GOST for water and gas pipes in force. Pipes steel water and gas. Price of steel pipes VGP

The water and gas pipe will be made of steel for a long time. Alternative options - metal-plastic conduits, ceramic, can only be used in certain areas: local water pipes, free-flow sewage, communication inside the building. However, when installed above ground, the pipeline is exposed to too much weather. This excludes the use of plastic or other products.

Characteristics of the VGP

Water and gas pipes are made from steel blanks - strips, by molding. The edges of the workpiece are welded. The seam is reinforced. Examination of the seam is the first task of quality control, as it represents a high-risk site. According to GOST 3262-75, radiography is used to determine the quality.

Water and gas pipes, as a rule, are made straight-seam, since for these products a more important quality is resistance to internal pressure, rather than resistance to external loads. Pictured is a gas pipeline.

Advantages:

• high strength, which allows the use of products for any installation method and in any areas;
• oxygen and gas impermeability - these are precisely the properties due to which gas pipelines are built and will be built only from steel products;
• low coefficient of expansion - changes in temperature and moisture do not affect the material. The pipeline does not expand, which allows the use of a rigid mount and does not require compensatory devices;
• durability - with proper maintenance is 50 years;
• affordable cost.

Disadvantages:

• rather large weight, which makes installation difficult and requires a large number of fasteners;
• the need for preventive maintenance - the metal accumulates electricity;
• the need for thermal insulation when laying in the ground - the freezing liquid expands, while the parameters of the conduit remain unchanged. This leads to damage and breakage.

VGP parameters

Dimensions and possible deviations are regulated by GOST 3262-75.

• Outer diameter - from 33 to 165 mm.
• Wall thickness - from 1 to 5.5 mm.
• Length - unmeasured ranges from 4 to 12 m, measured 4–8 or 8–12 m.

Since we are talking about water pipes, instead of the inner diameter, an indicator such as a conditional passage is used. It is given in both inches and mm.

Product varieties

Different ways of laying the pipeline and different operating conditions imply different technical characteristics from each other. Rental produces several modifications.

Material classification

The raw material in the manufacture of water and gas pipes is carbon steel of various grades. At the same time, GOST 3262-75 regulates two types of products:

• conduits made of steel of ordinary accuracy - only the mechanical qualities of the product are controlled. The chemical composition of steel is not investigated. Products are applied to household communication systems;
• high-precision steel pipeline - galvanized steel is used in the manufacture, mechanical properties are normalized by GOST 3262-75. Products are used in the construction of large highways, where high pressure resistance is important.

In fact, both types of water and gas pipes are made of steel, but they pass different levels of control. As a result, they get:

• black - without galvanizing, more often used when laying gas pipelines;
• galvanized - finished products are galvanized - immersed in a zinc melt. A protective layer is formed on the inner and outer surface of the product, which protects against corrosion. Large water mains are constructed from galvanized VGP.

Release form

Pipe water and gas GOST 3262-75 is available:

• with threaded ends (knurling or threading) - it is worth noting that the protective layer is damaged during welding, and therefore galvanized products are mounted only by the threaded method;
• without thread - welded connection is assumed.

Water pressure resistance

The wall thickness of the water and gas pipeline determines the strength and resistance to a certain hydraulic pressure. The classification is:

• light - the working pressure of the liquid should not exceed 25 kg / kV. cm;
• ordinary - assumes the same pressure, but allows water hammer;
• reinforced - pressure can reach a value of 32 kg / kV. cm.

Pipes of the VGP category are a group of water and gas pipes made of steel. Moreover, there are galvanized and non-galvanized options. Pipes are hollow, cylindrical in shape, having a longitudinal welded seam.

The category has three options for wall thickness - thick-walled, medium and thin-walled. An assortment of this nature makes it possible to use pipes suitable specifically for the project in which they are used.

Product parameters

The name speaks for itself - a pipe of this type can be used both in plumbing systems and in gas pipelines. In principle, the VGP pipe is considered a universal option for many applications.

Standard pipes have a length of segments from 4 m to 12 m. Moreover, there is a choice of material - without thread, or with cylindrical or knurled threads at the ends. Moreover, it can be short or long - it all depends on the nuances in use.

Typically, the VGP pipe has three strength categories:

1. Ordinary.
2. Lungs.
3. Reinforced.

Although such pipes are heavier than non-galvanized ones, by about 3%, the coating gives an excellent result when liquids pass through the line. The pipe does not rust, and its service life is extended significantly.

Advantages of VGP pipes

1. Standard pipes VGP GOST 3262 75 are made of high quality steel.
2. The so-called "black pipes" of the VGP have a reinforced welded seam.
3. Pipes of this type have three categories convenient for the consumer - light, reinforced and ordinary. This allows you to choose the right option for the perfect design of the highway.
4. The thread at the ends of the pipes can be long, short, or applied, depending on the wishes of the customer, to the desired side in the required parameters.
5. Pipes of this category are supplied either with or without couplings.
6. Pipe parameters can be indicated in inches, which is considered the norm.
7. The pipes being sold undergo mandatory hydro-vortex control, so compliance with the standards can be considered almost perfect.
8. Low cost with excellent product quality is the guarantor of the assigned standards and regulations.
9. Versatility in application. Pipes of the right type are ideal for installation and repair work of almost any category.
10. A huge range of pipe varieties - from hot-rolled seamless to cold-rolled and electric-welded options.
11. The presence of components - flanges, couplings, tees, bends, transitions and other things, as well as the possibility of their easy use in installation work.

As you understand, standard VGP pipes GOST 3262 75 have a wide range of applications. The presence of at least three types of this type makes it possible to use them in almost all areas of pipelines. Moreover, it is possible to select a category for the type of line, with a rich selection of pipe types for its installation.

The METALLSERVICE company supplies the entire range of steel water and gas pipes that meet the requirements of GOST 3262-75. Wholesale prices apply to all metal products.

The catalog contains galvanized and non-galvanized products DN 8–100 mm, with or without knurled or cut cylindrical threads. Rolled metal of this type is always available in warehouses in Moscow, St. Petersburg, Samara, Rostov-on-Don, Penza, Novosibirsk, Khabarovsk and other cities. Delivery is carried out throughout Russia and the Republic of Belarus. The speed of shipment depends on the ordered batch and averages 1-12 hours.

Classification of gas pipes according to GOST 3262-75

There are several length options available:

• measured (4–12 m);
• multiple measured (up to 12 m, allowance for each undercut - 5 mm, longitudinal deviation along the entire length - up to 10 mm);
• unmeasured (by individual size, within 4–12 m).

Up to 5% of the total number of off-gauge VGP pipes manufactured in accordance with GOST 3262-75 can be made with a length of 1.5–4 m. For the entire length of the thread made by knurling, the inner diameter of the products can be reduced by 10%.

The mass of 1 m of the presented metal products is indicated taking into account the density of the steel alloy of 7.85 g per cubic meter. see. At the same time, VGP galvanized pipes weigh 3% more than non-galvanized ones.

Depending on the degree of compliance with regulatory geometric parameters, pipes are divided into 2 classes:

According to the wall thickness, the products are divided into light, ordinary and reinforced. On products of the last two types, having a nominal bore of more than 10 mm, threads can be applied at both ends. The choice includes products both without thread and without couplings, and with both.

INTERSTATE STANDARD

TECHNICAL CONDITIONS

Official edition

Standartinform

UDC 669.14-462:006.354

INTERSTATE

Group B62

STANDARD

STEEL WATER AND GAS PIPES

Specifications

Water-supply and gas-supply steel pipes. Specifications

MKS 23.040.10 OKP 13 8500, 13 8501

Introduction date 01.01.77

This standard applies to non-galvanized and galvanized steel welded pipes with threaded or knurled cylindrical threads and without threads used for water and gas pipelines, heating systems, as well as for parts of water and gas pipeline structures.

(Changed edition, Rev. No. 2, 3, 5).

1. ASSORTMENT

1.1. Pipes are made according to the dimensions and weight given in table. one.

At the request of the consumer, light series pipes intended for thread rolling are manufactured according to the dimensions and weight given in Table. 2.

(Changed edition, Rev. No. 1, 3).

1.2. The length of the pipe is made from 4 to 12 m:

measured or multiple measured length with an allowance for each cut of 5 mm and a longitudinal deviation for the entire length plus 10 mm;

unmeasured length.

By agreement between the manufacturer and the consumer, up to 5% of pipes with a length of 1.5 to 4 m are allowed in a batch of off-gauge pipes.

Official edition

Reprint prohibited

© Standards Publishing House, 1976 © Standartinform, 2007

Dimensions, mm

Table 1

Table 2 Dimensions, mm

Notes:

1. For a thread made by knurling, a reduction in its inner diameter of up to 10% along the entire length of the thread is allowed on the pipe.

2. The mass of 1 m of pipes is calculated with a steel density of 7.85 g / cm 3. Galvanized pipes are 3% heavier than non-galvanized ones.

1.3. Limit deviations in pipe dimensions should not exceed those indicated in Table. 3.

Table 3

Notes:

1. The maximum deviation in the plus side along the wall thickness is limited by the maximum deviations in the mass of pipes.

2. Pipes of ordinary manufacturing accuracy are used for water pipes, gas pipelines and heating systems. Pipes of increased manufacturing accuracy are used for parts of water and gas pipeline structures.

1.4. Maximum deviations in the mass of pipes should not exceed +8%.

At the request of the consumer, the maximum deviations in mass should not exceed:

7.5% - for the party;

10% - for a single pipe.

(Changed edition, Rev. No. 2, 5).

1.5. The curvature of pipes per 1 m of length should not exceed:

2 mm - with nominal bore up to 20 mm inclusive;

1.5 mm - with nominal bore over 20 mm.

1.6. Pipe threads can be long or short. Thread requirements must comply with those specified in table. 4.

Table 4

Pipes with a nominal bore of 6, 8, 10, 15 and 20 mm, at the request of the consumer, are wound into Examples of symbols

Ordinary pipe, non-galvanized, of the usual manufacturing accuracy, random length, with a nominal bore of 20 mm, a wall thickness of 2.8 mm, without thread and without a coupling:

Pipe 20x2.8 GOST 3262-75

The same with the clutch:

Pipe M-20 x 2.8 GOST 3262-75 The same, measured length, threaded:

Pipe R-20x 2.8-4000 GOST 3262-75 The same, with zinc coating, random length, threaded:

Pipe Ts-R-20x 2.8 GOST 3262-75 The same, with zinc coating, measured length, threaded:

Pipe Ts-R-20x 2.8-4000 GOST3262-75

For pipes for thread rolling, the letter H is indicated after the word "pipe" in the symbol.

For pipes with a long thread, the letter D is indicated after the word “pipe” in the symbol. For pipes of increased manufacturing accuracy, the letter P is indicated in the symbol after the size of the nominal bore.

(Revised edition, Rev. No. 1).

2. TECHNICAL REQUIREMENTS

2.1. Pipes are manufactured in accordance with the requirements of this standard and according to the technological regulations approved in the prescribed manner, from steels according to GOST 380 and GOST 1050 without standardization of mechanical properties and chemical composition.

Pipes for parts of water and gas pipeline structures are made of steel according to GOST 1050.

2.2. At the request of the consumer, at the ends of pipes to be welded, with a wall thickness of 5 mm or more, chamfers must be removed at an angle of 35 ° -40 ° to the end of the pipe. In this case, an end ring with a width of 1-3 mm should be left.

At the request of the consumer, on ordinary and reinforced pipes with a nominal bore of more than 10 mm, the thread is applied to both ends of the pipe.

2.1, 2.2. (Changed edition, Rev. No. 3, 4).

2.3. At the request of the consumer, the pipes are equipped with couplings made in accordance with GOST 8944, GOST 8954, GOST 8965 and GOST 8966, at the rate of one coupling for each pipe.

(Revised edition, Rev. No. 3).

2.4. Cracks, captivity, swelling and sunsets are not allowed on the surface of the pipes.

At the ends of the pipes, delamination is not allowed.

Separate dents, ripples, risks, traces of stripping and other defects due to the production method are allowed, if they do not take the wall thickness beyond the minimum dimensions, as well as a scale layer that does not interfere with inspection.

On pipes made by furnace welding, it is allowed to reduce the outer diameter to 0.5 mm at the weld site if there is a gentle thickening of the inner diameter of not more than 1.0 mm in this place.

(Changed edition, Rev. No. 3, 4).

2.5. At the request of the consumer, on pipes with a nominal bore of 20 mm or more, on the inner surface of the pipe seam, the burr must be cut or flattened, while the height of the burr or its traces should not exceed 0.5 mm.

At the request of the consumer, on pipes with a nominal bore of more than 15 mm, made by the method of furnace welding and the method of hot reduction, a gentle thickening of a height of not more than 0.5 mm is allowed on the inner surface of the pipes in the weld zone.

(Changed edition, Rev. No. 2, 3, 4, 5, 6).

2.6. Pipe ends must be cut square. The value of the bevel of the end is allowed no more than 2 °. Burr residues should not exceed 0.5 mm. When removing burrs, the formation of blunting (rounding) of the ends is allowed. It is allowed to cut pipes in the mill line.

By agreement between the manufacturer and the consumer, burrs up to 1 mm are allowed on pipes with a nominal bore of 6-25 mm, made by furnace welding.

(Changed edition, Rev. No. 4, 6).

2.7. Galvanized pipes must have a continuous zinc coating over the entire surface with a thickness of at least 30 microns. The absence of zinc coating on the ends and threads of pipes is allowed.

On the surface of galvanized pipes, blistering and foreign inclusions (hardzinc, oxides, sintered charge), peeling of the coating from the base metal are not allowed.

Separate flux spots and traces of pipes being caught by lifting devices, roughness and slight local zinc deposits are allowed.

It is allowed to correct individual non-galvanized sections by 0.5% of the outer surface of the pipe in accordance with GOST 9.307.

(Changed edition, Rev. No. 3, 4).

2.8. Pipes must withstand hydraulic pressure:

2.4 MPa (25 kgf / cm 2) - ordinary and light pipes;

3.1 MPa (32 kgf / cm 2) - reinforced pipes.

At the request of the consumer, the pipes must withstand a hydraulic pressure of 4.9 MPa (50 kgf / cm 2).

2.9. Pipes with a nominal bore up to 40 mm inclusive must withstand a bend test around a mandrel with a radius equal to 2.5 of the outer diameter, and with a nominal bore of 50 mm - on a mandrel with a radius equal to 3.5 of the outer diameter.

At the request of the consumer, the pipes must withstand the expansion test:

for pipes with nominal bore from 15 to 50 mm - not less than 7%;

for pipes with a nominal bore of 65 mm or more - at least 4%.

At the request of the consumer, the pipes must withstand the flattening test up to a distance between the flattened surfaces equal to 2/3 of the outer diameter of the pipes.

2.8, 2.9. (Changed edition, Rev. No. 2, 3, 5).

2.10. At the request of the consumer, the mechanical properties of pipes for parts of water and gas pipeline structures must comply with GOST 1050.

2.11. The pipe thread must be clean, without flaws and burrs, and comply with GOST 6357, accuracy class B.

Pipes with cylindrical threads are used when assembling with seals.

2.10, 2.11. (Changed edition, Rev. No. 3, 4).

2.12. In the place of the seam, blackness is allowed on the threads of the thread, if the decrease in the normal height of the thread profile does not exceed 15%, and at the request of the consumer does not exceed 10%.

Threads with broken (for cut) or incomplete (for knurled) threads are allowed on threads, provided that their total length does not exceed 10% of the required thread length, and at the request of the consumer does not exceed 5%.

2.13. It is allowed on the thread to reduce the useful length of the thread (without run-off) up to 15% compared to that indicated in Table. 4, and at the request of the consumer - up to 10%.

2.12, 2.13. (Changed edition, Rev. No. 2, 3, 5).

2.14. Threading on galvanized pipes is carried out after galvanizing.

2.15. (Deleted, Rev. No. 3).

2.16. At the request of the consumer, welded seams of pipes are subjected to control by non-destructive methods.

(Revised edition, Rev. No. 5).

3. ACCEPTANCE RULES

3.1. Pipes are accepted in batches. The batch must consist of pipes of the same size, the same steel grade and be accompanied by one quality document in accordance with GOST 10692 with an addition for pipes intended for the manufacture of parts for water and gas pipeline structures, from steel in accordance with GOST 1050; chemical composition and mechanical properties of steel - in accordance with the document on the quality of the enterprise - the manufacturer of the workpiece.

Party weight - no more than 60 tons.

(Changed edition, Rev. No. 3, 4).

3.2. The surface, dimensions and curvature are checked for each pipe of the batch.

It is allowed to apply statistical control methods according to GOST 18242* with a normal level. Control plans are established by agreement between the manufacturer and the consumer.

The control of the outer diameter of the pipes is carried out at a distance of at least 15 mm from the end of the pipe.

(Changed edition, Rev. No. 3, 4, 5).

3.3. To control the parameters of the thread, to test for expansion, flattening, bending, the height of the internal burr, burr residues, right angle and chamfer angle (for pipes with beveled edges), mechanical properties, no more than 1%, but not less than two pipes from the lot are selected, and for pipes manufactured by continuous furnace welding, two pipes per batch.

(Changed edition, Rev. No. 3, 4).

3.4. All pipes are subjected to weight control.

(Revised edition, Rev. No. 3).

3.5. Each pipe is subjected to a hydraulic pressure test. With 100% quality control of the weld by non-destructive methods, hydraulic pressure testing may not be carried out. At the same time, the ability of the pipes to withstand the test hydraulic pressure is guaranteed.

(Revised edition, Rev. No. 6).

3.6. To check the thickness of the zinc coating on the outer surface and in accessible places on the inner surface, two pipes are taken from the batch.

(Revised edition, Rev. No. 2).

3.7. Upon receipt of unsatisfactory test results for at least one of the indicators, it is repeated tests on a double sample.

The retest results apply to the entire lot.

4. TEST METHODS

4.1. For quality control, one sample is cut from each selected pipe for each type of test.

The tensile test is carried out in accordance with GOST 10006. Instead of the tensile test, it is allowed to control the mechanical properties by non-destructive methods.

4.2. Inspection of the surface of the pipes is carried out visually.

4.3. Hydraulic testing is carried out in accordance with GOST 3845 with exposure under test pressure for at least 5 s.

4.4. The bend test is carried out according to GOST 3728. Galvanized pipes are tested before coating.

(Revised edition, Rev. No. 3).

4.4a. The expansion test is carried out according to GOST 8694 on a conical mandrel with a taper angle of 6°.

The test can be carried out on a mandrel with a taper angle of 30°.

(Changed edition, Rev. No. 3, 4).

GOST R 50779.71-99 is valid on the territory of the Russian Federation.

4.46. The flattening test is carried out according to GOST 8695.

(Revised edition, Rev. No. 3).

4.4c. Weld seam control is carried out by non-destructive methods according to normative documentation.

(Introduced additionally, Rev. No. 3).

4.5. The thickness of the zinc coating on the outer surface and in accessible places on the inner surface is controlled in accordance with GOST 9.301 and GOST 9.302, as well as with devices of the MT-41NTs, MTZON or Impulse types according to regulatory documentation.

4.6. The thread is checked with threaded ring gauges according to GOST 2533 (third class of accuracy).

In this case, the screwing of the non-going gauge-ring on the thread should be no more than three turns.

(Changed edition, Rev. No. 3, 4).

4.7. The curvature of the pipes is controlled by a straightedge according to GOST 8026 and a set of probes according to ID.

(Changed edition, Rev. No. 3, 5).

4.8. The right angle of the ends of the pipes is controlled by a 90 ° square with a size of 160 x 100 mm class 3 according to GOST 3749, with lamellar probes of set 4 according to ID or a goniometer according to GOST 5378. The bevel angle of the chamfer is controlled by a goniometer according to GOST 5378.

(Changed edition, Rev. No. 3, 6).

4.9. The control of the outer diameter is carried out with smooth micrometers in accordance with GOST 6507, with staple gauges in accordance with GOST 2216 or GOST 18360.

The wall thickness, the height of the internal burr and the height of the burrs are measured with a micrometer according to GOST 6507 or a wall gauge according to GOST 11358 from both ends of the pipe.

The length of the pipes is measured with a tape measure in accordance with GOST 7502. The thread is controlled with gauges in accordance with GOST 2533.

The control of the mass of a batch of pipes is carried out on scales not exceeding Utah with a division value of not more than 20 kg.

(Changed edition, Rev. No. 3, 4, 5, 6).

4.10. Weld seam control is carried out by non-destructive methods according to technical documentation.

(Introduced additionally, Rev. No. 4).

5. MARKING, PACKAGING, TRANSPORT AND STORAGE

5.1. Marking, packaging, transportation and storage are carried out in accordance with GOST 10692 with an addition.

5.1.1. Pipe threads must be protected from mechanical damage and corrosion by grease in accordance with regulatory documents.

Sec. 5. (Changed edition, Rev. No. 3).

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of Ferrous Metallurgy of the USSR DEVELOPERS

IN AND. Shavings, Ph.D. tech. sciences; V.M. Crow, Ph.D. tech. sciences; Yu.M. Mironov, Ph.D. tech. sciences; A.I. Postolova

2. APPROVED AND INTRODUCED BY Decree of the USSR State Committee for Standards No. 2379 of September 11, 1975

3. Periodicity of inspection - 5 years

4. REPLACE GOST 3262-62

5. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

6. The limitation of the validity period was removed by the Decree of the State Standard of the USSR dated 12.11.91 No. 1726

7. EDITION (May 2007) with Amendments No. 1, 2, 3, 4, 5, 6, approved in November 1977, December 1978, January 1987, May 1988, November 1989 , November 1991 (NUS 1-78, 2-79, 4-87, 8-88, 2-90, 2-92)

Editor L.I. Nakhimova Technical editor O.N. Vlasova Proofreader A.S. Chernousova Computer proofing I.A. Naleykina

Handed over to the set 05/14/2007. Signed for publication on 06/05/2007. Format 60 x 84 Vs - Offset paper. Headset Times. Offset printing. Uel. oven l. 0.93. Uch.-ed. l. 0.80. Circulation 126 copies. Zach. 421. From 4031.

FSUE "STANDARTINFORM", 123995 Moscow, Granatny per., 4. Typed in FSUE "STANDARTINFORM" on a PC

Printed in the branch of FSUE "STANDARTINFORM" - type. "Moscow printer", 105062 Moscow, Lyalin per., 6

GOST 3262-75 is a regulatory document in accordance with which steel water and gas pipes are produced. With the help of such pipes, which, unlike plastic products, can be successfully operated in open areas, they install pipelines for transporting liquid and gaseous media. Such steel pipes are practically indispensable in the field of capital and private construction, housing and communal services, and agriculture.

You can get acquainted with the GOST requirements for steel water and gas pipes by downloading the document in pdf format from the link below.

General information about VGP steel pipes

Water and gas steel pipes, the parameters of which are determined by GOST 3262-75, belong to products for the intended purpose, as their name indicates. The differences between their types are primarily in the method of production. However, no matter what type the steel pipes of the category under consideration belong to, all their parameters are stipulated by the provisions of such a document as GOST 3262 (75, 80, 85, 91).

So, according to this standard (3262-75, last edition of the 91st year), water and gas pipes made by welding can belong to one of the following types:

• non-galvanized;
• galvanized;
• originally made with threaded ends, which can be obtained by cutting or knurling;
• without carving.

Applications and individual parameters

The main areas of application for water and gas pipes, the geometric parameters and technical characteristics of which comply with the 3262-75 standard, are construction and repair. Pipes of this category are used for arranging gas, water communications and heating systems in cottages and multi-apartment buildings, office buildings, educational institutions, agricultural, industrial and any other facilities.

So, this type of rolled metal is used in:

• communications of cold and hot water supply;
• heating systems;
• gas pipeline networks.

GOST 3262 (75, 80, 85, 91) assumes that welded ones can be produced in measured, multiple measured and random lengths. So, according to this gradation, they have the following dimensions (according to the length of the manufactured products):

• measured - from 4 to 12 m long;
• having a length that is a multiple of the measured value;
• unmeasured with a length that is within the measured value.

The wall size is the criterion by which water and gas pipes are distinguished:

• ordinary;
• lungs;
• reinforced.

Reinforced VGP pipes are products (sometimes galvanized), the wall thickness of which is increased (accordingly, such products have more weight). They are used for the installation of pipelines through which liquid or gaseous media are transported under high pressure.

If the technical characteristics and basic geometric parameters of water and gas pipes are regulated by a regulatory document, then the customer determines the version of their design and the length of the cut. So, the most popular are pipes, at the ends of which threads are cut during the production process. The reason for their high popularity lies in the fact that they do not require welding operations for their installation.

The thread on VGP pipes can be created during their production:

• knurling (a technology that allows you to get a thread with the most accurate parameters, while it is assumed that the inner diameter of the pipe will be 10% less);
• cutting.

The thread on VGP pipes is cut or rolled at the request of the customer, and it can be either short or long.

When calculating the mass of water and gas pipes, it should be borne in mind that galvanized products weigh 3% more than those made of ferrous metal. The standard also imposes a restriction on deviations in batch weight: they should not exceed 8%.

Technical requirements

A range is formed from pipes of each type, in which their geometric parameters and theoretical weight are listed.

The steel from which pipes of the VGP category are made must also comply with the requirements specified in GOST (380, 1050), while the mechanical properties, as well as the chemical composition of the material of manufacture, are not standardized. Each type of pipe (welded, ferrous metal, galvanized, threaded) has special technical requirements, which should be discussed in more detail.

In accordance with the provisions of GOST, the following requirements are imposed on pipes of the VGP category of welded type.

1. If tubular products are connected using furnace welding technology, then in the area of ​​\u200b\u200bthe weld, their outer diameter can be reduced by half a millimeter. If there is a gentle thickening on the inside of the seam, its value should not exceed 1 mm.
2. If by welding it is necessary to connect water and gas pipes, the wall thickness of which is more than 5 mm, then chamfers must be removed at their ends at an angle of 35-40 degrees. In this case, the width of the end ring after chamfering should be in the range of 1–3 mm.
3. On the inside of the weld seam of water and gas pipes, the diameter of which exceeds 20 mm, the excess metal must be cut or flattened so that its height does not exceed half a millimeter.
4. The customer can additionally specify the characteristics of products with an internal through diameter of more than 15 mm, produced using hot reduction (drawing) technology and connected by furnace welding. According to such requirements, a gentle thickening may be present on the inside of the weld, the height of which is not more than 0.5 mm.

Threaded

Water and gas pipes, the threads at the ends of which are cut or rolled by the manufacturer, must have the following parameters.

1. The thread formed at the ends of water and gas pipes in the factory must correspond to the accuracy category "B". Its characteristics are stipulated by the provisions of GOST 6357. So, the thread must be clean, it cannot have flaws and burrs.
2. At the joints, on the threads, blackness is possible, while the height of the thread profile in such places should not be reduced by more than 15%. The customer has the right to set more stringent requirements, according to which the limit for reducing the height of the thread profile can be reduced to 10%.
3. Useful thread length (specified in the assortment and measured without run-out) can be reduced up to 15%, but the customer has the right to reduce this deviation to 10%.

1. The zinc layer, which is applied to the entire surface of the water and gas pipe at the factory, must have a thickness of at least 30 microns. At the same time, it is assumed that in the areas with threaded threads and on the ends, the zinc coating may be absent.
2. The zinc film must be applied with high quality, it must not have blistering, delamination from the base metal and foreign inclusions (oxides, sintered charge, zinc waste, etc.).
3. In GOST, the presence of flux spots on the surface of galvanized pipes, small influxes of zinc, roughness and traces left by elements of lifting devices is allowed.
4. If sections not covered with zinc are found on water and gas pipes, then they can be re-treated - provided that the total area of ​​such sections does not exceed 0.5% of the entire surface area of ​​\u200b\u200bthe given product.

1. The customer can discuss with the manufacturer the complete set of state-of-the-art couplings (8944, 8954, 8965, 8966) - one coupling for each product.
2. On the surface of the pipes, defects such as swelling, sunsets, cracks, oxide film are excluded, and on the ends of the products - delamination.
3. On the surface of water and gas pipes, there may be individual defects that are due to the production method (ripples, risks, dents, traces of stripping). At the same time, such defects should not reduce the pipe wall thickness below the tolerance specified in the assortment. A layer of scale may also be present, but it should not interfere with the inspection of the product.
4. The ends of the water and gas pipes sold to the consumer are cut at a right angle. The bevel, if it occurs during trimming, should not exceed 2 degrees. The size of the burrs remaining after trimming should not exceed half a millimeter.

The regulatory document also stipulates the control methods to which all pipes of the water and gas category are mandatory:

1. Hydraulic pressure test that the pipes must withstand:
   - ordinary and light type - 25 kgf / cm2 (2.4 MPa);
   - reinforced - 32 kgf / cm2 (3.1 MPa);
   - corresponding to special requirements - 50 kgf / cm2 (4.9 MPa).
2. Bending tests carried out on mandrels with a radius of:
   - 2.5 sizes of outer diameter - products with DN up to 40 mm;
   - 3.5 outer diameter sizes - pipes with a DN of 50 mm.
3. Expansion test for water and gas pipes with remote control:
   – 15–50 mm – not less than 7%;
   – more than 65 mm – not less than 4%.