—— Sanonpipe, Your Trusted Supplier of Russian Standard Precision Steel Tubes

I. Standard Overview: The Cornerstone of Russian Cold-Drawn Seamless Tubes

GOST 8734-75 (full title: Seamless steel tubes cold deformed. Range) is the Russian (former USSR) dimensional/assortment standard for cold-drawn or cold-rolled seamless steel tubes. It came into force on 1 January 1977. The standard covers cold-formed seamless tubes (produced by cold rolling or cold drawing) with an outside diameter range of 1 mm to 200 mm and wall thickness from 0.2 mm to 22 mm.

The cold-drawing / cold-rolling process gives the tubes exceptionally high dimensional accuracy and excellent surface quality. Through cold deformation, the steel grains are refined, and the metal density and mechanical properties are significantly improved. This high-precision cold-forming technology makes the tubes far superior to conventional hot-rolled tubes in terms of dimensional tolerances, concentricity and surface finish – making them ideal for precision instruments, hydraulic systems, high-accuracy mechanical structures and many other demanding applications.

The standard is based on the international standard СТ СЭВ 1483-78 and was approved by the USSR State Committee for Standards on 13 October 1975 (Decree No. 2604). The current valid edition is the 2007 reprint.

II. Standard System: The Matching Relationship between GOST 8734 and GOST 8733

In the Russian standards system, GOST 8734-75 must be used together with its companion technical specification GOST 8733-87 (Seamless cold-deformed steel tubes – Technical conditions). Together they form a complete product standard for steel tubes:

Standard	Scope	Role
GOST 8734-75	Outside diameter range, wall thickness series, dimensional tolerances, length types and permissible deviations, theoretical weight	“What it looks like” – dimensions
GOST 8733-87	Steel grades, chemical composition, mechanical properties, process tests, hydraulic tests, inspection rules, marking, packaging	“What material and how strong” – technical requirements

Procurement note: In engineering documents or purchase orders, GOST 8733 and GOST 8734 are almost always cited together – they form an inseparable pair.

III. Dimensional Range and Classification

3.1 Dimensional range

The GOST 8734-75 standard covers the following dimensions:

Parameter	Range
Outside diameter	1 – 200 mm
Wall thickness	0.2 – 22 mm
Length (random)	1.5 – 11.5 m
Length (fixed)	4.5 – 9 m (limit deviation +10 mm)

3.2 Classification by wall thickness

Based on the ratio of outside diameter (D) to wall thickness (s), tubes are divided into four categories:

Category	D/s ratio	Description
Extra-thin-wall	D/s > 40	Ultra-lightweight, for weight-saving applications
Thin-wall	D/s = 12.5 – 40	Conventional thin-wall tubes
Thick-wall	D/s = 6 – 12.5	Higher pressure-bearing capacity
Extra-thick-wall	D/s < 6	Extreme pressure applications

3.3 Outside diameter tolerances

Outside diameter range (mm)	Permissible deviation (mm)
4 – 10	±0.15
>10 – 30	±0.30
>30 – 50	±0.40
>50	±0.8%

3.4 Wall thickness tolerances

Wall thickness range (mm)	Permissible deviation
≤1.0	±0.12 mm
>1.0 – 5.0	±10%
>5.0	±8%

3.5 Straightness requirements

Outside diameter range (mm)	Maximum curvature per metre length
4 – 8	≤ 3 mm
>8 – 10	≤ 2 mm
>10	≤ 1.5 mm

Note: For tubes with outside diameter 20-90 mm, a stricter straightness requirement of ≤ 1 mm per metre length can be agreed upon.

IV. Theoretical Weight Calculation

GOST 8734-75 uses the following formula to calculate the theoretical weight per metre of tube:

M = 0.02466148 × s × (Dₙ − s)

Where:

M = weight per metre (kg)

Dₙ = nominal outside diameter (mm)

s = wall thickness (mm)

Steel density = 7.85 g/cm³

The standard appendix provides complete weight tables for all combinations of outside diameter and wall thickness from 0.3 mm to 24 mm. Examples:

For 30 mm OD × 2.5 mm wall, theoretical weight ≈ 1.696 kg/m

For 76 mm OD × 4.0 mm wall, theoretical weight ≈ 7.102 kg/m

V. Available Steel Grades

According to the companion standard GOST 8733-87, cold-drawn seamless tubes can be produced from a variety of carbon and alloy steel grades:

Steel grade	Type	Typical application
Grade 10, Grade 20	High-quality carbon structural steel	Fluid conveyance, general structures
Grade 35, Grade 45	High-quality carbon structural steel	Machinery manufacture, high-strength structural parts
09Г2С (09G2S)	Low-alloy steel	Low-temperature service, high-strength structures

International equivalence: GOST 8734-75 cold-drawn seamless tubes are very similar in process and application to ASTM A519 (seamless carbon and alloy steel mechanical tubing).

VI. Typical Application Fields

Thanks to high dimensional accuracy, smooth surface finish and excellent concentricity, GOST 8734-75 cold-drawn seamless tubes are widely used in:

Application field	Specific uses	Why chosen
Precision machinery	Precision shafts, hydraulic cylinders, pneumatic components	High accuracy, good concentricity
Hydraulic & pneumatic systems	High-pressure oil pipes, pneumatic lines	Smooth inner surface, low flow resistance
Automotive industry	Shock absorber tubes, steering gear tubes	Consistent dimensional uniformity
Petrochemical	Instrument tubing, tracer lines	Reliable pressure resistance
Power generation	Boiler auxiliary piping	Good high-temperature performance

Compared with hot-rolled tubes, the cold-drawn process makes GOST 8734-75 tubes superior in:

Dimensional accuracy: OD tolerances as tight as ±0.15 mm (small sizes), far better than hot-rolled.

Surface quality: Smooth inside and out – ready for precision assembly without additional machining.

Concentricity: Uniform wall thickness, ideal for subsequent precision processing.

VII. International Standard Equivalents

Standard system	Corresponding standard	Description
China (GB)	GB/T 3639-2021	Cold-drawn or cold-rolled precision seamless steel tubes
USA (ASTM)	ASTM A519	Seamless carbon and alloy steel mechanical tubing
Russia (GOST)	GOST 8734-75 (dimensions) + GOST 8733-87 (technical conditions)	Used together

Equivalence note: The closest Chinese standard to GOST 8734-75 is GB/T 3639-2021 (Cold-drawn or cold-rolled precision seamless steel tubes), which matches in both application (high-precision cold-working) and manufacturing process. Additionally, GB/T 8162 (structural seamless tubes) and GB/T 8163 (fluid conveyance seamless tubes) can be referenced, but GB/T 3639 offers the best match in precision and cold-working process.

VIII. Why Choose Sanonpipe?

Our advantages	Details
Standard expertise	Deep understanding of the GOST 8733/8734 system – we accurately interpret all Russian standard requirements
Material assurance	Full range of grades covered – 10#, 20#, 45#, 09Г2С, etc., with complete material certificates
Precision guaranteed	All tubes manufactured strictly to GOST 8734-75 tolerance requirements – reliable dimensional accuracy
Full size range	We supply the entire range of outside diameters 1–200 mm and wall thicknesses 0.2–22 mm
Fast delivery	With a standing stock of 20,000 tonnes, urgent orders are shipped within 7–15 days
End-to-end service	From enquiry, technical clarification and quotation to documentation and logistics – one-stop delivery
Zero-risk commitment	Over 240 internal quality control checkpoints, and documentation with zero discrepancies

IX. Contact Us

Sanonpipe is dedicated to providing high-quality GOST 8734-75 compliant cold-drawn seamless steel tubes to customers worldwide. Whether you need precision mechanical tubes, hydraulic tubes or structural tubes, we offer professional technical support and flexible supply solutions.

Typical specification description example:

Труба стальная бесшовная холоднодеформированная 57×3.5 ГОСТ 8734-75 / В 20 ГОСТ 873387
(Cold-drawn seamless steel tube 57×3.5, dimensions per GOST 8734-75, steel grade 20, technical conditions per GOST 8733-87)

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