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