Seamless cold formed pipes production
Seamless cold-worked pipes
is produced in accordance with GOST 8733-74 (standard for technical requirements) and GOST 8734-75 (standard for assortment). These pipes are made of carbon (10,20,30,45), alloyed and high-alloyed steels.
The range of cold-formed pipes, which, as a rule, are in our warehouse, ranges from 8 to 76 mm in diameter and from 1 to 10 mm in wall thickness.
In some cases, it is possible to consider the production of custom-made cold-formed pipes of larger diameter, up to 114 mm.
Seamless hot-rolled pipe is always used as a raw material for the production of seamless cold worked pipes. Thus, the final product always goes through at least two stages of processing: hot rolling (from a square billet to a hot-deformed pipe) and cold rolling (drawing): from a hot-deformed billet to a cold-deformed pipe.
& nbsp; Due to this, the characteristic features of cold-deformed pipes are, firstly, their mechanical properties, which allow them to withstand various dynamic forces (bending, torsion, tensile, flattening, etc.) and, secondly, their exact geometrical dimensions, achieved during production at the stage of cold working.
These features make it possible to find application of cold-worked pipes in those industries where increased requirements for certain parameters are deliberately imposed on the product.
In particular, the main consumers of cold-formed pipes are enterprises of various mechanical engineering industries, where products made from pipes are subject to high mechanical dynamic loads (auto construction, car building, tractor construction, shipbuilding, machine tool construction, etc. .д.
), the energy, oil refining and petrochemical industries, where pipes used in one or another equipment are subjected to high pressures and temperatures, precision engineering industries, where products obtained from cold-formed pipes must have particularly accurate geometric parameters of the inner or outer diameter and thickness walls. & nbsp;
& nbsp; Pipes according to the standard are made, as a rule, in unmeasured lengths (from 1.5 to 12 m). On request, it is possible to produce cold-deformed pipes in a specified measured length (for example, 6000 or 9000 mm), in some cases it is possible to manufacture pipes over 12 m.
& nbsp; The production process of cold-formed pipes consists of several sequential operations. At the first stage, chemical preparation of the pipe surface takes place, which consists in removing scale by placing it in an acidic solution.
As a result of a chemical reaction, the existing scale is separated from the surface. After the etching process, the pipes are rinsed, as a rule, first in hot and then in cold water under pressure.
The next, main stage of production is directly the process of cold rolling or drawing, as a result of which the pipe acquires the required specified parameters of length and wall thickness. The specific technological scheme of rolled products is selected depending on the steel grade, the dimensions of the pipe billet and the required final dimensions. & Nbsp;
& nbsp; In our warehouse in Fryazevo we always have the widest assortment (about 100 standard sizes) of cold-rolled pipes at guaranteed the best prices on the market. In the absence of a certain size in stock, we can always order it for you at the manufacturing plant and make this order as quickly as possible.
& nbsp; The price of cold-deformed pipes always depends on the specific ratio of diameter and wall thickness. Unlike hot-deformed pipes, which have practically the same price for the entire assortment, in cold-rolled pipes, each standard size has its own cost. The smaller the diameter & nbsp; and the wall thickness – the more expensive the cost of this standard size will be.
This is due to the production technology: the smaller the diameter and the smaller the wall thickness & nbsp; – the more passes during drawing must be made in order to reach the initial diametermeter of hot pipe to the required diameter of the cold pipe.
It may take from one to five passes, each of which, respectively, increases the cost and price of a given size.
Production of thin-walled pipes made of carbon and alloy steels for nuclear power, boiler construction, aviation, shipbuilding, machine-building, chemical industries
As for the methods of production of this type of pipes, in this article we will consider the main features and stages.
First of all, the production of a pipe is carried out from a strip, which is a strip of sheet steel. This strip is deformed on special shaping machines, as a result of which the strip turns into a profile or round blank.
After the workpiece is produced, the butt seam is welded, which is performed using argon-arc or resistance welding.
The weld seam should only be straight, as seams of other configurations can only be used in the production of thick-walled pipes.
Naturally, the pipe welding process is not performed manually, but using special equipment, where everything is automated.
After the longitudinal seam is formed, the pipe is subjected to low-temperature heating, followed by cooling (so-called tempering).
As a result of tempering, a ready-made hot-rolled electric-welded thin-walled pipe is obtained.
When producing round pipes of this type, they are calibrated.
In general, the entire assortment of thin-walled pipes is classified according to the following criteria:
- by the shape of the profile (where the standard option is circular pipes, the more rare is the profile option);
- the dimensions of the profile (outer and inner diameters).
On this basis, pipes are divided into round rolled products with a diameter of 10 – 76 mm. and profile rolled products with a diameter of 10 to 10 mm. up to 25 by 25 mm. In this case, the wall thickness can be from 1 to 1.5 mm.