Lviv large steel pipes (shells), thick wall is new. and used, seamless pipes 6-630mm, metal cutting and delivery

Lviv large steel pipes (shells), thick wall is new. and used, seamless pipes 6-630mm, metal cutting and delivery

Steel pipes are widely used in production schemes and, despite the emergence of new materials such as plastic or metal-plastic, have not lost popularity to this day, and in some cases are the only possible option for arranging pipelines.
Indispensable products include, in particular, large-diameter metal pipes used in laying communications under bridges and highways and in technological chains that ensure the operation of agricultural and industrial facilities.
Classification of pipes of large sections
  One of the main characteristics of the product is the material of manufacture.
Pipes of large diameters are made:

     From metals and alloys.
     From macromolecular compounds (plastics).

The second parameter that determines the selection of products when designing new pipelines or repairing existing ones is the diameter. This characteristic is considered together with the width of the pipe clearance and the thickness of its walls.
large diameter metal pipes
Manufactured products, in order to ensure universality, interchangeability and the lowest consumption of raw materials while maintaining the required quality, must comply with regulatory documents - GOSTs or technical specifications of the enterprise (TU).

The dimensions of ferrous metal pipes are regulated by GOST 10704-91.
According to this document, according to the diameter of the product are divided into:

     pipes of small diameter (the parameter value does not exceed 114 mm);
     pipes of medium diameter (the value lies in the range of 114 ... 530 mm);
     large diameter pipes (508 mm and above).
According to GOSTs and TUs, the following standardized geometric parameters of products should be indicated in the standardized tables:

     outer diameter. Important for a general assessment of the dimensions of the future pipeline and for calculating the required amount of coloring or insulating materials to protect the product.
     Internal diameter, or clearance. Used in hydraulic calculations.
     Wall thickness. The most important parameter for strength calculations that ensure the safety of the installed system for both people and the environment.
     Nominal diameter (conditional). It is used as the main characteristic of the pipe assortment; the main parameter for calculating the mass of products and their throughput.

The wall thickness of the pipe is divided into:

     Thin-walled.
     Standard.
     Thick-walled.

According to the manufacturing method, steel pipes and products from other metals and alloys are classified into:
     solid (seamless);
     welded (having a seam from electric welding or its other types).
Products of the first type, due to the complexity and increased accuracy of manufacturing, are more expensive; they are designed for use in systems carrying fluids under high internal pressure or under harsh environmental conditions. Products of the second type are cheaper and quite suitable for use in conventional pipelines.

     Provided that the pipes corresponding to GOSTs are used, there is no need to calculate their mass: it is given in the tables at an accepted steel density of 7.85 g / cm3 and calculated taking into account the length of the segment, wall thickness and product diameter. Deviations in mass, taking into account all tolerances, should not exceed 8% in any direction.

It should be noted that for steel pipes of large diameter, GOST assumes significant fluctuations in wall thickness. For example, if this parameter lies in the range of 8…12 mm, the permissible deviation is up to 0.8 mm in any direction. This seemingly insignificant discrepancy, taking into account the dimensions of the pipes and their supply in large quantities, develops into a serious difference in the weight indicated in the documentation and the actual weight, which can lead to misunderstanding between the parties to the transaction.

In tables and other forms of presentation of the assortment of rolled metal products, the cost of such pipes is usually indicated per ton, and not per linear meter.
  Steel is currently the most popular material for pipe production. Due to its high technological characteristics and well-established production schemes, steel pipes are produced with almost any diameter and, in addition to round, can be characterized by square, rectangular, oval and other profile geometries. The use of steel pipes in a particular area depends on their diameter.
Products of small and small diameter are used for:

     arrangement of heating circuits;
     designing gas pipelines and steam pipelines (read also: "Assortment of steel pipes for gas pipelines, advantages and disadvantages");
     installation of cold and hot water pipelines;
     the need to protect electrical cables and wires from damage.
  Pipes with diameters in the range of 273 ... 325 mm are required in technological schemes and circuits:

     boiler houses and heating plants;
     utility networks;
     all communication options;
     water supply units;
     energy and gas transportation industries;oil and gas industry;
     chemical industries.
Steel pipes with diameters in the range of 426 ... 530 mm are used in the same areas of activity, but in cases where the throughput of products of the previous type is not enough. Another area of application of such products is the design of supports and frames for various purposes.
According to GOST 20295 (straight-seam welded steel pipes, as well as spiral-seam pipes), the diameter of the main pipes is in the range of 114-1420 mm.
Main pipes of large diameters are of three types:

     Type 1 - straight-seam with a diameter of 114-530 mm, made by resistance welding with current
     Type 2 - spiral-seam with a diameter of 159-820 mm, made by electric arc welding
     Type 3 - longitudinally welded with a diameter of 530-1420 mm, made by electric arc welding

According to GOST 10706 (Linear welded steel pipes), all technical requirements, such as pipe diameters, tolerances, must comply with GOST 10704 (Linear welded steel pipes).
General-purpose electric-welded pipes with a diameter of 426-1620 mm are divided into 2 classes:

      - with cutting ends and deburring;
      - no trimming or deburring. The theoretical mass is calculated by increasing the mass of the GOST 10704 pipe by 1%, due to the strengthening of the seam.

In the manufacture of straight-seam electric-welded pipes up to 820 mm, one longitudinal and one transverse seam is allowed. In the manufacture of pipes of larger diameter, it is allowed to use two longitudinal and one transverse seams. When using a transverse seam (when two short pipes are factory welded together), the displacement of the longitudinal seams relative to each other must be at least 100 mm. In this case, according to the technical requirements, the outer seam is made first, then the inner one.
In addition to GOST, large-diameter pipes can be produced from shells according to specifications (for example, TU 14-3R-56-2001, TU 14-3R-96-2007, etc.). According to the specifications, the list of nomenclature of diameters and thicknesses of pipes is significantly expanded. In the manufacture of electric-welded pipes from shells, it is allowed to use the required number of transverse seams, depending on the length of the shells. The displacement of the longitudinal seams relative to each other must be at least 200 mm.