St3sp · Q235B · DN 15–100 · Ø57–219 · zinc 60–80 µm · GOST 3262 · GOST 10704
Galvanized pipe
Welded and water-gas pipe with hot-dip galvanizing. Water supply, external networks, unpainted structures
DN 15–100 · black and galvanized · GOST 3262
Water and gas pipe
Water and gas pipe to GOST 3262 for water, gas and heating. Nominal bore 15–100, light, standard, heavy
GOST 3262-75GB/T 3091-2015ASTM A53/A53MEN 10255St2spSt3spQ195Q235A53 Gr.AS195T
Parameters
| Parameters | |
|---|---|
| Nominal bore | DN 15, 20, 25, 32, 40, 50, 65, 80, 100 |
| Outside diameter | 21.3–114.0 mm per GOST 3262 |
| Wall thickness | light, standard, heavy: 2.5–5.0 mm per GOST 3262 table |
| Length | random length 4–12 m; fixed length to specification |
| Coating | black; hot-dip galvanized, zinc at least 30 µm |
| Ends | plain ends; threaded to specification |
| Testing | hydrostatic test of every pipe |
Sizes and weight
| Size, mm | Weight, kg/m | Metres per tonne |
|---|---|---|
| 21.3×2.8 | 1.28 | 782.8 |
| 26.8×2.8 | 1.66 | 603.4 |
| 33.5×3.2 | 2.39 | 418.2 |
| 42.3×3.2 | 3.09 | 324.1 |
| 48×3.5 | 3.84 | 260.3 |
| 60×3.5 | 4.88 | 205.1 |
| 75.5×4 | 7.05 | 141.8 |
| 88.5×4 | 8.34 | 120 |
| 114×4.5 | 12.2 | 82.3 |
Theoretical weight at steel density 7.85 g/cm³. Actual batch weight is by scale and mill certificate.
Description
Water and gas pipe is a small and medium diameter welded pipe to GOST 3262-75, designated not by outside diameter but by nominal bore DN: DN 15 has an outside diameter of 21.3 mm, DN 50 — 60.0 mm, DN 100 — 114.0 mm. For each nominal bore the standard sets three wall thicknesses: light, standard and heavy. The pipe is formed from strip and welded by high-frequency current, supplied black or hot-dip galvanized, with threaded or plain ends. At mills in China this size range corresponds to GB/T 3091-2015, for export ASTM A53/A53M and EN 10255.
GOST 3262 allows steel under GOST 380 and GOST 1050 without specifying mechanical properties or chemical composition; in practice this is St2sp and St3sp, at mills in China Q195 and Q235. This is why the grade comparison for this item is nominal: the pipe is accepted by dimensions, hydrostatic test and, for galvanized pipe, by zinc coating thickness. Galvanized pipe to GOST 3262 carries a zinc layer of at least 30 µm, and its weight is taken as 3 % higher than the weight of black pipe of the same size. Wall type, coating and threading are written into the specification: the words "water and gas pipe" alone do not define the size.
During inspection at the mill, the outside diameter and wall thickness of water and gas pipe are measured with a micrometer and callipers at the ends of the sampled pipes; the wall thickness is matched against the selected type: light, standard or heavy. The weld and ends are examined; on galvanized pipe the zinc layer is measured with a magnetic thickness gauge, on threaded pipe the thread is checked with a gauge. The heat number in the marking is matched against the mill test certificate (MTC), which states size, grade and hydrostatic test result. The bundle tag and strapping are checked. Rejects recorded in the report are replaced; the replacement is supplied by the manufacturing mill under its contract with the bureau.
Applications
- internal water supply and building heating
- low-pressure gas lines
- small-diameter external water supply networks
- fencing, posts and handrails
- irrigation and service water lines at agricultural enterprises
- greenhouse and canopy frames
Packing and shipment
Bundles strapped with steel band; threaded ends with protective caps; the bundle carries a mill tag with size, wall type, coating and heat number.
Grade equivalents
| GOST | GB (China) | ASTM | EN | Note |
|---|---|---|---|---|
| Steel 20 | 20# | A106 Gr.B | P235GH | Seamless pipes. Nearest equivalents by composition and strength; test requirements differ between the standards |
| Steel 45 | 45# | 1045 (A519) | C45 | Seamless pipes for machining, nearest equivalents. A519 is a standard for mechanical tubing; C45 under EN 10083 is a steel grade, tubes in it are made to EN 10297-1 |
| 09G2S | Q355B | A572 Gr.50 | S355J2H | Low-alloy steel, nearest equivalents. Before GB/T 1591-2018 the grade was designated Q345B; A572 is a standard for rolled products, not for pipe; S355J2H is a hollow section grade under EN 10219 |
| St3sp | Q235B | A53 Gr.B | P235TR1 | Welded pipes. A53 Gr.B is the nearest equivalent: its tensile strength is higher than that of Q235B |
| St3sp | Q235B | A500 Gr.B | S235JRH | Hollow sections. A500 specifies a higher yield strength than Q235B; structural design uses the standard stated in the specification |
| St2sp, St3sp | Q195, Q235 | A53 Gr.A | S195T | Water and gas pipes. GOST 3262 does not specify mechanical properties, so the grade comparison is nominal |
| K42 (GOST 20295) | L245 (GB/T 9711) | API 5L Gr.B | L245NB | Spiral-welded pipes. A strength class by tensile strength, not a steel grade |
| 08Kh18N10 | 06Cr19Ni10 | TP304 | 1.4301 | Stainless pipes. Austenitic 18-10 steel; 03Kh17N14M3 corresponds to TP316L and 1.4404 |
Equivalents are the closest match, not identical: chemistry and tolerances differ between standards. The exact grade and standard are written into the contract.
Related items
St3sp · Q235B · Ø57–530 · GOST 10704
Longitudinally welded pipe
Round pipe from strip with a high-frequency weld. Structures, fencing, low-pressure water and gas
Buyer questions
How to read a mill test certificate for pipe
The certificate (MTC) states the standard, steel grade, size, heat number, chemical composition by element, mechanical properties of the test specimens (yield strength, tensile strength, elongation), the hydrostatic test result and, for welded pipe, the result of non-destructive testing of the weld. The heat number in the certificate is matched against the marking on the pipe and the bundle tag: this is the only link between the document and the metal. The bureau checks this match at the mill before shipment and attaches the certificate to the inspection report.
How a seamless pipe differs from a welded one and when each is needed
A seamless pipe is rolled from a solid billet, it has no weld, and it goes where there is pressure, temperature or alternating load: boiler plants, steam, hydraulics, machine parts. A welded pipe is formed from strip and welded by high-frequency current; at the same size it is simpler to produce, and the weld passes a hydrostatic test and non-destructive testing. For structures, fencing, water lines and low-pressure gas lines a welded pipe does the job. The choice is fixed in the specification by the project, not by price.
How the tonnage of a pipe batch is calculated
The theoretical weight per metre of round pipe is calculated as 0.02466 · (D − t) · t, where D is the outside diameter and t the wall thickness in millimetres, steel density 7.85 g/cm³. For a hollow section: 0.0157 · t · (a + b − 2.86 · t). The actual weight is determined by weighing at the mill and is stated in the packing list. Whether settlement is by theoretical or actual weight is fixed in the specification before the order is placed: on thin walls the difference between them is noticeable.
What is checked during batch inspection of pipes at the mill
Outside diameter and wall thickness with a micrometer and callipers at both ends of the sampled pipes, ovality, wall-thickness variation, straightness, condition of the ends and bevel, the weld of welded pipe from outside and, where accessible, from inside, marking on every pipe, the bundle tag and matching of the heat number against the mill test certificate. The results are entered in a report with photo documentation. Rejects recorded in the report are replaced; the replacement is supplied by the manufacturing mill under its contract with the bureau.
What quantity can be ordered
The batch is sized to your quantity — send a specification with sizes, grades, acceptance standard and lengths. The manufacturing mill confirms the batch for a specific size range; the bureau agrees the inspection and acceptance procedure in the contract. Several sizes in one batch are sourced from one mill or from several if their size ranges differ.
Price request
Send your specification and we will quote your batch
Steel pricing depends on grade, size, tonnage and delivery terms on the day of contract. A number on the page would be wrong by the time you read it.
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