GOST 981-75 PDF

Full title and description

GOST 981-75 — Standard specifying dimensions, technical requirements and designation for rectangular and square steel tubes used in mechanical engineering and construction. This Soviet-era standard defines accepted sizes, tolerances, and marking for welded and seamless rectangular/square steel pipes.

Abstract

GOST 981-75 is a normative document that establishes the main parameters for rectangular and square steel tubes, including cross-sectional dimensions, wall thicknesses, permissible deviations, mechanical properties, surface condition, marking and packaging rules. It provides guidance for manufacture, inspection and acceptance of these profiles for general engineering and construction applications.

General information

• Status: Historically active Soviet standard; commonly treated as superseded or replaced by later GOST/R or interstate standards but may still be referenced for legacy products and documentation.
• Publication date: 1975
• Publisher: USSR State Committee for Standards (Gosstandart of the USSR)
• ICS / categories: 77.140.30 (Welded and seamless steel tubes), 21.060 (Ferrous metallurgy)
• Edition / version: Original edition, GOST 981-75
• Number of pages: Typically a short technical standard (around 8–16 pages, depending on publisher print); exact page count varies by reprint.

Scope

The standard applies to rectangular and square steel tubes manufactured from carbon and alloy steels by welding and by seamless processes for use in structural, mechanical and general engineering purposes. It specifies nominal sizes, wall thicknesses, dimensional tolerances and quality requirements for surfaces and ends, along with marking, testing and acceptance procedures. GOST 981-75 is intended for producers, purchasers and quality inspectors of steel tubing.

Key topics and requirements

• Nominal cross-sectional dimensions for rectangular and square tubes and corresponding wall thickness values.
• Permissible dimensional tolerances for width, height, diagonal and wall thickness.
• Requirements for manufacturing methods (welded and seamless) and acceptable steel grades.
• Rules for mechanical tests and inspection: dimensional checks, visual inspection for surface defects, and sometimes mechanical property verification.
• Marking, labeling and packaging requirements for transportation and storage.
• Acceptance criteria and procedures for lot inspection and sampling.

Typical use and users

Used by steel tube manufacturers, fabricators, structural and mechanical engineers, procurement specialists and quality control laboratories. Common applications include framework and structural members, supports, machine frames, conveyors, and other construction and industrial assemblies where rectangular or square hollow sections are required.

Related standards

Other GOST and international standards covering steel tubes and hollow sections, including later or replacement national standards for rectangular/square tubes, standards for welded/seamless steel pipes, and material-specific specifications. Examples include standards for steel grades, welding procedures and dimensional series for hollow structural sections.

Keywords

GOST 981-75, rectangular steel tubes, square steel tubes, welded tubes, seamless tubes, dimensional tolerances, marking, Soviet standard, hollow sections, steel profiles

FAQ

Q: What is this standard?

A: GOST 981-75 is a Soviet-era national standard that defines dimensions, tolerances, quality and marking requirements for rectangular and square steel tubes used in engineering and construction.

Q: What does it cover?

A: It covers nominal dimensions and wall thicknesses, permissible deviations, manufacturing and inspection requirements, marking and packaging rules for rectangular and square steel hollow sections made from carbon and alloy steels.

Q: Who typically uses it?

A: Manufacturers of steel tubes, fabricators, structural and mechanical engineers, procurement departments and quality control/inspection personnel dealing with hollow structural sections, particularly when working with legacy designs or documentation.

Q: Is it current or superseded?

A: GOST 981-75 dates from 1975 and many jurisdictions and organizations now use updated GOST, GOST-R or interstate standards; however, it may still be referenced for existing documentation, legacy equipment and materials produced to that specification.

Q: Is it part of a series?

A: It is part of the family of standards addressing steel tubes and profiles; related standards provide more detailed requirements for specific material grades, welding, testing methods and other tube types.

Q: What are the key keywords?

A: Rectangular tubes, square tubes, steel hollow sections, dimensional tolerances, welded tubes, seamless tubes, marking, GOST 981-75.