Editorial Technical Reference

Structural Steel I-Beam

This page explains how Structural Steel I-Beam is classified within Manufacture of Structural Metal Products. Technical values and manufacturer relationships are research references; confirm the current specification and supplier evidence for each order.

Technical Definition & Core Assembly

Hot-rolled structural steel beam with I-shaped cross-section for load-bearing frameworks.

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Product Specifications

Technical details and manufacturing context for Structural Steel I-Beam

Definition
Structural steel I-beams are standardized hot-rolled steel sections with an I-shaped cross-section, manufactured through continuous casting and rolling processes. They serve as primary load-bearing elements in construction frameworks, industrial structures, and infrastructure projects. These beams are essential components in B2B supply chains for structural fabricators, construction companies, and engineering firms. Their standardized dimensions and mechanical properties enable predictable performance in structural calculations and assembly.

Typical parameters for these beams include depth ranging from 100 to 600 mm, flange width from 55 to 300 mm, web thickness from 4.5 to 21 mm, and flange thickness from 7.2 to 32 mm. Yield strength values are commonly between 235 and 345 MPa, and weight per meter ranges from 9.5 to 222 kg/m. Standard lengths are 6 to 12 meters, with custom lengths available. Tolerances on depth, flange width, web thickness, and flange thickness are ±2.0 mm, ±2.5 mm, ±0.7 mm, and ±1.0 mm respectively. Straightness tolerance is limited to 0.1% of length. Surface treatments include painted, oiled, or galvanized options. Common material grades include Q235B, Q345B, S235JR, and S355JR, referencing standards such as GB/T 700, GB/T 1591, and EN 10025.

These beams are selected based on structural design requirements, including load capacity, span, and deflection limits. Verification of specific model values and compliance with applicable standards should be confirmed with the legal manufacturer or supplier. The listed parameters are reference ranges and must be validated for the intended application.
Working Principle
The I-beam distributes vertical and horizontal loads through its web and flanges. The web resists shear forces, while the flanges primarily resist bending moments. The I-shaped geometry provides an optimal strength-to-weight ratio, placing material away from the neutral axis to maximize bending resistance. This design allows efficient load transfer in structural frameworks, making the beam suitable for columns, beams, and girders. The beam's performance depends on its cross-sectional dimensions, material grade, and length. Proper installation and connection methods are critical to ensure load paths are correctly transferred. Failure can occur if loads exceed the beam's capacity, if connections are inadequate, or if corrosion reduces the effective cross-section. Regular inspection for deformation, cracking, or corrosion is necessary to maintain structural integrity.
Common Materials
Carbon steel, Low-alloy steel
Technical Parameters
ParameterTypical rangeNotes & selection driver
DepthRequired100–600 mmOverall height of the I-beam cross-sectionGB/T 706
Flange WidthRequired55–300 mmWidth of the top and bottom flangesGB/T 706
Web ThicknessRequired4.5–21 mmThickness of the vertical web sectionGB/T 706
Flange ThicknessRequired7.2–32 mmThickness of the top and bottom flangesGB/T 706
Yield StrengthRequired235–345 MPaMinimum yield strength of the steel materialGB/T 1591
Weight per MeterRequired9.5–222 kg/mLinear weight of the beamGB/T 706
Length6–12 mStandard stock lengths; custom lengths available.GB/T 706
Tolerance on Depth±2.0 mmPermissible deviation in depth.GB/T 706
Tolerance on Flange Width±2.5 mmPermissible deviation in flange width.GB/T 706
Tolerance on Web Thickness±0.7 mmPermissible deviation in web thickness.GB/T 706
Tolerance on Flange Thickness±1.0 mmPermissible deviation in flange thickness.GB/T 706
Straightness Tolerance≤0.1% of length mm/mMaximum deviation from straightness.GB/T 706
Surface TreatmentPainted, oiled, galvanizedOptions to prevent corrosion.
Material GradeQ235B, Q345B, S235JR, S355JRCommon structural steel grades.GB/T 700, GB/T 1591, EN 10025

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Components / BOM
  • Web Part
    Resists shear forces and connects flanges
    Material: Structural steel
  • Flange Part
    Resists bending moments and provides compression/tension resistance
    Material: Structural steel

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Structural Steel I-Beam.

Universal Beam I-Section Steel Rolled Steel Joist

Industrial Ecosystem & Supply Chain Structure

Complementary Systems
Downstream Applications
Specialized Tooling

Application Fit & Sizing Matrix

Operational Limits
pressure: Not applicable (structural load-bearing component, not pressure vessel)
other spec: Maximum deflection limit: L/360 typical for floors, L/240 for roofs (where L = span length); Corrosion allowance: 1-3mm depending on environment
temperature: -40°C to 400°C (ambient to elevated service, dependent on steel grade and coating)
Media Compatibility
✓ Indoor structural framing (dry environments) ✓ Bridge construction (protected with corrosion coating) ✓ Industrial mezzanine flooring (non-corrosive atmospheres)
Unsuitable: Continuous immersion in seawater or chemical processing environments with pH <4 or >10 without specialized coatings
Sizing Data Required
  • Maximum applied load (kN/m or total kN)
  • Span length between supports (meters)
  • Required safety factor (typically 1.5-2.0 for structural applications)

Reliability & Engineering Risk Analysis

Failure Mode & Root Cause
Fatigue cracking
Cause: Cyclic loading from operational vibrations, wind forces, or machinery leading to crack initiation and propagation at stress concentrators like welds, bolt holes, or sharp corners.
Corrosion-induced section loss
Cause: Exposure to moisture, chemicals, or salt leading to rust formation, pitting, and thinning of the flange or web, reducing load-bearing capacity.
Maintenance Indicators
  • Visible rust streaks or flaking paint indicating active corrosion
  • Audible creaking or popping noises under load suggesting joint loosening or crack propagation
Engineering Tips
  • Implement regular non-destructive testing (e.g., ultrasonic or magnetic particle inspection) at high-stress areas to detect early-stage cracks
  • Apply and maintain protective coatings (e.g., galvanizing or epoxy paints) and ensure proper drainage to prevent water accumulation on surfaces

Indicative industry ranges for design and RFQ preparation. Confirm the exact figures and applicable standard with the manufacturer before specifying.

Compliance & Manufacturing Standards

Applicable Standards
ASTM A6/A6M - Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling EN 10025 - Hot rolled products of structural steels ISO 630 - Structural steels

Quoted from the published standard.

Manufacturing Precision
  • Web thickness: +/- 0.5% of nominal thickness
  • Flange width: +/- 2 mm for widths up to 200 mm
Quality Inspection
  • Ultrasonic Testing for internal defects
  • Tensile Test for mechanical properties

Manufacturers of Structural Steel I-Beam

Manufacturer profiles associated with Structural Steel I-Beam.

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Frequently Asked Questions

What are the typical dimensions of a structural steel I-beam?

Typical depth ranges from 100 to 600 mm, flange width from 55 to 300 mm, web thickness from 4.5 to 21 mm, and flange thickness from 7.2 to 32 mm. Standard lengths are 6 to 12 meters, with custom lengths available. Always confirm exact dimensions with the supplier.

Which material grades are commonly used for structural steel I-beams?

Common grades include Q235B, Q345B, S235JR, and S355JR, referencing standards such as GB/T 700, GB/T 1591, and EN 10025. The appropriate grade depends on the structural requirements and applicable building codes.

What tolerances apply to the dimensions of I-beams?

Tolerances are typically ±2.0 mm on depth, ±2.5 mm on flange width, ±0.7 mm on web thickness, and ±1.0 mm on flange thickness. Straightness tolerance is limited to 0.1% of length. These values are reference ranges and should be verified with the manufacturer.

How should I verify the suitability of an I-beam for my project?

Consult the structural design specifications, including load requirements, span, and deflection limits. Confirm the beam's dimensions, material grade, and mechanical properties with the supplier. Ensure compliance with relevant standards and building codes.
Data basis: editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records.

Preliminary Technical Classification
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