Aluminium tee-sections

IS 6445: Scope Summary & Key Specifications

Scope:
IS 6445 covers the dimensions, sectional properties, and mass of aluminium tee-sections used in structural applications, assuming aluminium density as 2.7 g/cm³.

Key Points:

• Density Assumption: 2.7 g/cm³ (Clause 2.7)
• Rounding Off: Final test/calculation values rounded per IS 2-1960 (Clause 0.7)
• Sectional Properties: Includes mass, cross-sectional area, depth, flange width, thickness, radius at root, centroid location, moment of inertia, radii of gyration, and section moduli.

Important Table Extract (Example Tee-Sections):

IS 6445 - Definitions & Key Symbols

Key Letter Symbols (Clause 3.1)

Material Density (Clause 2.7)

• Aluminium density used: 2.7 g/cm³

Typical Section Properties Table (Excerpt from Clause 6.1)

IS 6445 - Designation and Marking of Aluminium Tee-Sections

Key Specifications:

• Clause 8.1: Aluminium tee-sections must be clearly marked with:

  • Designation
  • Alloy and temper
  • Manufacturer's name
  • Lot number/year of manufacture

• Clause 8.2: Tee-sections may bear the ISI Certification Mark, ensuring compliance with ISI inspection and quality control.

Important Symbols (Clause 3.1):

Table 4 (Clause 6.1) - Sample Aluminium Tee-Section Properties:

IS 6445: Materials and Alloys for Aluminium Structural Sections

1. Aluminium Alloys & Temper (Clause 5.1.1)

• Aluminium alloys must conform to IS: 733-1983.
• Common alloys used:
  • 19000, 24345, 24534, 52000, 53000, 54300, 63400, 64423, 64430, 65032, 74530.
• Temper condition as per IS:733 to ensure mechanical properties.

2. Key Dimensions & Sectional Properties (Clause 6.1, Table I)

• Aluminium Tee-Sections are detailed with:
  • Mass per meter (kg/m)
  • Sectional area (cm²)
  • Depth (h), Width (b), Thickness (t) in mm
  • Radius at root (mm)
  • Centroid location (cm)
  • Moment of inertia (Ix, Iy) in cm⁴
  • Radii of gyration (rx, ry) in cm
  • Section modulus (Zx, Zy) in cm³

Example Extract:

IS 6445: Aluminium Tee-Sections — Key Dimensions & Sectional Properties

1. Dimensions & Mass (Clause 6.1, Table 1)

• Designation (e.g., ALT 30x30-0.7)
• Mass per metre (kg/m)
• Sectional Area (cm²)
• Depth (h), Width of Flange (b), Thickness (t), Radius at Root (mm)
• Centre of Gravity (Gx, cm)
• Moment of Inertia (Ix, Iy, cm⁴)
• Radii of Gyration (rx, ry, cm)
• Section Moduli (Zx, Zy, cm³)

2. Dimensional Tolerances

• As per IS 3965-1981 for aluminium sections.

3. Aluminium Alloys & Temper

• Must conform to IS 733-1983 (Clause 5.1.1).

Example (ALT 30x30-0.7)

Dimensional Tolerances for Aluminium Tee-Sections (IS 6445)

• Reference: Clause 6.2 refers to IS 3965-1981 for dimensional tolerances of aluminium sections.
• Key Point: Dimensional tolerances are as specified in IS 3965-1981, which covers permissible deviations in depth, width, thickness, and radius at root.

Typical Dimensional Parameters (from Table 1, IS 6445)

General Dimensional Tolerance Guidelines (per IS 3965-1981)

Exact tolerances depend on section size and manufacturing process.

Notes:

• Sections outside Table 1 dimensions can be made by agreement (Clause 6.1.1).
• Mass and sectional properties are provided for design reference.
• For precise tolerances, consult IS 3965-1981 directly.

flowchart LR
    A[IS 6445 Aluminium Tee-Sections]
    B[Clause 6.2: Dimensional Tolerances]
    C[Refer IS 3965-1981]
    D[Dimensions: h, b, t, r]
    E[Tolerances per IS 3965]
    F[Manufacturing Agreement for other sizes]

    A --> B --> C --> D --> E
    D --> F

Summary: Use IS 3965-1981 for

IS 6445 - Manufacturing Requirements for Aluminium Tee Sections

Key Points from IS 6445:

• Clause 6.1.1: Custom dimensions beyond Table 1 allowed if purchaser and manufacturer agree.
• Density: Aluminium density = 2.7 g/cm³ (Clause 2.7).
• Table 1: Provides detailed sectional properties for standard tee sections.

Important Specifications from Table 1:

Typical Formula for Radii of Gyration:

[ r_x = \sqrt{\frac{I_x}{A}}, \quad r_y = \sqrt{\frac{I_y}{A}} ]

Where:

• (I_x, I_y) = Moments of inertia about x and y axes
• (A) = Sectional area

Summary

• Use Table 1 for standard tee-section dimensions and properties.
• Custom sizes require purchaser-manufacturer agreement.
• Properties given assume aluminium density = 2.7 g/cm³.
• Sectional properties essential for design: area, moment of inertia, section modulus, radii of gyration.

flowchart LR
    A[Start: Select Tee Section] --> B{Standard Size?}
    B -- Yes --> C[Use Table 1 Properties]
    B -- No --> D[Agreement between Purchaser & Manufacturer]
    D --> E[Manufacture Custom Section]
    C --> F[Design Calculations using Sectional Properties]
    E --> F
    F --> G[Structural Design & Verification]

This ensures proper manufacturing

IS 6445 - Marking and Identification of Aluminium Tee-Sections

Key Specifications (Clause 8):

• Marking on Tee-Sections (8.1):

  • Designation
  • Alloy and temper
  • Manufacturer's name
  • Lot number/year of manufacture

• ISI Certification Mark (8.2):

  • Tee-sections may carry the ISI mark.
  • ISI mark ensures compliance with ISI inspection, testing, and quality control.
  • Use governed by Indian Standards Institution (Certification Marks) Act.

Important Symbols (Clause 3.1):

Additional Data:

• Density of aluminium alloy: 2.7 g/cm³ (Clause 2.7)

Summary Table for Marking

This ensures traceability and quality assurance of aluminium tee-sections per IS 6445.

flowchart LR
    A[Aluminium Tee Section] --> B[Marking]
    B --> C[Designation]
    B --> D[Alloy & Temper]
    B --> E[Manufacturer's Name]
    B --> F[Lot Number/Year]
    B --> G{ISI Certification Mark?}
    G -->|Yes| H[ISI Mark applied]
    G -->|No| I[No ISI Mark]

IS 6445: Testing and Quality Control - Key Points

1. Rounding Off Test Values (Clause 0.7):

• Final test or analysis results must be rounded as per IS 2-1960.
• The number of significant figures in the rounded value should match that of the specified value in the standard.

2. Density Reference (Clause 2.7):

• Aluminium density used for calculations: 2.7 g/cm³.

3. Quality Control & Marking (Clause 8.2):

• Tee-sections may bear the ISI Certification Mark, indicating compliance with IS standards and continuous quality inspection by ISI.
• Use of ISI mark is governed by the Indian Standards Institution (Certification Marks) Act.

Practical Quality Control Steps:

Summary Diagram of Quality Control Flow

flowchart TD
    A[Raw Material] --> B[Dimensional Check]
    B --> C[Density Test]
    C --> D[Mechanical Tests]
    D --> E{Pass?}
    E -- Yes --> F[Mark with ISI Certification]
    E -- No --> G[Reject / Rework]

For detailed mechanical properties and dimensional tables, refer to the full IS 6445 document and related wrought aluminium alloy standards.

Rounding Off Numerical Values as per IS 6445 (Ref: IS 2-1960)

• Rule: Final values (observed or calculated) must be rounded off according to IS 2-1960.
• Significant Figures: The number of significant digits in the rounded value should match the specified value in the standard.
• General Practice:
  • If the digit after the last significant figure is < 5, round down.
  • If the digit is ≥ 5, round up.
• Example:
  • Specified value: 2.70 (3 significant figures)
  • Calculated value: 2.698 → Rounded to 2.70
  • Calculated value: 2.704 → Rounded to 2.70

Summary Table:

This ensures consistency and compliance with the standard's precision requirements.

flowchart TD
    A[Calculated Value] --> B{Check Next Digit}
    B -->|< 5| C[Round Down]
    B -->|≥ 5| D[Round Up]
    C --> E[Match Significant Figures]
    D --> E

Note: IS 6445 refers to IS 2-1960 for rounding rules; always verify the number of significant figures in the standard's specified values.

IS 6445 Annexures: Key Formulas, Tables & Specifications

Letter Symbols (Clause 3.1)

• a = Sectional area (cm²)
• M = Mass per unit length (kg/m)
• Ix, Iy = Moments of inertia about X-X & Y-Y axes (cm⁴)
• ex, ey = Distance of extreme fibre from X-X & Y-Y axes (cm)
• Zx, Zy = Section modulus about X-X & Y-Y axes (cm³)
• rx, ry = Radii of gyration about X-X & Y-Y axes (cm)

Important Table: Aluminium Tee-Sections (Clause 6.1)

Refer Table 1 in IS 6445 for full sectional properties.

Specifications:

• Aluminium alloys and tempers conform to IS 733-1983 (Clause 5.1.1).
• Tee-sections may carry the ISI Certification Mark (Clause 8.2).

Section Modulus Formulas:

[ Z_x = \frac{I_x}{