Range of round and shaped steel pipes

Steel pipes are included in the category of the most popular products in this segment of the building materials market. In everyday life, they are most often used to create heating and water supply systems, as well as gas pipelines. The range and types of steel pipes are determined, first of all, by the features of the technology for manufacturing such products. And their production is regulated by separate sections of the relevant GOST, which indicate all the technical characteristics of the pipes.

Methods for the production of steel pipes

In service with modern metallurgical plants there are only 4 classic technologies:

• cold rolling - production of seamless pipes from pre-chilled billets;
• hot rolled. This method produces seamless pipes from a heated preform;
• welded spiral rolling. The final product manufactured using this technology is characterized by the presence of a spiral seam. In this case, sheet blanks are used as raw materials;
• welded longitudinal hire. The source material is the same sheet blanks. Distinctive features - the presence of a longitudinal straight seam.

Using the aforementioned technologies makes it possible to produce steel pipes of any kind, from the "plumbing" round ones used in water supply, including oval and thick-walled ones, to the "structural" ones - square and rectangular. In addition, the features of the process impose restrictions on the sizes of pipe products. Let's touch on the assortment of steel pipes in more detail.

Electric-welded straight-seam products

The assortment of steel pipes of this type contains products with an external diameter of millimeters and a wall thickness of millimeters, which meets the requirements of GOST 10704-91.

Useful informationnation! This regulatory document also contains requirements for the mechanical properties of longitudinal pipes. In addition, the standard establishes the uniformity of wall thickness and the degree of their ovality. But at the same time, the need for chemical control is not specified.

The maximum permissible deviations in the dimensions of steel longitudinal pipes are presented in the table below.

Table 1

Outer diameter mm	Maximum deviations of the outer diameter depending on the accuracy of production
	Increased	Ordinary
Over 1020	± 6 mm	±0,6%
426,0-1020,0	±0,65%	±0,7%
193,70 – 426,0	±0,65%	±0,75%
51,0 – 193,7	±0,7%	±0,8%
30,0 – 51,0	± 0.35 mm	± 0.4 mm
10,0 – 30,0	± 0.25 mm	± 0.30 mm
10	3/4	± 0.2 mm

 

Permissible excess dimensions of the measuring tubes can be found in table No. 2.

table 2

Pipe length, meters	Limit deviations of length of measured pipes, millimeters, classes
	I	II
Up to 6.0	+10,0	+50,0
Over 6.0	+15,0	+70,0

 

In addition, in the assortment for steel pipes straight-seam, defined by GOST 10704-91, the requirements for the uniformity of the thickness of their walls and the degree of ovality are indicated.

Spiral welded pipes

The production and assortment of these products is regulated by GOST 8696-74.

Unlike straight-line-seam, as you might guess, the workpiece in this case is folded into a pipe in a spiral, and then welded. This technology gives the end product the ability to withstand higher pressures. In addition, it has the following advantages:

• the possibility of using high-speed technological welding provides a high molding speed (about 12 m / min.);
• improving the accuracy of molding (pipe geometry) by eliminating the obstacles produced by submerged arc welding. It is performed separately;
• the ability to fully automate the process. This eliminates the “human factor” and ensures the high quality of the final product.

This production method allows the use of these products as high-pressure steel pipes for heating pipelines, oil and gas pipelines and water supply systems.

The aforementioned GOST 8696-74 contains 21 sizes of spiral-seam pipes. In the assortment of products of this type determined by him, it is indicated that the minimum diameter is 159, and the maximum is 2520 millimeters. Recommended length - about 10 and 12 meters. The permissible deviation of the overall dimensions does not exceed 0.3 percent.

Hot and cold deformable seamless steel pipes

Hot and cold rolling are two fundamentally different technologies. Each of them has its advantages and disadvantages.

Cold rolling involves the processing of plastic material only by pressure. Hot rolled pipes are manufactured by rolling a billet heated to a predetermined temperature in a continuous mill.

Cold forming pipes. The product range of this type is determined by GOST 8734-75. The full list of possible sizes is very extensive. The diameter can be 5 ... 250 millimeters, and the wall thickness is from 0.3 to 24 millimeters. Pipes of measured and unmeasured lengths are produced. In the latter case, the value of this parameter ranges from 11.5 meters.

Helpful information! The advantage and distinguishing feature of a cold-deformed pipe is that it is significantly increased (in comparison with a conventional pipe, the safety factor is almost a quarter. Accordingly, the pressure of the working medium can be increased by the same amount.

Seamless hot deformation pipes. The production and assortment of such products is regulated by GOST 8732-78. The size chart is also very large. It includes pipes with a diameter of 20 ... 550 millimeters and with a wall thickness of 2.5 to 75 (!) Millimeters. Such sizes determine the considerable weight of hot-deformed products. It is enough to say that the mass of one linear meter of pipe 550 × 75 is almost a ton, or rather 878 kg. They are able to withstand high pressure. Even 16 MPa they are not afraid!

In today's market, you can find both types of pre-insulated products. The advantages of an insulated pipe abound. This is resistance to the effects of chemically aggressive compounds, and minimization of heat loss during transportation of the working environment, and so on. But perhaps the most important is that the service life of the steel insulated pipe is about 30 years.

Steel black pipe

This is the name of a steel pipe without any coating.

In the 70-90 years of the last century, this product was widely used to create pipelines for water supply, heating systems, as well as a gas steel pipe. Commonly used VGP pipemanufactured in accordance with the requirements of GOST 3262-75. Details of this type are easily welded by any type of welding - this is their indisputable advantage.Also, do not forget that bends, valves, tees, transitions and so on are made of black steel pipes.

The production and range of these products is regulated by the requirements of GOST 3262-75. The standard length of uncoated steel pipes is 5.5–11.7 meters. Their division into groups is carried out by such parameters as steel grade, outer and inner diameter, wall thickness and other physical and technical characteristics. Special marking of steel pipes is applied with indelible paint only with a wall thickness of more than 3.5 mm and a diameter of 159 mm

Depending on the scope of application, such pipe products are usually divided into the following classes.

• 1st grade. Used for transportation of gaseous or liquid compounds, in the construction of building supports and scaffolding, as well as building envelopes;
• 2nd grade. Products of this class are used in the construction of trunk pipelines designed for pumping gas, oil and oil products under high pressure. In addition, they can be used as steel pipes for water supply;
• 3rd grade. They are widely used in the most difficult operating conditions. This is a high temperature, and the same pressure. Most in demand in the chemical and food industries;
• 4th grade. Well suited for exploration of oil and gas fields, as well as their drilling and exploitation.
• 5th grade. They are used in the manufacture of furniture, stairs, metal structures for supports, drill rigs, transport equipment, etc.
• 6th grade. They play an important role in the manufacture of components in the engineering industry.

There are two types of black pipes, depending on the wall thickness:

• up to 3mm - thin-walled;
• more than 3 mm - thick-walled.

When choosing pipes for heating and water supply systems, one should not forget about the problems that await you when using ferrous metal products. Firstly, it is poor tolerance of contact with water. Rust, scale, slag, and also calcareous deposits and sand gradually reduce pipe clearance.

Drawattentione! This problem is more inherent in cold water pipelines. However, if you open the elevator unit, the degree of clogging of the heating pipes will also amaze you.

Secondly, theoretically, the heating system should be continuously filled with water. In practice, in the summer season, heating is turned off. The access of oxygen to the internal surfaces of the pipes in combination with moisture causes accelerated corrosion.

However, pipe products of ferrous metal are currently the most common. Their cost is determined by the production technology and the grade of steel used. AT in emergency cases, such pipes can withstand incredibly high pressure. And the increased level of thermal conductivity allows you to create radiant forms of water heating systems on their basis.

Of course, from an aesthetic point of view, black pipes are not particularly attractive. However, a steel chrome pipe does not have this drawback. In addition, the chrome product has new beneficial properties. The main ones are:

• non-susceptibility to corrosion;
• scale resistance;
• shiny surface.

The combination of these characteristics allows the use of a chrome-plated pipe not only when creating a water supply system, but also, for example, as a towel warmer that improves the interior of a bathroom, a curtain rod, a shower rack, a mirror holder, etc. And one more important detail.Chrome products are highly resistant to atmospheric oxidation. Therefore, pipes with such a coating can be installed in other extreme places of housing: kitchens and toilets.

Oval pipes

The production of oval steel pipes is regulated by the requirements of GOST 8642-68. Sizing of such products is carried out according to the following parameters:

• width and height. By width is meant the length of the major axis of the ellipse. And height is the value of this parameter of its minor axis. Moreover, the initial and final points of these segments do not lie on the inner, but on the outer surface of the pipe. When choosing a product, you need to know both of these dimensions. Due to the curvilinear shape, the assortment is formed on the basis of precisely these dimensional parameters. The height is within, and the width is mm;
• radii of curvature. These characteristics determine the level of bending of each side of the oval pipe. Values ​​of smaller radius are within mm. A larger one can be in the range of mm.

A steel pipe with an oval profile is used both in mechanical engineering and in the decoration of residential premises, buildings and porches (we are talking primarily about a variety of fences and railings).

A question may arise of such a plan: is it really impossible to dispense with a traditional round pipe in cooling radiators and hydraulic systems? So, its dignity, which consists in the maximum internal volume, is not always such. Often the most efficient heat removal from cooling coils and radiators is through their surface. And here the shape of the ellipse helps out: with the same internal volume, the surface of the oval steel pipe can be 2 times larger than that of a round one.

Good to know! Pipes with such a shape are also produced from other metals, which improves the operational characteristics of the pipelines created on their basis.

For example, a copper pipe has less thermal conductivity than a steel pipe. This has a positive effect on the quality of functioning of the hot water supply system. The aluminum pipe is characterized, among other things, by low resistance to water movement. Therefore, it is often installed in plumbing systems..

Branches - what is it and what are they for

These are the same steel pipes, only bent, used to connect the elements of pipelines in order to redirect the flow of the working medium from a certain angle. For their production, mainly carbon and low alloy steels are used, and in some cases heat and corrosion resistant steel grades. The angle of the bend of the branch can be 45, 60 or 90 degrees. The diameter of products of this type is within cm. The temperature mode of operation of the steel pipe at a nominal pressure of 16 KPa is -˚С. Depending on the production technology, these components of steel pipelines are of the following types:

1. Seamless bends;
2. Bends suture:
3. Threaded bends.

Seamless is performed using industrial casting technology, which is what distinguishes it from other types of such products. In addition, the design of these bends involves welding fittings to the ends of both connected pipes. Such a constructive solution, in fact, is the weakest point of seamless steel products, since the service life of steel pipes of this type due to the fact that they remain face to face in the fight against corrosion is reduced.

The best option is threaded bends. Thanks to the internal thread, they can be mounted at right angles.This connection provides the pipeline with a low degree of corrosion damage, a high level of safety and the ability to pump the working medium under high pressure.

Steel bending manufacturers have recently begun to apply special coatings to them. Such additional protection leads to an increase in the life of the pipelines as a whole. The most safe are spray bends.

Perforated pipe

Considering the scope of the perforated steel pipe, it goes without saying that we cannot talk about any water supply. Products of this type are used:

• in automobile mufflers. For effective sound suppression, a perforated tube is inserted into the casing with a solid wall;
• in order to organize ventilation of the premises;
• as an element of the supporting structure.

Useful informnation! Pay attention to the fact that the presence of perforation does not lead to a significant, but only to some decrease in bearing capacity. After all, the contours of the holes act as a kind of stiffeners.

Perforated pipes were widely used in the creation of drainage systems. The holes in the perforated drain pipe must be long and narrow. Wet soil forms lumps that easily penetrate round holes, but not slit-like ones. In this case, perforated drainage pipes should be characterized by a large volume. In fact, they act as a drainage channel.

The most popular are perforated products with a diameter of 100-110 millimeters. With the length of the drainage line up to 25 meters, such a section will not be enough. You will need perforated pipes with a large value of this parameter - 150-160 millimeters. If the drainage length exceeds 50 meters, it is recommended to opt for products with a diameter of at least 200 millimeters. Fortunately, modern industry produces such products with a wide range of sizes. So, the maximum length of the perforated pipe is 14 meters, the diameter can be in the range of millimeters, and the wall thickness ranges from 0.5 ... 15 millimeters.

Thick-walled steel pipe

The production and assortment of thick-walled steel pipes is regulated by the requirements of GOST 8734-75. Depending on the technology used, these products are of two types:

• seamless
• welded.

If strength is chosen when choosing the cornerstone, that is, the ability to withstand high pressure, the best solution would be to purchase a seamless thick-walled pipe. When the price factor prevails, in order to save money, preference should be given to welded thick-walled products. The weight characteristics of large diameter pipes with thick walls GOST 10706-76 are presented in the table.

Table 3

Outer diameter mm	Weight 1 meter (kg) of thick-walled pipe with wall thickness (mm)
	20	18	16	14	13	12	11	10	9	8
1420	697,4	628,6	559,5	490,3	455,6	420,9	386,1	351,2	_____	______
1220	597,8	538,9	479,8	420,5	390,8	361,1	331,3	301,4	271,5	______
1120	547,9	486,0	439,9	385,7	358,5	331,2	303,9	276,5	249,1	221,6
1020	498,2	449,2	400,1	350,8	326,1	301,3	276,5	251,6	226,6	201,7
920	448,4	404,4	360,3	315,9	293,7	271,4	249,1	226,7	204,2	181,7
820	398,5	359,6	320,4	281,1	261,3	241,5	221,7	201,8	181,8	161,8
720	348,7	314,7	280,6	246,2	228,9	211,6	194,3	176,9	159,4	141,9
630	303,9	274,4	244,7	214,8	199,8	184,7	169,6	154,4	139,2	123,9
530	254,1	229,6	204,9	179,9	167,4	154,8	142,2	129,5	116,8	104,0

 

Given the geometric dimensions of thick-walled pipes, their connection is carried out according to a special technology. Standard gas welding is ineffective here, since it cannot afford to heat the entire wall to the melting temperature of the material. The result is only an unreliable surface seam capable of collapsing under high pressure. Therefore, the installation of thick-walled pipes requires a special tool.

Helpful information! Electric welding is best suited. However, it is possible to work only with electrodes whose diameter exceeds 4 mm and exclusively at high voltages. Not every device is capable of producing such indicators over a long time interval when working with thick-walled pipes.

Before welding, these products must be cleaned and prepared.Often, a special composition is applied to the surface of a thick-walled steel pipe.

You must understand that the process of creating a quality connection will take a lot of time. You can’t call fast welding even ordinary products. And the duration of work with thick-walled pipes will increase even more.

Range of steel profile pipes

Profiled pipes - rectangular and square - are used in those structures where maximum stiffness is required with a minimum weight. This is for example:

• frameworks of canopies from pipes and greenhouses;
• racks, and also a handrail of a hand-rail;
• load-bearing racks and beams of metal structures.

Manufacturers, when they are released, must be guided by three regulatory documents:

1. GOST 13663-86. It contains technical requirements for the production process of these products. It is curious: despite the fact that for different lengths of steel profile pipes produced from corrosion-resistant steel and stainless steel, they are manufactured according to the same standards - GOST 8645-68 and 8639-82.
2. The range of profile products with a square section is taken in accordance with GOST 8639-82.
3. The assortment of rectangular pipes is specified in GOST 8645-68.

Seamless profile steel rolling is carried out according to the following technology:

• first a round billet pipe is made;
• then it is pressed into a square or rectangle;
• at the final stage, the heated pipe is calibrated to the desired size. This operation is performed on a rolling mill, or rather, on its rollers.

The production of welded shaped pipes includes the following technological operations:

• the steel sheet of the workpiece is cut into strips - measuring strips - and folded into a tape;
• the flat ribbon is deformed into a profile blank on the rollers of the molding machine, where it is refueled;
• welding of the joint is performed in a special chamber filled with an inert medium.

The strength characteristics of both options are almost identical. After all, the presence of a weld weakens the profile only to the level of 90-95% of the initial strength. In addition, during welding, heat treatment does not change the structure of ferrite grains.

Important! This is ensured by the fact that the temperature at which this process is performed does not reach a level critical for a particular grade of steel.

Marking of steel pipes of any of the above types is based on the requirements of GOST 10692-80. To do this, you can use:

• rubber stamp;
• electric pencil;
• indelible paint;
• an electrograph;
• branding method.

On the marking should be displayed: manufacturer’s trademark, dimensions, product name and steel grade.

A careful study of the assortment of steel pipes will allow you to evaluate the feasibility of using this or that product for certain purposes even at the stage of designing the structure.