ISO 657-2:1989

Overview

ISO 657-2:1989 is an international standard published by the International Organization for Standardization (ISO) that specifies the dimensions of hot-rolled steel sections, focusing on unequal-leg angles. This standard represents a technical revision of the earlier ISO Recommendation R 657-2:1968, providing updated specifications to ensure uniformity and interoperability in steel construction products worldwide.

This part of ISO 657 is part of a larger series with 21 parts covering various steel section shapes, including equal-leg angles, channels, beams, and other profiles. ISO 657-2 defines dimensional requirements such as leg lengths, thicknesses, radius of fillets, and provides associated characteristics like sectional area, mass, and centroid locations for unequal-leg hot-rolled steel angles.

Key Topics

• Dimensional Specifications: ISO 657-2 outlines the detailed geometric dimensions for unequal-leg angles, including:

  • Lengths of each leg (unequal in size)
  • Thickness of the steel section
  • Radius of fillet used for the inner corner (given for information)
  • Radius of rounding, which can be independently specified

• Sectional Characteristics: The standard provides comprehensive data related to the physical properties of the sections, such as:

  • Cross-sectional area
  • Mass per unit length, calculated assuming a steel density of 7.85 kg/dm³
  • Section modulus and moment of inertia about principal axes
  • Centroid and radius of gyration, vital for structural calculations

• Tolerances: Referenced from ISO 657-5, the standard includes guidance on permissible dimensional deviations to ensure manufacturing consistency across metric and inch series.

• Technical Revisions: It supersedes the older ISO Recommendation from 1968, reflecting advances in steel manufacturing and standardized profiling.

Applications

ISO 657-2:1989 is fundamental in many steel construction engineering applications, including:

• Structural Engineering: Unequal-leg angles are widely used as bracing, frameworks, supports, and reinforcements in buildings and bridges due to their strength and ease of connection.

• Fabrication and Manufacturing: This standard aids steel fabricators in producing components that meet globally recognized dimensions and quality specifications, enhancing interchangeability in the supply chain.

• Shipbuilding and Machinery: Unequal-leg angle sections standardized according to ISO 657-2 support construction tasks requiring optimized strength-to-weight ratios and reliable dimensional accuracy.

• Transportation and Infrastructure: Angle sections adhering to this standard are used in transportation equipment, storage racks, and general engineering structures.

Implementing ISO 657-2 ensures quality assurance, compatibility, and safety in steel structural components across international markets.

Related Standards

ISO 657 is a multipart standard concerning hot-rolled steel sections, and ISO 657-2:1989 relates closely to several other parts that provide complementary specifications:

• ISO 657-1: Hot-rolled steel sections - General purposes and definitions
• ISO 657-5: Tolerances for equal and unequal-leg angles in metric and inch series
• ISO 657-7: Equal-leg angles - Dimensions
• ISO 657-20: U-section hot-rolled profiles - Dimensions
• ISO 657-27: T-shaped hot-rolled steel profiles - Dimensions

These related parts cover additional shapes and tolerances, helping engineers select the correct profile type and ensure comprehensive dimensional conformity for all hot-rolled steel profiles.

Keywords: ISO 657-2, hot-rolled steel sections, unequal-leg angles, steel profile dimensions, structural steel standards, steel angle dimensions, ISO steel standards, construction steel profiles, steel manufacturing standards, ISO 657 series.