(6) Welded steel pipe (GB3092-93) for low-pressure fluid transportation and galvanized welded steel pipe (GB3091-93).
Standard:
Article 1: It is suitable for pipelines for conveying water, compressed air, gas, steam, condensed water and heating system. Galvanized pipes are used for conveying water and the condensed water, and the non-galvanized pipes for conveying air and gas;
Article 2: Common used materials are Q215AF, Q215A, Q235AF, and Q235A.
(7) Spiral welded steel pipe (SY5036-83, SY5037-83)
Standard:
Article 1: Applicable to steam, water, air, oil and oil and gas pipelines;
Article 2: Used in DN ≥ 200 (non-corrosive medium);
Article 3: The materials are Q235AF, Q235A, SS400, SM400B, 16Mn.
Requirements: Replace seamless steel tubes and glass steel tubes in non-corrosive media, which should be widely used.
(8) Steel coiled pipe
a. Austenitic stainless steel welded steel tubes (HG20537.2-92) for shell-and-tube heat exchangers.
Standard:
Article 1: Applicable to heat transfer tubes, coils, etc. with a design pressure not greater than 4.0 MPa;
Article 2: Steel No.: 304, 304L, 321, 316, 316 L;
Requirements: Priority 321 <304 < 304L < 316 < 316 L is selected.
b. Austenitic stainless steel welded steel pipe for piping (HG20537.3-92, HG20537.4-92).
Standard:
Article 1: It is applicable to chemical, pharmaceutical, biochemical, light industry, textile engineering piping and pipe fittings with pipeline pressure greater than 5.0 MPa, and can also be used for pressure vessel casing adapter tube, coil, etc.;
Article 2: The hot-rolled cold-rolled strip and steel sheet are formed by continuous process, and the welding is carried out by the process shown in Table 15-48 of the Second Handbook of Chemical Process Design Manual. HG20537.3-92 is suitable without welding wire. HG20537.4-92 is suitable for welded pipe with welding wire and with large diameter or thick wall.
Article 3: Common steel numbers 304, 321, and 304L.
The specifications of welded steel pipes are as follows:
| 材料 |
PN Mpa |
DN |
| 200 |
250 |
300 |
350 |
400 |
450 |
500 |
600 |
700 |
800 |
| welded carbon steel pipes (Q235, 20#) |
0.25 |
5 |
5 |
5 |
5 |
5 |
5 |
5 |
6 |
6 |
6 |
| 0.6 |
5 |
5 |
6 |
6 |
6 |
6 |
6 |
7 |
7 |
7 |
| 1 |
5 |
5 |
6 |
6 |
6 |
7 |
7 |
8 |
8 |
9 |
| 1.6 |
6 |
6 |
7 |
7 |
8 |
8 |
9 |
10 |
|
12 |
| 2.5 |
7 |
8 |
9 |
9 |
10 |
11 |
12 |
13 |
15 |
16 |
| welded stainless steel pipes |
0.25 |
3 |
3 |
3 |
3 |
3.5 |
3.5 |
3.5 |
4 |
4 |
|
| 0.6 |
3 |
3 |
3.5 |
3.5 |
3.5 |
4 |
4.5 |
5 |
5 |
|
| 1 |
3.5 |
3.5 |
4 |
4.5 |
4.5 |
5 |
6 |
7 |
7 |
|
| 1.6 |
4 |
4.5 |
5 |
6 |
6 |
7 |
8 |
9 |
10 |
|
| 2.5 |
5 |
6 |
7 |
9 |
9 |
9 |
12 |
13 |
15 |
|
(9) Cast iron pipe
Cast iron pipes are divided into ordinary cast iron pipes and ferrosilicon pipes.
A. Ordinary cast iron pipe
Ordinary cast iron pipes are made of high quality grey cast iron. They are often buried under the ground as water main pipe, gas main pipe and indoor drainage pipes. It can also be used to transport acid, alkali, and sexual solutions. It cannot be used to transport steam, and it cannot be used to transport explosive and toxic media. The cast iron pipe has a diameter of 50 to 1500 mm, a wall thickness of 7.5 to 30 mm, and a pipe length of 3 m, 4 m, and 6 m.
The drainage cast iron pipe has only one type of socket type, the diameter is 50-200mm, the wall thickness is 4-7mm, and the pipe length is 0.5m, 1m, 1.5m, 2, etc., but generally 2m.
B. Silicon cast iron pipe
The silicon cast iron pipe has two kinds of high silicon cast iron pipe and anti-chlorinated silicon iron pipe. The high silicon cast iron pipe can resist corrosion of various strong acids. The anti-chlorinated silicon iron pipe can resist hydrochloric acid of various concentrations and temperatures, and the ferrosilicon pipe is often used in chemical pipeline industry. High silicon cast iron pipe and anti-chlorinated silicon iron pipe are used to transport corrosive media with a nominal pressure of 0.25 MPa or less. The ferrosilicon tube has good heat resistance up to 900 °C. Ferrosilicon tubes are brittle and are prone to cracking when subjected to slight knocks, collisions, localized heat or rapid cooling. It is hard but brittle, hence difficult to maintain.
