Aluminium tee bars for marine application
1987 Edition

Aluminium Tee Bars for Marine Use - IS 6475 Overview

Symbol Definitions (Clause 3.1):

• a: Cross-sectional area excluding the plate (cm²)
• M: Mass per meter length excluding plate (kg/m)
• O: Centre of gravity
• ex: Distance from flange outer surface to CG (cm)
• Ix: Moment of inertia around X-X axis (cm⁴)
• Zx: Section modulus, calculated as Ix divided by ex (cm³)
• t: Thickness of plate (options: 5, 10, 15 mm)
• L: Plate width, defined as 40 times t (mm)

Tables of Sectional Properties (Clause 5.3)

• Table 1 & 2 list sectional data for tee bars:

  • Dimensions (H, B, S1, S2, etc.) in millimeters
  • Mass values (M) without plate
  • Cross-sectional area (a) without plate
  • CG distance (ex)
  • Moment of inertia (Ix)
  • Section modulus (Zx)

• Table 1: Tee bars without welding flange

• Table 2: Tee bars with welding flange

Sample Data (Table 1, AMT 100 without plate):

• H = 100 mm, B = 50 mm
• Mass = 2.31 kg/m
• Area = 8.82 cm²
• ex = 2.57 cm
• Ix = 78.1 cm⁴
• Zx = 30.4 cm³ (Ix/ex)

Section Modulus Calculation:

[ Z_x = \frac{I_x}{e_x} ]

Where:

• (I_x): Moment of inertia (cm⁴)
• (e_x): Distance to extreme fiber (cm)

Plate Width Formula:

[ L = 40 \times t ]

Where:

• (t): Plate thickness (mm)
• (L): Plate width (mm)

This information aids in choosing aluminium tee bars with or without welding flanges per the specified alloys.

Scope of Aluminium Tee Bars per IS 6475

This standard provides guidelines for using aluminium alloy tee bar sections—both with and without welding flanges—in structural frameworks, focusing on marine applications.

Symbol Definitions (Clause 3.1)

Important Tables (Clause 5.3)

• Tables 1 & 2 detail sectional properties for tee bars without welding flanges, with variations for plates.
• Dimensions such as height (H), width (B), and thicknesses (S1, S2) are included.
• Mass, area, centroid distance, moment of inertia, and section modulus values are tabulated for design reference.

Example from Table 1 (AMT 100 Tee Bar, no plate):

Section Modulus Formula

[ Z_x = \frac{I_x}{e_x} ]

Where:

• (I_x) is the moment of inertia
• (e_x) is the distance to outer fiber

Summary

• Utilize Tables 1 and 2 for sectional data.
• Section modulus and moment of inertia are critical for engineering calculations.
• Plate thickness and width follow the specified relations.

Definitions and Symbols per IS 6475

Letter Symbols (Clause 3.1):

Section Modulus Calculation:

[ Z_x = \frac{I_x}{e_x} ]

Where:

• (I_x) is the moment of inertia
• (e_x) is the distance from neutral axis to outer fiber

Sample Dimensions and Properties (from Table 1, tee bars without welding flange):

IS 6475: Notations for Aluminium Tee Bars

Letter Symbols (Clause 3.1):

• a: Cross-sectional area excluding plate (cm²)
• M: Mass per meter length excluding plate (kg/m)
• O: Centre of gravity
• ex: Distance from flange outer surface to CG (cm)
• Ix: Moment of inertia about X-X axis (cm⁴)
• Zx: Section modulus, calculated as Ix divided by ex (cm³)
• t: Plate thickness (5, 10, or 15 mm)
• L: Plate width equals 40 × t (mm)

Sectional Data (Tables 1 & 2):

• Dimensions such as height (H), width (B), thicknesses (S1, S2) are tabulated.
• Mass and sectional properties are provided for sections with and without plates.

Section Modulus Formula:

[ Z_x = \frac{I_x}{e_x} ]

Where:

• (I_x) is the moment of inertia
• (e_x) is the distance to extreme fiber

Example (AMT 100 Tee Bar without plate):

• Mass = 2.31 kg/m
• Area = 8.82 cm²
• ex = 2.57 cm
• Ix = 78.1 cm⁴
• Zx = 30.4 cm³

Summary Table Extract (AMT Series without Welding Flange):

IS 6475 Material and Alloy Requirements

• Aluminium alloys used must conform to IS 733-1983, which governs aluminium alloys in structural applications.

• Letter Symbols (Clause 3.1): | Symbol | Description | |--------|-------------------------------------------| | a | Cross-sectional area without plate | | M | Mass per unit length without plate | | O | Centre of gravity | | ex | Distance from flange outer face to CG | | Ix | Moment of inertia about X-X axis | | Zx | Section modulus (Ix divided by ex) | | t | Plate thickness (5, 10, or 15 mm) | | L | Plate width equal to 40 times thickness |

• Sectional properties are provided in Tables 1 and 2 for standard tee bar sections.

Section Modulus Computation:

[ Z_x = \frac{I_x}{e_x} ]

Where:

• (I_x) is the moment of inertia
• (e_x) is the distance from centroid to flange outer face

Plate Dimensions:

• Thickness options: 5, 10, or 15 mm
• Width calculated as 40 times thickness

This standard integrates aluminium alloys as per IS 733:1983 with sectional data for design use.

Dimensions and Sectional Properties for Aluminium Tee Bars

Symbols (Clause 3.1):

• a: Cross-sectional area without plate (cm²)
• M: Mass per unit length without plate (kg/m)
• ex: Centroid distance from flange outer face (cm)
• Ix: Moment of inertia about X-X axis (cm⁴)
• Zx: Section modulus (cm³)
• t: Plate thickness (5, 10, 15 mm)
• L: Plate width = 40 × t (mm)

Dimensional Data and Properties (Tables 1 & 2):

• Mass is calculated assuming aluminium density of 2.65 g/cm³.
• Properties are shown for sections without plate and with plates of thickness 5, 10, 15 mm.
• Plate width equals 40 times thickness (e.g., 200 mm for 5 mm plate).

Notes:

• Maximum flange radius allowed: 0.8 mm
• Maximum plate thickness (Tc) permitted: 2.0 mm
• Section modulus formula: (Z_x = \frac{I_x}{e_x})
• Moment of inertia and section modulus increase with plate thickness.

Summary of Applicable Alloys and Tempers in IS 6475

• Approved alloys include:

  • 53000 series
  • 54300 series
  • 64430 series

• Temper designations follow IS 733:1983, which specifies wrought aluminium alloys for engineering use.

Alloy and Temper Details (per IS 733)

• O Temper: Annealed (soft)
• H14 Temper: Strain-hardened and partially annealed (medium strength)
• H16 Temper: Strain-hardened and not annealed (high strength)

Temper Designation Syntax:

[ \text{Temper} = \text{Letter} + \text{Number} ] Where:

• Letter indicates processing type (O, H, T, etc.)
• Number indicates degree of strain hardening or heat treatment

Diagrammatic Overview:

graph TD
    Aluminium_Alloy --> Alloy_53000
    Aluminium_Alloy --> Alloy_54300
    Aluminium_Alloy --> Alloy_64430
    Alloy_53000 --> Tempers_O_H14_H16
    Alloy_54300 --> Tempers_O_H14_H16
    Alloy_64430 --> Tempers_O_H14_H16
    Tempers_O_H14_H16 --> Mechanical_Properties_IS733

This ensures use of specified alloys and tempers for marine structural aluminium tee bars.

Marking and Traceability for Aluminium Tee Bars as per IS 6475

Symbols (Clause 3.1):

• a: Sectional area without plate
• M: Mass per length without plate
• O: Centre of gravity
• ex: Distance from flange outer face to CG
• Ix: Moment of inertia about X-X axis
• Zx: Section modulus (Ix divided by ex)
• t: Plate thickness (5, 10, 15 mm)
• L: Plate width = 40 × t

Marking Requirements (Clause 7.1):

Each batch or bundle of aluminium tee bars must bear clear markings with:

• Section designation
• Alloy and temper details
• Manufacturer’s identification
• Lot number and year of production

BIS Standard Mark (Clause 7.1.1):

• Compliance with IS 6475 can be indicated by the BIS certification mark, ensuring quality control under BIS oversight.

Sectional Data Reference (Clause 5.3):

• Consult Tables 1 and 2 for sectional attributes including area, mass, moment of inertia, and section modulus for different tee bar sizes.

Section Modulus Calculation Reference:

Marking practices ensure product traceability and adherence to quality criteria for marine aluminium structural components.

Dimensional Tolerance Requirements in IS 6475

Reference Standard:

• Dimensional tolerances are governed by IS 3965-1981, as cited in Clause 5.4 of IS 6475.

Key Tolerances per IS 3965-1981

Example Sectional Dimensions (from Table 1 for tee bars without welding flange):

Note: Section modulus (Zx) and moment of inertia (Ix) vary with plate thickness.

Symbols (Clause 3.1)

• a: Sectional area without plate
• M: Mass per unit length without plate
• ex: Centroid distance from flange face
• Ix: Moment of inertia
• Zx: Section modulus

Manufacturing and Commercial Practices for Aluminium Tee Bars per IS 6475

Sectional Attributes (Clause 5.3 & Table 1)

• Tee bars without welding flange are standardized with fixed dimensions and properties.
• Key dimensions include height (H), width (B), thicknesses (S1, S2), plate thickness (t: 5, 10, 15 mm), and plate width (L = 40 × t).
• Mass (M) in kg/m and sectional area (a) in cm² exclude plate thickness.
• Sectional properties cover:
  • Distance from flange outer face to centroid (ex, cm)
  • Moment of inertia about X-X axis (Ix, cm⁴)
  • Section modulus (Zx, cm³), calculated as Ix divided by ex.

Symbol Definitions (Clause 3.1):

Example from Table 1 (AMT 100 Tee Bar):

Notes:

• Mass and sectional properties exclude any attached plate thickness.
• Dimensions must conform to specified tolerances to ensure interchangeability.

Rounding and Compliance Guidelines under IS 6475

1. Rounding Rules (Clause 0.7)

• Calculated or measured values should be rounded according to IS 2:1960.
• The number of significant digits in the rounded value must match the precision specified in IS 6475.
• This ensures uniformity and proper verification against the standard.

2. Letter Symbols and Sectional Properties (Clauses 3.1, 5.2, 5.3)

3. Sectional Properties Data

• Tables 1 and 2 provide detailed sectional properties for tee bars with welding flanges.
• Maximum flange radius allowed is 0.8 mm.

Section Modulus Formula:

[ Z_x = \frac{I_x}{e_x} ]

Where:

• (I_x) is the moment of inertia
• (e_x) is the centroid distance from flange

flowchart TD
    Measured_Calculated_Value --> Rounded_Value[Rounded as per IS 2:1960]
    Rounded_Value --> Significant_Figures[Maintain Specified Significant Figures]
    Significant_Figures --> Compliance_Check[Compliance Evaluation]

This process ensures that all structural aluminium section property values meet IS 6475 requirements.

Key References for IS 6475 Aluminium Tee Bars

1. Symbol Definitions (Clause 3.1)

• a: Cross-sectional area without plate (cm²)
• M: Mass per unit length (kg/m)
• O: Centre of gravity
• ex: Distance of centroid from outer flange face (cm)
• Ix: Moment of inertia about X-X axis (cm⁴)
• Zx: Section modulus, calculated as ( Z_x = I_x / e_x ) (cm³)
• t: Plate thickness (5, 10, or 15 mm)
• L: Plate width calculated as 40 × t (mm)

2. Tables for Sectional Properties (Clause 5.3)

• Table 1: Tee bars without welding flange (dimensions, mass, sectional properties)
• Table 2: Tee bars with welding flange (dimensions, mass, sectional properties)

3. Typical Sectional Data (Excerpt from Table 1, tee bars without welding flange)

Note: Section modulus calculated as (Z_x = I_x / e_x).

4. Plate Details for Sections with Plates

• Plate thickness options: 5, 10, or 15 mm
• Plate width: L = 40 × t (e.g., 200 mm width for 5 mm thick plate)