The steel pipe is a cylindrical tube and is the most used product in the steel industry. The main use of steel pipes is to transport oil, gas and water over long distances. In household appliances, for example, refrigerators, they use ordinary steel pipes, as well as in heating and water supply systems. Steel pipes are available in a wide variety of sizes and can also be used for structural requirements (hand rails and tube pins).
Main types
Metal pipes are distinguished by the most basic parameter - their diameter. It is possible to correctly calculate the transportation of a particular fluid through a pipe only by knowing the thickness of the pipe walls and its diameter. Masters often rely on calculations already tested by time and experience in their work. Standard diameters of metal pipes are very helpful in choosing the installation option for a particular pipeline.
Before proceeding with the classification of pipes by diameter and the immediate purpose associated with this parameter, you need to find out what characteristics the pipe has. They are needed in the calculations of the system, which will be laid from pipes, its throughput and to maintain operability under loads.
Types of diameters
There are several varieties of pipe diameters:
- Conditional - this is the diameter determined by the inner wall, calculated in millimeters, sometimes it is rounded in inches.
- Nominal.
- Outer. On this basis, pipes are classified into small, medium and large, as well as sizes - from 102 mm to 426 mm and above. A metal pipe with a diameter of 50 mm, according to this classification, is small.
- Interior. This parameter is very important for butt joints, the so-called fittings.
- The wall thickness of the pipe is not the most important, but indispensable indicator in any calculation.
Large diameter metal pipes are now in great competition with plastic counterparts. They are also available in different diameters, but manufacturers are trying to adhere to existing standards so that systems can be joined without additional effort.
Diameter Unit
An ordinary consumer is unlikely to immediately orient in the classification and labeling of pipes not only from metal, but also from plastic. If you can still determine the outer or inner diameter, then its size is more complicated. If it is indicated in millimeters, then everything is simple, but with inches it is not immediately clear. Professionals are used to the fact that the designation comes with such a “″” symbol, it is indicated after the numbers, often inches are determined with fractions, but you need to get used to it. Converting the diameter of metal pipes to centimeters is not so difficult, it is enough to multiply the desired figure by 2.54. If the figure is not integer, then it is customary to round it.
Measure the diameters of metal pipes yourself. When buying this parameter, you can look at the markings, but there are cases when it is necessary to measure already installed communications in order to partially replace them. For this, we will need the following information.
Parameter Definition
To know the diameter of the pipe is elementary, you just need to measure it. For this, special devices and tools are not required, just roulette or tape. She needs to wrap the pipe and record the result, then make the usual calculation: multiply the resulting number by Pi, that is, its value is 3.1415. For example, if after measuring it turns out 4 cm, multiplying by Pi, we get 12.56 mm.
You can find out the inner diameter yourself, for this you should know the thickness of the pipe wall. If there is a cut, then this is simple: just attach a ruler with a millimeter value to the end and write down the result. Any data obtained is multiplied by two, and then subtracted from the outer diameter, which you will find earlier. Masters often have a vernier caliper at hand: you need to attach it to the pipe and see the result on a scale.
Large diameters
Metallurgical enterprises produce pipes for various purposes, large diameters, which are used in various fields of activity. For example, in heating plants, industry and shipbuilding, as well as in road construction, for sewage and drainage systems, bridge building. There are pipes with a very large diameter, which are used in a specific direction, for example, when transporting gas or oil products, as well as when diverting a river bed during construction.
The diameters of metal pipes are important to consider during construction, especially if they are large. The length of the pipeline depends on this parameter. Despite the purpose of the pipe, it must be coated with compounds that reduce corrosion. Systems of large pipes are difficult to install and operate, all because they are difficult to bend, turning sections require careful welding and calculation. Underground, it is difficult to work with such structures and eliminate malfunctions that arise during operation.
Pipes of large diameter according to GOST have different deviations than pipes of smaller diameter. For example, if the wall thickness is up to 12 mm, then the fluctuation of the magnitude can be up to 0.8, both up and down. Large batches of such pipes indicate the total weight, so there may be significant discrepancies in the documents and the actual wall thickness if it is checked directly at the facility.
Price
Metal pipes, the diameters and price of which are highly dependent on each other, differ in cost:
- square profile steel pipe from 40 rubles per linear meter - up to 5697 rubles (it all depends on the diameter and wall thickness);
- rectangular profile pipe from 40 rubles. per linear meter - up to 611 rubles;
- VGP steel pipe from 73 rub. per meter - up to 595 rubles.
These are approximate values, which may vary in different regions. The cost of a profile depends on its purpose, on what steel it is made of, which protective coating is applied to metal pipes. Diameters, price - these are two parameters that determine the purpose of the pipe, its quality. Different prices exist for wholesale buyers, large companies or individuals. Black, un galvanized pipes are suitable for the gas pipeline, but galvanized pipes with diameters from 50 to 150 mm are intended for drainage and plumbing.
Large diameters of steel pipes during production require compliance with all norms and rules, therefore they are subjected to quality control. They must withstand significant bending, compression and high pressure loads.