The standard outlines specifications for aluminium unequal leg angles, detailing their material properties, dimensions, and sectional characteristics for use in structural and general engineering. It covers manufacturing criteria, allowable aluminium alloys, and geometric tolerances to guarantee uniform quality and performance. This code is crucial for professionals designing and fabricating aluminium angle sections in construction and industrial applications.
Overview
The standard outlines specifications for aluminium unequal leg angles, detailing their material properties, dimensions, and sectional characteristics for use in structural and general engineering. It covers manufacturing criteria, allowable aluminium alloys, and geometric tolerances to guarantee uniform quality and performance. This code is crucial for professionals designing and fabricating aluminium angle sections in construction and industrial applications.
Audience
Contents
Structure
This section defines the scope of the standard, detailing the sectional properties and symbols applicable to aluminium unequal leg angles. It specifies the assumed density of aluminium alloys as 2.7 gm/cm³ and introduces key letter symbols representing sectional parameters such as area, moments of inertia, section modulus, radii of gyration, and distances to extreme fibers. The section also emphasizes rounding off computed values in accordance with IS 2-1960 to maintain precision.
This part elaborates on the definitions of various symbols used throughout the standard, including sectional area (a), mass per unit length (M), moments of inertia about principal axes (Ix, Iy, Iu, Iv), distances to extreme fibers (ex, ey), section moduli (Zx, Zy), and radii of gyration (rx, ry, ru, rv). It also confirms the use of aluminium density at 2.7 gm/cm³ for calculations and provides fundamental formulae for design computations.
This section lists the letter symbols with their corresponding meanings and formulas, such as the calculation of mass per unit length from sectional area and density, moments of inertia about designated axes, and the derivation of section modulus and radius of gyration values. It points out that the aluminium density is standardized at 2.7 gm/cm³ and mentions the possibility of ISI certification marking on compliant products.
Discusses the physical properties of aluminium used for unequal leg angles, reaffirming the density value of 2.7 gm/cm³. It summarizes the relevant sectional properties and formulae, highlights ISI certification requirements ensuring quality compliance, and outlines SI units employed within the standard for consistency in measurements.
Details the standard dimensions and mass values as tabulated in Table 1 of the standard, allowing custom sizes and square fillet sections subject to mutual agreement. It specifies dimensional tolerances conforming to IS 3965-1981, including thickness, leg length, straightness, and twist limits. This section guides selection of sizes and adherence to tolerance limits for reliable fabrication.
Provides a comprehensive overview of sectional properties such as sectional area, mass per unit length, moments of inertia about principal axes, distances to extreme fibers, section moduli, and radii of gyration. It includes essential formulas for calculating these properties and presents typical examples and tabulated values for standard unequal leg angle sections.
Outlines the packaging and marking protocols to ensure product protection and traceability. It mentions that unequal leg angles may carry the ISI certification mark, indicating conformity with the standard and quality assurance processes. Packaging typically involves wrapping bundles in bituminized hessian cloth or wooden boxes, with bundle weights agreed upon between manufacturer and purchaser.
Highlights the need for rounding test and analysis results as per IS 2-1960, maintaining the number of significant figures specified by the standard. It reiterates the use of the ISI mark as a symbol of compliance and quality control. The section also summarizes units and density values used for testing and compliance verification.
Describes the rounding off rules based on IS 2-1960, ensuring that all observed or computed numerical values retain the same significant digits as those specified in the standard. This practice is essential for uniform reporting and verification of test results and design calculations.
Lists key references including the standard aluminium density, letter symbol definitions, unit systems, and ISI certification conditions. It provides a summary of sectional properties and directs users to related standards for further guidance on aluminium alloy specifications and structural applications.
Frequently Asked
The standard itself does not explicitly specify the permitted aluminium alloys for unequal leg angles. Nevertheless, typical alloys used in structural aluminium sections, as referenced in related standards like IS 737 and IS 1285, include alloys from the 1xxx, 3xxx, 5xxx, and 6xxx series—for example, Al 6061, Al 6063, Al 5052, and Al 3003. Each bundle must be clearly marked with the alloy and temper designations, and the choice of alloy depends on required mechanical properties such as strength and corrosion resistance.
According to the standard, dimensional tolerances for aluminium unequal leg angles generally include leg length tolerances of ±1.0 mm, thickness tolerances of ±0.2 mm, angle between legs tolerance of ±1° to 2°, and length tolerance of ±5 mm for standard lengths. These tolerances ensure interchangeability and structural reliability, with exact dimensions and mass values detailed in Table 1 of the code.
The standard defines sectional properties with specific symbols and formulas: moments of inertia about principal axes X-X and Y-Y are denoted as Ix and Iy, respectively, and about principal axes U-U and V-V as Iu and Iv. Radii of gyration rx and ry are calculated as the square root of Ix divided by sectional area a and Iy divided by a, respectively. Section modulus values Zx and Zy are obtained by dividing moments of inertia Ix and Iy by their corresponding distances to extreme fibers ex and ey. These definitions provide essential parameters for structural design.
Manufacturers are required to bundle aluminium unequal leg angle sections securely, typically wrapping them in bituminized hessian cloth or packing them in wooden boxes. Alternative packaging methods can be adopted if mutually agreed upon by the purchaser and manufacturer. Additionally, the weight of each bundle should be agreed between the parties to facilitate handling and transportation, ensuring protection against damage during transit.
The standard ensures quality and consistency by prescribing standardized dimensions and tolerances, mandating clear marking of each lot with alloy designation, temper, manufacturer details, and production year for traceability. It references material specifications for wrought aluminium alloys to maintain material integrity and encourages ISI certification marking to confirm compliance with quality control protocols. These measures collectively contribute to reliable and uniform production of aluminium unequal leg angles.
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