What is the size of a 4 in a steel pipe specification?

There is a misunderstanding among many people who have first contact with this question, taking the question as an example, they mistakenly believe that 4 points is an imperial unit of length.

Therefore, this kind of tube is not said to be the inner diameter, and the outer diameter should be equal to the actual score of the imperial system, but the essence is not like this, but it is called so, just close, such as 1 point converted to the metric system; 1 point =

So that the 4 points are; *4 =

But this kind of tube is not this value regardless of the inner or outer diameter;

According to the national standard YB (T)44 - 86 regulations, 4 points are divided into thin walls, ordinary, thickened three kinds, thin walls; Outer diameter Wall thickness;

Ordinary; Outer diameter Wall thickness;

Thickened; Outer diameter Wall thickness;

It can be seen that the outer diameter of these three tubes is the same, but due to the different wall thicknesses, the inner diameter is not the same, but it is not equal to the imperial 4 points.

I don't know what the 4 points I am referring to, so let's choose the answer for myself!

Concentrate; In engineering, this kind of pipe is called a low-pressure fluid transfer pipe. Only this kind of pipe is called according to the imperial size, in the early 80s of the last century, there was a regulation, that is, the abolition of the imperial standard, and the use of the metric standard, that is, according to the International system of units.

At the same time, there is a hard and fast rule, and all the pipes in the imperial standard are accordingly prescribed and called; For example, 4 points are called D15, 6 points are called D20, 1 inch is called D25--- and so on. But in practice, the British model name is still used.

The diameter of the tube refers to the inner diameter of the tube. Because the wall thickness is different, the outer diameter is also different, such as 4 pipes with many outer diameters. The imperial system divides 1 inch into 8 points, so 4 points is 1 2 inches, 6 points is 3 4 inches, and 8 points are 1 inches.

4 points, 6 points, and 1 inch are imperial expressions.

4 in charge of 1 2"--- pipe diameter.

15mm。That is, the length of the metric system is used in the units of the municipal system, and the habit of the Chinese is like always using kilograms instead of kilograms, and "points" is also a unit of length, 1 foot = 10 inches, 1 inch = 10 points.

6 mins 3 4 inches 20mm.

4 minutes 1 2 inches 15mm.

The pipes are calculated with the inner diameter, but the threads of the pipeline are calculated by the middle diameter, which is represented by the diameter DN, and the thread is divided into metric M and imperial G, and the pipe thread is generally used in the imperial system, and the thread angle is 55 degrees, and the metric system is 60 degrees.

Common specifications1 foot = 12 inches, 1 inch = 8 cents.

Imperial commonly known as imperial pipe thread specification, metric dn specification, pipe outer diameter.

1 point, G1 8, DN6, 10 mm.

2 points, G1 4, DN8, 12 mm.

3 points, G3 8, DN10, 16 mm.

4 points, G1 2, DN15, 20 mm.

6 points, G3 4, DN20, 25 mm.

4 is divided into corresponding caliber DN15, that is, the diameter is 15mm, and the outer diameter is close to 20mm.

Tube control:

4 is divided into the corresponding caliber DN15, that is, the diameter is 15mm;

6 is divided into corresponding caliber DN20, that is, diameter 20mm;

1 inch is the corresponding caliber DN25, that is, the diameter is 25mm;

The size is the corresponding caliber DN32, that is, the diameter is 32mm;

The inch is the corresponding caliber DN40, that is, the diameter is 40mm;

2 inches is the corresponding caliber DN50, that is, the diameter is 50mm;

The expression of the pipe diameter shall comply with the following provisions:

1) The diameter of water gas transmission steel pipes (galvanized or non-galvanized), cast iron pipes and other pipes should be expressed in the nominal diameter DN;

2) Seamless steel pipes, welded steel pipes (straight seams or spiral seams), copper pipes, stainless steel pipes and other pipes, the pipe diameter should be expressed by the outer diameter wall thickness;

3) Reinforced concrete (or concrete) pipes, clay pipes, acid-resistant ceramic pipes, cylinder tile pipes and other pipes, the pipe diameter should be represented by the inner diameter d;

4) For plastic pipes, the diameter of the pipe should be expressed according to the method of product standard;

5) When the design uses the nominal diameter dn to represent the pipe diameter, there should be a comparison table between the nominal diameter dn and the corresponding product specifications.

4 in charge of 1 2"- Pipe diameter, the diameter of the pipe refers to the inner diameter of the pipe. Due to the different wall thicknesses, its outer diameter is the inner diameter + 2 * wall thickness.

The size of the 4-point tube is DN15, i.e. the diameter is 15mm; The size of the 6-point tube is DN20, that is, the diameter is 20mm; The size of the 1-inch tube is DN25, i.e. the diameter is 25mm.

1. Calculation method

The so-called 4 division refers to the fact that the diameter (inner diameter) of the pipe is 4 points. 1 inch = millimeter, every 1 8 of an inch is a minute, two points is 1 4 of an inch, and a quarter is 1 2 of an inch, and so on. The conversion is as follows:

1 point = 1 8 inches = DN6

2 points = 1 4 inches = DN8

3 points = 3 8 inches = DN10

4 points = 1 2 inches = DN15

6 points = 3 4 inches = DN20

8 points = 1 inch = DN25

Here DN stands for nominal diameter, in mm, for example, the nominal diameter of a container with an inner diameter of 500mm is marked as DN500.

2. Pipe diameter

Generally speaking, the diameter of the tube can be divided into outer diameter, inner diameter, and nominal diameter. For example, the outer diameter of a seamless steel pipe with an outer diameter of 108 with a wall thickness of 5mm is represented by D108*5, and the plastic pipe is also represented by an outer diameter, such as DE63; Others, such as reinforced concrete pipes, cast iron pipes, galvanized steel pipes, etc., are represented by DN, and the nominal diameter is generally expressed in the design drawings, and the nominal diameter is a standard artificially specified for the convenience of design, manufacturing and maintenance, also known as the nominal diameter, which is the specification name of the pipe (or pipe fittings).

The data is as follows:

dn15 ，dn20 ，dn25 ，dn32 ，dn40 ，dn50 。

1、dn15...4 pipes, inner diameter 15mm, outer diameter 23mm, wall thickness 4m

2、dn20...6 pipes, inner diameter 20mm, outer diameter 27mm, wall thickness 3,5mm

3、dn25...1 inch tube, inner diameter 25mm, outer diameter 32mm, wall thickness 3.5mm

4、dn32...1. 3 inches by four molecules) inner diameter 32mm, outer diameter 38mm, wall thickness 3mm

5、dn40...1 by two molecules 1 inch).The inner diameter is 40mm, the outer diameter is 48mm, and the wall thickness is 4mm

6. DN50 is a 2-inch pipe with an inner diameter of 50mm, an outer diameter of 56mm and a wall thickness of 3mm

Usually the 4 subdivision is in inches, so the 4 subdivision is 1 2 inches (4 8 = 1 2), and one inch =, so the inner diameter of the 4 subdivision is, and this is the inner diameter of the DN15 water pipe. 4 points is the name given to the length of the diameter of the imperial pipe, which is 1 2 inches. The metric inch is equal to 8 cents, and the metric = 3 4 inches = 1 2 inches = 15mm

Also, keep in mind that pipes are calculated with inner diameters.

Household water pipe specifications and sizes: general household water pipe specifications.

There are: DN15 (4 pipes), DN20 (6 pipes), DN25 (1 inch tube), DN32 (1 inch 2 tubes), DN40 (1 inch half tube), DN50 (2 inch tubes), DN65 (2 inch half tubes), DN80 (3 inch tubes), DN100 (4 inch tubes), DN125 (5 inch tubes), DN150 (6 inch tubes), DN200 (8 inch tubes), DN250 (10 inch tubes), etc.

It means that the normal bearing pressure of the pipe is 16kg (kg), which is the larger the value.

The higher the pressure.

Water Hose 25 1

The meaning of 25 is that its outer diameter is 25The actual corresponding nominal diameter.

It's DN20 (which is often referred to as 6 points). You can go and buy a 6-point faucet. You can also go and buy a 4-point faucet (just add a variable diameter between the pipe and the faucet).

The style and material of household faucets are ever-changing, but they are connected to the pipes.

The parts are divided into sizes such as 4 points, 6 points, and 1 inch. Don't worry about buying the wrong one.

The diameter of the 4 subdivision is 15mm, the inch is 4 minutes, the outer diameter is, the approximate inner diameter is 15mm, and the wall thickness is. In the water supply at home, we often use a large number of water pipes, and there are many types of water pipes, among which 4 pipes and 6 pipes are more. In general, it is enough to use 4 pipes when wiring.

However, there are multiple outlets for actual water use, so as to avoid insufficient water supply such as slow water flow in the later stage, so it is recommended to choose 6 pipes for the main line pipeline.

The origin of the name of 4 in charge"4 points" is the name given to the length of the diameter of the pipe in the imperial system, that is, 1 2 inches is equal to the metric system. The international standard for the application of metal piped water supply systems was formulated by the British Empire in its heyday, and the size of this standard is based on inches. The pipe thread (thread connection) and faucet standards in the relevant standards have been used to this day, and the colloquial language is also mostly used "four pipes", "six points", "one inch pipe" and so on.