seamless tube

IMRI holds a broad variety of welded tubes and seamless pipes in different grades and dimensions in stock for its customers. Our relationships with many local and world leading tube producers allow us to supply material manufactured to suit customers’ individual design requirements.

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seamless tube

English name: seamless pipe

Alias: seamless steel pipe

A seamless pipe is a long strip of steel with a hollow section and no seams around it. There are more than 5,100 production plants under more than 1,850 companies in more than 110 countries in the world that produce seamless pipes, of which there are more than 260 plants under more than 170 companies in 44 countries that produce oil pipes.

Features of seamless pipe:
First, the thicker the wall thickness of the product, the more economical and practical it is, and the thinner the wall thickness, the higher the processing cost; secondly, the technology of the product determines its limited performance, generally The precision of seamless steel pipe is low: uneven wall thickness, low brightness inside and outside the pipe, high cost of sizing, and there are pits and black spots on the inside and outside that are not easy to remove; third, its detection and shaping must be processed offline. Therefore, it reflects its superiority in terms of high pressure, high strength, and mechanical structural materials.

ASTM/ASME Standard – Seamless Steel Pipe

Product nameExecutive standardSteel code/ Steel grade
Black and Hot-dipped Zinc-coated Steel Seamless PipesASTM A53GR.A, GR.B, GR.C
Seamless Carbon Steel for High Temperature ServiceASTM A106GR.B, GR.C
Seamless Cold-drawn Low-Carbon Steel Heat-Exchanger and Condenser TubesASTM A179Low Carbon Steel
Seamless Carbon Steel Boiler Tubes for High PressureASTM A192Low Carbon Steel
Seamless Cold-drawn Intermediate Alloy Steel Heat-exchanger and Condenser TubesASTM A199T5, T22
Seamless Medium-carbon Steel Boiler and Superheater TubesASTM A210A1, C
Seamless Ferritic and Austenitic Alloy Steel Boiler, Superheater and Heat-exchanger TubesASTM A213T5, T5b, T9 , T11, T22 ,T91
Seamless Carbon and Alloy Steel for Mechanical TubingASTM A333Grade1 Gr. 3,Gr..6, Gr.8 , Gr. 9
Seamless Cold-drawn Carbon Steel Feedwater Heater TubesASTM A556A2, B2
Round and shaped steel cold formed welded and seamless carbon steel structural pipe.ASTM A500Grade A, B, C, D
Welded and seamless steel pipe for piling purposes.ASTM A252A252 Grade 1, 2 & 3
For seamless ferritic alloy-steel pipe for high-temperature serviceASTM A335A/SA 335 P1, P2, P11, P12, P15, P22, P91, P92, P122

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Frequently asked questions

Seamless steel pipe is a round, square and rectangular steel with a hollow section and no joints around it. A large number of pipelines are used for transporting fluids, such as pipelines for transporting oil, natural gas, gas, water and certain solid materials.

Seamless steel pipes are widely used.

1.General-purpose seamless steel pipes are rolled from ordinary carbon structural steel, low-alloy structural steel or alloy structural steel, with the largest output, and are mainly used as pipelines or structural parts for conveying fluids.

2.According to different uses, there are three types of supply: a. Supply according to chemical composition and mechanical properties; b. Supply according to mechanical properties; c, according to the hydraulic test supply. Steel pipes supplied according to categories a and b, if they are used to withstand liquid pressure, shall also undergo a hydrostatic test.

3.There are many kinds of seamless pipes for special purposes, such as seamless pipes for boilers, seamless pipes for chemical power, seamless pipes for geological use and seamless pipes for petroleum. The seamless steel pipe has a hollow section and is widely used as a pipeline for transporting fluids, such as pipelines for transporting oil, natural gas, gas, water and certain solid materials. Compared with solid steel such as round steel, the steel pipe is lighter in weight when the bending and torsional strength is the same, and is an economical section steel. It is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile transmission shafts, bicycle frames, and steel scaffolding used in construction. The use of steel pipes to manufacture annular parts can improve material utilization, simplify manufacturing processes, and save materials and processing. Man-hours have been widely used to manufacture steel pipes.

The biggest difference between ERW steel pipe and seamless steel pipe is that ERW has weld seam, which is the key to the quality of ERW steel pipe. The production technology and equipment of modern ERW steel pipes, due to the unremitting efforts of many years in the world, especially the United States, have made seamless ERW steel pipes achieve relatively satisfactory results. The difference between ERW steel pipe and seamless steel pipe Some people divide the seamlessness of ERW steel pipes into geometric seamlessness and physical seamlessness. Geometric seamless is designed to eliminate internal and external burrs from ERW steel pipes. The removal of internal burrs in large and medium diameter steel pipes is better handled due to the continuous improvement and improvement of the structure of internal burr removal systems and cutters. Internal burr can be controlled between -0.2mm to 0.5mm. Physical seamlessness means that there is a difference between the metallographic structure inside the weld and the base metal, which can lead to a decrease in the mechanical properties of the weld area, requiring measures to be uniform. The high-frequency welding heat treatment of ERW steel pipes results in a temperature distribution gradient near the edge of the tube blank, and forms characteristic areas such as melting zone, semi-melting zone, superheated structure, normalizing zone, incomplete normalizing zone and tempering zone. Since the welding temperature is higher than 1000°C, the microstructure of the superheated zone has obvious austenite grain growth, and a hard and brittle coarse-grained phase is formed under cooling conditions. In addition, the presence of temperature gradients can create welding stress. In this way, the mechanical properties of the resulting weld zone are lower than in the case of the base material. The physical seamlessness is achieved by heating the weld area to AC3 through the traditional local heat treatment process of the weld using a medium frequency induction heating unit. (927°C), followed by air cooling at a length of 60 m and a speed of 20 m/min and, if necessary, water cooling. The use of this method achieves the purpose of relieving stress, softening and refining the structure, and improving the comprehensive mechanical properties of the welding heat-affected zone. So far, the world’s advanced ERW devices generally use this method to process welds, and have achieved good results. High- quality ERW steel pipes not only fail to identify welds, but also have a weld coefficient of 1, which matches the structure of the weld zone to the base metal. Since the ERW steel pipe is made of hot-rolled coil, the wall thickness can be uniformly controlled at about ±0.2mm. Both ends of the steel pipe meet the American APl standard or GB/T9711.1 standard, the slope is repaired, and the fixed length is delivered. In recent years, various natural gas pipeline network projects and natural gas companies have widely adopted ERW steel pipes as the main steel pipes for urban pipeline networks.

1: The production process is different Seamless steel pipe is a seamless steel pipe produced by round steel through tube blank, perforation, sizing and straightening, and has no welding seam as a whole; seamed steel pipe is also welded steel pipe, which can be divided into spiral welded pipe and straight seam welded pipe from the production process. . Spiral steel pipe is a spiral seam steel pipe made of strip steel coil as raw material, extruded at room temperature, and welded by automatic double-wire double-sided submerged arc welding process; It is a steel pipe obtained by straight seam welding on welding equipment.

2: Different pressure The general pressure of seamed steel pipe is about 10 kg, while the pressure of seamless steel pipe is higher, such as 20G high-pressure boiler tube, the pressure can reach 300-450 kg.

3: The limitations of the caliber are different At present, the diameter of seamless steel pipe can only reach 1020mm, which is relatively limited; the diameter of seamless steel pipe can reach 4000mm, and the diameter that can be produced is larger.

4: The price is different The price of seamless steel pipe is significantly higher than that of seamed steel pipe.

5: different lengths Seamless steel pipes are generally loose-length (5-11.9 meters) and fixed-length (6 meters, 9 meters, 12 meters), and can be delivered according to customer agreement. Seamed steel pipes are generally 6 meters and 12 meters.

1. Compression type: Insert the pipe into the nozzle of the pipe fitting, fasten it with a nut, and compress the casing at the nozzle through the sealing ring with a screw force, which plays a sealing role and completes the connection of the pipe.

2. Welding type: The end of the pipe is beveled, and the pipe is welded in a ring shape by manual or automatic welding.

3. Flange type: The flange and the piping are welded by annular argon arc, and fastened with quick clamps or bolts, so that the gasket between the flanges plays a sealing role and completes the piping connection.

4. Compression type: insert the pipe into the pipe fitting and use a special installation tool to press the pipe wall into a hexagon, and the internal sealing ring is also deformed into a hexagon

5. Taper thread type: that is, the outer thread and the piping are welded by annular argon arc, and the inner thread pipe fittings are connected with the tapered thread to play a sealing role to complete the piping connection.

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