GOST 2789-73 PDF

Full title and description

GOST 2789-73 — "Surface roughness. Parameters and characteristics". National (interstate) standard that defines the standard nomenclature, parameter set and basic rules for specifying and controlling surface roughness of manufactured parts and products (profile parameters such as Ra, Rz/Rmax, Sm, tp and associated conventions for sampling and lay/direction).

Abstract

GOST 2789-73 establishes a compact set of profile roughness parameters and characteristic values, the basic sampling/base lengths and the conventions for indicating lay (direction of irregularities) used when specifying surface finish on technical documentation. It applies across materials and production methods and provides a bridge from older 'surface finish classes' to parameter-based specification. The standard has been maintained with later amendments and remains a principal reference for surface-roughness specification in the GOST system.

General information

• Status: In force (interstate GOST; introduced 1975; maintained with amendments).
• Publication date: Approved 1973; date of introduction / effect: 1 January 1975 (editions/amendments issued later, including amendments introduced by Rosstandart in 2017).
• Publisher: Originally issued by the State Committee for Standards of the USSR (Gosstandart); current distribution/official records maintained by national standards bodies / Rosstandart and standard distributors.
• ICS / categories: Classified under surface properties / measurement categories (examples used in records: ICS 01.040.x and ICS 17.040.20 — Properties of surfaces / metrology-related classifiers).
• Edition / version: Designation GOST 2789-73 (original standard 1973 / introduced 1975) with later amendments (e.g., Amendment 1 — 1980 and amendments recorded up to Rosstandart orders in 2017).
• Number of pages: Short technical standard — commonly published as an 8-page document in distributed copies.

Scope

The standard applies to the roughness of product surfaces regardless of material and method of manufacture. It lists the profile parameters to be used when specifying and checking roughness (for example Ra, Rz, Rmax, Sm, S, tp), gives recommended base (sampling) lengths for different roughness ranges, and sets out general rules and conventions for establishing requirements and controls of surface roughness on drawings and in technical documents. The standard explicitly excludes surfaces whose texture cannot be normalized by the defined methods (for example highly fuzzy/nap surfaces) and defects arising from material faults or accidental damage.

Key topics and requirements

• Standard parameter set for profile roughness: Ra (arithmetic mean deviation), Rz / Rmax (height measures), Rmax (total profile height) and related spacing/shape parameters such as Sm and S.
• Specification of base (sampling) lengths tied to roughness magnitude (tables that relate Ra/Rz ranges to sampling/base lengths).
• Definitions and conventions for lay/direction of surface irregularities (parallel, perpendicular, etc.) and for selection of one or more parameters for requirement statements.
• Conversion guidance and continuity with earlier surface-finish class systems (tables for translating older classes into parameter values are provided in practice references).
• Notes on what the standard does not normalize (e.g., furred/nap surfaces, material defects) and on using multiple parameters where function demands it.

Typical use and users

Engineers, technical designers and draftsmen (for specifying surface finish on drawings), quality and metrology laboratories (for measurement and acceptance), machinists and process engineers (to set and check machining/polishing parameters), and standards/regulatory professionals referencing surface texture requirements in product specifications and procurement. The standard is widely used in mechanical engineering, tooling, surface treatment, metrology and manufacturing quality-control contexts.

Related standards

International and national surface texture standards are related and commonly referenced alongside GOST 2789-73: ISO/IEC series on surface texture (ISO 4287 family and successors), ISO 4288 (rules for assessment), the ISO 25178 family (areal surface texture), and related GOST/MI documents (for measurement methods, e.g., MI 41-75 method guidance for profile instruments) and sample standards (e.g., GOST 9378 series for roughness comparison specimens). Technical practice usually cites both the GOST text and modern ISO-based GPS documents where areal/profile differences matter.

Keywords

surface roughness, Ra, Rz, Rmax, Sm, tp, profile parameters, sampling length, lay (direction), surface texture, surface finish, metrology.

FAQ

Q: What is this standard?

A: GOST 2789-73 is the interstate (GOST) standard titled "Surface roughness. Parameters and characteristics" that defines a standard set of profile roughness parameters, sampling/base-length conventions and related characteristics used to specify and control surface roughness on technical documentation.

Q: What does it cover?

A: It covers the nomenclature and definitions of common profile roughness parameters (Ra, Rz/Rmax, Rmax, Sm, S, tp), recommended base (sampling) lengths for different roughness ranges, rules for indicating lay (direction) and general guidance for selecting parameters applicable to function and control. It excludes surface types that cannot be normalized by profile methods and visible defects due to material faults or accidental damage.

Q: Who typically uses it?

A: Mechanical designers and draftsmen specifying surface finish, metrology and quality-control specialists measuring and accepting parts, process engineers and machinists who set manufacturing processes, and standards bodies or regulators who reference surface specification practices.

Q: Is it current or superseded?

A: The document GOST 2789-73 remains a referenced interstate standard in the GOST system and has been maintained with amendments (historical amendments from 1980 and later administrative updates; Rosstandart records note amendments/orders as late as 2017). In international practice, ISO GPS standards and the ISO 25178 family offer more recent areal/profile guidance, but GOST 2789-73 continues to be used for parameter-based specification within the GOST/Regional practice.

Q: Is it part of a series?

A: It is part of the body of surface texture and metrology standards — used together with measurement-method documents (national MI/measurement instructions), specimen/verification standards (e.g., roughness comparison specimens) and later ISO-based GPS standards; it replaced earlier surface-finish class documents and is linked by reference in other GOSTs and technical regulations.

Q: What are the key keywords?

A: Ra, Rz, Rmax, Sm, tp, profile, sampling length, lay, surface roughness, surface texture, metrology.