GOST 8734-75 is the Russian assortment standard for seamless cold-deformed (cold-drawn and cold-rolled) steel pipes. It fixes the size range, the wall series, the length options and the precision categories. What it does not fix is the technical delivery requirement – that lives in GOST 8733-74. Reading one without the other is the most common mistake we see on Russian enquiries.
What GOST 8734-75 covers
| Item | Range in the standard | Practical note |
|---|---|---|
| Outside diameter | 5–250 mm | Below 5 mm and above 250 mm are outside the standard |
| Wall thickness | 0.3–24 mm | The wall series is tabulated by OD; not every combination exists |
| Length | Measured, unmeasured (random), or multiple of a measured length | Unmeasured is normally 4.5–9 m; state it on the order |
| Precision | Normal, increased, high, extra high | Applies separately to OD and to wall |
| Delivery condition | Heat treated or without heat treatment | Russian drawings mark these as soft or hard |
The four precision categories
This is where most of the price difference sits. A Russian drawing will normally say повышенная точность (increased) or высокая точность (high) next to the size, and the mill has to draw to that category rather than to the commercial default.
| Category | Russian marking | What it buys you |
|---|---|---|
| Normal | нормальная точность | Commercial tolerance; fine for machining with a generous allowance |
| Increased | повышенная точность | Roughly half the normal band; the usual choice for hydraulic parts |
| High | высокая точность | Tight enough to machine with a small allowance, needs a controlled draw |
| Extra high | особо высокая точность | Special order; usually only on small and medium diameters |
The exact micrometre values are tabulated in the standard by diameter band and are different for OD and for wall. Send us the size and the category and we quote against the table, rather than guessing from a percentage.
Groups А, Б, В, Г and Д
When a Russian order names a group letter, it is telling the mill what is guaranteed. This is the part Western buyers usually miss, and it is the reason two pipes with identical dimensions can carry very different certificates.
| Group | What is guaranteed | Typical use |
|---|---|---|
| А | Mechanical properties only | Parts where strength is the design driver and chemistry is not called out |
| Б | Chemical composition only | Parts that are heat treated or welded by the customer |
| В | Mechanical properties and chemical composition | Pressure and critical machine parts |
| Г | Mechanical and chemical, plus hydraulic pressure test | Pressure lines that must be proven leak-tight |
| Д | Hydraulic pressure test only, without guaranteed mechanical or chemical values | Non-structural lines where leak-tightness is the only requirement |
If the drawing just says “GOST 8734-75” with no group, the mill will supply the commercial default – usually group В or the mill’s own routine. That is fine until a Russian inspector asks for the group on the certificate.
Steel grades and chemistry
Cold-deformed pipe to GOST 8734 is normally made from the steels of GOST 1050, with 09G2S from GOST 19281 for low temperature and higher strength. 09G2S is the grade Russian buyers ask for when the part works outdoors in winter.
| Steel | C % | Si % | Mn % | P % max | S % max | Note |
|---|---|---|---|---|---|---|
| 10 | 0.07–0.14 | 0.17–0.37 | 0.35–0.65 | 0.030 | 0.035 | Soft, easy to bend and flare |
| 20 | 0.17–0.24 | 0.17–0.37 | 0.35–0.65 | 0.030 | 0.035 | The workhorse grade |
| 35 | 0.32–0.40 | 0.17–0.37 | 0.50–0.80 | 0.030 | 0.035 | Higher strength, less formable |
| 45 | 0.42–0.50 | 0.17–0.37 | 0.50–0.80 | 0.030 | 0.035 | Machined parts, not for flaring |
| 09G2S | ≤ 0.12 | 0.50–0.80 | 1.30–1.70 | 0.035 | 0.040 | Low temperature, higher yield |
Mechanical properties, heat treated condition
| Steel | Tensile Rm | Yield Re | Elongation A |
|---|---|---|---|
| 10 | ≥ 333 MPa | ≥ 196 MPa | ≥ 24 % |
| 20 | ≥ 412 MPa | ≥ 245 MPa | ≥ 21 % |
| 35 | ≥ 510 MPa | ≥ 294 MPa | ≥ 17 % |
| 45 | ≥ 598 MPa | ≥ 343 MPa | ≥ 14 % |
| 09G2S | ≥ 470 MPa | ≥ 325 MPa | ≥ 21 % |
Without heat treatment the tube is harder and stronger but far less ductile. Russian drawings usually mark the soft condition when the part is going to be bent, flared or rolled; if the drawing is silent, ask, because a hard tube that cannot be flared is scrap.
GOST 8734 against the European and American standards
| Standard | Country | Relationship |
|---|---|---|
| GOST 8734-75 | Russia | Assortment – sizes, wall series, precision, length |
| GOST 8733-74 | Russia | Technical requirements – chemistry, mechanical properties, tests |
| GOST 9567-75 | Russia | High precision seamless pipe; a tighter companion to 8734 |
| EN 10305-1 | Europe | Closest European family: seamless cold drawn precision tube |
| DIN 2391 | Germany | Predecessor of EN 10305-1; still written on older drawings |
| ASTM A519 | USA | Seamless mechanical tubing; different grades, not interchangeable |
Do not substitute a GOST grade for an EN grade on the strength of the carbon range alone. 09G2S and E355 look similar on paper and behave differently in welding and at low temperature.
How to write it on a purchase order
Pipe 25 × 3.0 GOST 8734-75, increased precision, group В, steel 20, heat treated, length 6 m measured, GOST 8733-74 technical requirements, certificate 3.1 in Russian. Note that the dimensions come from 8734 and the quality from 8733 – a complete Russian order line names both.
Applications
- Hydraulic and pneumatic lines on Russian-built machinery
- Shock absorber and suspension parts
- Bearing sleeves and machined bushes
- Low temperature structures using 09G2S
- General engineering where a Russian drawing must be matched exactly
Frequently asked questions
What is the difference between GOST 8734 and GOST 8733?
8734-75 is the assortment: which diameters and walls exist, how precise they are, what lengths are supplied. 8733-74 is the technical requirement: which steels, what mechanical properties, which tests. A Russian drawing normally cites both, and the certificate should too.
Can you provide a Russian certificate?
Yes. We issue an EN 10204 3.1 certificate with the GOST references, the group letter (А, Б, В, Г or Д), the steel grade, chemistry and mechanical results, and we can supply Russian language marking on the bundles. Tell us at enquiry stage if the end customer’s inspector will read the documents in Russian.
Is GOST 8734 the same as GOST 9567?
No. 9567-75 is the high precision standard and is used when the drawing needs tighter tolerances than 8734 can offer. Many buyers quote 8734 by habit and then discover their drawing actually says 9567.
Can you supply 09G2S in the cold-deformed condition?
Yes, cold drawn and heat treated. It is the grade to specify for outdoor equipment in a cold climate. Confirm the impact test requirement at enquiry, because it drives both price and lead time.
Request a quotation: send your size list or drawing through our contact page. We reply within one working day with price, tolerance and lead time. Russian speaking contact available on WhatsApp.