The existence of gas and water pipelines forces manufacturers to master the production of universal products. As a result, steel products of a new type ˗ water-gas-supply (VGP) pipes were developed. They are characterized by a cylindrical shape and have a weld along the length. Carbon steel is used as a raw material for their production, and the manufacturing technology is regulated by the requirements of GOST 3262-75.
Steel pipes have been used in water and gas pipelines for decades
Content
Types, advantages and disadvantages
The main scope of water and gas steel pipes is housing and communal services. The reason for this lies in the fact that mounting products from other materials in many areas is not allowed. In particular, the regulatory documents in force in our country prohibit the creation of a gas pipeline based on plastic pipes, including from those at the peak of popularity today polyethylene and metal-plastic. As a result, steel is still indispensable in the manufacture of water and gas pipeline elements. In terms of resistance to external load, pipes made from it are comparable with all-metal bars of the same diameter.
GOST 3262 subdivides these products into the following types:
- without thread;
- with knurled or cut threads;
- galvanized;
- un galvanized (black).
Versatility is far from the only advantage of a steel water pipe.
Other advantages include:
- Relatively light weight combined with high strength
- steel is characterized by a small coefficient of expansion during heating;
- affordable price;
- wide selection of fittings. Damaged steel water pipe can always be easily replaced;
- galvanized products show excellent corrosion resistance. Their only drawback is the difficulty of assembling the gas pipeline using fittings.
The advantage of galvanized steel pipes is corrosion resistance
In general, gas and water metal pipes have no obvious minuses. Welds are perhaps the weakest link. However, leading manufacturers use expensive radiographic equipment to control their quality. Therefore, as a rule, no claims are made against their products.
Helpful information! In industry and construction, with the help of non-galvanized GWP pipes, telecommunication networks are also laid.
Classification and Specifications
The division into types of steel water and gas pipes is carried out according to the following criteria:
- production technology;
- processing method (galvanized, non-galvanized);
- manufacturing accuracy;
- Wall thickness. According to this parameter, the products are reinforced (with a wall thickness of 2.5 ... 5.5 mm), ordinary (2 ... 4.50 mm) and light (1.8 ... 4 mm).
Each type of steel pipe is manufactured using a specific technology.
Manufacturing accuracy is divided into ordinary and high. This group includes products intended for domestic use. An increased category includes a range of water and gas pipes used to create industrial communications.
Table 1. The range of VGP steel pipes in accordance with GOST 3262-75
| Outside diameter | Conditional pass | Weight 1 meter pipe kilograms | Pipe wall thickness | ||||||
| reinforced | ordinary | easy | reinforced | ordinary | lungs | ||||
| 165 | 150 | 21,63 | 17,81 | 15,88 | 5,50 | 4,5 | 4 | ||
| 140 | 125 | 18,24 | 15,04 | 13,42 | 5,50 | 4,5 | 4 | ||
| 114 | 100 | 13,44 | 12,15 | 10,85 | 5 | 4,50 | 4 | ||
| 101,3 | 90 | 10,74 | 9,6 | 8,44 | 4,50 | 4 | 3,50 | ||
| 88,5 | 80 | 9,32 | 8,34 | 7,34 | 4,50 | 4 | 3,50 | ||
| 75,5 | 60 | 7,88 | 7,05 | 5,71 | 4,50 | 4 | 3,2 | ||
| 60 | 50 | 6,16 | 4,88 | 4,22 | 4,5 | 3,50 | 3 | ||
| 48 | 40 | 4,34 | 3,84 | 3,33 | 4 | 3,5 | 3 | ||
| 42,3 | 32 | 3,78 | 3,09 | 2,73 | 4 | 3,20 | 2,8 | ||
| 33,5 | 25 | 2,91 | 2,39 | 2,12 | 4,0 | 3,20 | 2,80 | ||
| 26,80 | 20,0 | 1,86 | 1,66 | 1,5 | 3,20 | 2,80 | 2,50 | ||
| 26,80 | 20,0 | — | — | 1,42 | — | — | 2,35 | ||
| 21,3 | 15 | 1,43 | 1,28 | 1,16 | 3,20 | 2,80 | 2,5 | ||
| 21,3 | 15 | — | — | 1,1 | — | — | 2,35 | ||
| 17 | 10 | 0,98 | 0,80 | 0,74 | 2,8 | 2,20 | 2 | ||
| 13,5 | 8,0 | 0,74 | 0,61 | 0,57 | 2,8 | 2,20 | 2 | ||
| 10,2 | 6 | 0,47 | 0,40 | 0,37 | 2,50 | 2,0 | 1,8 | ||
The main characteristics of water and gas steel pipes include a conditional passage (generally accepted designation of remote control). Its value in VGP products ranges from 6 ... 150 millimeters. Other parameters, including diameter, must exactly correspond to the above GOST. The same applies to the assortment of water and gas pipes. Specific figures are presented in table No. 1. The length of these products ranges from 4-12 meters.
Are produced VGP pipes of carbon steels, grades of which are indicated in two state standards dated 1988 - 380 and 1050. The deviation of the mass of products of any standard size from the nominal value should not be more than 8%. The permissible curvature of the welded water and gas pipes depends on the nominal bore. If the remote control exceeds 20 mm, the value of this parameter should be less than 2 mm. For pipes with remote control up to 2 centimeters - no more than 1.5 millimeters.
Special requirements GOST 3262
In this regulatory document, in addition to the requirements for the assortment of steel water and gas pipes, additional quality criteria are contained. Let us briefly dwell on them.
Finished pipes pass quality control in accordance with GOST
Cracks, visible swellings, sunsets, delamination are not allowed. However, if the flaws are insignificant and are due to pipe manufacturing technology (for example, welding was carried out in a furnace), then the finished product is not considered defective. The “allowed” defects include traces of stripping, small dents, and a layer of scale.
During the tests, standard pipes are required to withstand pressure (in this case, hydraulic) up to 2.40, and reinforced pipes up to 3.10 MPa. Particularly responsible structures should use products that will not fail at a pressure of 4.90 MPa.
Important! When evaluating the quality of galvanized steel water and gas pipes, pay special attention to the protective zinc coating. It must be continuous. The thickness of this layer is at least 30 micrometers.
GOST 3262 allows the presence on the surface of pipes of flux spots, local zinc sagging and traces of transportation using special equipment to capture cargo. At the same time, products cannot have bubbling and any inclusions (hartsink, metal oxides, sintered charge).
At the request of the customer, tests for bending, flattening and distribution are carried out. The requirements for such studies should be formulated by the consumer.
VGP pipes are galvanized. Assortment and recommendations for use
These products are classified in accordance with the already familiar to us GOST 3262-75. That is, they are reinforced, ordinary and light.
Reinforced steel pipes VGP pipes are used in industrial highways
If we talk about the assortment, then the geometric dimensions should be as follows:
- wall thickness - not less than 2.5 and not more than 4.5 millimeters;
- the diameter of the gas and water steel galvanized pipe ranges from 10-80 millimeters;
- length varies in the range of 4m ≤ L ≤12m.
This variety allows you to make the right choice of pipe options for the intended operating conditions. For example, if aggressive liquids capable of destroying communications are transported through the pipeline, reinforced products are recommended. Moreover, the installation must be carried out using galvanized parts. In addition to the fact that this metal gives products strength, reliability and durability, it acts as a kind of water purifier.
Another argument in favor of the use of galvanized water and gas pipes is as follows: in comparison with products made of ferrous metal, they withstand more pressure.The limit value of this parameter is 50 atmospheres! As competitors, maybe only seamless steel pipes. And the operational characteristics of both types of products are comparable. However, the cost affordable to the wallet of our average compatriot has made the galvanized water and gas pipe one of the leaders in this segment of the building materials market.
