, high-quality steel pipes are required to withstand the effects of high pressure, high temperature and highly corrosive environments.

Ordinary steel tubes: Ordinary steel tubes are mostly used in basic engineering facilities, such as bridges, building structures, water pipes, etc. These fields do not have high requirements on the strength and durability of steel pipes, and more emphasis is placed on cost factors.

In summary, there are significant differences between seamless tubes and ordinary steel tubes in manufacturing processes, performance and application fields. When choosing which type of steel pipe to use, the decision needs to be made based on actual needs and application environment.

https://www.steelweldedpipe.com/news/what-is-the-difference-between-seamless-pipe-and-ordinary-steel-pipe-159373.html

India Seamless steel pipe delivered successfully

In the field of steel pipe, Xinyue has been committed to build the world, serve the globe. Whether welded pipe or seamless pipe, all kinds of steel pipes exported by Xinyue serve projects in more than 100 countries around the world. High quality and strict requirements are our guarantee for the quality control of all export products.

The products shipped this time were 4140 alloy seamless pipe, 630mm large outer diameter and thick wall thickness seamless steel pipe. The cooperation orders came from regular Indian customers who have cooperated with us for many years. Due to the repeated epidemic in India, the order was delayed. The customer restarted the project after nearly two months of delay. Finally, the contract was officially signed with our company at the end of September. At this time, it coincided with National Day holiday. Both production and space booking gave us challenges.

The market demand for special steel grades is small, and the inventory is mainly conventional products, so special steel grades generally need customized production, and the production cycle is long. The production cycle, which negotiated with customers before, also leads to extremely tight construction period due to delayed procurement. Customers urgently turned to us and hoped that our company would make every effort to coordinate and deliver goods on schedule. The needs of customers was our mission. Xinyue immediately prepared to establish a special team. In the next process, all departments worked together to arrange the most skilled production force, urgently book space and kept the closest communication with customers from time to time. After carrying out a series of pre plans and countermeasures, and finally with the full cooperation of business, documents, procurement and logistics departments, We shortened the preparation time of nearly two weeks and successfully shipped this batch of goods in early October.

No matter the size of the order, we are eager to meet the needs of customers and think about the needs of customers. Xinyue always adheres to the business philosophy of "taking customers as the center" and will do a good job in every order!

https://www.tjxysteel.com/news/India-Seamless-steel-pipe-delivered-successfully-2047.html

Xinyue Steel Pipe’s Application in Dredging Service Worldwide

Dredging is a process of removing sediment and debris from the bottom of a water body, such as rivers, lakes, and harbors. Dredging plays a crucial role in maintaining waterways for navigation, recreation, and environmental purposes. As a leading steel pipe manufacturer, Xinyue Steel has extensive experience in providing high-quality steel pipes for dredging service.

Xinyue Steel offers a range of steel pipes for dredging service, including spiral submerged arc welded (SSAW) pipes, straight seam submerged arc welded (LSAW) pipes, and seamless pipes. The pipes are available in a variety of materials, including carbon steel, alloy steel, and stainless steel, to meet the specific requirements of dredging service.

One of the main advantages of Xinyue Steel’s pipes is their durability and strength. Dredging service often involves harsh environments, such as abrasive sediments, saltwater, and extreme temperatures. Xinyue Steel’s pipes are designed to withstand these conditions and provide reliable performance for extended periods.

Another benefit of Xinyue Steel’s pipes is their excellent corrosion resistance. The pipes are coated with a layer of anti-corrosion material, such as zinc, to prevent rust and corrosion caused by exposure to water and other elements. This ensures that the pipes have a longer lifespan and require less maintenance, reducing the overall cost of dredging operations.

Xinyue Steel’s pipes are also designed to have a smooth interior surface, which reduces the resistance to the flow of water and sediment. This improves the efficiency of the dredging process and allows for faster removal of sediment and debris.

Xinyue Steel’s pipes have been widely used in various dredging projects around the world, including harbor dredging, river dredging, and offshore dredging. In harbor dredging, Xinyue Steel’s pipes have been used to create breakwaters, shorelines, and berths. In river dredging, the pipes have been used to maintain the navigability of waterways and prevent flooding. In offshore dredging, the pipes have been used to create artificial islands and reclaim land from the sea.

In conclusion, Xinyue Steel’s pipes have proven to be a reliable and cost-effective solution for dredging service. Their durability, strength, corrosion resistance, and smooth interior surface make them an ideal choice for various dredging projects. Xinyue Steel’s commitment to quality and customer satisfaction has earned them a reputation as a leading steel pipe manufacturer in the industry.

https://www.xysteelpipe.com/xinyue-steel-pipes-application-in-dredging-service-worldwide/

Thermal Expansion Seamless Steel Pipe Manufacturing Process

Cross rolling is a rolling method between longitudinal rolling and cross rolling. The rolling of the rolled piece rotates along its own axis, deforms and advances between two or three rolls whose longitudinal axes intersect (or incline) in the same direction of rotation. Cross rolling is mainly used for piercing and rolling of pipes (such as the production of thermal expansion seamless pipes), and periodic section rolling of steel balls.

The cross rolling method has been widely used in the production process of heat-expanded seamless steel pipes. In addition to the main thermal expansion process of piercing, it is also used in rolling, leveling, sizing, elongation, expansion and spinning, etc. in the basic process.

The difference between cross rolling and longitudinal rolling and cross rolling is mainly in the fluidity of metal. The main direction of metal flow during longitudinal rolling is the same as that of the roll surface, and the main direction of metal flow during cross rolling is the same as that of the roll surface. Cross rolling is between longitudinal rolling and cross rolling, and the flow direction of deformed metal is Forming an angle with the direction of movement of the deformation tool roll, in addition to the forward movement, the metal also rotates around its own axis, which is a spiral forward movement. There are two types of skew rolling mills used in production: two-roll and three-roll systems.

The piercing process in the production of thermal expansion seamless steel pipe is more reasonable today, and the piercing process has been automated. The whole process of cross-rolling piercing can be divided into 3 stages:

1. Unstable process. The metal at the front end of the tube blank gradually fills the deformation zone stage, that is, the tube blank and the roll begin to contact the front metal and exit the deformation zone. In this stage, there are primary bite and secondary bite.

2. Stabilization process. This is the main stage of the piercing process, from the metal at the front end of the tube blank to the deformation zone until the metal at the tail end of the tube blank begins to leave the deformation zone.

3. Unstable process. The metal at the end of the tube blank gradually leaves the deformation zone until all the metal leaves the roll.

There is a clear difference between a stable process and an unstable process, which can be easily observed in the production process. For example, there is a difference between the size of the head and tail and the middle size of a capillary. Generally, the diameter of the front end of the capillary is large, the diameter of the tail end is small, and the middle part is consistent. Large head-to-tail size deviation is one of the characteristics of an unstable process.

The reason for the large diameter of the head is that as the metal at the front end gradually fills the deformation zone, the friction force on the contact surface between the metal and the roll increases gradually, and it reaches a maximum value in the complete deformation zone, especially when the front end of the tube billet meets the plug At the same time, due to the axial resistance of the plug, the metal is resisted in the axial extension, so that the axial extension deformation is reduced, and the lateral deformation is increased. In addition, there is no outer end restriction, resulting in a large front diameter. The diameter of the tail end is small, because when the tail end of the tube blank is penetrated by the plug, the resistance of the plug drops significantly, and it is easy to extend and deform. At the same time, the lateral rolling is small, so the outer diameter is small.

The front and rear jams that appear in production are also one of the unstable features. Although the three processes are different, they are all realized in the same deformation zone. The deformation zone is composed of rolls, plugs and guide discs.

https://www.xysteelpipe.com/thermal-expansion-seamless-steel-pipe-manufacturing-process/

Factors affecting the quality of seamless pipe

There are two categories of factors that affect the quality of seamless tubes: steel quality and rolling process factors.

Many factors of the rolling process are discussed here. The main influencing factors are: temperature, process adjustment, tool quality, process cooling and lubrication, removal and control of sundries on the surface of rolled pieces, etc.

1. Temperature

Temperature is the most important factor affecting the quality of seamless tubes. First of all, the uniformity of the heating temperature of the tube blank directly affects the uniform wall thickness and inner surface quality of the perforated capillary, which in turn affects the wall thickness quality of the product. Secondly, the temperature level and uniformity of the seamless steel tube during rolling (especially the final rolling temperature) are related to the mechanical properties, dimensional accuracy and surface quality of the product delivered in the hot-rolled state, especially when the steel billet or tube blank When it is overheated or even overburned, it will cause waste products. Therefore, in the production process of hot-rolled seamless tubes, heating and controlling the deformation temperature strictly according to the process requirements must be done first.

2. Process adjustment

The quality of process adjustment and work quality mainly affects the geometric and appearance quality of seamless steel tubes.

For example, the adjustment of the piercing machine and the rolling mill affects the wall thickness accuracy of the product, and the adjustment of the sizing machine is related to the outer diameter accuracy and straightness of the product. Moreover, process adjustment also affects whether the rolling process can be carried out normally.

3. Tool quality

Whether the tool quality is good or bad, stable or not, is directly related to whether the dimensional accuracy, surface quality and tool consumption of the product can be effectively controlled; Surface, the second is to affect mandrel consumption and production costs.

4. Process cooling and lubrication

The cooling quality of piercing plugs and rolls not only affects their life, but also affects the quality control of the inner and outer surfaces of finished products. The cooling and lubrication quality of the mandrel first affects the inner surface quality, wall thickness accuracy and mandrel consumption of the seamless steel tube; at the same time, it will also affect the load during rolling.

5. Removal and control of impurities on the surface of the rolled piece

This refers to the timely and effective removal of oxide scale on the inner and outer surfaces of capillary and barren pipes and the control of re-oxidation before rolling deformation. Nitrogen blowing and borax spraying treatment on the inner hole of the capillary tube, high-pressure water descaling at the entrance of the rolled tube and the fixed (reduced) diameter can effectively improve and improve the quality of the inner and outer surfaces.

In short, there are many factors that affect the quality of seamless steel tubes, and they are often the combined effect of various factors. Therefore, the above-mentioned main influencing factors must be effectively controlled. Only in this way can we control the quality of seamless steel tubes and produce hot-rolled seamless steel tubes with high dimensional accuracy, good performance and excellent quality.

https://www.xysteelpipe.com/factors-affecting-the-quality-of-seamless-pipe/

8 Precautions for seamless pipe forming

Forming and sizing of seamless pipes, some hole design and adjustment methods will directly affect the quality, so we should pay attention to the following eight points when handling the forming of seamless pipes:

1. Before there is no perforation, the hole shape of each rack should be adjusted, and the size of each pass should be measured to ensure that the seamless steel pipe enters each rack stably. In the adjustment, the force should be balanced, and it should not be forced to deform on one frame, so as to ensure the stable and uniform change of the raising angle;

2. Traditional roll forming skills, with single radius, double radius, plus two, three, four or five rolls kneading rolls, two or four rolls sizing to ensure the forming quality. This traditional roll forming technology is mostly used for rectangular tube units with a diameter less than φ114mm;

3. In the production of seamless pipes, control and adjust the equipment errors of the forming and sizing machine bases and the amount of roll bounce, so that even the more old-fashioned units can produce fine high-quality steel pipes;

4. The roll forming skills of the United States, the CTA forming skills of voestalpine, the FF or FFX flexible forming skills of Nakata, Japan, etc., can ensure the shape of the welded joint after forming and good appearance quality, and are suitable for standard A wider range of seamless pipes;

5. During the adjustment process of the unit, first of all, it should be ensured that each pass of the vertical center line is consistent, and the center is used as the base axis to find the positioning scale and the center sleeve. ) is a straight line, and can not show curve beating;

6. In order to reduce elastic deformation, 2 to 3 passes are added to the processing deformation of seamless pipes than the general rectangular pipes;

7. In the deformation structure, the initial deformation point of view should be reduced to ensure a stable bite, the central curved point of view should be appropriately increased, and the rear deformation should be appropriately reduced. Adding deformation passes not only reduces the deformation force, but also makes the strip There is an opportunity to release the surface stress, so that the gradient of the surface stress increases slowly, which can prevent the seamless pipe from cracking;

8. Various forming skills have different advantages and disadvantages, and are suitable for different conditions. According to the use of seamless carbon steel pipes, careful consideration should be given when selecting equipment, and different forming methods should be selected.

https://www.xysteelpipe.com/8-precautions-for-seamless-pipe-forming/

Meeting With Middle Eastern Customers Again After Four Years

 It is always remember the special memory of my first customer. In 2014, we would follow the normal business process like quoting , sending samples, confirming the contract, checking the goods, and delivering to the customer.

Because of the first cooperation, the customer decided to inspection that the goods before loading. , A group of 3 peoples, They were very careful measurement and taking photos, Finally, customer recognized the service and quality of Xinyue and successfully sent the goods away.

Following four years, the customer did not come to China considering to our trust and recognition. Unluckily, When I cooperated for 2 years, there was a very regrettable thing to occur, Mr. Vinod, my dear friends, who went away suddenly. I wouldn’t accept this fact when I receive the email. In fact, a week ago we were still chatting the interesting things of their travels on the WhatAPP.

Another colleague, who we met in 2014, took over his job. They opened up their gas market. We provided product service support. And the annual small diameter seamless pipe orders for gas transfer grew steadily.

When we picked up customers , we looks like old friends, talking about the documents provided by the collection, the market needs to grow, their company continues to expand the market, in addition to diverge neighboring countries beside local market. ,It is expected to have a procurement plan in January 2018, And Hope to offer him the best Service and support as before.

We are serious about steel pipes business. We treat our friends with sincerity also. Build the world getting better and Serve for the global market. Warmly welcome to send Inquiry to Tianjin Xinyue Steel at any time.

http://www.tjxysteel.com/news/Meeting-WITH-Middle-Eastern-Customers-Again-688.html

How to Prevent Surface Decarburization of Seamless Pipe Products?

 The carbon element in the seamless steel tube (smls) has a great influence on its own performance, so when the seamless tube is decarburized, its service life will be greatly reduced, and if the surface of the seamless tube is decarburized If it is not cleaned, the hardness and wear resistance of the surface layer of the seamless pipe will be reduced, and during quenching, cracks will be formed on the surface of the workpiece due to the different volume changes of the inner and outer layers. Therefore, how to prevent the surface decarburization of seamless pipes is a problem that should be paid attention to in the production process.

The key to solving the problem of surface decarburization lies in the heat treatment process. Since the decarburization and the oxidation of the steel wire are carried out at the same time, the purpose of improving decarburization can be achieved as long as the non-tin seamless pipe is kept in contact with air as little as possible during the heat treatment process. The production process is: the first molten lead tank is used to austenitize the steel wire. The lead liquid is heated to 871? in advance, the steel wire is passed in the lead liquid to achieve austenitization, and then enters the oil tank for quenching, and then enters the second Two molten lead tanks are tempered (482°C). Since the steel wire is not in contact with air in the molten lead, decarburization is effectively avoided. The main problem that needs to be solved with this process is how to prevent lead dust pollution.

The atmosphere that causes decarburization on the surface of seamless pipes is mainly oxidizing gases such as oxygen, water vapor, and carbon dioxide. When these oxidizing gases contact the surface of the heated steel wire, oxidation and decarburization occur simultaneously; because the solid-solution carbon in the iron has a relatively large affinity for these gases, the carbon on the surface is removed first. The above-mentioned gases are generally brought in from outside the furnace; the iron oxide scale, rust on the surface of the seamless pipe and the residues on the surface of the steel wire after cold drawing will also decompose after being heated in the furnace and react to generate some oxidizing gases. We can purposely control the atmosphere in the furnace to make it in a reducing state, which can effectively avoid surface decarburization. For example, controlling the ratio of carbon dioxide to carbon monoxide in the furnace, at the equilibrium point, neither oxidation nor decarburization; when the ratio of carbon dioxide exceeds the equilibrium point, oxidation and decarburization will occur; when the ratio is below the equilibrium point, oxidation and decarburization will not occur . The specific value of the equilibrium point should be calculated based on the carbon content and temperature of the iron.

In addition, it is also an effective measure to inject neutral protective nitrogen into the furnace from the seamless tube. At the same time, it can maintain the positive pressure in the furnace, prevent air infiltration, and reduce or avoid decarburization of steel parts.

https://www.xysteelpipe.com/how-to-prevent-surface-decarburization-of-seamless-pipe-products/

Advantages and disadvantages of cold rolled steel pipe

    Hot-rolled seamless pipe is relative to cold-rolled seamless pipe. Cold-rolled seamless pipe is rolled below the recrystallization temperature, and hot-rolled seamless pipe is rolled above the recrystallization temperature.

    Advantages: It can destroy the casting structure of the steel ingot, refine the grains of the steel, and eliminate the defects of the microstructure, thereby making the steel structure dense and improving the mechanical properties. This improvement is mainly reflected in the rolling direction, so that the steel is no longer an isotropic body to a certain extent. Bubbles, cracks and looseness formed during casting can also be welded under high temperature and pressure.

    Disadvantages:

    1. After hot rolling, non-metallic inclusions (mainly sulfides and oxides, as well as silicates) inside the steel are pressed into flakes, and delamination (interlayer) occurs. Delamination greatly deteriorates the tensile properties of the steel in the thickness direction, and interlayer tearing may occur when the weld seam shrinks. The local strain induced by the shrinkage of the weld often reaches several times the yield point strain, which is much larger than the strain caused by the load.

    2. Residual stress caused by uneven cooling. Residual stress is the internal self-phase equilibrium stress without external force. Hot-rolled sections of various sections have this type of residual stress. Generally, the larger the section size of the section, the larger the residual stress. Although the residual stress is self-balanced, it still has a certain effect on the performance of steel members under external forces. For example, it may have adverse effects on deformation, stability, and fatigue resistance.

    3.Hot rolled steel products are difficult to control in terms of thickness and edge width. We are familiar with thermal expansion and contraction. Since hot rolling at the beginning, even if the length and thickness are up to standard,there will still be a certain negative difference after cooling. The wider the negative difference, the thicker the thickness, the more obvious the performance. Therefore, for large steel, the width, thickness, length, angle,and edge of the steel cannot be required to be too precise.

    http://www.xysteelpipe.com/info/Advantages-and-disadvantages-of-cold-rolled-steel-pipe-1621-1.htm

Carbon Steel Alloy-ASTM A53

　　ASTM A53 is a carbon steel alloy,used as structural steel or for low-pressure plumbing.The alloy specifications are set by ASTM international,in specifications ASTM A53/A53M.

　　A53 pipe comes in three types and two grades,A53 Type F,which is longitudinally furnace butt welded or continuous welded(Grade A only),A53 Type E，which is longitudinally electric resistance welded(Grades A and B)，and A53 Type S,which is seamless pipe,produced by hot working,and possibly cold finishing,the steel(Grade A and B).ASTM A53 pipe is sized according to the nominal pipe size(NPS)system.It is commonly available with national pipe thread ends or with plain cut ends.It can be used for steam,water,and air conveyance.It is also weldable and can be used in structural application,although ASTM A500 tube,which is available in the same NPS

　　Sizes,is sometime preferred.

　　This is a standard set by the standards organization ASTM international,a voluntary standards development organizations that sets technical standards for materials,products,systems,and service.

Application of Boiler Tubes

　　The boiler tube is a type of seamless tube. The manufacturing method is the same as that of the seamless pipe, but there are strict requirements for the steel used in the manufacture of the steel pipe. According to the use of high and low temperature is divided into two types of general boiler tubes and high pressure boiler tubes.

　　The mechanical properties of the boiler tube are important indicators to ensure the final performance of the steel (mechanical properties), which depends on the chemical composition of the steel and the heat treatment system. In the steel pipe standard, according to different use requirements, tensile properties (tensile strength, yield strength or yield point, elongation), hardness and toughness index, as well as high and low temperature properties required by users are specified.

　　1. The general boiler tube use temperature is below 450 °C, and the domestic tube is mainly made of 10 or 20 carbon steel hot rolled tube or cold drawn tube.

　　2. High-pressure boiler tubes are often subjected to high temperature and high pressure conditions, and the tubes will oxidize and corrode under the action of high temperature flue gas and water vapor. Steel pipes are required to have high durability, high corrosion resistance and good structural stability.

　　Use of boiler tubes

　　1. General boiler tubes are mainly used to manufacture water-cooled wall pipes, boiling water pipes, superheated steam pipes, superheated steam pipes for locomotive boilers, large and small smoke pipes and arch brick pipes.

　　2. High-pressure boiler tubes are mainly used to manufacture superheater tubes, reheater tubes, air ducts, main steam tubes, etc. for high-pressure and ultra-high pressure boilers. The supply and demand trend of the high-pressure boiler tube industry is generally stable, but the supply and demand situation of each specific sub-sector will be further differentiated. Insiders pointed out that the most critical link is the use and promotion of new energy-saving insulation 20g high-pressure boiler tube equipment.

　　New energy-saving 20g high-pressure boiler tube products are gradually increasing in the market, for example, green environmental protection coatings, energy-saving and water-saving sanitary ware products, environmentally-friendly stone materials, environmentally-friendly external cement foam insulation boards, etc., energy-saving and environmental protection products in the vast market of 20g high-pressure boiler tube industry The prospects are optimistic.

　　http://www.xysteelpipe.com/info/Application-of-Boiler-Tubes-1490-1.htm

Exotic Advantages Of Spiral Submerged Arc Pipe

　　The spiral submerged arc pipe is divided into three layers from the inside to the outside. The working steel pipe layer is generally made of seamless pipe (gb8163-87) and spiral welded pipe (gb9711-88). According to the planning and customer requirements. SY t5038-92) and straight seam welded pipe (gb3092-93). After the appearance of the steel pipe is advanced by the shot blasting process, the corrosion grade of the steel pipe can reach the level of gb8923-1988 SA2, and the roughness of the surface can reach the specification of gb6060.5-88 R = 12.5 microns.

　　The polyurethane insulation layer is formed by injection molding a rigid polyurethane foam into a cavity between the steel pipe and the outer jacket by a high pressure foaming machine. This is the so-called tube foaming process. Its function is waterproof, the second is insulation, and the third is to support the weight of the heat network. When the medium temperature is: 50 ° C, 120 ° C, a rigid polyurethane foam insulation layer is used. High-density polyethylene protective layer Prefabricated black (yellow) plastic pipe with a certain wall thickness, its function is to protect the mechanical hard disk damage of the polyurethane insulation layer, and the second is anti-corrosion and waterproof.

　　The spiral pipe is used for heating (refrigeration) project, and its heat sealing effect is remarkable. It is directly used for direct burial, which not only saves energy but also reduces dross, and does not occupy the environment and beautify the environment. It is used for oil and gas transportation, can meet the requirements of long-distance transportation, avoid operation and protection, meet the requirements of heat preservation and antifreeze, reduce heating equipment, and is particularly convenient for installation and shorten the construction period.

　　When used for geothermal and hot spring transportation, the cooling requirements can be satisfied and the long loss can be reached. Applicable to water conservancy, mining and other areas, to meet the requirements of cold, antifreeze, anti-corrosion. In addition, the transportation of chemical raw materials has a wide use space. In total, the polyurethane direct insulation pipe has the advantages of energy saving, anti-corrosion, cold, and economical beauty. In addition, it has been widely used throughout the country and is well received by users.

　　Polyurethane insulation pipe adopts polyurethane insulation characteristics: the thermal conductivity is small, and the thermal conductivity of polyurethane foam is the lowest in the insulation data, which can minimize the heat loss of the data. Waterproof, anti-corrosion, high old: Because the closed cell rate of polyurethane foam is over 92%, the use of polyurethane foam as the insulation layer of buried pipeline can not only play the role of thermal insulation, but also can be used to avoid water, moisture, etc. Soaking of various corrosive liquids and gases to prevent microbial growth and development.

　　http://www.xysteelpipe.com/info/Exotic-Advantages-Of-Spiral-Submerged-Arc-Pipe-1341-1.htm

The cutting method of fluid seamless pipe is introduced

　　Pipe fluid seamless pipe cutting methods include shearing, breaking, sawing, flame cutting and anode cutting. Their characteristics are as follows:

　　(1) Flame cutting method: This cutting method has the lowest operating cost, but the fluid seamless tube consumes more and the cutting quality is poor. Therefore, manual flame cutting is often used as a supplementary cutting means. However, due to the improvement of flame cutting technology, some factories have used automatic cutting with a multi-head flame cutting machine as the main method for fluid seamless pipe cutting.

　　(2) Shearing method: This method has high production efficiency and low cutting cost. Carbon-carbon seamless pipes and alloy structural steel pipes in low-carbon species are mainly cut by shearing. In order to improve the shearing efficiency, the double-cutting is carried out by using a large-tonnage shearing machine; in order to reduce the flattening degree of the end portion of the steel pipe when cutting, the cutting edge is generally formed by a forming blade; for a seamless steel pipe which is prone to shear cracking, shearing The steel pipe was preheated to 300 ° C when cut.

　　(3) Fracture method: The equipment used is the breaking press. The breaking process is to cut all the holes at the predetermined breaking fluid pipe with the torch, and then put it into the breaking press and break it with a triangular axe. The distance between the two points is 1-4 times the diameter Dp of the tube blank.

　　(4) Saw cutting method: This cutting method has the best cutting quality and is widely used for alloy steel pipes, high-pressure steel pipes, fluid seamless pipes, especially for the cutting of large-diameter fluid seamless steel pipes and high-alloy steel pipes. The sawing device has a bow saw, a band saw and a circular saw. Cold circular saws with high-speed steel sector blades are used for cold-saw alloy steel tubes; cold circular saws with carbide inserts are used for high-alloy steel saws.

What are the disadvantages of hot and cold rolling processes for seamless tubes

　　Hot rolled and cold rolled (dial) seamless tubes

　　1. The cross-section of the cold-rolled seamless pipe is partially embossed, and then the bearing capacity of the bar can be fully utilized; and the hot-rolled steel does not agree with the section of the section.

　　2. The causes of residual stress in hot-rolled seamless square tubes and cold-rolled sections are different, so the dispersion on the sections is also very different. The residual stress distribution on the section of the cold-formed thin-walled steel is a tortuous type, and the residual stress distribution on the section of the hot-drawn steel or welded steel is a film type.

　　3. The freely changing stiffness of hot-rolled steel is higher than that of cold-rolled steel, so the torsional function of hot-rolled steel is better than that of cold-rolled steel. Cold-rolled seamless pipe cold-rolled seamless steel pipe refers to steel that is processed into various types by cold drawing, cold bending, cold drawing and other cold working at normal temperature.

　　Strengths: fast forming speed, high output value, and no damage to the coating, can be made into a variety of cross-sections to meet the needs of the conditions; cold rolling can cause large plastic deformation of the steel, and then improve the yield of the steel point.

　　Defect:

　　1. Although there is no hot plastic shrinkage during the forming process, there is still residual stress in the cross section, which inevitably affects the characteristics of the whole steel and part of the steel;

　　2. The cold-rolled steel profile is generally an open section, so that the freeness of the section changes less. It is simple to change when it is bent. It is simple to show bending and torsion when pressed, and the torsion resistance is poor.

　　3. The wall thickness of cold-rolled steel is small, and there is no thickening at the corner of the joint of the plate. The ability to gather loads is weak.

　　http://www.xysteelpipe.com/info/What-are-the-disadvantages-of-hot-and-cold-rolling-processes-for-seamless-tubes-1279-1.htm

Difference between Stainless Steel Seamless Pipe and Carbon Steel Seamless Pipe

The so-called difference between stainless steel seamless pipe and carbon steel seamless pipe, stainless steel and carbon steel mainly refers to the difference in the design rules, that is, the design rules of these two types of steel are not universal.
These differences are summarized as follows: The design rules of stainless steel can not be used for carbon steel because there are 3 fundamental differences between stainless steel and carbon steel:

First, when cold working stainless steel produce work hardening, for example, when bending anisotropy, namely: the horizontal and vertical performance are different. The strength increased by cold working can be utilized, but if the bending area is small compared to the total area and negligible, the increase in strength can improve the safety factor to a certain extent.

Second, the shape of the stress / strain curve is different. The elastic limit of stainless steel is about 50% of the yield stress. The yield stress is lower than the yield stress of medium carbon steel in terms of the minimum specified in the standard.

Third, stainless steel does not yield point, usually ó0.2 that yield stress is considered equivalent.

Treatment Technology of Stainless Steel Seamless Pipes

　　Stainless steel seamless pipes treatment technology refers to the processing of achieving uniform silver, and has a metallic luster. This is generally referred to the production of large stainless steel seamless pipes. Because large stainless steel seamless pipe is manufactured through stamping, folding and welding process, the surface of workpiece has oil, rust, macular, which is neither beautiful, and easy to rust, reducing its stainless steel quality and value.

　　To make stainless steel seamless pipes achieve the standard, the surface must be finished. After forming matte treatment, that can achieve beautiful appearance, but also improve its anti-corrosion and anti-discoloration performance. After the above method, the corrosion resistance of stainless steel seamless pipes can be increased by 2 to 3 times.

　　Stainless steel seamless pipes does not rust due to the existence of chromium, nickel components, and then through the matt treatment, not only can eliminate the matrix impurities and iron-rich layer, but also can make chromium on the surface, forming a complete purification film, play a better anti-corrosion effect. According to the complexity of stainless steel seamless pipes and user requirements, we can choose different processing technology, such as mechanical polishing, chemical polishing, electro chemical polishing and other methods to achieve specular gloss.

Seamless Stainless Steel Pipe Crack Detection Method

　　We know that the seamless stainless steel pipe has a quality demanding for seamless pipe in the environment of high temperature and pressure.

　　The cracks on the pipe, as a result of improper machining operation process in the production process may roll or drawing die setting improper reasons, folded, Alice skin, scratches or strain, surface and internal defects. In order to ensure seamless pipe quality, according to the relevant technical standards for products, seamless steel pipe production line required nondestructive testing of surface and interior. Commonly used eddy current testing and magnetic flux leakage detection technology.

　　Eddy current testing is to establish a non-destructive detection method on the basis of the electromagnetic induction, it will sine current excitation probes coil, when the probe near the Seamless surface, an alternating magnetic field in the coil around the rims surface induced electromotive force generated induced current, i.e. a vortex. The snails and feelings generated magnetic field acting on the coil, thereby changing the electrical parameters of the coil.

　　The loss resistance of the vortex channel and the eddy-current generation of anti-flux, but also reflected to the probe coil, changing the size and phase of the current in the coil, which changes the impedance of the coil. The probe in the seamless steel surface is moved relative defects encountered, so that the reaction of the eddy current magnetic field of the coil, causing the change of coil impedance, thereby measuring the amount of change identified seamless steel pipe surface defects.

　　Stainless steel seamless pipe has a high requirement on quality in the environment of high temperature and pressure. Improper machining operation process in the production process may roll or drawing die setting improper reasons and on the pipe, as a result of a crack. Folding, warping, scratches, or strain, surface and internal defects. In order to ensure seamless pipe quality, according to the relevant technical standards for products, seamless steel pipe production line required nondestructive testing of surface and interior. Commonly used eddy current testing and magnetic flux leakage detection technology.

　　Eddy current testing is to establish a non-destructive detection method, on the basis of the electromagnetic induction it sine current excitation probe coil, the induced electromotive force generated when the probe near the Seamless surface, the alternating magnetic field around the coil rims surface generates an induction current, i.e. vortex. The vortex is also the feelings generated magnetic field acting on the coil, thereby changing the electrical parameters of the coil. The loss resistance of the vortex channel and the eddy-current generation of anti-flux, but also reflected to the probe coil, changing the size and phase of the current in the coil, which changes the impedance of the coil. The probe in the seamless steel surface is moved relative defects encountered, so that the reaction of the eddy current magnetic field of the coil, causing the change of coil impedance, thereby measuring the amount of change identified seamless steel pipe surface defects.

Seamless stainless steel tube for high temperature applications

　　Seamless stainless steel pipes are the preferred choice for high-temperature applications across industries due to their several superior properties. They possess greater strength under loading, exhibit exceptional corrosion resistance, can withstand shocks and vibrations, and offer reliable performance even under the toughest and harsh conditions. Due to these benefits, seamless stainless steel tubes and pipes are used in heating-pipelines, containers, coal-saving devices, super-heaters and repeaters, high press boiler, heat exchanger and condenser tubes, mechanical and structural tubing, among several others. This post discusses the various material grades of stainless steel used for producing these seamless pipes and tubes.

　　Grades of Stainless Steel Used in Producing Seamless Tubes and Pipes

　　Steel tubes and pipes used for the high-temperature applications must be of superior quality to resist high temperatures ranging from 400 degree Celsius to 1100 degree Celsius. For this reason, manufacturers use the following grades of stainless steel to fabricate seamless tubes and pipes.

　　304/304L: Oxidation resistance up to 1650°F, non- hardenable, and non-magnetic.

　　316/316L: Excellent tensile strength at elevated temperatures, exceptional creep and stress-rupture strength, and improved corrosion resistance.

　　310S: Exceptional resistance to oxidation under constant temperatures to 2000°F, better creep strength at elevated temperatures, impeccable strength, and toughness at cryogenic temperatures.

　　317L: Good resistance to chemical attack, higher creep resistance, excellent tensile strength at elevated temperatures, resistance to pitting and crevice corrosion.

　　321/321H: Excellent resistance to intergranular corrosion, can withstand continuous exposure to the temperature between 800-1500 degree F, and higher creep and stress rupture properties.

　　410: Good strength and hardness, excellent toughness in the hardened and tempered condition, resists oxidation up to 1292°F (700°C) continuously, and up to 1500°F (816°C) on an intermittent basis.

　　Due to all these advantages, the seamless stainless steel tubes and pipes manufactured from the aforementioned grades find immense applications in aerospace, oil and gas, manufacturing, marine, food processing, nuclear, chemical, military, paper and pulp, and pharmaceutical industries.

Dimensions Tolerance for API 5L Seamless Pipe

　　Dimensions tolerance for API 5L seamless pipe.

　　1. For outer diameters less than 2 3/8 in (60.3 mm), pipe body diameter tolerance +/-0.5 mm. Pipe end +/- 0.5 mm; Out of Roundness tolerance for pipe body is 0.9 mm (0.036 in), pipe end 0.6 mm (0.024 mm).

　　2. For OD equal or above 2 3/8 in (60.3) to 24 in (610 mm), (diameter tolerance) for pipe body is +/- 0.0075D, pipe end +/- 0.005D but max to +/- 1.6 mm (0.063mm); Roundness tolerance for pipe body ≤ 0.015D, pipe end ≤ 0.01D.

　　(In case agreed with manufacturer and client, more strictly tolerances could be applied)

　　3. For wall thickness

　　Below than 4 mm (0.0157 in), tolerance +0.6 (0.024 mm), -0.5 mm (0.020 in);

　　For API 5L seamless steel pipe thickness in 4 mm to 10 mm (0.394 in), +0.150t, -0.125t;

　　For API seamless pipe thickness 10 mm to 25mm (0.984 in), +/-0.125t;

　　Wall thickness ≥ 25 mm, +3.7mm or +0.1t (if larger) and -3.0 mm (0.120 in) or -0.1t (if larger).

　　t for thickness;

　　4. For straightness, max for full length, tolerance maximum 0.15% of length.

　　5. Straightness, max deviation for pipe end, shall be ≤ 0.3 mm /m.

　　6. Length +/- 200 mm for general, +/- 25.4 mm for special.

　　http://www.xysteelpipe.com/info/Dimensions-Tolerance-for-API-5L-Seamless-Pipe-1097-1.htm

Seamless tube production line cooling bed type

　　The cooling bed of seamless pipe production line has single chain cooling bed, double chain cooling bed, new chain cooling bed, step cooling bed and spiral cooling bed.

　　1, double strand cold bed

　　The dual cooling bed includes a forward transport chain and a reverse transport chain, each transmission chain with a transmission system. The steel pipe is placed between the two lines of the forward transport chain, and the reverse chain carries the weight of the pipe body. The double bed cooling bed pushes the steel pipe forward with the thrust of the forward transport chain, and makes use of the friction of the reverse chain to continuously rotate the steel pipe. The movement of the reverse chain also makes the steel pipe always rely on the jaw plate of the front transmission chain to achieve smooth rotation and uniform cooling.

　　2, single chain cold bed

　　The single strand cold bed adopts a climbing structure. The cooling bed includes a forward conveyor chain and a fixed guide rail with a drive system. The steel tube is placed between the two handles of the forward transport chain, and the fixed rail bears the weight of the steel tube body. The single strand cooling bed uses the friction force of the forward chain claw and the fixed guide rail to rotate the steel tube, and at the same time, depending on the weight and the lifting angle of the steel, the steel pipe is always close to the forward chain claw to achieve the smooth rotation of the steel.

　　3, a new chain of cold bed

　　Combined with the characteristics of single cooling bed and double share cooling bed, the cold bed is divided into uphill and downhill. The uphill part is a double chain structure consisting of the forward transport chain and the reverse transport chain. The positive and negative interactions make the steel tube move forward and climb. The downhill section is a single chain structure parallel to the progressive transportation chain and the steel pipe, which realizes self rotation by self weight and makes the landslide movement.

　　4, step type cold bed

　　The step type cooling bed is made up of two groups of shelves. One group is fixed on the fixed beam, which is called static frame and the other is assembled on the movable beam, which is called mobile frame. When the mechanism moves, the mobile rack is lifted, the steel pipe is lifted, and the steel pipe is rolled into a toothed shape when it is raised. After the mobile gear reaches the highest position, the stepping mechanism moves the mobile frame along the direction of the cooling bed output to a step. The lifting mechanism continues to move, driving the moving bracket down, inserting the steel pipe into the stator slot, rolling the steel tube along the tooth tooth again, and moving the frame back to the initial position to complete the working cycle.

　　5, spiral cold bed

　　The screw is composed of main drive, screw and fixed cooling platform. The screw includes screw and screw screw. The working surface of the fixed cooling platform is higher than that of the spiral core and the helix. The weight of the steel pipe body is borne by the fixed cooling platform. The main drive drives the screw to rotate synchronously, and the screw on the screw drives the steel tube to roll forward and cool on the fixed cooling table.

　　Single strand cold bed is not suitable for continuous operation, double cold bed is better, new chain type cold bed has good effect and low cost. The step type cold bed is usually used for large or high configuration production line, and spiral cold bed is usually used to cool small diameter seamless pipe.