Steel pipes are widely used in a variety ofindustries. They are used in machine building, oil and gas industry, municipal services, etc. There are several types of steel metal pipes. They can differ according to the method of manufacture, size and type of material used for production. The range of steel pipes of different types is determined by GOSTs.
Basically all modern steel pipesare divided into two large groups: hot-rolled and welded. The first variety is more costly. Therefore, such products are used less often than welded ones. The range of seamless steel pipes is determined by GOST 8732-78. The ratio of the size of these pipes and their weight is given in special tables. The parameters can be, for example, as described below.
Weight 1 m
The assortment of steel pipes of electrically welded and made with the help of furnace welding will be considered below. Their parameters are also exactly determined by GOSTs.
Produce products of this variety of steelsgrades 35 and 45 on a continuous mill. The so-called black blanks are used. The latter are stitched on a rolling mill, and then sent to a circular saw for trimming the end of the pipe. Then the finished product is fed to the skew-forging mill to straighten and reduce the ovality of the section.
Products of this type, as already mentioned, aremore popular than seamless. Such pipes have been used in the national economy for quite some time. However, in recent years their popularity has increased significantly. This is primarily due to the development of new, more sophisticated methods of welding, which make it possible to obtain the most reliable and durable products. So, for example, in 1941 only 38.8% of welded pipes were produced. The rest was in seamless. At the same time, the share of electric welded was only 0.8%. By 1965, these indicators had increased to 50% and 35%, respectively.
Today such products are used everywhere. Most often they are used for laying various kinds of trunk lines designed for pumping oil, gas, water, etc. It is also this type of pipe that is usually used in the municipal economy. In this case, they are used for laying water pipes and sewage systems. Welded pipes are also used for assembling gas overhead lines, drainage systems, etc.
Mechanical engineering is another area in whichwelded pipes are used. They are also used for the manufacture of various architectural elements: visors over the porches, canopies, children's swings, horizontal bars, etc. In agriculture, irrigation systems are being built with their use.
Distinguish products of this type can by:
Method of manufacture. In this case, the pipes made withuse of furnace welding and electric welding. Both types are considered quite reliable. Electro-welded pipes can be made by methods of arc, contact or induction welding.
The kind of coverage. This feature distinguishes between galvanized and non-galvanized pipes.
Depending on the from the seam direction (straight and spiral).
The kind used to make material. Welded pipes are usually produced fromlow-alloy or carbon steel. In this case, either sheet rolling or strips are used. Sometimes for the production of pipes, other metals can be used: nickel, copper, magnesium, etc. In this case, gas or gas-electric welding is usually used.
The type of profile. By this feature, there are round, rectangular profile, oval pipes.
Next, let's see how thewelded steel pipe. The GOST range in this case regulates in accuracy. This applies to both the dimensions and weight of the products. Actually the process of production itself consists of the following stages:
preparation and formation of the sheet;
welding, consisting in creating an electric arc between the edges of the workpiece and the electrode;
final finishing (calibration, chamfering, straightening, etc.).
The main stages of manufacturing pipes with spiralseam forming sheet, welding and cutting on the move. In this case, sheet metal in the form of a tape is fed into a special assembly of the mill, where it is wound into a spiral. At the same time, welding takes place.
Despite the fact that it is easier to make spiral pipes, the production is mainly concerned with the production of straight-legged pipes. The fact is that such products are more popular on the market.
In the production of welded steel pipes inCertain standards must be observed without fail. The quality of such products is regulated by GOST 10704-91. The range of pipes of steel electrically welded stitches according to the standards specified in this document includes the product groups:
with the normalization of mechanical properties (marked "A");
with the control of the chemical composition ("B");
with the control of both these parameters ("B");
with normalization of hydraulic pressure during testing ("D").
As for dimensions and weight, welded straight-end pipes are manufactured in accordance with GOST 10705-80 (for products with a diameter of 10-500 mm) and GOST 10706-76 (for diameters of 478-1420 mm).
Below we present to your attention the table of the ratios of the pipe diameters, the thickness of their walls and the permissible deviations according to GOST.
The thickness of the wall
-15, + 8%
from 0.5 mm to 40 mm, 1 - over 40.
0.1 mm to 0.75 mm and 10% to more than 0.75 mm
from 0.3 mm to 2 cm,
from 2 to 5.1 cm - 0.5 mm, more than 51 - 1%
In accordance with the regulations on the thickness deviations used for the production of metal sheets (according to GOST 5587-58 and 8597-57)
1% to 400 mm, over 400 mm, the pipe ends are calibrated
from 2 mm to 720 mm,
from 3 mm to 1020 mm,
from 4 mm to 1220 mm,
from 5 mm more than 1220 mm
The GOST also adjusts the ratio of the outdoordiameter and weight of 1 m of pipe at a certain wall thickness. The range of steel pipes in this case is also presented in special tables. Below, for example, several such relations are given.
Weight of 1 m pipe with wall thickness
Stainless steel pipes, the assortment of which is presented above, can also vary by:
Products measuring length (from five to 12 m);
immense (2-12 m);
Products of multiple and dimensional length can have two classes of accuracy: with trimming ends and sharpening of burrs and with cutting in the line of the mill (without hatching).
From English this term is translated as"Tape", or "strip". Strips for the production of welded pipes are used very often. Actually, these tapes themselves are made of sheet metal. There are strips:
with a polymer coating.
Weigh strip according to thicknessthe material used for its manufacture can range from fifty kilograms to five tons. Applies to the enterprises that specialize in the manufacture of pipes, he is in the tub or in a bundle, always on a pallet.
Such equipment can be used for the manufacture of both spiral and longitudinal products. In the latter case, the machine design includes the following elements:
receiving and loading device;
the correct machine;
scissors for cutting strip ends;
furnace for heating strip;
forming, welding and calibration mills;
a flying saw, etc.
Before welding, the workpieces pass through a special forming press or rollers.
The spiral pipe mill consists of the following elements:
unwinding and receiving rolls;
a scraping device;
trolley with a cutter;
the welding head bracket, etc.
There is a process of forming a pipe in such amill with a speed of up to 1.1 meters per minute. The quality of the welded seam in modern enterprises is verified with the help of ultrasound. The produced cut pipes after the mill are sent for calibration.
Thus, you now know how to do andwhat are the steel electric welded pipes. GOST assortment of this product determines exactly. Also we have understood with what standards are provided for the manufacture of seamless pipes. Accurate observance of technologies during manufacturing allows to receive high-quality and reliable products of this type, used in many areas of the national economy.</ p>>