Steel 20 · 09G2S · Ø32–426 · GOST 8732
Seamless hot-finished pipe
Pipe without a weld from a solid billet for pressure, steam and hydraulics. Steel 10, 20, 45, 09G2S
AISI 304 · 316L · 08Kh18N10 · 03Kh17N14M3 · Ø10–325 · GOST 9941 · ASTM A312
Stainless steel pipe
Pipe in austenitic 304 and 316L steel, welded and seamless. Food, chemical and water media
GOST 9941-81GOST 11068-81GB/T 14976-2012GB/T 12771-2019ASTM A312/A312MEN 10216-5EN 10217-708Kh18N1012Kh18N10T03Kh17N14M3304304L321316L06Cr19Ni10022Cr17Ni12Mo21.43011.4404
Parameters
| Parameters | |
|---|---|
| Outside diameter | 10–325 mm |
| Wall thickness | 1.0–12 mm |
| Length | 6 m; fixed length to specification |
| Steel grade | 304, 304L, 316L, 321; 08Kh18N10, 03Kh17N14M3, 12Kh18N10T per GOST |
| Production method | seamless per GOST 9941; welded per GOST 11068 |
| Surface | matte pickled; ground; polished to specification |
| Testing | hydrostatic test or eddy-current test; chemical composition per heat |
Sizes and weight
| Size, mm | Weight, kg/m | Metres per tonne |
|---|---|---|
| 12×1 | 0.271 | 3 686 |
| 16×1.5 | 0.536 | 1 864 |
| 20×1.5 | 0.684 | 1 461 |
| 25×2 | 1.13 | 881.5 |
| 32×2 | 1.48 | 675.8 |
| 38×2 | 1.78 | 563.2 |
| 45×2 | 2.12 | 471.5 |
| 51×2 | 2.42 | 413.8 |
| 57×3 | 4 | 250.3 |
| 76×3 | 5.4 | 185.2 |
| 89×3 | 6.36 | 157.2 |
| 108×4 | 10.3 | 97.5 |
| 159×4.5 | 17.1 | 58.3 |
| 219×6 | 31.5 | 31.7 |
| 325×8 | 62.5 | 16 |
Theoretical weight at steel density 7.85 g/cm³. Actual batch weight is by scale and mill certificate.
Description
Stainless pipe is produced from austenitic chromium-nickel steel in two ways. Seamless pipe is hot-worked from a billet and finished by cold or warm rolling to precise size and a smooth surface — size range to GOST 9941-81, at mills in China GB/T 14976-2012, for export ASTM A312/A312M and EN 10216-5. Welded pipe is formed from cold-rolled coil and welded by TIG or plasma welding without filler, after which the weld is rolled and the pipe is heat treated — to GOST 11068-81, GB/T 12771-2019, ASTM A312 in the welded version and EN 10217-7. Seamless pipe is taken for pressure media; welded for structures, railings and low-pressure pipelines.
Grade 304 is an 18-10 type steel, about 18 % chromium and 8–10 % nickel; under GOST it corresponds to 08Kh18N10, at mills in China 06Cr19Ni10, under EN 1.4301. Grade 316L contains 2–3 % molybdenum and reduced carbon, resists chlorides and acids; the nearest GOST equivalent is 03Kh17N14M3, at mills in China 022Cr17Ni12Mo2, under EN 1.4404. Grade 321 is 304 stabilised with titanium, the equivalent of 12Kh18N10T, for welded assemblies at elevated temperature. The surface finish is written into the specification: matt after heat treatment and pickling, ground or polished with the grit stated. The density of austenitic steel is about 7.9 g/cm³, so the theoretical weight in the mill certificate differs from the carbon steel calculation by about 1 %.
During inspection at the mill, the outside diameter and wall thickness of stainless pipe are measured with a micrometer and callipers at the ends of the sampled pipes; the wall of welded pipe away from the weld and on the weld. The surface is examined for scratches, heat tint after welding and traces of contact with carbon steel; on polished pipe, for uniformity of grain. The grade is confirmed on site with a handheld X-ray fluorescence analyser by chromium, nickel and molybdenum content, and the result is matched against the mill test certificate (MTC) by heat number: chemical composition, mechanical properties, heat treatment, hydrostatic test or eddy-current test. The bundle tag and packaging are checked. Rejects recorded in the report are replaced; the replacement is supplied by the manufacturing mill under its contract with the bureau.
Applications
- food and dairy plants, product pipelines
- chemical and pharmaceutical media
- water treatment and reverse osmosis systems
- heat exchangers and steam
- railings, fencing, facade structures
- process piping in the oil and gas industry
Packing and shipment
Each pipe in a polyethylene sleeve or film, bundles in woven wrapping with wooden spacers without contact with carbon steel; the bundle carries a mill tag with grade, size, surface finish 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
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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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