GOST 5640-2020 PDF

Full title and description

GOST 5640-2020 — "Steel. Metallographic method for evaluation (determination) of the microstructure of flat rolled steel products". The standard specifies metallographic procedures, reference images and scoring scales for assessing microstructural constituents (free cementite, pearlite, banding/striping, Widmanstätten structures) in flat rolled steel such as sheets, strips and coils.

Abstract

This interstate (GOST) standard establishes visual and image-analysis–based metallographic methods to evaluate and score the microstructure of flat rolled steel. It provides sample preparation rules, descriptive and illustrated scales (reference images) for assigning microstructure scores, and optional procedures for quantitative assessment of structural banding using automated image analysis. The document replaces the earlier 1968 edition and was adopted as a national standard by Rosstandart.

General information

• Status: Active / in force.
• Publication date: Approved 30 December 2020; introduced into force (date of application) 01 October 2021.
• Publisher: Federal Agency on Technical Regulating and Metrology (Rosstandart) — issued as an interstate standard (GOST).
• ICS / categories: ICS 77.140.20 (Metallurgy — iron and steel products; stainless steels / metallographic methods).
• Edition / version: Edition 2020 (GOST 5640-2020); replaces GOST 5640-68.
• Number of pages: Commercial listings and normative libraries report approximately 20–25 pages (official text and appendices).

Scope

The standard applies to flat rolled steel products (sheets, strips, coils, bands) and defines procedures for metallographic sample selection, preparation (cutting, mounting, grinding, polishing, etching), visual comparison with reference microstructure images and, where applicable, quantitative evaluation using image analysis. It covers assessment of structurally free (secondary/tertiary) cementite, pearlite morphology and distribution, structural banding (striping) and Widmanstätten-type structures for both unalloyed and alloyed steels.

Key topics and requirements

• Sample taking and preparation steps (recommended cutting, mounting and multi-stage polishing; etching reagents and procedures to reveal ferrite/pearlite and carbide features).
• Descriptive scoring scales with illustrated reference images (appendices with tables of microstructure descriptions and images used to assign scores).
• Separate scales for different microstructural features: free cementite, pearlite (including granular vs. sorbitic forms), banding/striping and Widmanstätten structures.
• Optional quantitative method for evaluating microstructural banding using automated image analysis (calculation of banding and anisotropy coefficients).
• Criteria for selecting fields of view and magnifications (visual search at low magnification, detailed assessment at higher magnification e.g., 100×–500×).
• Normative references and cross-references to related metallographic and measurement standards used in steel quality control.

Typical use and users

Used by metallurgists, quality-control laboratories, steel producers, heat-treatment shops, inspection bodies and R&D labs to classify and document microstructure in rolled steel for acceptance testing, production control, failure analysis and materials certification. It supports both manual comparative assessment and automated image-analysis workflows for suppliers and end-users who require reproducible microstructure scoring.

Related standards

References and related documents commonly cited alongside this standard include earlier metallographic and microstructure reference standards (for example GOST 5640-68 which it replaces), standards for grain-size measurement (e.g., GOST 5639 series), standards for non-metallic inclusions and etching procedures, and product-specific technical standards that reference microstructural acceptance criteria.

Keywords

steel; flat rolled product; metallography; microstructure; pearlite; cementite; banding; Widmanstätten; image analysis; sample preparation; GOST 5640-2020.

FAQ

Q: What is this standard?

A: GOST 5640-2020 is an interstate metallographic standard that defines methods for evaluation of the microstructure of flat rolled steel products (sheets, strips, coils). It provides preparation procedures, descriptive scales and illustrated references used to assign microstructure scores.

Q: What does it cover?

A: It covers sampling, metallographic preparation (cutting, mounting, grinding, polishing, etching), visual comparison with reference images and, optionally, automated image-analysis methods to assess free cementite, pearlite, structural banding (striping) and Widmanstätten structures in unalloyed and alloyed flat rolled steels.

Q: Who typically uses it?

A: Metallurgical laboratories, steel mills, heat-treatment shops, inspection authorities, research institutions and quality assurance personnel involved in acceptance testing, production control and failure analysis for rolled steel products.

Q: Is it current or superseded?

A: Current — GOST 5640-2020 was approved 30 December 2020 and entered into force on 01 October 2021; it replaces GOST 5640-68. Users should check national registries for any later amendments or corrigenda.

Q: Is it part of a series?

A: It is part of the body of metallography and metallurgy standards (GOST series) and is often used alongside related GOST documents on grain-size measurement, etching procedures and product-specific technical standards; it is designated under ICS 77.140.20.

Q: What are the key keywords?

A: Steel, metallography, microstructure, flat rolled product, pearlite, cementite, banding, image analysis, GOST 5640-2020.