Aluminium bulb angles for marine application

IS 6449: Scope & Key Specifications

Scope (Clause 2.0)

• Defines aluminium bulb angles for structural use.
• Applies to aluminium alloys in structural applications.
• Covers sectional dimensions, mass, and sectional properties.

Key Symbols (Clause 3.1)

Table 1: Aluminium Bulb Angles (Excerpt)

Mass based on density 2.56 g/cm³.

Notes on Rounding (Clause 0.7)

• Final values rounded as per IS 2-1960.
• Maintain significant figures consistent with specified values.

flowchart LR
    A[Aluminium Bulb Angle] --> B[Sectional Dimensions (H, B, t)]
    B --> C[Mass

IS 6449: Definitions & Key Specifications for Aluminium Bulb Angles

Key Symbols (Clause 3.1)

Important Formula:

• Width of plate:
  [ L = 40 \times t ]

• Mass calculation:
  [ M = \rho \times a ] where (\rho = 2.56 \text{ g/cm}^3) (density of aluminium alloy)

Table 1: Aluminium Bulb Angles (Excerpt)

Full table includes dimensions, sectional properties, and mass without plate.

Summary:

• Sectional properties like moment of inertia and section modulus are provided for design.
• Aluminium bulb angles conform to standard thicknesses and dimensions.
• Mass and sectional area are based on aluminium density of 2.56 g/cm³.
• Plate width is standardized as 40 times the thickness.

IS 6449: Material Requirements - Key Formulas & Tables

Material Density:

• Aluminium alloy density used: 25.6 g/cm³ (Clause 25.6)

Key Symbols (Clause 3.1)

Table 1: Aluminium Bulb Angles (Summary)

Full table available in IS 6449 Table 1 for all sizes and plate thicknesses.

Important Notes:

• **Plate width (L) =

IS 6449 - Designation of Aluminium Bulb Angles

Key Symbols (Clause 3.1)

• a = Sectional area (cm², without plate)
• M = Mass per unit length (kg/m, without plate)
• ex = Distance of centre of gravity from outer face of bulb (cm)
• Ix = Moment of inertia about X-X axis (cm⁴)
• Zx = Section modulus (cm³)
• t = Plate thickness (5, 10, or 15 mm)
• L = Width of plate = 40 × t (mm)

Designation Table Highlights (Table 1)

• H, B, C are key dimensional parameters of the bulb angle.
• Mass and sectional properties are given without plate; properties with plates of thickness 5, 10, 15 mm are also tabulated.
• Density used: 2.56 g/cm³.

Notes:

• Sectional properties are essential for structural design calculations.
• Refer to IS 8147 for design provisions using aluminium alloys.
• Dimensions and properties align with ISO 1175-1976

IS 6449: Aluminium Bulb Angles - Dimensions & Sectional Properties

Key Symbols (Clause 3.1)

• a = Sectional area (without plate) (cm²)
• M = Mass per unit length (kg/m)
• ex = Distance of centroid from outer face of bulb (cm)
• Ix = Moment of inertia about X-X axis (cm⁴)
• Zx = Section modulus (cm³)
• t = Plate thickness (5, 10, 15 mm)
• L = Width of plate = 40 × t (mm)

Dimensions & Sectional Properties (Table 1 Summary)

• H = Height of angle
• B = Width of angle
• Mass and sectional properties increase with size and plate thickness.

Dimensional Tolerances

• As per IS 3936-1981 for aluminium sections.

Notes:

• Mass based on aluminium density = 2.56 g/cm³
• Sectional properties include values with and without plates of thickness

Tolerances as per IS 6449 (Clause 5.2)

• Dimensional tolerances for aluminium bulb angles are specified by IS 3936-1981 (Code of practice for use of aluminium alloys in structures).
• Exact tolerance values are not detailed in IS 6449 but must comply with IS 3936-1981.

Key Specifications from IS 6449

• Sectional dimensions and mass are given in Table 1 (see excerpt).
• Plate thickness (t) options: 5, 10, or 15 mm
• Width of plate (L) = 40 × t
• Mass is based on aluminium density: 2.56 g/cm³

Rounding Off (Clause None: 0.7)

• Final test or analysis values should be rounded off per IS 2-1960.
• Retain the same number of significant digits as specified values.

Example: Dimensional Symbols (Clause 3.1)

Summary Table Extract (Typical Dimensions & Mass)

If you need tolerance values, refer to IS 3936-1981 for detailed permissible deviations on dimensions like thickness, length, and angles.

IS 6449: Marking of Aluminium Bulb Angles (Clause 7.1 & 7.2)

Key Specifications:

• Marking Requirements (7.1):
  Each lot/bundle must be clearly marked with:

  • Designation (e.g., AMBA 30, AMBA 40...)
  • Alloy and temper
  • Manufacturer's name
  • Lot number/year of manufacture

• Standard Mark (7.2):
  Bulb angles may carry the BIS Standard Mark, indicating compliance with BIS quality control and inspection.

Sectional Properties Table (Excerpt from Table 1)

• Density used: 2.56 g/cm³

Symbols (Clause 3.1)

• a = Sectional area (cm²)
• M = Mass per unit length (kg/m)
• ex = Distance of CG from bulb outer face (cm)
• Ix = Moment of inertia about X-X axis (cm⁴)
• Zx = Section modulus (cm³)
• t = Plate thickness (5, 10, or 15 mm)
• L = Width of plate = 40 × t

Rounding Off (Clause 0.7)

• Final test or calculation values must be rounded as per IS 2:1960 rules, maintaining the same significant figures as specified.

IS 6449: Compliance and Testing - Key Points

Rounding Off (Clause 0.7):

• Final test or calculation results must be rounded as per IS 2-1960 rules.
• Retain the same number of significant digits as the specified standard value.

Symbols (Clause 3.1):

• ( a ) = sectional area (without plate)
• ( M ) = mass per unit length (without plate)
• ( e_x ) = distance of centroid from outer face of bulb
• ( I_x ) = moment of inertia about X-X axis
• ( Z_x ) = section modulus
• ( t ) = plate thickness (5, 10, or 15 mm)
• ( L = 40t ) = width of plate

Important Table: Aluminium Bulb Angles Sectional Properties (Excerpt)

Mass based on density = 2.56 g/cm³

Compliance Testing Summary

• Use specified sectional properties for design checks.
• Verify mass, centroid location, moment of inertia, and section modulus against table values.
• Ensure rounding follows IS 2-1960 for test results.

flowchart TD
    A[Test/Calculation Result] --> B{Round off as per IS 

IS 6449 Key References: Aluminium Bulb Angles

Letter Symbols (Clause 3.1)

• a = sectional area (cm²) without plate
• M = mass per unit length (kg/m) without plate
• ex = distance of center of gravity from outer face of bulb (cm)
• Ix = moment of inertia about X-X axis (cm⁴)
• Za = section modulus (cm³)
• t = plate thickness (5, 10, or 15 mm)
• L = width of plate = 40 × t (mm)

Table 1: Aluminium Bulb Angles (Clause 5.1)

• Dimensions (H, B, C, S, etc.) and sectional properties (area, Ix, Za, ex) for standard sizes AMBA 30 to AMBA 150.
• Mass based on aluminium density = 2.56 g/cm³.
• Plate sizes for sectional properties: 200×5 mm, 400×10 mm, 600×15 mm.

(Refer Table 1 in IS 6449 for full details)

Additional Reference

• IS 8147-1976 covers design provisions for aluminium alloy structures except bridges