Workshop Design of Large Diameter LSAW Steel Pipe

In 1940 the United States first use UOE method to produce large diameter LSAW steel pipe. In the early 1950s, the United States built a LIOE pipe workshop with a diameter of 607 to 915 mm. 1955 ~ 1967 years of Europe, the United States, Japan UOE welded pipe construction workshop, the diameter of its pipe range of 406 ~ 1067mm, the maximum length of steel pipe is 12m. From 1967 to 1976, the maximum diameter of welded steel pipe was 1626mm, the pipe wall thickness was 40mm, the length of pipe was 18m, and continuous pre-welding and automatic nondestructive testing and automatic control were used in Germany and Japan.

Design scale and product program UOE pipe workshop design scale is generally 40 to 110 million t/a, the main varieties of high-quality carbon steel pipe, steel pipe yield strength of 750MPa, product specifications for the diameter of 406 ~ 1626mm, wall thickness 6. 4 ~ 40mm, length up to 18m.

Process UOE pipe material for the thick and thick steel plate, planing edge of the front of the pre-bending, U-type press it will be pressed into a U-shaped, and then in the 0-type press it into a round tube, after pre-welding , Round tube to send a few welding lines, welding the arc plate on both inside and outside the welding, the formation of steel pipe, and then in the expansion pipe on the pipe expansion pipe diameter, and improve the dimensional accuracy, After passing the inspection, inside and outside the surface coated with anti-corrosion layer.

The selection of process equipment is mainly based on the production scale, product program, construction funds and raw materials, energy and other conditions to choose steel planing machine, pre-curved machine, U-type presses, 0-type presses, pre-welding machine, Pipe machine, non-destructive testing equipment and steel pipe coating equipment inside and outside.

The Welded Steel Pipe Used for Structure

Structural welded steel pipe is used in steel structure, bridge support, building structural pipe, pile foundation tube, etc.. As the structural tube needs great egret capacity to pressure-bearing and withstand voltage, generally, we use the pipe that the wall thickness is greater than 8mm. The main material of the structural welded steel pipe is carbon steel, and mainly includes LSAW steel pipe, ERW steel pipe, and spiral welded pipe. The main parameters of the structural welded steel pipe include diameter, wall thickness, length, welding technology, whether the need for surface corrosion insulation treatment. The welded steel pipe for exporting needs to be grooved, painted, added the cap. Structural welded steel pipe is made with double-sided submerged arc welding or high-frequency welding.

Structural welded steel pipe is manufactured by continuous on-line production, the thicker the wall thickness is, the greater the unit and welding equipment investment is, the structural welded steel pipe has more no economical and practical. The wall thickness is thinner, its input-output ratio will decrease accordingly. Secondly, the process of the product determines its advantages and disadvantages. General welded steel pipe has high precision and uniform wall thickness, and the surface brightness of the pipe is high (surface grade of steel pipe determines the brightness of pipes), and it can be sized any length. Therefore, it reflects its economy and aesthetics in the high-precision, low-pressure fluid applications. According to the welding technology section structural welded steel pipe is divided into automatic welding, manual welding, automatic welding commonly used submerged arc welding, plasma welding; manual welding general use of argon arc welding. According to the weld section is divided into straight LSAW steel pipe and SSAW steel pipe.

Prime Steel Pipe has many year experience to manufacture and export all kinds of welded steel pipe with high-quality, if you have any requirements of that, please inquiry us without any hesitation.

The Application of Large Diameter LSAW Steel Pipe

Large diameter LSAW steel pipe, also known as welded steel pipe, is made of steel plate or steel strip after bending (electric model 0317 and check 6012755 standard) and then is made of by high-frequency welding and submerged arc welding. According to the form of seam welded steel pipe is divided into LSAW steel pipe and spiral welded pipe. According to the use it is divided into general welded pipe, galvanized steel pipe, blowing oxygen pipe, wire casing, metric pipe, roller tube, deep well pump, automotive tube, transformer tube, welded thin-walled tube, welded pipe and spiral welded pipe.

General pipe (manufactured bu Prime Steel Pipe) is used to transport low pressure fluid. Implementation of the standard is GB/T0317 No. 6012889. It is manufactured with Q195A, Q215A, Q235A steel. It can also be made of other mild steel that is easy to weld. Steel pipe must be tested by water pressure, bending, flattening and other experiments, the surface quality has certain requirements, the delivery length usually is 4-10m, and it often requires delivery by length (or double length). The specifications of the welded pipe are denoted by nominal caliber (mm or inch). Nominal caliber is different from the actual one. The welded pipe has two different kinds of steel pipe according to the specified wall thickness, including ordinary steel pipe and thickened steel pipe.

Advantages and Disadvantages of Scaffolding Pipe

Several days ago, Prime Steel Pipe shared the brief introduction of scaffolding pipe, I believed that those people who saw that article must have a basic understanding to scaffolding pipe. Today, Prime Steel Pipe will continue to share some information of that, its advantages and disadvantages will be listed below.

Advantages of scaffolding pipe:

1) Bearing capacity is large. When the scaffolding geometry and construction in line with the relevant requirements of the specification, under normal circumstances, the capacity that single tube of scaffolding can bear will reach up to 15kN ~ 35kN (1.5tf ~ 3.5tf, design).
2) Easy assembly and disassembly, erection flexible. As the length of the pipe is easy to adjust, fastener connection is simple, thus it can be adapted to a variety of flat, facade buildings and structures with scaffolding.
3) More economical. Processing is simple, primary investment costs is low; if carefully designing scaffold geometry, paying attention to improve the use of steel pipe turnover, the amount of material can also achieve better economic results. The amount of steel in the building per square meter of fastener steel pipe frame equivalent is about 15 kg.

Disadvantages of scaffolding pipe:

1) Fasteners (especially its screw) are easy to lose;
2) The bar at the node for the eccentric connection, by the anti-slip force transmission load and internal force, thus reducing its carrying capacity;
3) The connection quality of the fastener joint is significantly affected by the quality of the fastener itself and the operation of the worker.

The Definition and Use of Seamless Steel Pipe

Seamless steel pipe is a hollow section, the surrounding no seam of the long steel. The steel pipe has a hollow section, a large number of pipes used to transport fluid, such as the transmission of oil, natural gas, gas, water and some solid materials pipeline.

Steel and round steel and other solid steel compared to the same bending strength, the weight is light, is an economic section of steel, widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, car drive shaft, bicycle Racks and steel scaffolds for construction purposes.

The use of steel pipe manufacturing ring parts, can improve the utilization of materials, simplify the manufacturing process, saving materials and processing time, such as rolling bearing rings, jack sets, etc., has been widely used to manufacture steel. Steel pipe or a variety of conventional weapons indispensable materials, barrels, barrels and so on to steel to manufacture. Steel pipe by cross-sectional area of the shape can be divided into tube and shaped tube. As the circumference of the same conditions, the largest circular area, with a circular tube can transport more fluid.

In addition, the ring cross section in the internal or external radial pressure, the force is more uniform, so the vast majority of steel pipe is a tube. However, the tube also has some limitations, such as in the plane under the conditions of bending, the tube is not as good as the square tube bending strength, some agricultural machinery skeleton, steel and wood furniture on the commonly used side, rectangular tube. According to different purposes need to have other cross-shaped shape shaped steel pipe.

Seamless steel pipe is divided into sub-cold drawn and hot bar, but their surface did not go through any treatment.

Seamless steel pipe is divided into several, it is the material and the implementation of standards, materials are ordinary tube, alloy tube, the implementation of the standard;

1, Structural seamless steel tube: GB8162-99;
2, Seamless steel pipe for fluid transport: GB8163-99;
3, Seamless steel boiler tube for power generation service: GB3087-1999;
4, High pressure boiler tube: GB5310-95 (ST45.8-ⅲ type);
5, Seamless steel pipe for high pressure fertilizer equipment: GB6479-1999;
6, Seamless steel pipe for geological drilling: YB235-70;
7, Seamless steel pipe for oil drilling: YB528-65;
8, Seamless steel pipe for petroleum cracking process: GB9948-88;
9, Seamless steel pipe for oil drill collar: YB691-70;
10, Seamless steel pipe for auto semi-axle: GB3088-1999;
11, Seamless steel pipe for shipping: GB5312-1999;
12, Cold drawn cold rolled precision seamless steel tube: GB3639-1999;
13, All kinds of alloy pipe: 16Mn, 27SiMn, 15CrMo, 35CrMo, 12CrMov, 20G, 40Cr, 12Cr1MoV, 15CrMo.

The Groove of The Welded Steel Pipe

In the production of welded steel pipe, the groove of the tube is the shape of the cross-section, the general manufacturers in the slitting directly into the high-frequency welding, the groove is a "I" shape. When the thickness of the welding material is greater than 8 ~ 10mm above the pipe, if the use of this "I" shaped groove, because the relationship between the curved arc, you need to melt off the tube first contact with the inner layer, forming a high Burr, and easy to cause the center of the plate and the outer layer of insufficient heating, affecting the welding strength of high-frequency weld. Therefore, in the production of thick-walled tube, the tube is best through the planing or milling edge treatment, so that the groove was "X" shape, the practice proved that this groove for the uniform heating to ensure the quality of the weld seam of welded steel pipe has a great relationship. The selection of the groove shape also affects the size of the adjustment angle. The design of the welded joint is a weak link in the design of the welding project of welded steel pipe. It is not uncommon for the construction of many steel structures. The design of the groove is not from the hand of the welding engineering technician, the hard sleeve standard and the poor performance. The groove form plays an important role in controlling the internal quality of the weld and the quality of the welded structure. The groove design must test the fusion ratio of the base metal, the welding space, the welding position and the comprehensive economic benefits. The lateral shrinkage value ΔB should be calculated by the following equation.

ΔB = 5.1Aω / t + 1.27d

Where Aω - weld cross-sectional area, mm,
           t - plate thickness, mm,
           d - weld root gap, mm.

After finding the relationship between ΔB and Aω, we can analyze and process the data according to the relationship list, optimize the design, and finally determine the form of butt weld.